Human aging presents an evolutionary paradox: while aging rates remain constant, healthspan and lifespan vary widely. We address this conundrum via salutogenesis-the active production of health-through immune resilience (IR), the capacity to resist disease despite aging and inflammation. Analyzing ~17,500 individuals across lifespan stages and inflammatory challenges, we identified a core salutogenic mechanism: IR centered on TCF7, a conserved transcription factor maintaining T-cell stemness and regenerative potential. IR integrates innate and adaptive immunity to counter three aging and mortality drivers: chronic inflammation (inflammaging), immune aging, and cellular senescence. By mitigating these aging mechanisms, IR confers survival advantages: At age 40, individuals with poor IR face a 9.7-fold higher mortality rate-a risk equivalent to that of 55.5-year-olds with optimal IR-resulting in a 15.5-year gap in survival. Optimal IR preserves youthful immune profiles at any age, enhances vaccine responses, and reduces burdens of cardiovascular disease, Alzheimer's, and serious infections. Two key salutogenic evolutionary themes emerge: first, female-predominant IR, including TCF7, likely reflects evolutionary pressures favoring reproductive success and caregiving; second, midlife (40-70 years) is a critical window where optimal IR reduces mortality by 69%. After age 70, mortality rates converge between resilient and non-resilient groups, reflecting biological limits on longevity extension. TNFα-blockers restore salutogenesis pathways, indicating IR delays aging-related processes rather than altering aging rates. By reframing aging as a salutogenic-pathogenic balance, we establish TCF7-centered IR as central to healthy longevity. Targeted midlife interventions to enhance IR offer actionable strategies to maximize healthspan before biological constraints limit benefits.

Some people remain healthier throughout life than others but the underlying reasons are poorly understood. Here we hypothesize this advantage is attributable in part to optimal immune resilience (IR), defined as the capacity to preserve and/or rapidly restore immune functions that promote disease resistance (immunocompetence) and control inflammation in infectious diseases as well as other causes of inflammatory stress. We gauge IR levels with two distinct peripheral blood metrics that quantify the balance between (i) CD8 + and CD4 + T-cell levels and (ii) gene expression signatures tracking longevity-associated immunocompetence and mortality-associated inflammation. Profiles of IR metrics in ~48,500 individuals collectively indicate that some persons resist degradation of IR both during aging and when challenged with varied inflammatory stressors. With this resistance, preservation of optimal IR tracked (i) a lower risk of HIV acquisition, AIDS development, symptomatic influenza infection, and recurrent skin cancer; (ii) survival during COVID-19 and sepsis; and (iii) longevity. IR degradation is potentially reversible by decreasing inflammatory stress. Overall, we show that optimal IR is a trait observed across the age spectrum, more common in females, and aligned with a specific immunocompetence-inflammation balance linked to favorable immunity-dependent health outcomes. IR metrics and mechanisms have utility both as biomarkers for measuring immune health and for improving health outcomes.

BACKGROUND:Allergic asthma (AA) and allergic rhinoconjunctivitis (ARC) are common comorbid environmentally triggered diseases. We hypothesized that severe AA/ARC reflects a maladaptive or unrestrained response to ubiquitous aeroallergens. METHODS:We performed provocation studies wherein six separate cohorts of persons (total n = 217) with ARC, with or without AA, were challenged once or more with fixed concentrations of seasonal or perennial aeroallergens in an aeroallergen challenge chamber (ACC). RESULTS:Aeroallergen challenges elicited fully or partially restrained vs. unrestrained evoked symptom responsiveness, corresponding to the resilient and adaptive vs. maladaptive AA/ARC phenotypes, respectively. The maladaptive phenotype was evoked more commonly during challenge with a non-endemic versus endemic seasonal aeroallergen. In an AA cohort, symptom responses evoked after house dust mite (HDM) challenges vs. recorded in the natural environment were more accurate and precise predictors of asthma severity and control, lung function (FEV1), and mechanistic correlates of maladaptation. Correlates included elevated levels of peripheral blood CD4+ and CD8+ T-cells, eosinophils, and T-cell activation, as well as gene expression proxies for ineffectual epithelial injury/repair responses. Evoked symptom severity after HDM challenge appeared to be more closely related to levels of CD4+ and CD8+ T-cells than eosinophils, neutrophils, or HDM-specific IgE. CONCLUSIONS:Provocation studies support the concept that resilience, adaptation, and maladaptation to environmental disease triggers calibrate AA/ARC severity. Despite the ubiquity of aeroallergens, in response to these disease triggers in controlled settings (ie, ACC), most atopic persons manifest the resilient or adaptive phenotype. Thus, ARC/AA disease progression may reflect the failure to preserve the resilient or adaptive phenotype. The triangulation of CD8+ T-cell activation, airway epithelial injury/repair processes and maladaptation in mediating AA disease severity needs more investigation.

BACKGROUND:Signifying the 2-compartments/1-disease paradigm, allergic rhinoconjunctivitis (ARC) and asthma (AA) are prevalent, comorbid conditions triggered by environmental factors (eg, house dust mites [HDMs]). However, despite the ubiquity of triggers, progression to severe ARC/AA is infrequent, suggesting either resilience or adaptation.OBJECTIVE:We sought to determine whether ARC/AA severity relates to maladaptive responses to disease triggers.METHODS:Adults with HDM-associated ARC were challenged repetitively with HDMs in an aeroallergen challenge chamber. Mechanistic traits associated with disease severity were identified.RESULTS:HDM challenges evoked maladaptive (persistently higher ARC symptoms), adaptive (progressive symptom reduction), and resilient (resistance to symptom induction) phenotypes. Symptom severity in the natural environment was an imprecise correlate of the phenotypes. Nasal airway traits, defined by low inflammation-effectual epithelial integrity, moderate inflammation-effectual epithelial integrity, and higher inflammation-ineffectual epithelial integrity, were hallmarks of the resilient, adaptive, and maladaptive evoked phenotypes, respectively. Highlighting a crosstalk mechanism, peripheral blood inflammatory tone calibrated these traits: ineffectual epithelial integrity associated with CD8+ T cells, whereas airway inflammation associated with both CD8+ T cells and eosinophils. Hallmark peripheral blood maladaptive traits were increased natural killer and CD8+ T cells, lower CD4+ mucosal-associated invariant T cells, and deficiencies along the TLR-IRF-IFN antiviral pathway. Maladaptive traits tracking HDM-associated ARC also contributed to AA risk and severity models.CONCLUSIONS:Repetitive challenges with HDMs revealed that maladaptation to disease triggers may underpin ARC/AA disease severity. A combinatorial therapeutic approach may involve reversal of loss-of-beneficial-function traits (ineffectual epithelial integrity, TLR-IRF-IFN deficiencies), mitigation of gain-of-adverse-function traits (inflammation), and blocking of a detrimental crosstalk between the peripheral blood and airway compartments.

BACKGROUND:The risk of severe coronavirus disease 2019 (COVID-19) varies significantly among persons of similar age and is higher in males. Age-independent, sex-biased differences in susceptibility to severe COVID-19 may be ascribable to deficits in a sexually dimorphic protective attribute that we termed immunologic resilience (IR). OBJECTIVE:We sought to examine whether deficits in IR that antedate or are induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection independently predict COVID-19 mortality. METHODS:IR levels were quantified with 2 novel metrics: immune health grades (IHG-I [best] to IHG-IV) to gauge CD8+ and CD4+ T-cell count equilibrium, and blood gene expression signatures. IR metrics were examined in a prospective COVID-19 cohort (n = 522); primary outcome was 30-day mortality. Associations of IR metrics with outcomes in non-COVID-19 cohorts (n = 13,461) provided the framework for linking pre-COVID-19 IR status to IR during COVID-19, as well as to COVID-19 outcomes. RESULTS:IHG-I, tracking high-grade equilibrium between CD8+ and CD4+ T-cell counts, was the most common grade (73%) among healthy adults, particularly in females. SARS-CoV-2 infection was associated with underrepresentation of IHG-I (21%) versus overrepresentation (77%) of IHG-II or IHG-IV, especially in males versus females (P < .01). Presentation with IHG-I was associated with 88% lower mortality, after controlling for age and sex; reduced risk of hospitalization and respiratory failure; lower plasma IL-6 levels; rapid clearance of nasopharyngeal SARS-CoV-2 burden; and gene expression signatures correlating with survival that signify immunocompetence and controlled inflammation. In non-COVID-19 cohorts, IR-preserving metrics were associated with resistance to progressive influenza or HIV infection, as well as lower 9-year mortality in the Framingham Heart Study, especially in females. CONCLUSIONS:Preservation of immunocompetence with controlled inflammation during antigenic challenges is a hallmark of IR and associates with longevity and AIDS resistance. Independent of age, a male-biased proclivity to degrade IR before and/or during SARS-CoV-2 infection predisposes to severe COVID-19.

Background: An emerging paradigm holds that resistance to the development of allergic diseases, including allergic rhinoconjunctivitis, relates to an intact epithelial/epidermal barrier during early childhood. Conceivably, the immunologic and genomic footprint of this resistance is preserved in nonatopic, nonallergic adults and is unmasked during exposure to an aeroallergen.Objective: The aim of this study was to obtain direct support of the epithelial/epidermal barrier model for allergic rhinoconjunctivitis.Methods: Twenty-three adults allergic to house dust mites (HDMs) (M+) and 15 nonsensitive, nonallergic (M-) participants completed 3-hour exposures to aerosolized HDM (Dermatophagoides pteronyssinus) powder on 4 consecutive days in an allergen challenge chamber. We analyzed: (1) peripheral blood leukocyte levels and immune responses; and (2) RNA sequencing-derived expression profiles of nasal cells, before and after HDM exposure.Results: On HDM challenge: (1) onlyM+ persons developed allergic rhinoconjunctivitis symptoms; and (2) peripheral blood leukocyte levels/responses and gene expression patterns in nasal cells were largely concordant between M+ and M- participants; gross differences in these parameters were not observed at baseline (pre-exposure). Two key differences were observed. First, peripheral blood CD4(+) and CD8(+) T-cell activation levels initially decreased in M- participants versus increased in M+ participants. Second, in M-compared with M+ participants, genes that promoted epidermal/epithelial barrier function (eg, filament- aggregating protein [filaggrin]) versus inflammation (eg, chemokines) and innate immunity (interferon) were upregulated versus muted, respectively.Conclusion: An imprint of resistance to HDM challenge in nonatopic, nonallergic adults was muted T-cell activation in the peripheral blood and inflammatory response in the nasal compartment, coupled with upregulation of genes that promote epidermal/epithelial cell barrier function.

The proceedings of a National Institutes of Health workshop and a meeting of an Advisory Committee of the US Food and Drug Administration,1U.S. Food and Drug Administration Center for Biologics Evaluation and Research: Allergenic Products Advisory Committee, May 12, 2011. Available at: http://www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterials/BloodVaccinesandOtherBiologics/AllergenicProductsAdvisoryCommittee/UCM258587.pdf. Accessed May 28, 2014.Google Scholar, 2Togias A. Asthma, Allergy, and Inflammation Branch, Division of Allergy, Immunology and Transplantation, NIAID/NIHEnvironmental exposure units: clinical trial design for validation. National Institute for Allergy and Infectious Diseases/National Institutes of Health, Bethesda2010: 1-12Google Scholar as well as related commentaries,3Bernstein J.A. Correlation between a pollen challenge chamber and a natural allergen exposure study design for eliciting ocular and nasal symptoms: early evidence supporting a paradigm shift in drug investigation?.J Allergy Clin Immunol. 2012; 130: 128-129Abstract Full Text Full Text PDF PubMed Scopus (16) Google Scholar, 4Devillier P. Le Gall M. Horak F. The allergen challenge chamber: a valuable tool for optimizing the clinical development of pollen immunotherapy.Allergy. 2011; 66: 163-169Crossref PubMed Scopus (48) Google Scholar highlight the utility of an allergen challenge chamber (ACC) for conducting clinical trials for allergic rhinoconjunctivitis (AR). Mitigation of factors that might confound the design, analysis, and interpretation of these trials requires a systematic comparison of symptoms present in the natural setting versus those elicited after exposure to aeroallergens in an ACC. In prior studies we conducted out-of-season challenges with 3 separate pollens in patients with seasonal allergy.5Jacobs R.L. Harper N. He W. Andrews C.P. Rather C.G. Ramirez D.A. et al.Responses to ragweed pollen in a pollen challenge chamber versus seasonal exposure identify allergic rhinoconjunctivitis endotypes.J Allergy Clin Immunol. 2012; 130: 122-127.e8Abstract Full Text Full Text PDF PubMed Scopus (50) Google Scholar, 6Jacobs R.L. Harper N. He W. Andrews C.P. Rather C.G. Ramirez D.A. et al.Effect of confounding cofactors on responses to pollens during natural season versus pollen challenge chamber exposure.J Allergy Clin Immunol. 2014; 133 (e1-7): 1340-1346Abstract Full Text Full Text PDF PubMed Scopus (25) Google Scholar Although there was high correlation in symptom scores in the natural pollination seasons and ACC, competing environmental influences (eg, mold) in the natural setting blunted the responsiveness to these pollens, whereas this confounder was not present in the ACC.5Jacobs R.L. Harper N. He W. Andrews C.P. Rather C.G. Ramirez D.A. et al.Responses to ragweed pollen in a pollen challenge chamber versus seasonal exposure identify allergic rhinoconjunctivitis endotypes.J Allergy Clin Immunol. 2012; 130: 122-127.e8Abstract Full Text Full Text PDF PubMed Scopus (50) Google Scholar, 6Jacobs R.L. Harper N. He W. Andrews C.P. Rather C.G. Ramirez D.A. et al.Effect of confounding cofactors on responses to pollens during natural season versus pollen challenge chamber exposure.J Allergy Clin Immunol. 2014; 133 (e1-7): 1340-1346Abstract Full Text Full Text PDF PubMed Scopus (25) Google Scholar However, most patients with allergy are polysensitized to outdoor (eg, pollens) and indoor (eg, house dust mite [HDM]) aeroallergens. HDM exposure is common, associated with perennial allergy, and a significant risk factor for AR and asthma. Here we compared the symptom dynamics in the natural setting versus the ACC in HDM-sensitive (M+) and nonsensitive (M−) participants meeting the inclusion/exclusion criteria shown in Table E1 in this article's Online Repository at www.jacionline.org. M− subjects lacked both a history of AR and skin prick test (SPT) wheal reactivity (≥5 mm) to 17 allergens, including HDM (see Table E2 in this article's Online Repository at www.jacionline.org). The study comprised 4 study phases: a 4-day run-in phase followed by 2 ACC exposure phases (ACC-I and ACC-II) with an intervening 38-day observation phase (Fig 1, A). This design allowed for evaluation of the reproducibility of symptom responses and factors that could potentially confound clinical trials in the ACC, including mediators of nocebo effects,7Bingel U. Avoiding nocebo effects to optimize treatment outcome.JAMA. 2014; 312: 693-694Crossref PubMed Scopus (141) Google Scholar as discussed in the Methods section in this article's Online Repository at www.jacionline.org. The study was conducted in the early fall, when only weed pollens were detected in San Antonio, Texas (Fig 1, A and B).6Jacobs R.L. Harper N. He W. Andrews C.P. Rather C.G. Ramirez D.A. et al.Effect of confounding cofactors on responses to pollens during natural season versus pollen challenge chamber exposure.J Allergy Clin Immunol. 2014; 133 (e1-7): 1340-1346Abstract Full Text Full Text PDF PubMed Scopus (25) Google Scholar To mitigate this confounding factor, we selected M+ participants with negative SPT responses for weed pollens (see Table E2). All participants were allergy drug free throughout the study (see Table E3 in this article's Online Repository at www.jacionline.org). Each ACC phase comprised exposure for 3 hours on 4 consecutive days to a purified mite body powder of Dermatophagoides pteronyssinus (Fig 1, A and B, and see the Methods section in this article's Online Repository). The end point we targeted was an increase in instantaneous total symptom scores (iTSSs) of at least 6 units in 50% of participants from baseline levels. To achieve this goal, the ACC was calibrated to deliver 70 to 110 ng/m3 HDM Der p 1 antigen, as measured by means of ELISA (see Table E4 and the Methods section in this article's Online Repository at www.jacionline.org). iTSSs in the ACC and reflective total symptom scores (rTSSs) in the natural setting were recorded by using a 5-point Likert scale (see Table E5 in this article's Online Repository at www.jacionline.org). Of the 40 participants meeting inclusion criteria, 35 (21 M+ and 14 M− participants) completed all 4 study phases, and of these, 13 M+ participants and 1 M− participant had detectable (≥0.35 kU/L) serum specific IgE (ssIgE) to D pteronyssinus. This dichotomy between SPT reactivity but undetectable ssIgE has been reported for many allergens (see the Discussion section in this article's Online Repository at www.jacionline.org).8de Vos G. Skin testing versus serum-specific IgE testing: which is better for diagnosing aeroallergen sensitization and predicting clinical allergy?.Curr Allergy Asthma Rep. 2014; 14: 430Crossref PubMed Scopus (50) Google Scholar There were no differences in the key demographic characteristics between M+ and M− participants (see Table E6 in this article's Online Repository at www.jacionline.org). Five participants withdrew from the study for nonmedical reasons. M− participants had minimal symptoms in the ACC (mean iTSS, <1; Fig 1, B). In contrast, M+ participants experienced a mean increase of 3 units in the iTSS within 30 minutes of HDM challenge, and iTSSs reached a plateau after approximately 120 minutes (Fig 1, B). There was a high degree of concordance in symptom responses in M+ participants in the ACC recorded by using the Likert and visual analog scales (see Fig E1 in this article's Online Repository at www.jacionline.org). Eleven episodes of bronchospasm occurred in 5 M+ participants, a rate consistent with prior findings.9Horak F. Toth J. Marks B. Stubner U.P. Berger U.E. Jager S. et al.Efficacy and safety relative to placebo of an oral formulation of cetirizine and sustained-release pseudoephedrine in the management of nasal congestion.Allergy. 1998; 53: 849-856Crossref PubMed Scopus (43) Google Scholar These participants exhibited slightly higher total symptom scores (TSSs; see Fig E2 in this article's Online Repository at www.jacionline.org), had greater than 15% improvement in FEV1.0 after treatment with nebulized albuterol, and returned to the ACC without additional exacerbations (see the Discussion section in this article's Online Repository). These findings suggest that M+ participants with mild intermittent asthma can be safely evaluated within ACCs. The concordance in symptom responses during and between ACC-I and ACC-II was high (Fig 1, C, and see Table E7 in this article's Online Repository at www.jacionline.org). In contrast, the correlations between rTSSs recorded in the run-in versus observation phases or between rTSSs versus iTSSs were much lower (see Fig E3 in this article's Online Repository at www.jacionline.org). During ACC-I and ACC-II, an increase in iTSSs of 6 or greater from baseline (pre-exposure) was experienced in greater than 55% of participants (Fig 1, D). While less than 10% of participants had iTSSs of 15 or greater at baseline, 67% and 57% of M+ participants achieved iTSSs of 15 or greater in ACC-I and ACC-II, respectively (Fig 1, E). Substantial data indicate that ssIgE levels to allergens might serve as biomarkers for symptom severity.10Ciprandi G. Tosca M.A. Silvestri M. The practical role of serum allergen-specific IgE as potential biomarker for predicting responder to allergen immunotherapy.Expert Rev Clin Immunol. 2014; 10: 321-324Crossref PubMed Scopus (11) Google Scholar Accordingly, TSSs were greater in M+ participants with a detectable ssIgE level for D pteronyssinus in the ACC (Fig 2, A and B). The failure to detect such an association in the natural setting (Fig 2, A and B) might relate to variable HDM levels measured in dust from mattresses in the participants' homes (see Fig E4 and the Methods section in this article's Online Repository at www.jacionline.org). Pollen SPT reactivity (P+) stratified TSSs, with M+P+ participants having higher rTSSs and iTSSs when compared with those of M+P− participants (Fig 2, C). Levels of T-cell activation were greater in M+P+ participants compared with those seen in M+P− participants before and during ACCs (Fig 2, D, and see Fig E5 and the Methods section in this article's Online Repository at www.jacionline.org). Notably, T-cell activation has been associated with symptom responses during allergy.11Majori M. Piccoli M.L. Melej R. Pileggi V. Pesci A. Lymphocyte activation markers in peripheral blood before and after natural exposure to allergen in asthmatic patients.Respiration. 1997; 64: 45-49Crossref PubMed Scopus (7) Google Scholar Thus exposure to pollens in the months preceding the ACC exposures might have rendered M+P+ participants constitutively "primed," serving as a basis for the higher T-cell activation and symptoms in the natural and ACC settings (Fig 2, C and D). In the ACC phases the effects of pollen sensitization and ssIgE status were additive, with M+IgE+P+ participants manifesting maximal responsiveness after HDM exposure (Fig 2, E). The trigger for the constitutive priming could be winter and spring tree pollens because all M+P+ participants were reactive based on SPT reactivity to tree pollens (see Table E2). Moreover, the extended tree pollination season, which terminated a few months before the start of the ACC exposures, is typically associated with intense symptoms.6Jacobs R.L. Harper N. He W. Andrews C.P. Rather C.G. Ramirez D.A. et al.Effect of confounding cofactors on responses to pollens during natural season versus pollen challenge chamber exposure.J Allergy Clin Immunol. 2014; 133 (e1-7): 1340-1346Abstract Full Text Full Text PDF PubMed Scopus (25) Google Scholar At the 2 transition points from the natural settings to the ACC (run-in → ACC-I and observation phase → ACC-II), there was a decrease in TSSs (Fig 1, Fig 2, A). This decrease was greater in those with more symptoms (ie, higher in M+P+ participants than in M+P− participants [Fig 2, F] and higher in M+IgE+ participants than in M+IgE− participants [data not shown]). This decrease might relate to (1) differences in how TSSs were recorded in the natural versus ACC settings (reflective vs instantaneous scoring, respectively); (2) learned responses secondary to increased emphasis/education by research staff in the ACC on how to accurately record TSSs; and (3) the controlled environment in the ACC (see the Discussion in this article's Online Repository). Inspection of the overall TSS trajectory indicated that after initiation of ACC exposures, there was a downward shift in the TSS (Fig 1, B). The baseline (pre-ACC) iTSS recorded before commencing challenge 1 was higher than the baseline iTSS recorded before challenges 2 and 3, and the baseline iTSS before challenges 4 through 8 were similar (Fig 1, B). Furthermore, the rTSS in the observation phase was lower than the rTSS in the run-in phase (Fig 1, B). This downward shift in baseline iTSS would give the mistaken impression that responsiveness was greater in challenges 2 and 3 and lower thereafter, when in fact the responsiveness in exposures 1 and 4 through 8 was similar (Fig 2, G). These downward shifts in TSSs did not differ by pollen SPT or ssIgE status (data not shown), and we surmise this might relate to a combination of factors: learned responses (secondary to education in the ACC) and partial clinical tolerance akin to what has been observed after repetitive exposure to allergens, including HDM (see the Discussion section in this article's Online Repository).12Woodfolk J.A. High-dose allergen exposure leads to tolerance.Clin Rev Allergy Immunol. 2005; 28: 43-58Crossref PubMed Google Scholar, 13Liu L.Y. Swenson C.A. Kelly E.A. Kita H. Jarjour N.N. Busse W.W. Comparison of the effects of repetitive low-dose and single-dose antigen challenge on airway inflammation.J Allergy Clin Immunol. 2003; 111: 818-825Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar In this study exposure to HDM concentrations used in the ACC was associated with reliable and reproducible elicitation of symptoms. SPT reactivity to pollen, which was associated with increased inflammatory status, and ssIgE levels to HDM were biological markers that correlated with symptom responses in the ACC. These 2 biomarkers stratified M+ participants as higher versus lower responders in the ACC, whereas this stratification is obscured in the natural settings. Therefore we suggest that out-of-pollination season challenges with HDM in the ACC might help mitigate the confounding of factors present in the natural setting: variable or low exposure to HDM, lack of association of ssIgE levels with rTSSs, and effects of competing environmental influences in a primed polysensitized subject. We also suggest that the other factors that could potentially confound clinical trials in an ACC (and natural setting) are nocebo7Bingel U. Avoiding nocebo effects to optimize treatment outcome.JAMA. 2014; 312: 693-694Crossref PubMed Scopus (141) Google Scholar and placebo14Enck P. Bingel U. Schedlowski M. Rief W. The placebo response in medicine: minimize, maximize or personalize?.Nat Rev Drug Discov. 2013; 12: 191-204Crossref PubMed Scopus (476) Google Scholar effects (expectations, learning process, and participant-physician communication). Confounding could occur by (1) misattribution of positive therapy effects to decrease symptom scores related to more precise symptom scoring (because of learned behavior) and/or partial clinical tolerance (because of repetitive exposure) and (2) imbalance in the proportion of high versus low responders in the treatment versus placebo arms. An example that highlights the potential for this imbalance is the observation that the effectiveness of anti-IgE therapy for asthma differed by the overall sensitization status of the trial participants.15Busse W.W. Morgan W.J. Gergen P.J. Mitchell H.E. Gern J.E. Liu A.H. et al.Randomized trial of omalizumab (anti-IgE) for asthma in inner-city children.N Engl J Med. 2011; 364: 1005-1015Crossref PubMed Scopus (732) Google Scholar Therapies might be more effective in patients with greater responsiveness to allergen exposure, a trait that can be readily identified in an ACC. Thus we surmise that mindfulness of the abovementioned confounders and use of an ACC might together facilitate detection of differences in the effects of placebo versus therapy in clinical trials, especially in exploratory studies with novel therapeutic agents when both the participant numbers and therapy effect sizes might be modest. Download .docx (.23 MB) Help with docx files Online Repository Data Download .pdf (.39 MB) Help with pdf files Fig E1 Download .pdf (.16 MB) Help with pdf files Fig E2 Download .pdf (.4 MB) Help with pdf files Fig E3 Download .pdf (.37 MB) Help with pdf files Fig E4 Download .pdf (.68 MB) Help with pdf files Fig E5

BACKGROUND:Modifiers of symptom severity in patients with allergic rhinoconjunctivitis (AR) are imprecisely characterized. The hygiene hypothesis implicates childhood microbial exposure as a protective factor. Cockroach sensitization (C+) might be a proxy for microbial exposure. OBJECTIVE:We sought to determine whether C+ assayed by means of skin prick tests influenced AR symptom severity in controlled and natural settings. METHODS:Total symptom scores (TSSs) were recorded by 21 participants with house dust mite allergy (M+) in the natural setting and during repeated exposures of 3 hours per day to house dust mite allergen in an allergen challenge chamber (ACC). In M+ participants the peripheral blood and nasal cells were assayed for T-cell activation and transcriptomic profiles (by using RNA sequencing), respectively. Participants allergic to mountain cedar (n = 21), oak (n = 34), and ragweed (n = 23) recorded TSSs during separate out-of-season exposures to these pollens (any pollen sensitization [P+]) in the ACC; a subset recorded TSSs in the pollination seasons. RESULTS:The hierarchy of TSSs (highest to lowest) among M+ participants tracked the following skin prick test sensitization statuses: M+P+C- > M+P+C+ > M+P-C- > M+P-C+. In nasal cells and peripheral blood the immune/inflammatory responses were rapidly resolved in M+P+C+ compared with M+P+C- participants. Among those allergic to pollen, C+ was associated with a lower TSS during pollen challenges and the pollination season. After aggregated analysis of all 4 ACC studies, C+ status was associated with a 2.8-fold greater likelihood of a lower TSS compared with C- status (odds ratio, 2.78; 95% CI, 1.18-6.67; P = .02). CONCLUSIONS:C+ status is associated with mitigation of AR symptom severity in adults with AR.

Inflammation and oxidative stress through the production of reactive oxygen species (ROS) are consistently associated with metabolic syndrome/type 2 diabetes. Although the role of Nox2, a major ROS-generating enzyme, is well described in host defense and inflammation, little is known about its potential role in insulin resistance in skeletal muscle. Insulin resistance induced by a high fat diet was mitigated in Nox2-null mice compared with wild-type mice after 3 or 9 months on the diet. High fat feeding increased Nox2 expression, superoxide production, and impaired insulin signaling in skeletal muscle tissue of wild-type mice but not in Nox2-null mice. Exposure of C2C12 cultured myotubes to either high glucose concentration, palmitate, or H2O2 decreases insulin-induced Akt phosphorylation and glucose uptake. Pretreatment with catalase abrogated these effects, indicating a key role for H2O2 in mediating insulin resistance. Down-regulation of Nox2 in C2C12 cells by shRNA prevented insulin resistance induced by high glucose or palmitate but not H2O2. These data indicate that increased production of ROS in insulin resistance induced by high glucose in skeletal muscle cells is a consequence of Nox2 activation. This is the first report to show that Nox2 is a key mediator of insulin resistance in skeletal muscle.

SignificanceLevels of CC chemokine receptor 5 (CCR5) on T cells are a critical factor influencing HIV/AIDS susceptibility. DNA methylation is an epigenetic feature associated with lower gene expression. Here we show that the DNA methylation status ofCCR5 cis-regulatory regions (cis-regions) correlates inversely with CCR5 levels on T cells. T-cell activation induces demethylation ofCCR5 cis-regions, upregulating CCR5 expression. Higher vs. lower sensitivity ofCCR5 cis-regions to undergoing T-cell activation-induced demethylation is associated with increased vs. decreased CCR5 levels. Polymorphisms inCCR5 cis-regions that are associated with increased vs. decreased HIV/AIDS susceptibility are also associated with increased vs. decreased sensitivity to activation-induced demethylation. Thus, interactions among T-cell activation,CCR5epigenetics, and genetics influence CCR5 levels on T cells and, by extension, HIV/AIDS susceptibility.

ABSTRACT Malnutrition is thought to contribute to more than one-third of all childhood deaths via increased susceptibility to infection. Malnutrition is a significant risk factor for the development of visceral leishmaniasis, which results from skin inoculation of the intracellular protozoan Leishmania donovani . We previously established a murine model of childhood malnutrition and found that malnutrition decreased the lymph node barrier function and increased the early dissemination of L. donovani . In the present study, we found reduced numbers of resident dendritic cells (conventional and monocyte derived) but not migratory dermal dendritic cells in the skin-draining lymph nodes of L. donovani -infected malnourished mice. Expression of chemokines and their receptors involved in trafficking of dendritic cells and their progenitors to the lymph nodes was dysregulated. C-C chemokine receptor type 2 (CCR2) and its ligands (CCL2 and CCL7) were reduced in the lymph nodes of infected malnourished mice, as were CCR2-bearing monocytes/macrophages and monocyte-derived dendritic cells. However, CCR7 and its ligands (CCL19 and CCL21) were increased in the lymph node and CCR7 was increased in lymph node macrophages and dendritic cells. CCR2-deficient mice recapitulated the profound reduction in the number of resident (but not migratory dermal) dendritic cells in the lymph node but showed no alteration in the expression of CCL19 and CCL21. Collectively, these results suggest that the malnutrition-related reduction in the lymph node barrier to dissemination of L. donovani is related to insufficient numbers of lymph node-resident but not migratory dermal dendritic cells. This is likely driven by the altered activity of the CCR2 and CCR7 chemoattractant pathways.

Adverse remodeling following myocardial infarction (MI) leading to heart failure is driven by an imbalanced resolution of inflammation. The macrophage cell is an important control of post-MI inflammation, as macrophage subtypes secrete mediators to either promote inflammation and extend injury (M1 phenotype) or suppress inflammation and promote scar formation (M2 phenotype). We have previously shown that the absence of caveolin-1 (Cav1), a membrane scaffolding protein, is associated with adverse cardiac remodeling in mice, but the mechanisms responsible remain to be elucidated. We explore here the role of Cav1 in the activation of macrophages using wild type C57BL6/J (WT) and Cav1tm1Mls/J (Cav1−/−) mice. By echocardiography, cardiac function was comparable between WT and Cav1−/− mice at 3days post-MI. In the absence of Cav1, there were a surprisingly higher percentage of M2 macrophages (arginase-1 positive) detected in the infarcted zone. Conversely, restoring Cav1 function after MI in WT mice by adding back the Cav1 scaffolding domain reduced the M2 activation profile. Further, adoptive transfer of Cav1 null macrophages into WT mice on d3 post-MI exacerbated adverse cardiac remodeling at d14 post-MI. In vitro studies revealed that Cav1 null macrophages had a more pronounced M2 profile activation in response to IL-4 stimulation. In conclusion, Cav1 deletion promotes an array of maladaptive repair processes after MI, including increased TGF-β signaling, increased M2 macrophage infiltration and dysregulation of the M1/M2 balance. Our data also suggest that cardiac remodeling can be improved by therapeutic intervention regulating Cav1 function during the inflammatory response phase.

This study was performed to determine the operational characteristics of the Biogenics Research Chamber for elicitation of symptoms in dust mite allergic individuals. Twenty-five dust mite sensitive and 15 normal controls (32% male, mean age 40) were enrolled to undergo 4 consecutive 3 hour chamber exposures to a milled, purified mite body preparation of Dermatophagoides pteronyssinus. A 5-day run-in assessed symptoms in the natural setting. Symptoms were monitored at baseline and 30 minute intervals. Airborne samples were collected from 5 stations for 10 minutes at hourly intervals through a modified nylon filter for measurement of Der p1 by ELISA, and an Allergenco cassette sampler for microscopic evaluation of mite particles. Thirty-eight participants completed 4 consecutive chamber exposures. Mean Der p1 levels on days 1, 2, 3 and 4 in the chamber were 81, 78, 110, and 101 ng/m3, respectively. 70% of sensitive subjects had Maximum Total Nasal Symptom Scores of ≥9 (out of 16). 65% of sensitive participants had Maximum Total Symptom Scores (TSS) of ≥15 (out of 28). Three of 15 normal controls had TSS of 1, 2, and 4, and the remaining did not exhibit any symptoms. Administration of dust mite preparations containing an average of 92 ng/m3 of Der p1 levels induced symptoms in 70% of sensitive participants. The delivery and dispersal system of the Biogenics Chamber with dust mite was as efficient as previously reported for various pollens. This elicitation response will allow for testing of novel pharmacological agents.

RationaleThe effect of exposure to Mt. Cedar pollen in a pollen challenge chamber (PCC) on white blood cell (WBC) counts and cytokines is unknown.MethodsTwenty-two Mt. Cedar positive subjects (MCPS) and 11 Mt. Cedar negative subjects (MCNS) were challenged for Mt. Cedar in a PCC for 3 hours per day for 2 days. With exposure, total symptom scores (TSS) were calculated. Blood pre-challenge and following the second challenge was analyzed.ResultsIn MCPS, there was an increase in neutrophils, lymphocytes, monocytes, and eosinophils with exposure (P = 0.004, 1.50x10-11, 3.59x10-11, 1.04x10‑7). In MCNS, lymphocytes and eosinophils increased upon exposure (P = 2.05x10-6, 0.012). Comparing MCPS to MCNS, the changes in MCPS for both monocytes and eosinophils were significantly larger (P = 0.048, 0.022). After exposure,13 out of the 38 cytokines analyzed (IFNa2, BAC1, MCP4, I.309, CTACK, IFNg, IL10, IL-12p70, IL-1b, IL-2, IL-4, IL-5, IL-7) had significant increases in MCPS while only 3 (IL-10, Eotaxin-2, TRAIL) had significant decreases. In MCPS, the fold change of eosinophils, Eotaxin, MDC, and TRAIL after exposure were significantly associated with TSS (r2 = 0.29, 0.34, 0.39, 0.34). Although none of the cytokines had a significant change in MCNS, 32 had a concordant direction of change with MCPS after pollen exposure.ConclusionsChanges in both cell counts and cytokine levels characteristic of a Th2 response were observed in MCPS. MCNS had minimal symptoms, but also experienced concordant changes in cell counts and cytokine levels, although at lower levels than MCPS. RationaleThe effect of exposure to Mt. Cedar pollen in a pollen challenge chamber (PCC) on white blood cell (WBC) counts and cytokines is unknown. The effect of exposure to Mt. Cedar pollen in a pollen challenge chamber (PCC) on white blood cell (WBC) counts and cytokines is unknown. MethodsTwenty-two Mt. Cedar positive subjects (MCPS) and 11 Mt. Cedar negative subjects (MCNS) were challenged for Mt. Cedar in a PCC for 3 hours per day for 2 days. With exposure, total symptom scores (TSS) were calculated. Blood pre-challenge and following the second challenge was analyzed. Twenty-two Mt. Cedar positive subjects (MCPS) and 11 Mt. Cedar negative subjects (MCNS) were challenged for Mt. Cedar in a PCC for 3 hours per day for 2 days. With exposure, total symptom scores (TSS) were calculated. Blood pre-challenge and following the second challenge was analyzed. ResultsIn MCPS, there was an increase in neutrophils, lymphocytes, monocytes, and eosinophils with exposure (P = 0.004, 1.50x10-11, 3.59x10-11, 1.04x10‑7). In MCNS, lymphocytes and eosinophils increased upon exposure (P = 2.05x10-6, 0.012). Comparing MCPS to MCNS, the changes in MCPS for both monocytes and eosinophils were significantly larger (P = 0.048, 0.022). After exposure,13 out of the 38 cytokines analyzed (IFNa2, BAC1, MCP4, I.309, CTACK, IFNg, IL10, IL-12p70, IL-1b, IL-2, IL-4, IL-5, IL-7) had significant increases in MCPS while only 3 (IL-10, Eotaxin-2, TRAIL) had significant decreases. In MCPS, the fold change of eosinophils, Eotaxin, MDC, and TRAIL after exposure were significantly associated with TSS (r2 = 0.29, 0.34, 0.39, 0.34). Although none of the cytokines had a significant change in MCNS, 32 had a concordant direction of change with MCPS after pollen exposure. In MCPS, there was an increase in neutrophils, lymphocytes, monocytes, and eosinophils with exposure (P = 0.004, 1.50x10-11, 3.59x10-11, 1.04x10‑7). In MCNS, lymphocytes and eosinophils increased upon exposure (P = 2.05x10-6, 0.012). Comparing MCPS to MCNS, the changes in MCPS for both monocytes and eosinophils were significantly larger (P = 0.048, 0.022). After exposure,13 out of the 38 cytokines analyzed (IFNa2, BAC1, MCP4, I.309, CTACK, IFNg, IL10, IL-12p70, IL-1b, IL-2, IL-4, IL-5, IL-7) had significant increases in MCPS while only 3 (IL-10, Eotaxin-2, TRAIL) had significant decreases. In MCPS, the fold change of eosinophils, Eotaxin, MDC, and TRAIL after exposure were significantly associated with TSS (r2 = 0.29, 0.34, 0.39, 0.34). Although none of the cytokines had a significant change in MCNS, 32 had a concordant direction of change with MCPS after pollen exposure. ConclusionsChanges in both cell counts and cytokine levels characteristic of a Th2 response were observed in MCPS. MCNS had minimal symptoms, but also experienced concordant changes in cell counts and cytokine levels, although at lower levels than MCPS. Changes in both cell counts and cytokine levels characteristic of a Th2 response were observed in MCPS. MCNS had minimal symptoms, but also experienced concordant changes in cell counts and cytokine levels, although at lower levels than MCPS.

In a murine model of moderate childhood malnutrition we found that polynutrient deficiency led to a 4-5-fold increase in early visceralization of L. donovani (3 days post-infection) following cutaneous infection and a 16-fold decrease in lymph node barrier function (p<0.04 for all). To begin to understand the mechanistic basis for this malnutrition-related parasite dissemination we analyzed the cellularity, architecture, and function of the skin-draining lymph node. There was no difference in the localization of multiple cell populations in the lymph node of polynutrient deficient (PND) mice, but there was reduced cellularity with fewer CD11c(+) dendritic cells (DCs), fibroblastic reticular cells (FRCs), MOMA-2(+) macrophages, and CD169(+) subcapsular sinus macrophage (p<0.05 for all) compared to the well-nourished (WN) mice. The parasites were equally co-localized with DCs associated with the lymph node conduit network in the WN and PND mice, and were found in the high endothelial venule into which the conduits drain. When a fluorescent low molecular weight (10 kD) dextran was delivered in the skin, there was greater efflux of the marker from the lymph node conduit system to the spleens of PND mice (p<0.04), indicating that flow through the conduit system was altered. There was no evidence of disruption of the conduit or subcapsular sinus architecture, indicating that the movement of parasites into the subcortical conduit region was due to an active process and not from passive movement through a leaking barrier. These results indicate that the impaired capacity of the lymph node to act as a barrier to dissemination of L. donovani infection is associated with a reduced number of lymph node phagocytes, which most likely leads to reduced capture of parasites as they transit through the sinuses and conduit system.

Nephrogenic systemic fibrosis (NSF) is associated with gadolinium-based magnetic resonance imaging (MRI) contrast exposure in the setting of acute or chronic renal compromise. It has been proposed that circulating fibrocytes mediate the disease. A study was conducted to determine whether bone marrow-derived fibroblast precursors are involved in contributing to organ fibrosis in MRI contrast-treated rodents with renal insufficiency. Rats status post 5/6 nephrectomy underwent bone marrow transplant from human placental alkaline phosphatase (hPAP)-expressing donors. After engraftment, animals were treated with gadolinium-based MRI contrast (2.5 mmol/kg IP), during weekdays for 4 weeks, or an equivalent volume of normal saline. Dermal cellularity in the contrast-treated group was fourfold that of control. Skin cells from the contrast-treated group demonstrated greater hPAP expression with co-expression of pro-collagen I and alpha-smooth muscle actin-positive stress fibers. Donor and host cells expressed CD34. Dihydroethidium staining of skin was greater in the contrast-treated animals, indicating oxidative stress. This was abrogated when the animals were co-administered the superoxide dismutase mimetic tempol. In conclusion, a bone marrow-derived cell population is increased in the dermis of MRI contrast-treated rodents. The cell markers are consistent with fibrocytes mediating the disease. These changes correlate with oxidative stress and expression of Nox4, suggestive of a novel therapeutic target. Elucidation of the mechanisms of MRI contrast-induced fibrosis may aid in discovering therapies to this devastating disease. (Am J Pathol 2012, 181:1941-1952; http://dx.doi.org/10.1016/j.ajpath.2012.08.026)

Background Chemokines and their receptors play a role in the innate immune response as well as in the disruption of the balance between pro-inflammatory Th17 cells and regulatory T cells (Treg), underlying the pathogenesis of coronary vasculitis in Kawasaki disease (KD). Results Here we show that genetic inactivation of chemokine receptor (CCR)-2 is protective against the induction of aortic and coronary vasculitis following injection of Candida albicans water-soluble cell wall extracts (CAWS). Mechanistically, both T and B cells were required for the induction of vasculitis, a role that was directly modulated by CCR2. CAWS administration promoted mobilization of CCR2-dependent inflammatory monocytes (iMo) from the bone marrow (BM) to the periphery as well as production of IL-6. IL-6 was likely to contribute to the depletion of Treg and expansion of Th17 cells in CAWS-injected Ccr2 +/+ mice, processes that were ameliorated following the genetic inactivation of CCR2. Conclusion Collectively, our findings provide novel insights into the role of CCR2 in the pathogenesis of vasculitis as seen in KD and highlight novel therapeutic targets, specifically for individuals resistant to first-line treatments.