Alveolar macrophages in perinatal infants.

The presence of alveolar macrophages in the neonatal lung at the time of autopsy is correlated with the presence of pulmonary lesions and with the duration of postnatal life. Alveolar macrophages were noted at 20 weeks of gestation in infants with congenital pneumonia, but were not present in most full-term infants who were stillborn. They were found in nearly all infants who survived for 48 hours irrespective of pulmonary lesions or gestational age.