Endometriosis exhibits several immune dysfunctions, including deficient natural killer (NK) cell cytotoxicity. MICA (MHC class I chain-related molecule A) is induced by biological stress and soluble MICA (sMICA) negatively modulates the expression of the activating receptor, NKG2D, reducing NK cells activities. We investigated the involvement of soluble MICA in NK cell-deficient activity in endometriosis.sMICA levels (serum and peritoneal fluid-PF) were evaluated by ELISA. Circulating NK cell subsets quantification and its NKG2D receptor expression, NK cell cytotoxicity and CD107a, IFN-γ and IL-10 expressions by NK cells stimulated with K562 cells were determined by flow cytometry.We found higher sMICA levels (serum and PF) in endometriosis, especially in advanced and deep endometriosis. Endometriosis presented lower percentages of CD56dim CD16+ cytotoxic cells and impaired NK cell responses upon stimulation, resulting in lower CD107a and IFN-γ expressions, and deficient NK cell cytotoxicity. NK cell stimulation in the MICA-blocked condition (mimicking the effect of sMICA) showed decreased cytotoxicity in initial endometriosis stages and the emergence of a negative correlation between CD107a expression and sMICA levels.We suggest that soluble MICA is a potential player in endometriosis pathophysiology with involvement in disease progression and severity, contributing to NK cell impaired IFN-γ response and degranulation. NK cell compartment exhibits multiple perturbations, including quantitative deficiency and impaired cytotoxicity, contributing to inadequate elimination of ectopic endometrial tissue.

Background: Adaptive immunity in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection is decisive for disease control. Delayed activation of T cells is associated with a worse outcome in coronavirus disease 2019 (COVID-19). Although convalescent individuals exhibit solid T-cell immunity, to date, long-term immunity to SARS-CoV-2 is still under investigation. Objectives: We aimed to characterize the specific T-cell response on the basis of the in vitro recall of IFN-g-producing cells to in silico-predicted peptides in samples from SARS-CoV-2 convalescent individuals. Methods: The sequence of the SARS-CoV-2 genome was screened, leading to the identification of specific and promiscuous peptides predicted to be recognized by CD4+ and CD8+ T cells. Next, we performed an in vitro recall of specific T cells from PBMC samples from the participants. The results were analyzed according to clinical features of the cohort and Results: Our results indicated heterogeneous T-cell responsiveness among the participants. Compared with patients who exhibited mild symptoms, hospitalized patients had a significantly higher magnitude of response. In addition, male and older patients showed a lower number of IFN-g-producing cells. Analysis of samples collected after 180 days revealed a reduction in the number of specific circulating IFNg-producing T cells, suggesting decreased immunity against viral peptides. Conclusion: Our data are evidence that in silico-predicted peptides are highly recognized by T cells from convalescent individuals, suggesting a possible application for vaccine design. However, the number of specific T cells decreases 180 days after infection, which might be associated with reduced protection against reinfection over time. (J Allergy Clin Immunol Global 2022;1:112-21.)

Background Despite the high number of individuals infected by SARS-CoV-2 who develop COVID-19 symptoms worldwide, many exposed individuals remain asymptomatic and/or stay uninfected. This could be explained by a combination of environmental (exposure, previous infection), epigenetic, and genetic factors. Aiming to identify genetic variants involved in SARS-CoV-2 resistance, we analyzed 86 discordant Brazilian couples where one was infected and symptomatic while the partner remained asymptomatic and seronegative despite sharing the same bedroom during the infection. The discordant partners had comparable ages, and genetic ancestry proportions. Methods Whole-exome sequencing followed by a state-of-the-art method to call genotypes and haplotypes across the highly polymorphic MHC and LRC. Results We observed a minor impact in antigen-presentation genes and KIR genes associated with resistance. Interestingly, genes related to immune modulation, mainly involved in NK cell killing activation/inhibition harbor variants potentially contributing to infection resistance. We hypothesize that individuals prone to produce higher amounts of MICA (possibly soluble), LILRB1, LILRB2, and low amounts of MICB, would be more susceptible to infection. Conclusion According to this hypothesis, quantitative differences in these NK activity-related molecules could contribute to resistance to COVID-19 down regulating NK cell cytotoxic activity in infected individuals but not in resistant partners.

Despite the high number of individuals infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) who develop coronavirus disease 2019 (COVID-19) symptoms worldwide, many exposed individuals remain asymptomatic and/or uninfected and seronegative. This could be explained by a combination of environmental (exposure), immunological (previous infection), epigenetic, and genetic factors. Aiming to identify genetic factors involved in immune response in symptomatic COVID-19 as compared to asymptomatic exposed individuals, we analyzed 83 Brazilian couples where one individual was infected and symptomatic while the partner remained asymptomatic and serum-negative for at least 6 months despite sharing the same bedroom during the infection. We refer to these as “discordant couples”. We performed whole-exome sequencing followed by a state-of-the-art method to call genotypes and haplotypes across the highly polymorphic major histocompatibility complex (MHC) region. The discordant partners had comparable ages and genetic ancestry, but women were overrepresented (65%) in the asymptomatic group. In the antigen-presentation pathway, we observed an association between HLA-DRB1 alleles encoding Lys at residue 71 (mostly DRB1*03:01 and DRB1*04:01) and DOB*01:02 with symptomatic infections and HLA-A alleles encoding 144Q/151R with asymptomatic seronegative women. Among the genes related to immune modulation, we detected variants in MICA and MICB associated with symptomatic infections. These variants are related to higher expression of soluble MICA and low expression of MICB. Thus, quantitative differences in these molecules that modulate natural killer (NK) activity could contribute to susceptibility to COVID-19 by downregulating NK cell cytotoxic activity in infected individuals but not in the asymptomatic partners.

Endometriosis (EDT) is an inflammatory disease characterized by implantation/growth of endometrial tissue, glands, and/or stroma, outside the uterus. Reduced NK cell cytotoxic activity has been implicated in its pathogenesis, together with other immunologic alterations. We investigated the influence of KIR gene polymorphisms and their HLA ligand combinations in deep endometriosis (DE) susceptibility. One hundred sixty women with a histological diagnosis of DE and 202 control women without the disease, who underwent laparoscopy, were enrolled. The DE group was subdivided into initial (I/II; n = 60) and advanced stages (III/IV, n = 100). KIR and HLA class I gene polymorphisms were typed by PCR-SSP and sequence-based-typing (SBT), respectively. We observed a significant association of KIR2DL2, an inhibitory gene of B haplotype, conferring risk for DE in Euro-descendants. Positive associations of Bx haplotype and centromeric AB segments were also found. However, no association with KIR-HLA ligand combination was observed. Our data suggest KIR2DL2 gene to be a relevant factor favoring NK inhibition in DE in Euro-descendants, contributing to the defective NK cytotoxic activity and impaired clearance of ectopic endometrial cells in the disease.

OBJECTIVE:To assess whether the HLA-G immunomodulatory protein is potentially involved in the pathophysiology of endometriosis or disease progression. STUDY DESIGN:Cross-sectional observational study of 227 women who underwent laparoscopy, being 146 for endometriosis excision and 81 for elective tubal ligation (control group). Soluble HLA-G (sHLA-G) levels in the serum and peritoneal fluid (PF), as well as the HLA-G protein expression in matched eutopic and ectopic endometrium of women with and without endometriosis were evaluated by ELISA and immunohistochemistry assays, respectively. Women with endometriosis were separated into groups according to the initial (I/II, n = 60) and advanced (III/IV, n = 86) stages of disease. sHLA-G measurement was performed only in women with matched serum and PF samples in both the control (CTRL; n = 77) and endometriosis (EDT; I-II, n = 60; III-IV, n = 83) groups. HLA-G protein expression was evaluated in 26 women with deep endometriosis (I-II, n = 12; III-IV, n = 14) and 22 controls. RESULTS:Higher concentrations of sHLA-G (P = 0.013) in the serum but not in the PF were observed in women with advanced endometriosis compared to the control group. In situ expression of HLA-G protein was also higher in ectopic (P = 0.018) but not in eutopic endometrium of women with advanced endometriosis compared to control group. CONCLUSION:Our findings suggest that HLA-G upregulation in advanced stages may contribute to the state of immunosuppression in endometriosis as disease progresses.

Pediatric autoimmune hepatitis (AIH) patients present hypergammaglobulinemia, periportal CD8+ cytotoxic T cell infiltration, and cirrhosis. Autoantibody profile defines AIH types 1 and 2 in addition to strong association with HLA-DRB1. We previously detected increased IgE serum levels and sought to compare clinical and histological features according to IgE levels in AIH (n=74, ages 1–14 years) patients. Additionally, we typed 117 patients and 227 controls for functional polymorphisms of IL4, IL13, IL5, and IL4RA genes involved in IgE switching and eosinophil maturation that might contribute to overall genetic susceptibility to AIH. Serum IgE levels were high in 55% of AIH-1, but only in 12% of AIH-2 (P=0.003) patients. Liver IgE was present in 91.3% of AIH-1 patients. The A alleles at both IL13 rs20541 and IL4RA rs1805011 were associated with AIH-1 (P=0.024, OR = 1.55 and P<0.0001, OR = 2.15, resp.). Furthermore, individuals presenting homozygosis for the A allele at IL4RA rs1805011 and HLA-DRB103∗ and/or 13∗ allele had sixfold greater risk to develop the disease (OR = 14.00, P<0.001). The novel association suggests an additional role for IgE-linked immune response genes in the pathogenesis of AIH.

To analyse the rate of clinical recurrences in Brazilian patients with Vogt–Koyanagi–Harada (VKH) disease after early high-dose corticosteroid treatment.

STUDY OBJECTIVE:To estimate the concentration of natural killer (NK) cells in the peripheral blood in patients with and without endometriosis.DESIGN:Case-control study (Canadian Task Force classification II-2).SETTING:Tertiary referral hospital.PATIENTS:One hundred fifty-five patients who had undergone videolaparoscopy were divided into 2 groups: those with endometriosis (n = 100) and those without endometriosis (n = 55).INTERVENTIONS:The percentage of NK cells relative to peripheral lymphocytes was quantified at flow cytometry in 155 patients who had undergone laparoscopy. In addition to verifying the presence of endometriosis, stage of disease and the sites affected were also evaluated.MEASUREMENTS AND MAIN RESULTS:The mean (SD) percentage of NK cells was higher (15.3% [9.8%]) in patients with endometriosis than in the group without the disease (10.6% [5.8%]) (p < .001). The percentage of NK cells was highest (19.8 [10.3%]) in patients with advanced stages of endometriosis and in those in whom the rectosigmoid colon was affected. In a statistical model of probability, the association of this marker (NK cells ≥11%) with the presence of symptoms such as pain and intestinal bleeding during menstruation and the absence of previous pregnancy yielded a 78% likelihood of the rectosigmoid colon being affected.CONCLUSION:Compared with patients without endometriosis, those with endometriosis demonstrate a higher concentration of peripheral NK cells. The percentage of NK cells is greater, primarily in patients with advanced stages of endometriosis involving the rectosigmoid colon. Therefore, it may serve as a diagnostic marker for this type of severe endometriosis, in particular if considered in conjunction with the symptoms.

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease. Characteristic liver-infiltrating immune cells in portal and periportal areas, hypergammaglobulinemia and typical autoantibodies indicate an ongoing autoimmune reaction against liver self antigens, which lead to irreversible cellular damage and ultimately to severe hepatic failure. A significant part of adult, but not pediatric AIH patients, exhibit concurrent autoimmune diseases, further strengthening the immunological etiology of the disease. Genetic susceptibility to autoimmune hepatitis is strongly associated with HLA-DRB1 alleles. In Caucasian European and North American patients, AIH-1 is associated with the presence of DRB1 * 0301, DRB3 * 0101 and DRB1 * 0401 alleles, while AIH-2 is associated with DRB1 * 0301 or DRB1 * 07. In Brazil, the primary susceptibility allele for AIH-1 is DRB1 * 1301, but a secondary association with DRB1 * 0301 has also been identified. We looked for additional susceptibility factors in the extended MHC region. We genotyped 107 AIH-1 children and up to 326 healthy subjects for TNFA G-308A, TNFA G-238A, LTA A + 252 G, LTA A + 80 C, NFKBIL1 T-63A, BAT1 C-348 T, BAT1 G-22 C, MICA, and HLA-B polymorphisms. The TNFA-308 A allele was significantly increased in AIH-1 when compared with healthy controls, confirming data from other studies. Linkage disequilibrium analysis was carried out. The ancestral haplotype comprising TNFA-308A, TNFA-238 G, LTA + 252 G, LTA + 80 C, NFKBIL1-63A, BAT1-348 C, BAT1-22 C, HLA-B * 08, MICA * 08 was more common in DRB1 * 03 positive patients than in controls (40% vs. 14%), showing a seven-fold increased risk for the disease [OR = 7.8 (95%CI 2.04–29.9.2, p = 0.0021). In contrast, the remaining patients carrying DRB1 * 03 exhibited varied haplotypes. Finally, a variety of class III haplotypes was also present in HLA-DRB1 * 13 patients, without a predominant pattern. The most common of the 98 haplotypes present in patients were completely absent in controls. The extended haplotype analysis in this sample of AIH-1 patients highlights not only the genetic diversity present in the Brazilian population, but is also in accordance with the previously documented microdiversity within the MHC region. The present knowledge of AIH suggests that the same or a very similar disease can be induced by yet unknown, but different, triggers followed by presentation on different HLA-DR molecules of the epitopes derived from the corresponding autoantigens, characterizing a much more complex disease than previously thought.

Objective: To present the frequency of single nucleotide polymorphisms of a few immune response genes in a population sample from Sao Paulo City (SP), Brazil. Methods: Data on allele frequencies of known polymorphisms of innate and acquired immunity genes were presented, the majority with proven impact on gene function. Data were gathered from a sample of healthy individuals, non-HLA identical siblings of bone marrow transplant recipients from the Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, obtained between 1998 and 2005. The number of samples varied for each single nucleotide polymorphism analyzed by polymerase chain reaction followed by restriction enzyme cleavage. Results: Allele and genotype distribution of 41 different gene polymorphisms, mostly cytokines, but also including other immune response genes, were presented. Conclusion: We believe that the data presented here can be of great value for case-control studies, to define which polymorphisms are present in biologically relevant frequencies and to assess targets for therapeutic intervention in polygenic diseases with a component of immune and inflammatory responses.

BACKGROUND Approximately one-half of Brazilian patients with hereditary hemochromatosis (HH) are neither homozygous for the C282Y mutation nor compound heterozygous for the H63D and C282Y mutations that are associated with HH in Caucasians. Other mutations have been described in the HFE gene as well as in genes involved in iron metabolism, such as transferrin receptor 2 (TfR2) and ferroportin 1 (SCL40A1). AIMS To evaluate the role of HFE, TfR2 and SCL40A1 mutations in Brazilian subjects with HH. PATIENTS AND METHODS Nineteen male subjects (median age 42 [range: 20–72] years) with HH were evaluated using the Haemochromatosis StripAssay A®. This assay is capable of detecting twelve HFE mutations, which are V53M, V59M, H63D, H63H, S65C, Q127H, P160delC, E168Q, E168X, W169X, C282Y and Q283, four TfR2 mutations, which are E60X, M172K, Y250X, AVAQ594-597del, and two SCL40A1 mutations, which are N144H and V162del. RESULTS In our cohort, nine (47%) patients were homozygous for the C282Y mutation, two (11%) were heterozygous for the H63D mutation, and one each (5%) was either heterozygous for C282Y or compound heterozygous for C282Y and H63D. No other mutations in the HFE, TfR2 or SCL40A1 genes were observed in the studied patients. CONCLUSIONS One-third of Brazilian subjects with the classical phenotype of HH do not carry HFE or other mutations that are currently associated with the disease in Caucasians. This observation suggests a role for other yet unknown mutations in the aforementioned genes or in other genes involved in iron homeostasis in the pathogenesis of HH in Brazil.

PURPOSE: To evalulate the applicability of the Revised Diagnostic Criteria for Vogt-Koyanagi-Harada (VKH) disease to Brazilian patients and to verify the association between different disease categories, clinical parameters, and the presence of HLA-DRB1*0405.DESIGN: A retrospective observational case series.METHODS: Medical charts of 67 patients (10 to 64 years in age; 12 men and 55 women), from the Uveitis Service, Hospital das Clinicas, University of Sao Paulo School of Medicine (HCFMUSP), Sao Paulo, Brazil were reviewed. Patients, previously diagnosed with VKH disease using criteria proposed by the American Uveitis Society, underwent retrospective classification based on the Revised Diagnostic Criteria. The degree of concordance was assessed. At presentation, 46 patients (69%) were in the early phase. In this group, the mean time from disease onset to treatment was 15 days (range, one to 30 days). Forty-eight patients (72%) were typed for HLA-DRB1*0405 by polymerase chain reaction-sequence specific primer and polymerase chain reaction,sequence, specific oligonucleotides primer. Disease categories, phase at initial presentation, and ocular complications were analyzed.RESULTS: There was a 100% of concordance between the two criteria. Disease was classified as complete in 10 patients (15%), incomplete in 37 patients (55%), and probable in 20 patients (30%). In each group, respectively, 90%, 76%, and 45% were in the early phase at presentation (P = .017). There was no association between disease categories, the presence of HLA-DRB1*0405, and clinical parameters.CONCLUSION. The Revised Diagnostic Criteria proved useful for diagnosis of VKH disease in Brazilian patients. The present retrospective study did not find any association between disease category and severity parameters. To better understand the relevance of disease categories, a minimum follow-up period to categorize patients should be included in future prospective studies. (Am J Ophthalmol 2009;147:339-345. (C) 2009 by Elsevier Inc. All rights reserved.)

Autoimmune hepatitis is an immune cell-mediated chronic liver disease of unknown cause that leads, when untreated, to cirrhosis and liver failure. Importantly, this disease affects not only adults but children as well. Genetic susceptibility is clearly important and the major susceptibility factor identified up to now is the HLA-DRB1 locus, but other genes may play a role as well. HLA-DRB1 alleles present in South American patients differ from those found in patients in other parts of the world. In addition, we have recently identified two chromosomal regions where additional susceptibility factors may be found in Brazilian patients, namely, the class III MHC region and the 5q31 region where the IL-4 and IL-13 genes are located. This review discusses the current knowledge of the pathogenesis of this autoimmune disease occurring in the setting of an immune-privileged organ, the liver, and compares the data on gene polymorphisms studied in Brazil and in other parts of the world.