Ghrelin and leptin are two hormones that possess multiple functions, including appetite regulation, maintenance of the tissue homeostasis and regulation of proinflammatory cytokines. A few studies on serum ghrelin and leptin levels in autoimmune diseases have exhibited conflicting results. Therefore, the present study aimed to investigate the relationship between the two energy balance hormones and autoimmune diseases. Serum ghrelin and leptin levels were assessed in 94 adult patients, 61 females and 33 males, with various autoimmune diseases (celiac disease, type 1 diabetes mellitus and rheumatoid arthritis) as well as in 35 healthy people as controls, using commercially available ELISA kits. Statistically important distinctions (P < 0.05) were found between the patients and controls with regard to serum ghrelin and leptin levels. Moreover, females had higher mean serum ghrelin and leptin levels than males. On the other hand, serum ghrelin level was positively correlated with serum leptin levels (r = 0.399, P < 0.05) in the RA group. Whereas no significant correlation (P > 0.05) was found between serum ghrelin and leptin levels in both CD and T1DM groups. As well as the correlation of the diseases biomarkers (tissue transglutaminase antibodies, anti-tTG; glutamic acid decarboxylase antibodies, anti-GAD; and cyclic citrullinated peptide antibodies, anti-CCP) with ghrelin/leptin levels revealed that anti-CCP was the only marker that significantly (P < 0.05) associated with ghrelin and leptin in patients with RA. The current study indicates a linkage between the immune system and metabolic hormones depending on response to different autoimmune conditions. Additional studies are required to understand whether changes in ghrelin-leptin levels influence the emergence of autoimmune diseases or vice versa.
