Adipokines as novel biomarkers in paediatric systemic lupus erythematosus

Patients with SLE are at risk for premature atherosclerosis and metabolic syndrome. Cytokines produced by adipocytes, adipokines, are important in glucose/lipid metabolism and the development of atherosclerosis. The objectives of this study were to evaluate leptin, adiponectin and ghrelin concentrations in paediatric SLE (pSLE) and to correlate these concentrations with measures of disease activity, serum lipid concentrations, measures of insulin resistance and serum homocysteine concentrations.

Two hundred and eight samples from 105 patients with pSLE and 77 samples from 77 healthy paediatric controls were evaluated by ELISA to measure leptin, adiopnectin and ghrelin. Students' t-test was used for analysis. Concentrations of adipokines were correlated with disease activity, serum lipids, insulin resistance and homocysteine.

Overall 35 SLE patients (34%) had an abnormally elevated leptin level. The only significant correlation of leptin concentrations was with homocysteine concentrations but not disease activity, prednisone dose, lipids or insulin resistance. There was no difference in the mean adiponectin concentrations between the control and patient groups and none of the patient samples were below the normal lower limit while seven were elevated. There was a significant correlation of adiponectin concentrations with prednisone dose, lipid concentrations and insulin resistance but not with disease activity or homocysteine. Elevated ghrelin concentrations were found in 20% of the pSLE patients. The only correlation of ghrelin concentrations was with homocysteine.

Adipokines are novel biomarkers in pSLE. They may represent cardiovascular risk and are not just surrogate markers for disease activity, therapy or serum lipids. Their correlation with atherosclerosis needs to be explored.