Pneumocystis carinii pneumonia in HIV-positive and HIV-negative patients. An epidemiological, clinical and histopathological study of 18 patients.
Pulmonary histopathological and clinical changes associated with Pneumocystis carinii pneumonia (PCP) were found to be less severe in 10 HIV-positive patients (group A) with acquired immunodeficiency syndrome (AIDS) than in 8 patients (group B) with other immune deficiencies. Lung biopsies from group A showed minimal thickening of the alveolar walls from oedema and slight mononuclear cell infiltration, while in group B alveolar wall thickening was more prominent with distinct mononuclear cell infiltration and evidence of diffuse alveolar damage and interstitial fibrosis. Infection with P. carinii cysts was heavy in 60%, moderate in 30% and mild in 10% in group A patients v. heavy in 0%, moderate in 14% and mild in 86% in group B patients. These findings appear to suggest that AIDS/PCP presents with a heavy parasite load but only minimal histopathological changes that are reversible and that atypical change as observed in PCP in other immune deficiencies are caused by previous or concomitant insults other than pneumocystosis. Milder propagation of P. carinii in HIV-negative patients may be because there is a lack of undamaged type I pneumocytes to which trophozoites probably need to be attached at a certain developmental stage.
Ziefer
A
A
Department of Tropical Diseases, School of Pathology, South African Institute for Medical Research, Johannesburg.
Abramowitz
J A
JA
D000163:Acquired Immunodeficiency Syndrome / Q000150:complications*; D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007153:Immunologic Deficiency Syndromes / Q000150:complications*; D008297:Male; D008875:Middle Aged; D011020:Pneumonia, Pneumocystis / Q000150:complications / Q000473:pathology*; D011650:Pulmonary Alveoli / Q000473:pathology