HIV-related metabolic abnormalities include hypertriglyceridemia, hypercholesterolemia, insulin resistance, and diabetes mellitus. Recent studies suggest a role of ghrelin in promoting the deposition of triglycerides (TG) in the liver and regulating the metabolic action of adiponectin. Visceral fat is a key regulator of inflammation and it secretes proinflammatory cytokines (eg, interleukin-18, IL-18), with potential atherogenic activity. The aim of this study was to assay serum concentrations of ghrelin, adiponectin, and IL-18 in HIV+ patients, with and without hypertriglyceridemia, who were receiving highly active antiretroviral therapy (HAART). The 49 HIV+ patients were divided in 2 groups: 17 patients with serum TG concentration >200 mg/dl (group A) and 32 patients with normal serum TG concentration (group B). All subjects underwent viral and immunological evaluations and determinations of serum cholesterol, glucose, ghrelin, adiponectin, and IL-18. No differences of viral and immunological parameters were observed between the 2 groups. Serum levels of ghrelin were 768 +/- 596 pg/dl in group A and 470 +/- 248 pg/dl in group B (p = 0.01). Group A had lower serum adiponectin levels (8.4 +/- 3.6 microg/dl) than group B (18.2 +/- 10.1 microg/dl; p = 0.0001). Serum IL-18 levels were 455 +/- 199 pg/ml in group A and 258 +/- 233 pg/ml in group B (p = 0.005). The patients with hypertriglyceridemia showed a positive correlation between serum triglyceride and ghrelin levels (r = 0.51, p = 0.03). These findings suggest potential roles of ghrelin, adiponectin, and IL-18 in the pathogenesis of metabolic disorders in HIV-infected patients.