ABSTRACT
Background: Leptin is a cytokine-like peptide produced mostly by adipose tissue and regulating food intake, basal metabolism and the B- oxidation of fatty acids. It has recently been recognized as a modulator of inflammatory and immune responses, with a possible significant role in the pathogenesis of several autoimmune diseases
Objective: to evaluate the serum leptin levels in patients with systemic Lupus erythematosus [SLE] and rheumatoid arthritis [RA], and its relation to disease activity and systemic complications of each disease
Subjects and Methods: Leptin was measured in the serum of 20 patients with SLE and 20 patients with RA and in 10 healthy control subjects of similar body mass index [BMI]. Each group of SLE and RA patients were subdivided into two subgroups according to disease activity. Clinical characteristics and disease activity score for both SLE and RA patients were assessed. Serum leptin levels [ng/dl] were measured using enzymelinked immunosorbent assay [ELISA]
Results: Both patients with SLE and RA had significantly higher leptin levels than healthy control subjects [38.27 +/- 27.66, 27.73 + 14.58 and 2.73 +/- 0.85 ng/dl respectively; P < 0.0001]. Patients with active SLE showed significantly higher leptin levels in comparison to inactive group [51.57 +/- 35.47 versus 26.62 +/- 10.92 ng/dl; P < 0.0001]. While as, there were no significant difference in serum leptin levels between active and inactive groups of RA patients. Moreover, significant positive correlation was detected between serum leptin levels and degree of proteinuria in lupus nephritis patients. However, no relation could be detected between serum leptin and any of the clinical or laboratory parameters in patients with rheumatoid arthritis
Conclusion: Serum leptin levels significantly increases in both SLE and RA patients, and related to markers of disease activity in SLE but not in RA patients. Moreover, increased serum leptin levels were found to be related to degree of proteinuria in SLE patients. These results suggest that leptin could play a role in the pathogenesis of inflammatory phenomenon and disease activity in patients with systemic lupus erythematosus. While as, the precise role of leptin in rheumatoid arthritis patients remains uncertain, thus further studies including serum and synovial leptin in RA patients are recommended