Leptin and C-reactive protein levels correlate during minor infection in children.

BACKGROUND Leptin, a pleiotropic hormone, has been suggested to be part of an acute-phase response during an inflammatory stimulus. Its correlation with other acute-phase reactants during minor infection in children has not been investigated. OBJECTIVES To study the correlation between levels of serum leptin and those of C-reactive protein, a well-documented acute-phase reactant, in a series of pediatric patients with acute minor infections. METHODS Leptin and CRP levels were measured in 62 blood samples of pediatric patients presenting with mild febrile illness who were admitted to Dana Children's Hospital in Israel. All children were finally diagnosed as having minor infection based on the negative blood/urine cultures and favorable outcome. RESULTS Serum leptin level was positively correlated with CRP (r2 = 0.5), total white blood cells (r2 = 0.33) and absolute neutrophil count (r2 = 0.31). The regression coefficient was the highest between leptin and CRP. CONCLUSIONS Circulating leptin concentrations are positively correlated with CRP levels during acute minor infection in children visiting the emergency room for febrile illnesses. Our observation suggests that leptin is indeed a part of acute-phase proteins. The wide scattering showed that it is not a better marker in minor infections than CRP, but it may contribute to weight loss and anorexia seen in a minority of patients during mild infections.