[Autoantibodies in systemic sclerosis and their clinical correlation in patients from a Midwestern region of Brazil]

Abstract

Introduction: Systemic sclerosis (SSc) is a connective tissue disease of autoimmune nature characterized by the triad of vascular injury, autoimmunity (cellular and humoral) and tissue fibrosis. Autoantibodies do not seem to be simply epiphenomena, but are involved in disease pathogenesis. It is believed that the SSc-specific autoantibodies are responsible both for amplifying immune response and targeting cell types that are relevant in the pathophysiology of SSc.

Objectives: To correlate the profile of the following specific autoantibodies: anti-centromere (ACA), anti-topoisomerase I (topo I) and anti-RNA polymerase III (RNAP III) with clinical and laboratory manifestations observed in 46 patients with SSc in the Midwest region of Brazil.

Methods: The occurrence of specific autoantibodies in 46 patients with SSc was investigated, correlating the type of autoantibody with clinical and laboratory manifestations found.

Results: Among all patients evaluated, we found a predominance of females (97.8%), mean age 50.21 years old, Caucasian (50%), limited cutaneous SSc (47.8%), time of diagnosis between 5-10 years (50%), and disease duration of 9.38 years. According to the specific autoantibody profile, 24 patients were ACA-positive (52.2%), 15 were positive for anti-topo I (32.6%), and 7 showed positive anti-RNAP III (15.2%). The anti-topo I autoantibody correlated with diffuse scleroderma, with greater disease severity and activity, with worse quality of life measured by the SHAQ index, with a higher prevalence of objective Raynaud's phenomenon and digital pitting scars of fingertips. The ACA correlated with limited scleroderma, with earlier onset of disease, as well as higher prevalence of telangiectasias. The anti- RNAP III correlated with diffuse scleroderma, with a higher occurrence of subjective Raynaud's phenomenon and muscle atrophy. There was no association between the positivity for anti-topo I, ACA and anti-RNAP III antibodies and other variables related to laboratory abnormalities, as well as Rodnan skin score and skin, vascular, musculoskeletal, gastrointestinal, cardiopulmonary and renal manifestations.

Conclusions: The clinical subtype of the disease and some clinical manifestations in SSc may correlate positively with the presence of specific autoantibodies.

Keywords: Anticentrômero; Antitopoisomerase I; Anti‐RNA polimerase III; Anti‐RNA polymerase III; Anti‐centromere; Anti‐topoisomerase I; Autoantibodies; Autoanticorpos; Esclerose sistêmica; Systemic sclerosis.