Immune phenotype and serum leptin in children with obesity-related liver disease.

Context: Little is known about pathogenesis of obesity-related liver disease in childhood. Data on the relationship among leptin, immunological parameters, and liver disease in obese children are lacking. Objective: Thus, the objective of this study was to evaluate immune phenotype and leptin serum levels in obese children with and without obesity-related liver disease. Design: The study was performed in two groups of consecutive obese children: the first formed by children with obesity-related liver disease, diagnosed in the presence of chronic hypertransaminasemia, liver steatosis at ultrasound, and absence of known etiologies; the second composed of children with isolated obesity. In all patients serum leptin, immunoglobulins, peripheral T, B, and natural killer (NK) cells were evaluated. Results: Twenty-three children in the first group and 16 children in the second were considered eligible. Serum leptin was increased in both groups but without any significant difference. No significant correlation was found between leptin and aminotransferases, lipid serum levels, and all tested lymphocyte subpopulations. Patients with obesity-related liver disease showed significantly higher peripheral NK and B cell counts and IgA levels than children with isolated obesity. Furthermore, no correlation was found between severity of liver disease and lymphocyte subpopulations. Conclusion: In our study, leptin did not correlate with hepatic steatosis, aminotransferases, and serum lipids. Children with obesity-related liver disease showed significantly higher peripheral NK and B cells and IgA levels. Additional studies are required to define the pathogenetic role of these immunological findings.