Disease-specific autoantibody production in the lungs and salivary glands of anti-synthetase syndrome.

Interstitial lung disease is a common complication of anti-synthetase syndrome (ASS), and lymphocytic infiltration is often observed in the lesion. We have recently reported that disease-specific autoantibodies are produced by infiltrating lymphocytes in some autoimmune diseases. Here, we investigate the antigen specificity of B cells in the lung lesions of ASS patients. A total of 177 antibodies were produced from antibody-secreting cells in bronchoalveolar fluid (BALF) of three each of serum anti-Jo-1 and serum anti-EJ antibody-positive patients. Twelve to 30% and 50 to 62% of these antibodies were disease-specific autoantibodies, respectively. These autoantibodies recognized conformational epitopes of the whole self-antigen and had affinity maturations, indicating that self-antigens themselves are the target of humoral immunity. In addition, 100 antibodies were produced from two salivary gland tissues, obtained by chance, of ASS patients. Salivary glands are not generally recognized as lesions of ASS, but unexpectedly, ASS-related autoantibody production was also observed similar to that of BALF. Immunostaining confirmed the presence of ASS-related autoantibody-producing cells in salivary glands. Our results suggest that disease-specific autoantibody production at lesion sites is a common pathogenesis of autoimmune diseases, and that tissue-specific production of autoantibodies can provide insights regarding the distribution of organ manifestations in autoimmune diseases.

Effect of Recent Antirheumatic Drug on Features of Rheumatoid Arthritis-Associated Lymphoproliferative Disorders.

OBJECTIVE: In this study, we examine how advancements in novel antirheumatic drugs affect the clinicopathologic features of lymphoproliferative disorder (LPD) in patients with rheumatoid arthritis (RA). METHODS: In this multicenter study across 53 hospitals in Japan, we characterized patients with RA who developed LPDs and visited the hospitals between January 1999 and March 2021. The statistical tools used included Fisher's exact test, the Mann-Whitney U-test, the log-rank test, logistic regression analysis, and Cox proportional hazards models. RESULTS: Overall, 752 patients with RA-associated LPD (RA-LPD) and 770 with sporadic LPD were included in the study. We observed significant differences in the clinicopathologic features between patients with RA-LPD and those with sporadic LPD. Histopathological analysis revealed a high frequency of LPD-associated immunosuppressive conditions. Furthermore, patients with RA-LPD were evaluated based on the antirheumatic drugs administered. The methotrexate (MTX) plus tacrolimus and MTX plus tumor necrosis factor inhibitor (TNFi) groups had different affected site frequencies and histologic subtypes than the MTX-only group. Moreover, MTX and TNFi may synergistically affect susceptibility to Epstein-Barr virus infection. In case of antirheumatic drugs administered after LPD onset, tocilizumab (TCZ)-only therapy was associated with lower frequency of regrowth after spontaneous regression than other regimens. CONCLUSION: Antirheumatic drugs administered before LPD onset may influence the clinicopathologic features of RA-LPD, with patterns changing over time. Furthermore, TCZ-only regimens are recommended after LPD onset.

Successful treatment of PR3-ANCA-positive interstitial pneumonia with a moderate dose of glucocorticoid and rituximab.

Antineutrophil cytoplasmic antibody (ANCA)-positive interstitial pneumonia (IP) is reported as IP that is ANCA-positive and does not involve organ damage associated with vasculitis other than the lungs. While the combination of glucocorticoid and rituximab is effective in ANCA-associated vasculitis, the treatment strategy for ANCA-positive IP has not been established. Here, we report the first case of successful treatment of proteinase 3 (PR3)-ANCA-positive IP with a moderate dose of glucocorticoid and rituximab. The patient was an 80-year-old male who presented with subacute dry cough and dyspnoea. Blood tests revealed elevated levels of C-reactive protein, Krebs von den Lungen 6 (KL-6), and PR3-ANCA. Chest computed tomography (CT) showed interstitial shadows and infiltrates around honeycomb cysts. 18F-fluorodeoxyglucose (FDG) positron emission tomography CT revealed an uptake of FDG in the IP area. After starting treatment with a moderate dose of prednisolone and rituximab, the patient's clinical symptoms disappeared, C-reactive protein and KL-6 turned to be normal, and infiltrates around the cysts of honeycomb lungs disappeared. Prednisolone was gradually decreased to 2 mg, and no relapse or adverse events were observed during the course of treatment. Our case suggests that early treatment with a moderate dose of glucocorticoid and rituximab is effective for PR3-ANCA-positive IP.

Atypical Cogan's Syndrome with Large-vessel Vasculitis Successfully Treated with Tocilizumab.

A 61-year-old man presented with weight loss, bilateral ocular redness, blurred vision, and sensorineural hearing loss. Fluorodeoxyglucose-position emission tomography/computed tomography demonstrated an uptake in the ascending and descending aorta, abdominal aorta and femoral arteries. Atypical Cogan's syndrome complicated with large-vessel vasculitis (LVV) was diagnosed. He was treated with high-dose prednisolone and subcutaneous tocilizumab (162 mg/week), resulting in successful improvements in his ocular and vascular involvements. Although there is currently no established treatment strategy for LVV associated with Cogan's syndrome, our case and literature review suggest that tocilizumab is a viable treatment option for this rare but life-threatening complication.

Allergic disorders and their risk factors in primary Sjögren's syndrome.

Objective: This study aimed to evaluate the prevalence of allergic disorders in patients with primary Sjögren's syndrome (pSS), compare it with that of patients with rheumatoid arthritis (RA), and examine the risk factors in patients with pSS. Methods: We retrospectively examined the records of patients diagnosed with pSS and RA who regularly visited our department between 2010 and 2020. Allergic disorders included drug allergy, food allergy, allergic contact dermatitis (ACD), allergic rhinitis (AR)/allergic conjunctivitis (AC), and asthma. Results: Patients with pSS (292 patients) had a higher prevalence of food allergy, drug allergy, and AR/AC than those with RA (413 patients). The multivariate analysis revealed that patients with pSS who had drug allergy had a higher prevalence of food allergy, higher eosinophil levels, and higher positivity rates of anti-SS-related antigen A (SSA) antibodies than those without drug allergy; those with food allergy had a higher rate of ACD than those without food allergy and vice versa; those with AR/AC had a higher rate of ACD and asthma and higher eosinophil levels than those without AR/AC; those with asthma had a higher rate of AR/AC than those without asthma. Conclusions: Patients with pSS had a higher prevalence of allergic disorders than those with RA. Among patients with pSS, the risk factors for drug allergy were food allergy, higher eosinophil levels, and positivity for anti-SSA antibodies, the risk factor for food allergy was ACD and vice versa, the risk factors for AR/AC were ACD, asthma, and high eosinophil levels, and the risk factor for asthma was AR/AC.

Successful treatment with tofacitinib for relapse of rapidly progressive interstitial lung disease in anti-melanoma differentiation-associated gene 5 antibody-positive clinically amyopathic dermatomyositis.

Anti-melanoma differentiation-associated gene 5 (MDA5) antibody is associated with clinically amyopathic dermatomyositis (CADM) with rapidly progressive interstitial lung disease (RP-ILD). Recently, several studies have reported that tofacitinib (TOF), a Janus kinase inhibitor, might be effective for cases of new or refractory RP-ILD in anti-MDA5 antibody-positive CADM; however, it is unknown whether TOF can also be effective for relapsed cases. We herein report a relapsed case of RP-ILD in anti-MDA5 antibody-positive CADM, which was successfully treated by combination therapy with TOF (5 mg twice daily). Our case suggests that TOF may also be a potential treatment option for relapsed cases of this disease.

Aseptic meningitis as an initial manifestation of primary Sjögren's syndrome.

Aseptic meningitis is a rare life-threatening complication of primary Sjögren's syndrome (pSS), and its characteristics and prognosis remain unknown. We present our case of aseptic meningitis associated with pSS and reviewed the published literature to elucidate their characteristics and prognosis. An 84-year-old man was admitted to our hospital for fever and disturbance of consciousness. Acute aseptic meningitis was diagnosed based on the results for cerebrospinal fluid and head imaging tests. As an aetiological investigation for his aseptic meningitis, serum anti-Sjögren's-syndrome-related antigen A and anti-Sjögren's-syndrome-related antigen B antibodies were found to be positive, and the biopsy specimen of his labial salivary gland revealed lymphocytic sialadenitis, confirming a diagnosis of pSS. Treatment with moderate-dose glucocorticoid completely improved his aseptic meningitis. Relapse of the disease was not observed during his clinical course over 12 months. Our present case and literature review suggest that aseptic meningitis can be an initial manifestation of pSS and be treatable by immunosuppressive therapy. Thus, early recognition and treatment initiation are critical to prevent the irreversible damage of central nervous system in pSS-associated aseptic meningitis. In aseptic meningitis of unknown origin, pSS should be included in differential diagnoses, and testing for serum anti-Sjögren's-syndrome-related antigen A and anti-Sjögren's-syndrome-related antigen A antibodies may be useful as an initial screening.

Giant cell arteritis successfully treated with subcutaneous tocilizumab monotherapy.

Glucocorticoid remains the mainstay for treatment of large vessel vasculitis (LVV) including giant cell arteritis (GCA); however, the disease affects the elderly for whom the adverse effects of glucocorticoid are problematic. Recently, some reports have suggested that intravenous tocilizumab (TCZ) monotherapy is effective for this disease. To date, it remains unknown whether subcutaneous TCZ monotherapy is also effective. Here, we present a first case of GCA successfully treated with subcutaneous TCZ monotherapy. A 75-year-old woman presented with shoulder and hip pain. She was diagnosed with polymyalgia rheumatica (PMR) and treated with low-dose prednisolone (15 mg daily); however, she discontinued glucocorticoid therapy at her discretion due to the psychiatric adverse effect (cognitive dysfunction). Seven months later, her shoulder and hip pain relapsed. Furthermore, 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) revealed uptake in the descending thoracic aorta, indicating a complication of LVV. She refused to take glucocorticoid for fear of psychiatric adverse effects and chose subcutaneous TCZ monotherapy (162 mg weekly) for treating this life-threatening urgent condition. Nine months later, her shoulder and hip pain resolved and FDG-PET/CT demonstrated no uptake in the descending thoracic aorta, indicating a successful treatment with subcutaneous TCZ monotherapy for the disease. No adverse events and disease relapse were found during observation period. Our case and the literature review suggest that not only intravenous injection but also subcutaneous injection of TCZ monotherapy can serve as an alternative treatment for patients with GCA who have comorbidities or refuse to take glucocorticoid.

Risk factors associated with cytomegalovirus reactivation in patients receiving immunosuppressive therapy for rheumatic diseases: a retrospective study.

Immunosuppressive treatment is a common cause of cytomegalovirus (CMV) reactivation. However, there is no consensus regarding the risk factors for CMV reactivation in rheumatic diseases. Therefore, this study aimed to elucidate the risk factors associated with CMV reactivation. We retrospectively collected the data of 472 patients with rheumatic diseases whose CMV pp65 antigen (C7-HRP) titer was measured. We divided the patients into those with and those without C7-HRP. We retrospectively collected data on age, sex, primary condition and organ involvement, and blood test results. We also investigated the use of immunosuppressants and the maximum and cumulative doses of prednisolone (PSL). We performed univariate and multivariate analyses to identify risk factors for CMV reactivation. Multivariate analysis showed that higher age (71.2 vs. 64.4 years, p = 0.0022), hypoalbuminemia (2.9 vs. 3.4 g/dL, p = 0.0104), higher creatinine level (1.2 vs. 0.9 mg/dL, p = 0.0026), cyclosporine use (8.2 vs. 3.6%, p = 0.0101), and higher maximum (552.4 vs. 243.3 mg, p < 0.0001) and cumulative (2785.9 vs. 1330.5 mg, p < 0.0001) doses of PSL were associated with CMV reactivation. Older age, hypoalbuminemia, higher creatinine level, cyclosporine use, and higher maximum and cumulative doses of PSL were significant risk factors for CMV reactivation in rheumatic diseases.

Dermatomyositis Which Was Double Positive for Anti-MDA5 and Anti-ARS Antibodies That Was Successfully Treated by Intensive Immunosuppressive Therapy.

Myositis-specific autoantibody is associated with the clinical phenotype and prognosis of dermatomyositis. Anti-melanoma differentiation-associated gene 5 (MDA5) and anti-aminoacyl-tRNA synthetase (ARS) antibodies are generally mutually exclusive. We herein present an extremely rare case of dermatomyositis which showed double positivity for anti-MDA5 and anti-ARS antibodies. There have been very few reported cases of double positive anti-MDA5, anti-ARS antibodies. In such cases, the clinical characteristics of each autoantibody can coexist. Thus, we should pay attention to the rapidly progressing features of anti-MDA5 as well as the chronic relapsing features of anti-ARS for the better management of this rare condition.

Immune-mediated necrotizing myopathy which showed deposition of C5b-9 in the necrotic muscle fibers and was successfully treated with intensive combined therapy with high-dose glucocorticoids, tacrolimus, and intravenous immunoglobulins.

Currently, no standard treatment strategy has been established for immune-mediated necrotizing myopathy (IMNM). Here we present a case of IMNM which was successfully treated with intensive combined therapy with high-dose glucocorticoids, tacrolimus, and intravenous immunoglobulins. Her muscle weakness was rapidly progressive and severe so that she became bedridden one week after admission. She was complicated with dysphagia and had serum myogenic enzymes elevation, ventricular diastolic dysfunction, and interstitial lung disease. Serum anti-SRP antibody was positive and her muscle biopsy revealed many necrotic fibers with minimal inflammation. Further histological analysis demonstrated infiltration of phagocytic macrophages with deposition of membrane attack complex (C5b-9) in the necrotic muscle fibers, suggesting activation of complement pathway and macrophages as a pathomechanism of this disease. She was diagnosed as IMNM and was immediately initiated a combination therapy described above, which led to dramatic clinical improvements. Recent studies suggest that intravenous immunoglobulins and tacrolimus can inhibit the activation of complement pathway and macrophages. Our present case suggests that early initiation of intensive combined therapy including intravenous immunoglobulins and tacrolimus might be effective for preventing irreversible muscle damages by disrupting a pathogenic activation of complement and macrophages in IMNM.

Acute encephalitis in primary Sjögren's syndrome: A case report and literature review.

Acute encephalitis is an extremely rare condition in primary Sjogren's syndrome (pSS), and its characteristics and prognosis remain unclear. Here, we report the case of pSS presented with acute encephalitis. She was admitted to our hospital for acute disturbance of consciousness. Acute encephalitis was diagnosed based on the results of the cerebrospinal fluid test (the increase of leucocyte counts, proteins, and interleukin-6 levels), magnetic resonance imaging, and single-photon emission computed tomography with 99mTc. The infectious aetiologies and underlying malignancies were excluded. Serum anti-Sjogren's syndrome-related antigen A autoantibody was positive with extremely high titre. The biopsy specimen of her labial salivary gland revealed a focal lymphocytic sialadenitis with a score of grade 4 in the Greenspan grade. She also developed diffuse alveolar haemorrhage during the clinical course. She was diagnosed with pSS complicated with acute encephalitis followed by diffuse alveolar haemorrhage and successfully treated with pulse steroids, high dose of prednisolone and intravenous cyclophosphamide. Our present case and literature review suggest that acute encephalitis associated with pSS can be treatable with the immunosuppressive therapy, and thus early recognition and treatment initiation are important for this life-threatening condition. Thus, pSS should be included in the differential diagnosis of unexplained encephalitis. Notably, our case characteristically showed diffuse alveolar haemorrhage, adding new insights into the pathogenesis of acute encephalitis associated with pSS that capillaritis might be the underlying cause of this condition.

Dropped head in systemic sclerosis: a case based review.

Dropped head syndrome is a rare disease entity characterized by severe weakness of the cervical para-spinal muscles, resulting in a chin-on-chest deformity. Systemic sclerosis is one of the causes of dropped head syndrome, but its characteristics and prognosis remain unclear due to the extreme rarity of this condition. We present a case of dropped head which occurred in systemic sclerosis. He presented with severe dropped head and relatively mild weakness of the proximal limb muscles. Serum level of creatine kinase was elevated, myopathic change was observed in electromyography, and gadolinium enhancement was found in magnetic resonance imaging of his posterior neck muscles. Anti-topoisomerase I antibody was positive, while other autoantibodies such as anti-PM/Scl and anti-Ku antibodies were negative. Since his dropped head acutely progressed, high dose of glucocorticoid therapy was initiated, which successfully improved dropped head, serum level of creatine kinase, and gadolinium enhancement in magnetic resonance imaging. Our present case and literature review suggest that dropped head occurring in systemic sclerosis can be treatable with immunosuppressive therapy. It is important to recognize this rare but treatable involvement of systemic sclerosis because early diagnosis and treatment initiation are crucial to prevent the irreversible organ damage and the significant decrease of daily activities.

Efficacy of once-weekly teriparatide for primary prevention of glucocorticoid-induced osteoporosis: A post hoc analysis of the TOWER-GO study.

OBJECTIVES: A post hoc analysis of the Teriparatide Once-Weekly Efficacy Research for Glucocorticoid-induced Osteoporosis (TOWER-GO) study was performed to examine the effect of once-weekly administration of 56.5 µg teriparatide on primary prevention of glucocorticoid-induced osteoporosis (GIOP). METHODS: Of the subjects of the TOWER-GO study, 73 were included. The percentage changes from baseline in lumbar spine bone mineral density (BMD) and bone turnover markers were evaluated over 72 weeks with once-weekly teriparatide and once-weekly alendronate. RESULTS: The percentage change of lumbar spine BMD from baseline at 72 weeks was significantly increased in both groups. Bone formation markers were significantly increased by teriparatide administration, although they were slightly decreased by alendronate administration. Bone resorption markers were gradually decreased by teriparatide, whereas alendronate markedly decreased them within 4 weeks. No major safety concerns arose. CONCLUSIONS: In this primary prevention study of GIOP, comparable increases in BMD were observed between alendronate and once-weekly teriparatide. More desirable changes in bone markers were observed with teriparatide administration. These data suggest that once-weekly teriparatide is effective in primary prevention of GIOP.

[ALLERGIC DISEASES IN ADULT-ONSET STILL'S DISEASE AND RHEUMATOID ARTHRITIS].

BACKGROUND: A high prevalence of allergic diseases was found in patients with adult-onset Still's disease (AOSD). However, the relative prevalence is unknown compared with other diseases. OBJECTIVES: We sought to compare the prevalence of allergic diseases in the control group of patients with rheumatoid arthritis (RA). METHODS: We retrospectively examined consecutive patients diagnosed with AOSD or RA in our hospital from 2010 to 2020. The patients with AOSD met the preliminary criteria for classification of AOSD. The patients with RA met the EULAR/ACR 2010 criteria. We included patients with RA without other rheumatic diseases. The analysis was performed on six types of allergic reactions: food allergy, drug allergy, allergic contact dermatitis, allergic rhinitis and/or allergic conjunctivitis, and asthma. RESULTS: Twenty-four patients with AOSD and 409 patients with RA were enrolled. The median ages (AOSD, RA) were 46.6, 68.2 years old. Females were 83.3%, 78.0%. Fifty% of AOSD patients and 34.5% of RA patients presented at least one type of allergic diseases (p = 0.12). These included food allergy (4.2%, 6.4%: p = 1.0), drug allergy (37.5%, 16.6%: p = 0.02), allergic rhinitis/allergic conjunctivitis (25.0%, 8.6%: p = 0.02), contact dermatitis (4.2%, 4.4%: p = 1.0), and asthma (4.2%, 5.9%: p = 1.0). CONCLUSION: Patients with AOSD had a higher prevalence of drug allergy, and allergic rhinitis/allergic conjunctivitis than patients with RA.

Steroid-Sparing Effect of Tocilizumab and Methotrexate in Patients with Polymyalgia Rheumatica: A Retrospective Cohort Study.

Polymyalgia rheumatica (PMR) is an inflammatory disorder characterized by pain and stiffness in the shoulders, hips, and proximal limbs; it usually affects elderly patients. The effectiveness of methotrexate and tocilizumab in PMR treatment has not been extensively studied. Thus, we aimed to assess the steroid-sparing effect of tocilizumab and methotrexate in PMR in clinical practice. Consecutive patients with PMR in our hospitals, who were included in our retrospective cohort, were reviewed between 2005 and 2015 and divided into the following groups according to their treatments: prednisolone or none (prednisolone group), methotrexate ± prednisolone (methotrexate group), or tocilizumab ± prednisolone (tocilizumab group). The prednisolone dose at the last follow-up was compared. A total of 227 patients with an average age of 74 years were enrolled. No difference in baseline characteristics was found among the three groups. The prednisolone dose at the last follow-up was lower (0 vs. 3.0 vs. 3.5 mg/day, p < 0.001) and the prednisolone discontinuation rate was higher (80.0% vs. 28.3% vs. 18.8%, p < 0.0001) in the tocilizumab group than in the prednisolone and methotrexate groups. This study suggested that tocilizumab has a steroid-sparing effect in PMR. Tocilizumab can be an option in the management of PMR. Future studies are warranted to confirm our findings.

Antigen-driven autoantibody production in lungs of interstitial lung disease with autoimmune disease.

Interstitial lung disease (ILD) sometimes becomes a life-threatening complication of systemic autoimmune diseases; however, little is known about the immune response in lung lesions. We aimed to investigate humoural immunity in ILD associated with rheumatoid arthritis (RA), sjögren's syndrome (SjS), and mixed connective tissue disease (MCTD), using bronchoalveolar fluid (BALF) and serum samples from 15 patients with autoimmune disease associated-ILD. We first showed that BALF contained higher titers of disease-related autoantibodies than serum, suggesting the possibility of autoantibody production in lungs. Next, we produced 326 monoclonal antibodies from antibody-secreting cells in BALF, and the reactivity and their revertants, in which somatic hypermutations were reverted to germline, were analyzed. Among 123 antibodies from RA-ILD, 16 disease-related antibodies (anti-modified protein antibodies and rheumatoid factors) were identified, of which one antibody had both properties. The revertant antibodies changed their target modification in a complicated manner, suggesting that the antibodies were selected against various modifications in lungs. Among 146 antibodies from SjS-ILD and/or MCTD-ILD, seven anti-SSA/Ro60 antibodies and 15 anti-RNP antibodies were identified. Some of the anti-RNP antibodies recognized multiple RNP constituent proteins simultaneously, indicating that epitope spreading may progress in lungs. Our results revealed the existence of an active autoimmunity in the lungs of autoimmune disease associated-ILD.

Efficacy of once-weekly teriparatide in patients with glucocorticoid-induced osteoporosis: the TOWER-GO study.

INTRODUCTION: Bisphosphonates are the standard treatment for glucocorticoid-induced osteoporosis (GIOP) with teriparatide being another option. While daily teriparatide has been shown to be effective in increasing bone mineral density (BMD), the efficacy of once-weekly teriparatide (56.5 µg) has not yet been evaluated. The TOWER-GO study, a 72-week, multicenter, open-label, randomized controlled trial, was conducted in patients with GIOP to compare the effects of once-weekly teriparatide and once-weekly alendronate 35 mg on BMD. MATERIALS AND METHODS: Patients (N = 180) with GIOP for whom drug treatment was indicated according to the 2004 guidelines in Japan were randomized to receive once-weekly teriparatide (n = 89) or once-weekly alendronate (n = 91). The primary endpoint was the non-inferiority of percentage change in lumbar spine BMD at final follow-up. The secondary endpoints were the percentage change in BMD from baseline, incidence of bone fractures, and changes in bone turnover markers. RESULTS: While the non-inferiority of teriparatide to alendronate was not confirmed, BMD increased significantly from baseline with teriparatide and alendronate by 5.09% and 4.04%, respectively (both p < 0.05), at 72 weeks. The incidence of vertebral and non-vertebral fractures was similar in both groups. Bone formation markers increased in the teriparatide group and decreased in the alendronate group. CONCLUSIONS: The non-inferiority of once-weekly teriparatide versus once-weekly alendronate in BMD change at 72 weeks was not shown, but the increase in bone formation markers over time and the increase of BMD in GIOP patients treated with once-weekly teriparatide were confirmed.

Distinct Expression of Coinhibitory Molecules on Alveolar T Cells in Patients With Rheumatoid Arthritis-Associated and Idiopathic Inflammatory Myopathy-Associated Interstitial Lung Disease.

OBJECTIVE: To identify immunologic factors in the lungs of patients with rheumatoid arthritis-associated interstitial lung disease (RA-ILD) and patients with idiopathic inflammatory myopathy-associated ILD (IIM-ILD) and to examine their pathologic mechanisms. METHODS: Eleven patients with RA-ILD, 16 with IIM-ILD, 6 with drug-induced ILD (DI-ILD), and 8 healthy controls were enrolled. Peripheral blood (PB) and bronchoalveolar lavage (BAL) fluid were immunophenotyped by flow cytometry. Alveolar macrophages (AMs) were analyzed by coculture assay with PB naive CD4+ T cells from healthy individuals and RNA sequencing. RESULTS: Several coinhibitory molecules were coexpressed on BAL fluid T cells (CTLA-4, programmed death 1 [PD-1], T cell immunoglobulin and mucin domain-containing protein 3 [TIM-3], and lymphocyte activation gene 3 protein, from most to least), whereas only PD-1 was expressed on PB T cells. CTLA-4+PD-1+CD4+ T cells were characteristic of RA-ILD, whereas CTLA-4+PD-1+TIM-3+CD8+ T cells were characteristic of IIM-ILD. BAL fluid PD-1+CD4+ T cells rarely expressed CXCR5, but their levels correlated with levels of plasmablasts and plasma cells (ρ = 0.57, P = 0.006), indicating that most of them would be considered peripheral helper T cells. In coculture experiments, AMs from patients with RA-ILD and IIM-ILD induced more PD-1 and TIM-3 on T cells (P < 0.05), suggesting that coinhibitory molecule expression on BAL fluid T cells was partly due to AMs. RNA sequencing showed significant down-regulation of PD ligand 1/2 genes in AMs from patients with RA-ILD compared to those with DI-ILD. CONCLUSION: We have identified differences in coinhibitory molecule expression between patients with RA-ILD and those with IIM-ILD. PD-1 on T cells in RA-ILD and TIM-3 on CD8+ T cells in IIM-ILD might be key factors in the disease process. Evaluation of coinhibitory molecules on BAL fluid T cells could be clinically useful.