Detection of various autoantibodies in patients with pulmonary sarcoidosis

Introduction: Sarcoidosis (SD) – is a granulomatous disease with unknown nature. The autoimmune nature of the disease is considered as one of the possible theories. An increase level of several autoantibodies was published in patients with SD: antinuclear antibodies, rheumatoid factor, antibodies to cyclic citrullinated peptides, antibodies to double-stranded DNA (Kobak, 2014; Weinberg, 2000). Material and methods: A prospective study with the inclusion of 56 patients with verified pulmonary SD was conducted in 2018. 20 different autoantibodies were studied using indirect immunofluorescence, immunoblotting, enzyme immunoassay. Statistical analysis was performed using GraphPad 5.0. The study was supported by the grant from the Russian Federation Government (contract № 14.W03.31.0009 of 13.02.2017). Results: The most significant results were obtained in the following antibodies: to Hep-2-cell antigens (ANA IIF) - 7% (5/75); to beta2-glycoprotein (b2GPI) - 8% (6/75); to thyroperoxidase (ATP) - 8% (6/75); to tyroglobulin (aTG) - 9% (7/75); rheumatoid factor (RF) -15% (11/75); component C3 complement systems (C3) – 40% (30/75); complement system component C4 (C4) - 25% (19/75); to mutated citrullinated vimentin (MCV) - 39% (22/57). Conclusion: The total frequency of the detection of different autoantibodies in SD varies widely. The frequency of antibodies to the MCV detected in 39%, that allows us to consider this laboratory indicator as one of the main targets of the immunological reaction in SD.