Endemic infantile pneumocystis carinii infection: the Shiraz study.

Orphanage epidemics of interstitial plasma cell pneumonia (IPCP) occur among premature infants whose passive immunity due to maternally transferred antibodies has lost its effectiveness before the infants' humoral immune systems have reached sufficient maturity to respond effectively to Pneumocystis carinii. IPCP occurs also among mature newborns receiving substandard care in understaffed and crowded orphanages. Infantile diarrhea in these institutions leads to marasmus and deficient immune response in infants 3-4 months after birth. The P. carinii organisms in the alveoli elicit a plasma cell response in the interstitial tissues of the lung, which may be so massive that it interferes with respiration and leads to death by asphyxiation. Such observations at the Shiraz Orphanage are discussed.