Pneumocystis carinii pneumonia and primary immune deficiency diseases.

During a 3-year period, 50 cases of Pneumocystis carinii pneumonia in children less than 5 years old were reported to the Parasitic Disease Drug Service, Center for disease Control. Primary immune deficiency diseses constituted the most frequent underlying diseases in patients less than 1 year old (24/29 cases, 83%), whereas acute lymphatic leukemia was the most common underlying diseases in children 1-4 years old (17/21 cases, 81%). Severe combined immunodeficiency was the most common type of immune deficiency disease (15/25 cases, 60%). Six (24%) of the immunodeficient patients each had a sibling who died during infancy of an immunologic deficiency disease and P. carinii penumonia. Although the pathogenesis of the association between immune deficiency and P. carinii pneumonia is poorly understood, defects in both humora and cellular immunity appear to be operative.--Natl Cancer lst Monogr 43: 65-72, 1976.