IFNG rs2430561 polymorphism and its association with disease onset, cutaneous severity, and activity in Vietnamese patients with lupus erythematosus.

Interferon (IFN)-γ plays a central role in lupus pathogenesis, and the IFNG rs2430561 (+874 T/A) polymorphism has been linked to systemic lupus erythematosus (SLE) in several populations. This study investigated the association of rs2430561 with disease onset, cutaneous severity, and global activity in Vietnamese patients with lupus erythematosus (LE). A case-control study was conducted on 34 LE patients and 34 age- and sex-matched healthy controls. Clinical characteristics, Cutaneous Lupus Disease Area and Severity Index (CLASI), and Systemic Lupus Erythematosus Disease Activity Index-2K (SLEDAI-2K) were collected. Genotyping was performed using allele-specific polymerase chain reaction (PCR). Genotype distribution differed significantly between patients and controls (p=0.048). Carriers of the A allele had a younger disease onset than TT patients (33.6±7.7 vs. 47.1±13.6 years) and showed a higher likelihood of onset ≤40 years (odds ratio [OR]=2.4; p=0.026). The rs2430561 genotype was associated with cutaneous severity: mean CLASI scores were AA 14.7, TA 11.8, and TT 5.8 (p=0.003). A-allele carriers had a 5.8-fold higher prevalence of severe CLASI (≥21; p=0.010). Systemic disease activity also differed: mean SLEDAI-2K scores were AA 12.0, TA 11.8, and TT 6.3 (p=0.010). The A allele was associated with a 4.7-fold higher prevalence of severe activity (>12; p=0.001). The IFNG rs2430561 A allele is associated with earlier onset and more severe cutaneous and systemic disease in Vietnamese LE patients, highlighting the potential contribution of IFN-γ pathway variation to disease expression.