Antinuclear Antibody Immunofluorescence Patterns and Their Clinical Correlations in Patients with Systemic Lupus Erythematosus: A Study from a Tertiary Center in Nepal

Abstract

Introduction: Antinuclear antibodies (ANAs) detected by indirect immunofluorescence (IIF) on HEp-2 cells are a diagnostic hallmark of systemic lupus erythematosus (SLE). Specific patterns are linked to clinical manifestations. Data on ANA patterns and their clinical correlations in South Asian populations, particularly Nepal, remain limited. Methods: This hospital-based cross-sectional study included 167 SLE patients (≥16 years) diagnosed by 2019 EULAR/ACR criteria. ANA testing was performed using IIF on HEp-2 cells, with patterns classified according to ICAP. Clinical data and immunological markers (anti-dsDNA, ENAs) were collected. Statistical analysis used Chi-square tests, with p < 0.05 considered significant. Results: Among 167 patients (82% female, median age 39 years), the most prevalent patterns were nuclear homogeneous (NH; 45.5%), nuclear fine speckled (NFS; 25.7%), and nuclear coarse speckled (NCS; 16.8%). NH significantly associated with arthritis (p = 0.02), non-scarring alopecia (p = 0.03), lupus nephritis (p = 0.02), thrombocytopenia (p = 0.02), direct Coombs test (p = 0.04), anti-dsDNA (p < 0.001), anticardiolipin IgG (p = 0.03), lupus anticoagulant (p = 0.01), anti-histone (p = 0.01), and anti-nucleosome antibodies (p < 0.001). NFS associated with malar rash (p = 0.01). Anti-Sm/RNP and anti-RNP 68 strongly associated with NCS (p < 0.001 for both). Conclusions: This study reveals specific ANA patterns and their significant clinical and immunological associations in Nepalese SLE patients. The NH pattern correlates strongly with severe manifestations such as lupus nephritis and with multiple autoantibodies, highlighting the importance of ANA pattern analysis for diagnosis and risk stratification.