Neonatal septicemia is an infection-induced syndrome characterized by a number of symptoms and clinical signs, including fever or hypothermia, leukocytosis or leucopenia, tachycardia and tachypnea (Wheeler and Bernard, 1999).

The earliest signs of sepsis are often non specific, poor feeding, diminished responsiveness or just not looking well, may provide the only evidence that infection is present. More prominent findings are respiratory distress, apnea, lethargy, fever or hypothermia, jaundice, vomiting, diahrrea and skin manifestations including petechiae, abcesses and sclerema (Abraham et al., 2000).

The incidence of neonatal sepsis varies from 1 to 8/1000 live births. This incidence may be related to rates of prematurity, prenatal care, conduct of labour and environmental conditions in nurseries (Guerina, 1998).

Recently, increased plasma concentrations of leptin were reported in patients with acute sepsis (Stenvinkel, 1998).

Leptin levels increase actually during infection and inflammation. More important, leptin deficiency increases susceptibility to infectious and inflammatory stimuli (Faggioni et al., 2001).