Autoimmune disease, caused by unwanted immune responses to self-antigens, affects millions of people each year and poses a great social and economic burden to individuals and communities. In the course of autoimmune disorders, including rheumatoid arthritis, systemic lupus erythematosus, type 1 diabetes mellitus, and multiple sclerosis, disturbances in the balance between the immune response against harmful agents and tolerance towards self-antigens lead to an immune response against self-tissues. In recent years, various regulatory immune cells have been identified. Disruptions in the quality, quantity, and function of these cells have been implicated in autoimmune disease development. Therefore, targeting or engineering these cells is a promising therapeutic for different autoimmune diseases. Regulatory T cells, regulatory B cells, regulatory dendritic cells, myeloid suppressor cells, and some subsets of innate lymphoid cells are arising as important players among this class of cells. Here, we review the roles of each suppressive cell type in the immune system during homeostasis and in the development of autoimmunity. Moreover, we discuss the current and future therapeutic potential of each one of these cell types for autoimmune diseases.

Background Coronavirus disease-2019 (COVID-19) is a novel infectious disease, which presents with various clinical manifestations. There is growing evidence of an association between COVID-19 infection and autoimmune diseases. The aim of this case report was to demonstrate the association of COVID-19 infection and the development of systemic lupus erythematosus (SLE). Case presentation A 38 year old Iranian woman presented with progressive icterus, pleuritic chest pain, palpitation, dyspnea, photosensitivity and arthralgia 18-days after COVID-19 symptoms proved by a positive polymerized chain reaction (PCR). The chest and abdomen computerized tomography (CT) scan showed pericardial and pleural effusion and enlarged liver and abdominal lymph nodes. Antinuclear antibody (ANA), anti-double stranded deoxyribonucleic acid (anti-ds DNA) antibody and perinuclear anti-neutrophil cytoplasmic antibody (P-ANCA) were positive. She was diagnosed as SLE and was successfully treated with prednisolone 30 mg daily, hydroxychloroquine 200 mg daily and azathioprine 150 mg daily and she remarkably improved. Repeated anti-ds DNA antibody was positive. Due to nausea and abdominal discomfort, azathioprine was discontinued and replaced with mycophenolate mofetil 1500 mg daily. In the article, similar cases were presented; the mean interval between COVID symptoms and SLE presentations was 24.86 days. Pulmonary and renal involvements were the most common presentations of SLE triggered by COVID-19. The most frequently reported autoantibody was ANA. Conclusion : It is necessary to be aware of the development of lupus disease in COVID-19 infected patients, because prompt diagnosis and treatment is very important to improve their outcome.

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Autoantibodies (AABs) play a critical role in the pathogenesis of autoimmune diseases (AIDs) and serve as a diagnostic and prognostic tool in assessing these complex disorders. Viral infections have long been recognized as a principal environmental factor affecting the production of AABs and the development of autoimmunity. COVID‐19 has primarily been considered a hyperinflammatory syndrome triggered by a cytokine storm. In the following, the role of maladaptive B cell response and AABs became more apparent in COVID‐19 pathogenesis. The current review will primarily focus on the role of extrafollicular B cell response, Toll‐like receptor‐7 (TLR‐7) activation, and neutrophil extracellular traps (NETs) formation in the development of AABs following SARS‐CoV‐2 infection. In the following, this review will clarify how these AABs dysregulate immune response to SARS‐CoV‐2 by disrupting cytokine function and triggering neutrophil hyper‐reactivity. Finally, the pathologic effects of these AABs will be further described in COVID‐19 associate clinical manifestations, including venous and arterial thrombosis, a multisystem inflammatory syndrome in children (MIS‐C), acute respiratory distress syndrome (ARDS), and recently described post‐acute sequelae of COVID‐19 (PASC) or long‐COVID.

Background Microscopic polyangiitis (MPA) is an antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) that affects predominantly small- sized vessels. A causal relationship between viral infections and vasculitis has been postulated. Aim of the work : To present the concomitant association of coronavirus disease 2019 (COVID-19) infection with MPA in an elderly Iranian male. Case presentation A 67 year old Iranian man with the history of COVID-19 infection and a positive polymerized chain reaction (PCR) test four weeks before admission to the neurology department with acute onset pain, numbness and progressive weakness in both hands grip, sudden left foot drop and paresthesia. Erythrocyte sedimentation rate (ESR) was 95 mm/hr, ferritin 912 ng/ml and C-reactive protein (CRP) positive, proteinuria 1.1 g/24h and markedly elevated perinuclear (P-ANCA): 526 IU/ml. Diagnosis of MPA was held presenting with mononeuritis multiplex, glomerulonephritis followed by diffuse alveolar hemorrhage and infiltration of lymphocytes in muscle fibers and vessels wall in sural nerve biopsy. He was successfully treated by methylprednisolone (1g/day for 3 days) followed by 1 mg/kg with gradual tapering along with cyclophosphamide (CYC) (2 mg/kg). Intravenous immunoglobulin (IVIG, 2 g/kg in four divided doses) started for the management of inflammatory mononeuritis multiplex with gradual improvement. During hospitalization, plasmapheresis was performed due to alveolar hemorrhage for 5 day. The patient returned home on day 32 and followed-up in the rheumatology clinic with improvement of muscle power and handgrip strength. Conclusion Vasculitis is potentially one of COVID-19’s presenting symptoms and prompt diagnosis and treatment is crucial in improving outcome of patients.

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