Hypercalcemia and suppressed PTH levels in a renal transplant patient infected with Pneumocystis carinii.

Pneumocystis carinii pneumonia is a serious and relatively common complication of immunosuppressive therapy. In immunocompromised patients, P. carinii pneumonia can cause significant morbidity and mortality. Another common complication, typically seen in the subpopulation of renal transplant recipients, is hypercalcemia. The prevalence of hypercalcemia varies, reaching as high as 71%. We report the case of a renal transplant recipient who developed P. carinii pneumonia and hypercalcemia, the latter being resolved after the successful treatment of the former. We argue that there is a causal relationship between P. carinii pneumonia and hypercalcemia in renal transplant recipients. In immunocompromised patients, pulmonary infection accompanied by hypercalcemia should raise the suspicion of P. carinii pneumonia.

Dysfunction of natural killer cells in human immunodeficiency virus-infected children with or without Pneumocystis carinii pneumonia.

The development of Pneumocystis carinii pneumonia (PCP) in human immunodeficiency virus (HIV)-infected children with normal T-cell numbers is contrary to previous experience with HIV-infected adults, in whom low CD4+ T-cell numbers predict susceptibility to PCP. To determine whether PCP in HIV-infected children reflects a qualitative T-cell or other immune defect, we studied four HIV-infected children who also had PCP and 10 others without PCP for T-cell and natural killer (NK) cell function. Most of the HIV-infected children had normal T-cell numbers for age, and all had CD4+ T-cell numbers greater than those predictive of PCP in HIV-infected adults. All HIV-infected children had normal T-cell function in vitro. The HIV-infected children as a whole had deficient NK cell cytolysis. We obtained a significant interactive effect of age by health status for NK cell function between patients and age-matched control subjects. All HIV-infected children with defective NK cell function failed to enhance their NK cell cytolysis when their mononuclear cells were stimulated with recombinant interferon alfa (r-IFN-alpha). This NK cell defect in HIV-infected children may facilitate the development of secondary infection.

Acute respiratory illness in children with acute lymphoblastic leukemia.

Ten of 70 children (14%) with acute lymphoblastic leukemia developed severe interstitial pneumonitis within three weeks after induction of central nervous system prophylactic therapy. The clinical picture was characterized by fever, cough, progressive dyspnea, and hypoxemia with complete resolution in one to three weeks, except in one patient who died during the acute illness from respiratory failure. P. carinii organisms were found in the lung tissue of only one patient. The etiology of the pneumonitis in the other nine children was probably viral, acquired or activated during a period of lymphopenia and immunosuppression. The morbidity and potential mortality from the pneumonitis warrants early recognition by open lung biopsy and intensive supportive therapy.