Not all biomarkers are equal, and some arguably should not be classified as biomarkers at all. Despite an explosion in putative biomarker discoveries from high-throughput proteomic technologies, very few advance beyond initial excitement to become validated, clinically actionable tools. Most stall in a biomarker 'valley of death', where promising signals fail to meet robust technical, scientific, and regulatory standards for clinical use. We propose a framework to distinguish between unvalidated protein findings and validated biomarkers with specific utility. We highlight the need to separate exploratory protein measurements from biomarkers that meet predefined analytical criteria and progress through validation, including qualification as a reasonably likely surrogate endpoint (RLSE) or a validated surrogate endpoint (VSE). This review article delineates differences between biomarker discovery, development, regulatory qualification, and commercialisation pathways, emphasising nomenclature according to the BEST (Biomarkers, EndpointS, and other Tools) Resource, analytical validation in accordance with CLSI guidelines, clinical relevance, and alignment with regulatory frameworks, including the FDA's Premarket Approval (PMA) and Biomarker Qualification Program (BQP), and the EU's In Vitro Diagnostic Regulation (IVDR) and Drug Development Tool (DDT) programmes. We introduce the concept of the 'unicorn biomarker' - an extremely rare class of biomarker with validated multipurpose utility (diagnostic, prognostic, and pharmacodynamic/monitoring) - to highlight the value of such biomarkers in clinical decision-making. We propose that minimum technical and biological standards must be met before a molecular measurement can be designated a "biomarker", as an association between a biological signal and disease state alone is insufficient. By raising the bar with unicorn biomarkers, this framework aims to guide researchers, regulators, and industry stakeholders in identifying actionable biomarkers and advancing precision medicine.

SARS-CoV-2 infections lead to a wide-range of outcomes from mild or asymptomatic illness to serious complications and death. While many studies have characterized hospitalized SARS-CoV-2 patient immune responses, we were interested in whether serious complications of SARS-CoV-2 infection could be predicted early in ambulatory subjects. To that end, we used samples from SARS-CoV-2-infected individuals from the placebo arm of the BLAZE-1 clinical trial who progressed to hospitalization or death compared to individuals in the same study who did not require medical intervention and investigated whether baseline serum cytokines and chemokines could predict severe outcome. High-risk demographic factors at baseline, including age, nasal pharyngeal viral load, duration from symptom onset, and BMI provide significant predictive capacity for a hospitalization or death with an AUC of ROC = 0.77. The predictive performance of our outcome modeling increased when baseline serum protein markers were included. In fact, the one-marker model indicated that there were 51 individual proteins (including known markers of inflammation like IL-6, MCP-3, CXCL10, IL-1Ra, and PTX3) that significantly increased the AUC of ROC beyond high-risk patient demographics alone to range between 0.78 to 0.88. Moreover, a two-marker model incorporating levels of both IL-6 and PTX3 further improved the prediction over the addition of a single protein marker to an AUC of ROC = 0.91. While the analytes identified in this study have been well-documented to be altered in SARS-CoV-2 infection, this analysis demonstrates the potential value of their use in predicting hospitalization or death in ambulatory participants infected with SARS-CoV-2 and could guide early treatment decisions.

OBJECTIVES:Giant cell arteritis (GCA) is an immune-mediated vasculitis of large- and medium-sized arteries that can lead to systemic symptoms and irreversible vision loss. Glucocorticoids (GCs) remain the primary treatment but fail to induce sustained remission (SR) in approximately half of patients, resulting in disease relapses and significant treatment-related toxicity. We aimed to identify tissue-based markers at disease onset capable of distinguishing patients who later achieve SR from those who do not (non-remission [NR]) under GC monotherapy. METHODS:Using spatial biology techniques, we performed a comprehensive analysis of GCA-affected arterial tissues obtained at disease onset, correlating molecular profiles with clinical trajectory. We compared gene expression and immune cell populations between SR and NR groups, corroborated key findings by immunohistochemistry, and evaluated the diagnostic performance of identified biomarkers. RESULTS:Patients with NR exhibited an upregulation of extracellular matrix remodelling (ECM) and T cell activation pathways, reflecting persistent inflammation and fibrotic-like responses. By contrast, SR cases were distinguished by an enrichment of immunoglobulin G-producing plasma cells in the adventitia, which correlated with increased macrophage infiltration in the intima. Quantitative analyses suggested that combining plasma cell and macrophage markers could accurately predict GC responsiveness. CONCLUSIONS:Our findings reveal an immunopathologic signature in GCA at diagnosis, characterised by plasma cell-rich infiltrates associated with favourable outcomes, and ECM- and T cell-associated inflammation enriched in GC-refractory cases. These insights could foster a precision medicine approach to GCA management, enabling patient stratification for GC-sparing therapies and optimising patient outcomes.

Cadherins (CDH), such as CDH11, are glycoprotein adhesion molecules contributing to cell-cell interactions in health and disease. CDH11 has demonstrated important functions in rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS). In transcriptome expression studies, we observed that Cadherin 6 (CDH6) expression was higher in RA compared to osteoarthritis (OA). CDH6 is associated with cancer progression, but little information is known on the role of CDH6 in RA. The present study investigates CDH6 expression, regulation, function in FLS, and distribution in RA synovia. Synovial tissue and FLS were obtained from RA or OA patients undergoing joint replacement. CDH6 epigenetic marks and expression in RA and OA FLS were evaluated using public databases. CDH6 expression was determined by RT-PCR, Western blot, and immunostaining. RA and OA FLS were stimulated with cytokines and growth factors, and CDH6 mRNA expression was determined. CDH6 was silenced using siRNA, and the effect on migration, cell growth, apoptosis, autophagy, cell cycle, and signaling was studied. In our analysis of cadherin family expression, CDH6 expression was higher in RA than OA FLS. This was associated with differential chromatin accessibility and histone marks in the CDH6 promoter of RA FLS. H3K27ac was identified as an important regulator of CDH6 expression in RA FLS based on experiments using histone deacetylase inhibitors. TGFß, but not IL-1β, TNF, IL-17A, IFNγ, IL-6, or PDGF, increased CDH6 expression of cultured RA FLS. CDH6 knockdown significantly decreased RA FLS migration and cell growth. The latter was associated with increased apoptosis in CDH6 deficient FLS. Immunofluorescence showed CDH6 protein distribution in the membrane, perinuclear, and nuclear regions of cultured FLS. In RA synovial tissue, CDH6 expression was noted in FLS and macrophages within the lining and sublining regions. CDH6 expression is elevated in RA FLS due to epigenetic and local conditions of synovitis promoting migration, survival and cell growth, which are characteristic features of aggressive RA FLS. The intracellular distribution suggests additional functions beyond adhesion and homotypic aggregation, such as signaling and gene regulation. These data suggest CDH6 contributes to RA pathogenesis by influencing pathologic FLS behavior and could be a therapeutic target.

BACKGROUND:Baricitinib has previously been shown to improve clinical response in patients with juvenile idiopathic arthritis (JIA) in the JUVE-BASIS trial. In this post-hoc analysis we aimed to identify whether pharmacodynamic changes in serum biomarkers in response to baricitinib treatment could help reaffirm the clinical utility of baricitinib in patients with JIA. METHODS:JUVE-BASIS was a randomised, double-blind, placebo-controlled, withdrawal, efficacy, safety, phase 3 trial, done in 75 centres in 20 countries. Eligible patients were children and adolescents (aged 2 to <18 years), with polyarticular JIA (positive or negative for rheumatoid factor), extended oligoarticular JIA, enthesitis-related arthritis, or juvenile psoriatic arthritis, as per the International League of Associations for Rheumatology criteria and an inadequate response (≥12 weeks) or intolerance to one or more conventional synthetic or biological disease-modifying antirheumatic drugs (DMARDs). Here we report post-hoc analyses of serum samples from patients who received open-label baricitinib in the 12-week lead-in period of the JUVE-BASIS trial. Samples were assessed using an Olink Explore 3072 panel at baseline and week 12. Baricitinib-mediated pharmacodynamic changes in serum protein markers were measured as changes from baseline to week 12 derived from a mixed model with repeated measurement. Pearson correlations of the change in serum biomarkers and clinical disease activity (JADAS-27 scores) comparing baseline with week 12 were examined. Proportional changes in biomarkers were classified into three response subsets based on JIA-ACR response rates: JIA-ACR <30% (non-responders), JIA-ACR 30-70% (responders), and JIA-ACR 70-100% (super-responders). People with lived experience of JIA were not involved in the design or conduct of this study. The JUVE-BASIS trial was registered with ClinicalTrials.gov, NCT03773978, and is completed. FINDINGS:Between Dec 17, 2018 and March 3, 2021, 220 patients were enrolled in JUVE-BASIS and received at least one dose of baricitinib in the open-label lead-in period. In this post-hoc analysis, 168 serum samples from 84 patients were analysed: 67 (80%) of 84 patients were female, 17 (20%) were male, 67 (80%) were White and the mean age was 14 years (SD 2). 10 (12%) of 84 were non-responders, 27 (32%) were responders, and 47 (56%) were super-responders based on clinical response. Several serum biomarkers showed significant changes following 12 weeks of baricitinib treatment for all patients with higher magnitude changes seen in responders and super-responders. Changes in biomarkers associated with macrophage activation (CCL7, CCL18, and IL-6) and regulation of matrix composition (matrix metalloproteinase-3) were positively correlated with clinical response. INTERPRETATION:To our knowledge, this is the first study measuring serum protein markers in the context of an intervention trial with baricitinib in patients with JIA. Associated biomarker changes with clinical response might allow physicians to potentially identify patients who are most likely to be responsive to baricitinib treatment. FUNDING:Eli Lilly and Company under licence from Incyte.

IntroductionAtopic dermatitis (AD) is an inflammatory skin disease that is heterogeneous in clinical presentation and biological mechanisms. Several studies have suggested biomarker-defined molecular endotypes in AD. This study aimed to characterize potential endotypes in Japanese patients with moderate-to-severe AD and comprehensively evaluate their circulating protein profiles to better understand disease etiology.MethodsSerum samples from Japanese patients with moderate-to-severe AD (n = 73) enrolled in a phase 3 study of baricitinib (BREEZE-AD2; NCT03334422) and samples from healthy controls (n = 15) were analyzed using the Olink Explore 1536 assay. Patient clusters were identified through k-means clustering. Differential expression analysis and weighted gene co-expression network analysis were performed for in-depth examination of proteomic profiles.ResultsTwo patient clusters, characterized by high (AD_HI) and low (AD_LO) inflammatory profiles, were found to be stable and reproducible. Canonical AD inflammatory mediators—including interleukin (IL)-13, IL-19, pulmonary and activation-regulated chemokine (PARC), thymus and activation-regulated chemokine (TARC), chemokine (C-C motif) ligand (CCL)22, CCL26, and CCL27—were upregulated in both clusters, with greater upregulation in the AD_HI cluster. Additionally, proteins not typically associated with AD-related inflammation were upregulated in AD_HI patients. The AD_HI cluster was associated with protein networks representing a range of immune and non-immune pathways. Dysregulated protein signatures associated with the AD_HI cluster were also correlated with skin-based disease severity scores.ConclusionThis study characterizes the circulating proteome and clinical characteristics across putative molecular endotypes in AD. The findings corroborate current knowledge on AD pathophysiology and suggest other axes of dysregulation in a subset of patients with AD. These results may support the development of personalized therapeutic approaches.

Lebrikizumab is a novel monoclonal antibody that selectively binds to interleukin (IL)-13 with high affinity and a slow dissociation rate. We assayed serum from select patients enrolled in ADvocate1 and ADvocate2 to determine the impact of lebrikizumab on circulating biomarkers and pathways relevant to atopic dermatitis (AD) and to assess the correlation between key biomarkers and clinical measures of improvement. At baseline, IL-13, CC motif chemokine ligand (CCL)13, CCL17, CCL22, total immunoglobulin (Ig)E, IL-5, and periostin were elevated in patients with moderate-to-severe AD versus healthy controls (p < 0.001). Baseline Eczema and Area Severity Index (EASI) and Investigator’s Global Assessment (IGA) scores were significantly correlated with IL-13, IL-5, CCL13, CCL22, and CCL26. Lebrikizumab induced rapid and progressive reductions in CCL13, CCL17, CCL22, and periostin at weeks 4, 16, and 52 compared with baseline (p < 0.05). AD-associated pathways linked to cytokine signaling were significantly improved at weeks 4 and 16. Improvements in EASI, IGA, and the Pruritus Numeric Rating Scale were correlated with reductions in CCL13, CCL17, CCL22, CCL26, and periostin across all time points. After multiple testing correction and adjusting for sex and race as covariates, we identified the chemokine CCL26 as a pharmacodynamic marker for lebrikizumab response at weeks 4 and 16. Selective inhibition of IL-13 with lebrikizumab monotherapy induced progressive inhibition of systemic biomarkers and pathways of type 2 inflammation, which correlated with clinical measures of improvement in patients with moderate-to-severe AD. NCT04146363 and NCT04178967. Atopic dermatitis (AD, also called atopic eczema) can cause various debilitating symptoms including red, scaly, and itchy skin that can worsen a person’s quality of life. Imbalance of normal immune system molecules, such as cytokines (substances released by cells involved in inflammation), play a central role in the development of AD. The aim of this study was to assess the impact of lebrikizumab, a treatment for AD that targets a cytokine called interleukin (IL)-13, on normalizing the levels of immune system molecules. Patients with AD were treated with lebrikizumab in two phase 3, placebo-controlled studies for 52 weeks. The results of this analysis demonstrated that numerous cytokines and other immune system molecules, including IL-13, were elevated in patients with moderate-to-severe AD at the start of the study compared with healthy controls (people who did not have AD). However, after patients with AD received treatment with lebrikizumab, rapid and progressive reductions in molecules associated with AD were observed through 52 weeks. In addition, the pathways that signal the cytokines associated with AD were significantly improved 4 and 16 weeks after receiving treatment. These improvements correlated with improved disease activity measures. Overall, this analysis demonstrated that treatment with lebrikizumab normalized several molecular pathways in patients with moderate-to-severe AD as compared with the levels of these molecules in healthy controls. These results suggest that lebrikizumab works in inhibiting IL-13 levels in patients with AD and is sufficient to improve the signs and symptoms of the disease.

Objective Rheumatoid arthritis (RA) synovium displays cellular heterogeneity, with gene expression driving pathogenesis. Prior transcriptomic studies relied on disaggregated tissue, which causes cell loss and induction. We applied spatial transcriptomics to investigate synovial lining and sublining fibroblasts and macrophages from RA and osteoarthritis (OA) patients. Methods Fresh frozen synovial tissues from 7 RA and 8 OA patients were analyzed using the NanoString GeoMX DSP Whole Transcriptome Assay. Lining and sublining regions were segmented into fibroblasts and macrophages. Principal component analysis separated samples by cell type and disease. Differentially expressed genes (DEG) were analyzed by linear mixed models (p-value<0.05 and |log2 fold change|>0.5) and Reactome pathway (FDR<0.02) analysis. Results DEG analysis of RA compared to OA revealed distinct gene signatures across regions and cell types. RA lining fibroblasts exhibited a strong pro-inflammatory and matrix-destructive signature, while RA sublining fibroblasts showed an unexpected role in antigen presentation and adaptive immunity. RA lining macrophages exhibited enrichment for interleukin signaling, extracellular matrix organization, and translation-related pathways. In contrast, sublining macrophages showed minimal transcriptional differences between RA and OA, suggesting limited pathogenic involvement. Comparison between lining and sublining within RA showed that lining fibroblasts display a higher activated phenotype than sublining cells. Conclusion Spatial transcriptomic analysis uncovers distinct region- and cell-type-specific transcriptional profiles in RA synovium. Lining fibroblasts are highly activated and destructive, and sublining fibroblasts contribute surprisingly to adaptive immunity. This data provides clues to region-cell-type-specific functions that could be exploited to identify novel therapeutic targets. ### Competing Interest Statement The authors have declared no competing interest. Eli Lilly (United States), https://ror.org/01qat3289

Abstract Introduction In ADvocate1 (NCT04146363) and ADvocate2 (NCT04178967), lebrikizumab demonstrated statistical superiority vs. placebo in patients with moderate-to-severe atopic dermatitis (AD). The objective of this analysis is to test for correlations between improvements in clinical outcomes and reductions in AD-relevant serum biomarkers during ADvocate1 and ADvocate2. Objectives To assess the correlation between clinical measures of atopic dermatitis (AD) and AD-specific biomarkers at baseline; and to assess the correlation between clinical measures of AD and changes in AD-specific biomarkers after treatment with lebrikizumab. Methods Full details of these studies were previously reported. Protein biomarkers were determined in available serum samples from patients receiving lebrikizumab 250 mg every 2 weeks (n=72) or placebo (n=36). Tested biomarkers included: IL-13 (baseline only), CCL2, CCL4, CCL11, CCL13, CCL17 (TARC), CCL22, CCL26 (eotaxin-3), CXCL10, total IgE, IL-4, IL-5, and periostin. Baseline biomarker levels and baseline clinical endpoints were compared using a Spearman correlation. A repeated measures correlation analysis was used to characterize paired measurement of within-patient biomarker levels and clinical endpoints at baseline, week 4, week 16, and week 52. Clinical measures of AD included Investigator’s Global Assessment (IGA), Eczema Area and Severity Index (EASI), and Pruritus Numeric Rating Scale (NRS). Results At baseline, EASI score was positively correlated with IL-13, periostin, IL-5, IgE, CCL13, CCL17, CCL22 and CCL26 (correlation coefficient>0.3, p<0.05), but not IL-4. During the studies, improvements in EASI, IGA, and Pruritus NRS were each correlated with reductions in periostin, CCL13, CCL17, CCL22, and CCL26 (correlation coefficient>0.3, p<0.05). Improvement in IGA was also correlated with a reduction in IgE (correlation coefficient>0.3, p<0.05). Conclusions Clinical measures of improvement in the signs and symptoms of AD are correlated with reductions in AD biomarkers in patients treated with lebrikizumab.

OBJECTIVE:Fibroblast-like synoviocytes (FLS) contribute to the pathogenesis of rheumatoid arthritis (RA), in part due to activation of the proinflammatory transcription factor NF-κB. Neddylation is modulated by the negative regulator of ubiquitin-like protein (NUB) 1. We determined whether NUB1 and neddylation are aberrant in the models with RA FLS, thereby contributing to their aggressive phenotype. METHODS:Models with RA or osteoarthritis (OA) FLS were obtained from arthroplasty synovia. Real-time quantitative polymerase chain reaction and Western blot analysis assessed gene and protein expression, respectively. NUB1 was overexpressed using an expression vector. NF-κB activation was assessed by stimulating FLS with interleukin (IL)-1β. Neddylation inhibitor (MLN4924) and proteasome inhibitor were used in migration and gene expression assays. MLN4924 was used in the model with K/BxN serum-transfer arthritis. RESULTS:Enhanced H3K27ac and H3K27me3 peaks were observed in the NUB1 promoter in the OA FLS compared with the RA FLS. NUB1 was constitutively expressed by FLS, but induction by IL-1β was significantly greater in the OA FLS. The ratio of neddylated cullin (CUL) 1 to nonneddylated CUL1 was lower in the OA FLS than the RA FLS. NUB1 overexpression decreased NF-κB nuclear translocation and IL-6 messenger RNA (mRNA) in IL-1β-stimulated the RA FLS. MLN4924 decreased CUL1 neddylation, NF-κB nuclear translocation, and IL-6 mRNA in IL-1β-stimulated the RA FLS. MLN4924 significantly decreased arthritis severity in the model with K/BxN serum-transfer arthritis. CONCLUSION:CUL1 neddylation and NUB1 induction is dysregulated in the models with RA, which increases FLS activation. Inhibition of neddylation is an effective therapy in an animal model of arthritis. These data suggest that the neddylation system contributes to the pathogenesis of RA and that regulation of neddylation could be a novel therapeutic approach.

OBJECTIVE:Rheumatoid arthritis (RA) is an autoimmune disease in which the joint lining or synovium becomes highly inflamed and majorly contributes to disease progression. Understanding pathogenic processes in RA synovium is critical for identifying therapeutic targets. We performed laser capture microscopy (LCM) followed by RNA sequencing (LCM-RNAseq) to study regional transcriptomes throughout RA synovium. METHODS:Synovial lining, sublining, and vessel samples were captured by LCM from seven patients with RA and seven patients with osteoarthritis (OA). RNAseq was performed on RNA extracted from captured tissue. Principal component analysis was performed on the sample set by disease state. Differential expression analysis was performed between disease states based on log2 fold change and q value parameters. Pathway analysis was performed using the Reactome Pathway Database on differentially expressed genes among disease states. Significantly enriched pathways in each synovial region were selected based on the false discovery rate. RESULTS:RA and OA transcriptomes were distinguishable by principal component analysis. Pairwise comparisons of synovial lining, sublining, and vessel samples between RA and OA revealed substantial differences in transcriptional patterns throughout the synovium. Hierarchical clustering of pathways based on significance revealed a pattern of association between biologic function and synovial topology. Analysis of pathways uniquely enriched in each region revealed distinct phenotypic abnormalities. As examples, RA lining samples were marked by anomalous immune cell signaling, RA sublining samples were marked by aberrant cell cycle, and RA vessel samples were marked by alterations in heme scavenging. CONCLUSION:LCM-RNAseq confirms reported transcriptional differences between the RA synovium and the OA synovium and provides evidence supporting a relationship between synovial topology and molecular anomalies in RA.

IL-21 is a multifunctional cytokine linked with the pathophysiology of several autoimmune diseases, including type 1 diabetes. In this study, our aim was to examine plasma IL-21 levels in individuals at different stages of type 1 diabetes progression. We measured plasma IL-21 levels, as well as levels of other key pro-inflammatory cytokines (IL-17A, TNF-α and IL-6), from 37 adults with established type 1 diabetes and 46 healthy age-matched adult controls, as well as from 53 children with newly diagnosed type 1 diabetes, 48 at-risk children positive for type 1 diabetes-associated autoantibodies and 123 healthy age-matched pediatric controls using the ultrasensitive Quanterix SiMoA technology. Adults with established type 1 diabetes had higher plasma IL-21 levels compared to healthy controls. However, the plasma IL-21 levels showed no statistically significant correlation with clinical variables, such as BMI, C-peptide, HbA1c, or hsCRP levels, evaluated in parallel. In children, plasma IL-21 levels were almost ten times higher than in adults. However, no significant differences in plasma IL-21 levels were detected between healthy children, autoantibody-positive at-risk children, and children with newly diagnosed type 1 diabetes. In conclusion, plasma IL-21 levels in adults with established type 1 diabetes were increased, which may be associated with autoimmunity. The physiologically high plasma IL-21 levels in children may, however, reduce the potential of IL-21 as a biomarker for autoimmunity in pediatric subjects.

Interleukin (IL)-23 exists as a heterodimer consisting of p19 and p40 and is a key cytokine for promoting inflammatory responses in a variety of target organs. IL-23 plays a key role in the differentiation and maintenance of T helper 17 cells, and deregulation of IL-23 can result in autoimmune pathologies of the skin, lungs, and gut. This study describes the generation and characterization of mirikizumab (miri), a humanized IgG4 monoclonal antibody directed against the p19 subunit of IL-23. Miri binds human and cynomolgus monkey IL-23 with high affinity and binds rabbit IL-23 weakly but does not bind to rodent IL-23 or the other IL-23 family members IL-12, IL-27, or IL-35. Miri effectively inhibits the interaction of IL-23 with its receptor, and potently blocks IL-23-induced IL-17 production in cell-based assays while preserving the function of IL-12. In both local and systemic in vivo mouse models, miri blocked IL-23-induced keratin mRNA or IL-17 production, respectively. These data provide a comprehensive preclinical characterization of miri, for which efficacy and safety have been demonstrated in human clinical trials for psoriasis, ulcerative colitis, and Crohn's disease. SIGNIFICANCE STATEMENT: This article describes the generation and characterization of mirikizumab, a high affinity, neutralizing IgG4 variant monoclonal antibody that is under development for the treatment of ulcerative colitis and Crohn's disease. Neutralization of interleukin (IL)-23 is achieved by preventing the binding of IL-23 p19 subunit to the IL-23 receptor and does not affect the IL-12 pathway.

IL-13 is the primary upregulated cytokine in atopic dermatitis (AD) skin and is the pathogenic mediator driving AD pathophysiology. Lebrikizumab, tralokinumab and cendakimab are therapeutic monoclonal antibodies (mAb) that target IL-13. We undertook studies to compare in vitro binding affinities and cell-based functional activities of lebrikizumab, tralokinumab and cendakimab. Lebrikizumab bound IL-13 with higher affinity (as determined using surface plasma resonance) and slower off-rate. It was more potent in neutralizing IL-13-induced effects in STAT6 reporter and primary dermal fibroblast periostin secretion assays than either tralokinumab or cendakimab. Live imaging confocal microscopy was employed to determine the mAb effects on IL-13 internalization into cells via the decoy receptor IL-13Rα2, using A375 and HaCaT cells. The results showed that only the IL-13/lebrikizumab complex was internalized and co-localized with lysosomes, whereas IL-13/tralokinumab or IL-13/cendakimab complexes did not internalize. Lebrikizumab is a potent, neutralizing high-affinity antibody with a slow disassociation rate from IL-13. Additionally, lebrikizumab does not interfere with IL-13 clearance. Lebrikizumab has a different mode of action to both tralokinumab and cendakimab, possibly contributing to the clinical efficacy observed by lebrikizumab in Ph2b/3 AD studies.

Background The humoral response to SARS-CoV-2 can provide immunity and prevent reinfection. However, less is known about how the diversity, magnitude, and length of the antibody response after a primary infection is associated with symptoms, post-infection immunity, and post-vaccinated immunity. Methods Cook County Health employees provided blood samples and completed an online survey 8–10 weeks after a PCR-confirmed positive SARS-CoV-2 test (pre-vaccinated, N = 41) and again, 1–4 weeks after completion of a 2-dose series mRNA BNT162b2 COVID-19 vaccine (post-vaccinated, N = 27). Associations were evaluated between SARS-CoV-2 antibody titers, participant demographics, and clinical characteristics. Antibody titers and angiotensin-converting enzyme 2 (ACE2) neutralization were compared before and after the mRNA BNT162b2 COVID-19 vaccine. Results Antibody titers to the spike protein (ST4), receptor binding domain (RBD), and RBD mutant D614G were significantly associated with anosmia and ageusia, cough, and fever. Spike protein antibody titers and ACE2 neutralization were significantly higher in participants that presented with these symptoms. Antibody titers to the spike protein N-terminal domain (NTD), RBD, and ST4, and ACE2 IC50 were significantly higher in all post-vaccinated participant samples compared to pre-vaccinated participant sample, and not dependent on previously reported symptoms. Conclusions Spike protein antibody titers and ACE2 neutralization are associated with the presentation of anosmia and ageusia, cough, and fever after SARS-CoV-2 infection. Symptom response to previous SARS-CoV-2 infection did not influence the antibody response from subsequent vaccination. These results suggest a relationship between infection severity and the magnitude of the immune response and provide meaningful insights into COVID-19 immunity according to discrete symptom presentation.