Elevated serum leptin levels in patients with systemic lupus erythematosus

Previous studies have indicated that leptin and the soluble leptin receptor (SLR) might influence inflammatory and immune processes in autoimmune diseases, but this remains unclear in systemic lupus erythematosus (SLE). The aim of our study was to assess if leptin and SLR are involved in the etiopathology of SLE and the possible mechanism of immune regulation. We studied 87 patients with SLE and 85 matched subjects. We assessed the levels of serum leptin and SLR, tested the long isoform leptin receptor (Ob-Rb) mRNA levels in SLE patients and a control group. Furthermore, we measured Th1 and Th2 percentage in SLE patients' lymphocytes and examined lymphocytes activation and proliferation assays with leptin stimulation in vitro. The study found a higher level of serum leptin in SLE patients, however, no difference was found in serum SLR levels or Ob-Rb mRNA levels between SLE patients and the control group. The percentage of Th1 cells decreased and Th2 cells increased after treatment with glucocorticoids in SLE patients. Leptin stimulated the proliferation of T cells in vitro, and differentiation to Th1 cells increased. The present study demonstrated that leptin may play an important role in the pathogenesis of SLE, inducing dysfunction of autoimmune processes.