Association of Interleukin-4 Gene Polymorphism in Patients with Systemic Lupus Erythematosus Attending Tertiary Care Hospital of Southern Assam

Background: Interleukin-4 (IL-4) is an important Th2 cytokine that modulates B-cell isotype switching andantibody production; promoter polymorphisms (notably −590 C>T / rs2243250) have been reported to alter IL-4expression and to associate with autoimmune disorders including SLE in some populations.Objective: To evaluate the association between IL-4 promoter polymorphism (−590C>T, rs2243250) andsusceptibility to SLE among patients attending a tertiary care hospital in southern Assam, and to exploregenotype–phenotype correlations with clinical features and disease activity.Methods: Case–control study enrolling adult SLE patients and age-, sex-matched healthy controls. GenomicDNA was extracted from peripheral blood and IL-4−590C>T genotyping was done by PCR-RFLP.Allele/genotype frequencies will be compared between cases and controls; logistic regression will estimate oddsratios adjusted for age and sex. Power and sample size were calculated to detect an OR of 2.0 for the T allele.Statistical significance p<0.05.Expected results & conclusion: We will determine whether the IL-4 −590Talleleorspecificgenotypes areoverrepresented in SLE patients from this region, and whether genotype correlates with clinical phenotypes(renal involvement, serology, disease activity). Findings will addregion-specific genetic data and may informpathophysiology and future biomarker studies.