[The characteristics of the anti-infectious defenses in newborn infants].

The authors reviewed the up to date conceptions concerning the temporary alterations of the host defense mechanisms in the neonatal period (natural barriers, macrophages, complement system, cell-mediated and humoral immunity). They try to establish correlations between this temporary alterations and the high infectious risk and the severity of most of the infections in the newborn. A special attention is paid to the peculiar situation of the premature, and also to the modifications needed in the therapeutic schedules for serious neonatal infections.