Serum Adipokine Leptin Levels in Systemic Lupus Erythematosus Patients and its Correlation with Clinical Manifestations and Disease Activity - A Cross-sectional Study from a Tertiary Care Center

Background: Leptin is an adipokine that has an important role in body weight regulation and endocrine function. Leptin also acts as a pro-inflammatory cytokine by inducing the production of Th1 cytokines. The aim of our study was to estimate the serum leptin levels in systemic lupus erythematosus (SLE) patients and analyze its associations with clinical manifestations of lupus and disease activity. Materials and Methods: This study was conducted on 80 patients who satisfied Systemic Lupus International Collaborating Clinics 2012 criteria for SLE and 40 healthy controls. Demographic, clinical, and laboratory parameters were recorded. SLE disease activity index (SLEDAI) was scored for all SLE patients. Serum leptin levels (ng/dl) were estimated by enzyme-linked immunosorbent assay and the results were analyzed by SPSS. Results: Baseline characteristics were comparable in both cases and controls. SLE patients had higher serum leptin levels as compared to controls (mean 16.01 vs. 5.86 ng/ml) which were statistically significant (P < 0.00001). Cutaneous lupus (85%) was the most common manifestation observed in patients with elevated leptin levels. Patients with lupus nephritis had high serum leptin levels (P = 0.04) in comparison to patients with nonrenal lupus. Serum leptin levels correlated positively with higher body mass index (BMI), higher uric acid levels, and lower high-density lipoproteins (HDL) cholesterol levels (P < 0.0001). Serum leptin levels showed no correlation with disease activity markers such as erythrocyte sedimentation rate, C-reactive protein, anti-double-stranded deoxyribonucleic acid titers, complements C3 and C4, and SLEDAI. Conclusion: Patients with SLE had high serum leptin levels. High leptin levels were seen predominantly in mucocutaneous lupus and lupus nephritis. Serum leptin levels correlated positively with BMI and serum uric acid and negatively with serum HDL cholesterol levels but showed no correlation with disease activity markers.