Autoantibody Profiles and Clinical Correlations in Systemic Sclerosis: A Cross-Sectional Study.

BACKGROUND: Systemic sclerosis (SSc) is a rare autoimmune disease marked by immune dysregulation, vascular injury, and fibrosis. Antinuclear antibodies (ANA) are pivotal for diagnosis and prognosis, yet Indian data remain scarce. This study assessed ANA patterns and autoantibody profiles in SSc and their clinical relevance. METHODS: A cross-sectional study was conducted in the Department of Dermatology, AIIMS Patna, from September 2022 to September 2023. Eighty-five patients fulfilling ACR/EULAR criteria for SSc were enrolled. Clinical features were documented using a structured proforma, and patients were classified into diffuse cutaneous (dcSSc) and limited cutaneous (lcSSc) subsets. ANA screening was performed by indirect immunofluorescence (IIF) on HEp2 cells, followed by autoantibody profiling with line immunoassay (LIA). Statistical analyses were performed using JAMOVI v2.3.28, with p<0.05 considered significant. RESULTS: Of 85 patients, 70 (82.4%) were female (ratio of 5:1), with a mean age of 34.7 ± 10.7 years. dcSSc accounted for 55.3%. Common manifestations included arthralgia (69.4%), respiratory symptoms (68.2%), and interstitial lung disease (ILD) (64.1%). Homogeneous ANA was the predominant IIF pattern (41.2%), followed by centromere (10.6%) and speckled (8.2%). LIA revealed anti-Scl70 as the most frequent autoantibody (58.3%), significantly associated with ILD and Raynaud's phenomenon. Anti-U1 snRNP and anti-PMScl antibodies correlated with musculoskeletal involvement. CONCLUSION: SSc in this cohort showed female predominance with frequent arthralgia and respiratory symptoms. Anti-Scl-70 antibodies were most common, strongly linked to diffuse disease and ILD. ANA profiling provides disease characterization in Indian SSc.