The optimal use of tildrakizumab in the elderly via improvement of Treg function and its preventive effect of psoriatic arthritis.

Introduction: As a form of precision medicine, this study aimed to investigate the specific patient population that would derive the greatest benefit from tildrakizumab, as well as the mechanism of action and efficacy of tildrakizumab in reducing the occurrence of psoriatic arthritis (PsA). Methods: To achieve this, a multi-center, prospective cohort study was conducted, involving a population of 246 psoriasis patients who had not received any systemic therapy or topical finger therapy between January 2020 and April 2023. Two independent clinicians, who were blinded to the study, analyzed nailfold capillary (NFC) abnormalities, such as nailfold bleeding (NFB) and enlarged capillaries, as well as the incidence of new PsA. Additionally, the factors that determined the response of psoriasis after seven months of tildrakizumab treatment were examined. The study also examined the quantity and role of regulatory T cells (Tregs) and T helper 17 cells both pre- and post-treatment. Results: The severity of psoriasis, as measured by the Psoriasis Area and Severity Index (PASI), was found to be more pronounced in the tildrakizumab group (n=20) in comparison to the topical group (n=226). At 7 months after tildrakizumab treatment, multivariate analysis showed that those 65 years and older had a significantly better response to treatment in those achieved PASI clear or PASI 2 or less (Likelihood ratio (LR) 16.15, p<0.0001; LR 6. 16, p=0.01). Tildrakizumab improved the number and function of Tregs, which had been reduced by aging. Tildrakizumab demonstrated significant efficacy in improving various pathological factors associated with PsA. These factors include the reduction of NFB, enlargement of capillaries, and inhibition of PsA progression. The hazard ratio for progression to PsA was found to be 0.06 (95% confidence interval: 0.0007-0.46, p=0.007), indicating a substantial reduction in the risk of developing PsA. Discussion: Tildrakizumab's effectiveness in improving skin lesions can be attributed to its ability to enhance the number and function of Tregs, which are known to decline with age. Furthermore, the drug's positive impact on NFB activity and capillary enlargement, both of which are recognized as risk factors for PsA, further contribute to its inhibitory effect on PsA progression.

Carriers of HLA-DRB1*04:05 have a better clinical response to abatacept in rheumatoid arthritis.

HLA-DRB1 shared epitope risk alleles are the strongest genetic risk factors for rheumatoid arthritis (RA) and potential biomarkers for treatment response to biological disease-modifying antirheumatic drugs (bDMARDs). This study aimed to investigate the association between treatment response and individual HLA-DRB1 alleles in RA patients receiving different bDMARDs. We recruited 106 patients with active RA who had started abatacept, tocilizumab, or TNF inhibitors as a first-line bDMARDs. We examined the relationship between Simplified Disease Activity Index (SDAI) improvement at 3 months and HLA-DRB1 allele carriage. The results revealed that the HLA-DRB1*04:05 allele, a shared-epitope allele, was significantly associated with better SDAI improvement only after abatacept treatment (SDAI improvement 28.5% without the allele vs 59.8% with allele, p = 0.003). However, no significant association was found with other treatments. Both multivariate linear regression and mediation analysis confirmed that the HLA-DRB1*04:05 allele was independently associated with abatacept treatment response, regardless of anti-CCP antibody titers. The study concluded that in patients with RA receiving their first-line bDMARD treatment, carrying the HLA-DRB1*04:05 allele was associated with better SDAI improvement specifically in abatacept-treated patients. These disease-risk HLA alleles have the potential to serve as genomic biomarkers for predicting treatment response with co-stimulation blockage therapy.

Utility of nailfold capillary assessment for predicting pustulotic arthro-osteitis in palmoplantar pustulosis based on a prospective cohort study.

BACKGROUND: Pustulotic arthro-osteitis (PAO) is 1 of the most serious comorbidities associated with palmoplantar pustulosis (PPP). Risk factors of PAO development are not well-known. OBJECTIVE: To evaluate the clinical significance of nailfold capillary (NFC) changes in patients with PPP. METHODS: We conducted a prospective cohort study in a population of 102 PPP patients. Correlations of NFC abnormalities, including nailfold bleeding and enlarged capillaries, with the prevalence of PAO, the incidence of new PAO, and serum levels of cytokines were analyzed. RESULTS: Detailed examination revealed that of 102 PPP patients, 52 without PAO and 50 with PAO. Both nailfold bleeding and enlarged capillaries were significantly more frequent in patients with PAO (50.0% vs 92.0%, P < .0001; 50.0% vs 94.0%, P < .0001). In addition, PPP patients without PAO were prospectively observed before they developed PAO (mean 28 months [1-52 months]). Multivariate analysis suggested that these NFC abnormalities were predictors of PAO development (hazard ratio 3.37, 95% confidence interval 1.13-10.07; 3.37, 1.13-10.07) and guselkumab prevent PAO development (0.093, 0.012-0.76). The degree of NFC abnormalities correlated with the severity of PAO and serum cytokine levels. LIMITATIONS: All participants were Japanese. CONCLUSION: NFC abnormalities could be predictors of PAO in PPP patients, and their degree indicators of disease severity.

Utility of nailfold capillary assessment for predicting psoriatic arthritis based on a prospective observational cohort study.

OBJECTIVES: PsA is one of the most serious comorbidities associated with psoriasis. While the early intervention in PsA is demanded, risk factors of PsA development are not well-known. This is the first prospective study to evaluate the clinical significance of nailfold capillary (NFC) changes in patients with psoriasis. METHODS: We conducted a prospective cohort study in a population of 449 psoriasis patients who had not been treated with systemic therapy or topical finger therapy. NFCs were observed by dermoscopy and capillaroscopy, and the correlation of NFC abnormalities, including nailfold bleeding (NFB) and enlarged capillaries, with the prevalence of PsA, incidence of new PsA, and serum levels of TNF-a, IL-17A and IL-23 were analysed. RESULTS: Detailed examination at the time of inclusion revealed that of 449 patients, 236 had Psoriasis vulgaris (PsV) and 213 had PsA. Both NFB and enlarged capillaries were significantly more frequent in patients with PsA (34.7% vs 84.5%, P < 0.0001; 25.4% vs 100%, P < 0.0001). In addition, PsV patients were prospectively observed before they developed PsA (mean 21 months, 95% CI 2, 77 months). Multivariate analysis suggested that the appearance of NFB and enlarged capillaries was a predictor of PsA development (HR 2.75, 95% CI 1.38, 5.47 and HR 4.49, 95% CI 2.25, 8.96, respectively). The degree of NFC abnormalities also correlated with the severity of PsA and serum cytokine levels. CONCLUSIONS: NFC abnormalities were suggested to be a predictor of PsA in psoriasis patients, and at the same time, its degree could be an indicator of disease severity.

Interpretations of SARS-CoV-2 IgM and IgG antibody titers in the seroepidemiological study of asymptomatic healthy volunteers.

INTRODUCTION: The usefulness of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody tests in asymptomatic individuals has not been well validated, although they have satisfied sensitivity and specificity in symptomatic patients. In this study, we investigated the significance of IgM and IgG antibody titers against SARS-CoV-2 in the serum of asymptomatic healthy subjects. METHODS: From June 2020, we recruited 10,039 participants to the project named the University of Tokyo COVID-19 Antibody Titer Survey (UT-CATS), and measured iFlash-SARS-CoV-2 IgM and IgG (YHLO IgM and IgG) titers in the collected serum. For the samples with increased IgM or IgG titers, we performed additional measurements using Elecsys Anti-SARS-CoV-2 Ig (Roche total Ig) and Architect SARS-CoV-2 IgG (Abbott IgG) and investigated the reactivity to N, S1, and receptor binding domain (RBD) proteins. RESULTS: After setting the cutoff value at 5 AU/mL, 61 (0.61%) were positive for YHLO IgM and 104 (1.04%) for YHLO IgG. Few samples with elevated YHLO IgM showed reactivity to S1 or RBD proteins, and IgG titers did not increase during the follow-up in any samples. The samples with elevated YHLO IgG consisted of two groups: one reacted to S1 or RBD proteins and the other did not, which was reflected in the results of Roche total Ig. CONCLUSIONS: In SARS-CoV-2 seroepidemiological studies of asymptomatic participants, sufficient attention should be given to the interpretation of the results of YHLO IgM and IgG, and the combined use of YHLO IgG and Roche total Ig might be more reliable.

Epidemiological study using IgM and IgG antibody titers against SARS-CoV-2 in The University of Tokyo, Japan (UT-CATS).

INTRODUCTION: The worldwide pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has continued to date. Given that some of the patients with coronavirus disease 2019 (COVID-19) are asymptomatic, antibody tests are useful to determine whether there is a previous infection with SARS-CoV-2. In this study, we measured IgM and IgG antibody titers against SARS-CoV-2 in the serum of asymptomatic healthy subjects in The University of Tokyo, Japan. METHODS: From June 2020, we recruited participants, who were students, staff, and faculty members of The University of Tokyo in the project named The University of Tokyo COVID-19 Antibody Titer Survey (UT-CATS). Following blood sample collection, participants were required to answer an online questionnaire about their social and health information. We measured IgG and IgM titers against SARS-CoV-2 using iFlash-SARS-CoV-2 IgM and IgG detection kit which applies a chemiluminescent immunoassay (CLIA) for the qualitative detection. RESULTS: There were 6609 volunteers in this study. After setting the cutoff value at 10 AU/mL, 32 (0.48%) were positive for IgG and 16 (0.24%) for IgM. Of six participants with a history of COVID-19, five were positive for IgG, whereas all were negative for IgM. The median titer of IgG was 0.40 AU/mL and 0.39 AU/mL for IgM. Both IgG and IgM titers were affected by gender, age, smoking status, and comorbidities. CONCLUSIONS: Positive rates of IgG and IgM titers were relatively low in our university. Serum levels of these antibodies were affected by several factors, which might affect the clinical course of COVID-19.

Decreased peripheral blood memory B cells are associated with the presence of interstitial lung disease in rheumatoid arthritis: a case-control study.

OBJECTIVES: Interstitial lung disease sometimes occurs in rheumatoid arthritis patients. Although the underlying immunological mechanisms responsible for interstitial lung disease associated with rheumatoid arthritis have not yet been clarified, some reports have suggested possible roles of B cells. To examine the role of B-cell subsets in interstitial lung disease in rheumatoid arthritis patients, we analyzed peripheral blood B-cell subsets. METHODS: We analyzed the frequencies of the peripheral blood B-cell subsets by flow cytometry in rheumatoid arthritis patients with and without interstitial lung disease (n = 16 and 81, respectively) and in healthy donors (n = 110) by high-resolution computed tomography. RESULTS: Compared with healthy donors, rheumatoid arthritis patients showed statistically higher frequencies of naive B cells and lower frequencies of memory B cells. Moreover, the frequencies of memory B cells were lower in rheumatoid arthritis patients with interstitial lung disease than in those without. Multivariate analysis showed that the frequency of memory B cells, particularly switched memory B cells, was significantly decreased in rheumatoid arthritis patients with interstitial lung disease, even after adjusting for prednisolone dose. CONCLUSIONS: We suspect memory B cells play important roles in interstitial lung disease associated with rheumatoid arthritis.

Evaluation of Response Criteria in Rheumatoid Arthritis Treated With Biologic Disease-Modifying Antirheumatic Drugs.

OBJECTIVE: Biologic disease-modifying antirheumatic drugs (bDMARDs) used for rheumatoid arthritis (RA) treatment have several mechanisms of action. Interleukin-6 inhibitors (IL-6i) block the production of acute-phase reactants (APRs), which are some of the composite measures of disease activity. We undertook this study to examine the agreement between the European League Against Rheumatism (EULAR) response based on the erythrocyte sedimentation rate (ESR) or C-reactive protein level, the Simplified Disease Activity Index 50% response measure (SDAI50), and the Clinical Disease Activity Index 50% response measure (CDAI50) in patients treated with IL-6i and other bDMARDs. METHODS: We enrolled 306 patients with RA who started or switched bDMARDs. Treatment response at 6 months was analyzed. Kappa statistics were used to evaluate the agreement between different response measures. The contribution of APRs to improvement in disease activity scores was examined. The change of Health Assessment Questionnaire (HAQ) score was analyzed in IL-6i-treated patients. RESULTS: Good agreement was achieved between response measures, with κ >0.6 in patients treated with tumor necrosis factor inhibitors or cytotoxic T-lymphocyte-associated antigen 4 immunoglobulin fusion protein. In IL-6i-treated patients, the agreement was low between the EULAR response (ESR) and the SDAI50 or the CDAI50 (κ = 0.43 and 0.37, respectively). Under IL-6i treatment, APR improvement accounted for 56.0% of total improvement of the Disease Activity Score in 28 joints (DAS28) using the ESR. When discordance was found between the CDAI50 and EULAR response in IL-6i-treated patients, all patients were classified as EULAR-only responders; there was no HAQ improvement in EULAR-only responders. CONCLUSION: EULAR response criteria overestimate the response under IL-6i treatment because the APR improvement largely contributes to the DAS28 improvement.

Factors associated with discontinuation of glucocorticoids after starting biological disease-modifying antirheumatic drugs in rheumatoid arthritis patients.

Objectives: Glucocorticoids (GCs) are effective treatments for rheumatoid arthritis (RA) but long-term use has adverse effects. This study aimed to elucidate whether GCs can be discontinued by introducing biological disease-modifying antirheumatic drugs (bDMARDs) and the factors influencing the outcome.Method: We included RA patients who had been orally taking GCs at the initiation of bDMARDs. The changes in GC dose after starting bDMARDs were evaluated and the GC discontinuation rate was analyzed using Kaplan-Meier analysis. The factors associated with discontinuation of GCs were assessed by Cox hazard models.Results: Eighty RA patients were included in the study. The dosage of oral prednisolone (PSL) was significantly reduced from 5.0 to 3.0 mg/day by 3 months (p = .013). GCs were discontinued in 31.3% of patients and the median time until GC discontinuation was 10.1 months. The GC discontinuation rate was significantly higher in patients with Class 1 and 2 (p = .024), with an initial PSL dose <5 mg/day (p = .040), and with low DAS28(ESR) (p = .038). In multivariate analyses, higher DAS28(ESR) (odds ratio, 0.200; p = .039), and higher PSL dose (odds ratio, 0.748; p = .029) were significantly associated with less frequent GC discontinuation.Conclusion: DAS28(ESR) high and PSL dose were factors associated with discontinuation of GC use after starting bDMARDs.

CD4+CD25+LAG3+ T Cells With a Feature of Th17 Cells Associated With Systemic Lupus Erythematosus Disease Activity.

Systemic lupus erythematosus (SLE) is an autoimmune disease that involves multiple immune cell subsets. We analyzed immune cell subsets in human peripheral blood mononuclear cells (PBMC) in order to identify the cells that are significantly associated with SLE disease activity and treatment. The frequencies of various subsets of CD4+ T cells, B cells, monocytes and NK cells in PBMC were assessed in 30 healthy controls (HC), 30 rheumatoid arthritis (RA) patients and 26 SLE patients using flow cytometry. The correlations between subset frequencies in SLE and clinical traits including Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) were examined. Changes in subset frequencies after the treatment in SLE patients were investigated. We focused on CD25+LAG3+ T cells and investigated their characteristics, including cytokine secretion, mRNA expression and suppression capacity. We assessed correlations between CD25+LAG3+ T cells and SLEDAI by Spearman's rank correlation coefficient. CD25+LAG3+ T cells were significantly increased in SLE whereas there were few in RA and HC groups. CD25+LAG3+ T cell frequencies were significantly correlated with SLEDAI and were increased in patients with a high SLEDAI score (> 10). CD25+LAG3+ T cells produced both IL-17 and FOXP3, expressed mRNA of both FOXP3 and RORC and lacked suppressive capacity. CD25+LAG3+ T cells were associated with disease activity of SLE. CD25+LAG3+ T cells had features of both CD25+FOXP3+ regulatory T cells (CD25+ Treg) and Th17. CD25+LAG3+ T cells could be associated with the inflammatory pathophysiology of SLE.

Polymorphic lymphoproliferative disorders in patients with rheumatoid arthritis are associated with a better clinical outcome.

OBJECTIVES: The characteristics of lymphoproliferative disorders (LPD) in patients with rheumatoid arthritis (RA) remain unclear. Therefore, we retrospectively analyzed the clinical characteristics of these patients in our department. METHODS: Twenty RA patients who developed LPD between April 2003 and August 2016 in our department were analyzed. RESULTS: All of the RA patients who developed LPD had been treated with methotrexate (MTX). The median weekly and total dosages of MTX were 6.8 mg/week and 2530 mg, respectively. The median duration of MTX administration was eight years. Nineteen patients (95%) achieved complete remission (CR) and 15 (75%) achieved CR with MTX cessation alone. Based on the pathological findings, we divided MTX-associated LPD patients into two groups (n = 16); polymorphic LPD (31%) and other groups. CR with MTX cessation alone was achieved in 5 (100%) and 6 (54.5%) patients in the polymorphic LPD and other groups, respectively (p = .12). Moreover, the duration from the cessation of MTX to CR was significantly shorter in the polymorphic LPD group than in the other group (5.3 months vs 12.6 months, p = .01, respectively). CONCLUSION: Polymorphic LPD, which was the most frequent pathological diagnosis in this cohort, was associated with a higher incidence of CR and a significantly shorter duration to CR.

A gene module associated with dysregulated TCR signaling pathways in CD4+ T cell subsets in rheumatoid arthritis.

We analyzed the transcriptome of detailed CD4+ T cell subsets including them after abatacept treatment, and examined the difference among CD4+ T cell subsets and identified gene sets that are closely associated disease activity and abatacept treatment. Seven CD4+ T cell subsets (naive, Th1, Th17, Th1/17, nonTh1/17, Tfh and Treg) were sorted from PBMCs taken from 10 RA patients and 10 healthy controls, and three RA patients donated samples before and 6 months after abatacept treatment. Paired-end RNA sequencing was performed using HiSeq 2500. A total of 149 samples except for 12 outliers were analyzed. Overview of expression pattern of RA revealed that administration of abatacept exerts a large shift toward the expression pattern of HC. Most of differentially expressed gene (DEG) upregulated in RA (n = 1776) were downregulated with abatacept treatment (n = 1349). Inversely, most of DEG downregulated in RA (n = 1860) were upregulated with abatacept treatment (n = 1294). This DEG-based analysis revealed shared pathway changes in RA CD4+ T cell subsets. Knowledge-based pathway analysis revealed the upregulation of activation-related pathways in RA that was substantially ameliorated by abatacept. Weighted gene co-expression network analysis (WGCNA) evaluated CD4+ T cells collectively and identified a gene module that consisted of 227 genes and was correlated with DAS28-CRP (Spearman's rho = 0.46, p = 4 × 10-9) and abatacept administration (Spearman's rho = -0.91, p = 5 × 10-57). The most highly connected 30 genes of this module included ZAP70 and JAK3, and pathway analysis of this module revealed dysregulation of the TCR signaling pathway network, which was ameliorated by abatacept.

Interleukin-10-producing LAG3+ regulatory T cells are associated with disease activity and abatacept treatment in rheumatoid arthritis.

BACKGROUND: Regulatory T cells (Tregs) play a role in the suppression of inflammation in autoimmune diseases, and lymphocyte activation gene 3 (LAG3) was reported as a marker of interleukin (IL)-10-producing Tregs. We aimed to clarify the function of human IL-10-producing CD4+CD25-LAG3+ T cells (LAG3+ Tregs) and their association with rheumatoid arthritis (RA). METHODS: LAG3+ Tregs of human peripheral blood mononuclear cells (PBMCs) were cultured with B cells and follicular helper T cells to examine antibody suppression effects. The frequency of LAG3+ Tregs was evaluated in peripheral blood samples from 101 healthy donors and 85 patients with RA. In patients treated with abatacept, PBMC samples were analyzed before and after treatment. Naive CD4+ T cells were sorted and cultured in the presence of abatacept, followed by flow cytometric analysis and function assays. RESULTS: LAG3+ Tregs produced high amounts of IL-10 and interferon-γ, and they suppressed B-cell antibody production more strongly than CD25+ Tregs. Cell-to-cell contact was required for the suppressive function of LAG3+ Tregs. The frequency of LAG3+ Tregs was lower in patients with RA, especially those with higher Clinical Disease Activity Index scores. LAG3+ Tregs significantly increased after 6 months of abatacept treatment, whereas CD25+ Tregs generally decreased. Abatacept treatment in vitro conferred LAG3 and EGR2 expression on naive CD4+ T cells, and abatacept-treated CD4+ T cells exhibited suppressive activity. CONCLUSIONS: IL-10-producing LAG3+ Tregs are associated with the immunopathology and therapeutic response in RA. LAG3+ Tregs may participate in a mechanism for the anti-inflammatory and immune-modulating effects of targeted therapy for costimulation.

Enhanced gut homing receptor expression of unswitched memory B cells in rheumatoid arthritis.

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Immunophenotyping of rheumatoid arthritis reveals a linkage between HLA-DRB1 genotype, CXCR4 expression on memory CD4(+) T cells, and disease activity.

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease that leads to destructive arthritis. Although the HLA class II locus is the strongest genetic risk factor for rheumatoid arthritis, the relationship between HLA class II alleles and lymphocyte activation remains unclear. We performed immunophenotyping of peripheral blood mononuclear cells on 91 HLA-DRB1-genotyped RA patients and 110 healthy donors. The frequency of memory CXCR4(+)CD4(+) T cells, and not Th1 and Th17 cells, was significantly associated with disease severity by multiple linear regression analysis. RA patients with one or more susceptible HLA-DR haplotypes (shared epitope: SE) displayed a significantly higher frequency of memory CXCR4(+)CD4(+) T cells. Moreover, the frequency of memory CXCR4(+)CD4(+) T cells significantly correlated with the expression level of HLA-DR on B cells, which was elevated in RA patients with SE. In vitro analysis and transcriptomic pathway analysis suggested that the interaction between HLA-DR and T cell receptors is an important regulator of memory CXCR4(+)CD4(+) T cells. Clinically, a higher frequency of memory CXCR4(+)CD4(+) T cells predicted a better response to CTLA4-Ig. Memory CXCR4(+)CD4(+) T cells may serve as a powerful biomarker for unraveling the linkage between HLA-DRB1 genotype and disease activity in RA.

Membranous nephropathy with repeated flares in IgG4-related disease.

IgG4-related disease (IgG4-RD) is associated with the infiltration of IgG4-positive plasma cells into various organs. Nephropathy of IgG4-RD is generally interstitial nephritis and glomerulonephritis is rare. We describe a case of membranous nephropathy (MN) without interstitial nephritis associated with IgG4-RD symptoms including lymphadenopathy and pulmonary and pleural lesions. Treatment with steroids improved these clinical symptoms, but withdrawal of steroids induced the repeated relapse of MN. Finally, flaring of MN was prevented by the combination of steroids and cyclosporine. This is the first report of the successful treatment of MN associated with IgG4-RD by this combination therapy.

Downregulation of IL-12 and a novel negative feedback system mediated by CD25+CD4+ T cells.

CD25(+)CD4(+) regulatory T cells suppress immune responses and are believed to play roles in preventing autoimmune diseases. However, the mechanism(s) underlying the suppression and the regulation of their homeostasis remain to be elucidated. Here we show that these regulatory T cells downregulated CD25(-)CD4(+) T-cell-mediated production of IL-12 from antigen-presenting cells, which can act as a growth factor for CD25(-)CD4(+) T cells. We further found that CD25(+)CD4(+) T cells, despite their well-documented "anergic" nature, proliferate significantly in vitro only when CD25(-)CD4(+) T cells are present. Notably, this proliferation was strongly dependent on IL-2 and relatively independent of IL-12. Thus, CD25(+)CD4(+) T cells suppress CD25(-)CD4(+) T-cell responses, at least in part, by inhibiting IL-12 production while they themselves can undergo proliferation with the mediation of CD25(-)CD4(+) T cells in vitro. These results offer a novel negative feedback system involving a tripartite interaction among CD25(+)CD4(+) and CD25(-)CD4(+) T cells, and APCs that may contribute to the termination of immune responses.

Aire downregulates multiple molecules that have contradicting immune-enhancing and immune-suppressive functions.

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a systemic disease with autoimmune characteristics caused by mutations in a single gene called AIRE. Although a defect in negative selection has been emphasized for the pathogenesis of the autoimmune symptoms on the basis of studies of Aire-targeted mice, the function of the gene in the peripheral immune system and the cause of immunodeficiency noted in the disease have not been clarified yet. In this study, we demonstrated using murine Aire transfectants that Aire downregulates IL-1 receptor antagonist (IL-1Ra), which is important for immune suppression, and major histocompatibility complex (MHC) class II molecules, which are critical for acquired immunity. It was surprising to learn that Aire, which has been supposed to positively regulate transcription, downregulates multiple molecules. This downregulation of IL-1Ra and MHC class II molecules seems to be caused by the competition for transcriptional coactivator, CREB-binding protein (CBP), and may explain part of the contradictory (i.e., both autoimmune and immunodeficient) nature of APECED.