Transplant lung--a new syndrome

Pneumocystis carinii pneumonia in cancer patients

Concern has been arisen about the recently reported increasing incidence of PCP in patients with cancer and the potential transmissibility of this infection. Whether or not there is an increase in the incidence of P. carinii infections, PCP should be considered in the differential diagnosis of pulmonary infiltrates in bone marrow transplant recipients, in patients with hematologic neoplasms and in patients with primary or metastatic brain neoplasms. Intensity of immunosuppression plays a crucial role, especially long-term (> 2 months) corticosteroid treatment. PCP is usually manifested clinically during augmentation or during tapering of corticosteroid dose. Thus, if the chest radiograph of a high-risk patient shows diffuse infiltrates, bronchoscopy and bronchoalveolar lavage should be done immediately. Treatment options are the same as for the AIDS population, except that TMP-SMX is tolerated better in non-AIDS patients. The role of supportive care, including mechanical ventilation in such patients should not be underestimated. Oral therapy with dapsone-trimethoprim or with atovaquone, can be as effective as conventional therapy in mild disease, permitting treatment on an outpatient basis. PCP is often preventable and our understanding has improved about when prophylaxis should be initiated. In the future, the emergence of new technologies for diagnosis and of new agents for treatment and prophylaxis, will bring us closer to the goal of controlling this serious infection.

Pneumocystis carinii pneumonia during steroid taper in patients with primary brain tumors

Pneumocystis carinii causes life-threatening pneumonitis (PCP) in immunocompromised individuals. In the non-AIDS (acquired immunodeficiency syndrome) population, PCP is frequently associated with corticosteroid therapy, and the rodent model uses corticosteroid-induced immunosuppression to provoke PCP. Although patients with intracranial tumors are frequently treated with long courses of corticosteroids, there have been very few descriptions of PCP in this population. We report the diagnosis and treatment of PCP in four patients over a 12-month period with intracranial neoplasms who developed symptoms during corticosteroid taper. Effective prophylaxis against PCP exists and should be considered for patients with intracranial neoplasms receiving long-term steroids.

The lungs in renal failure

Pulmonary function was studied in 55 patients with renal failure and no clinical or radiographic evidence of lung disease. A defect of gas transfer was found to be the rule due to a reduction in the diffusing capacity across the alveolar capillary membrane; this abnormality appeared to be related to the severity of the renal impairment. There was also a restrictive ventilatory defect which was more marked in male than in female patients. The significance of these findings is discussed, and attention is drawn to their relevance for patients receiving immuno-suppressive therapy or renal transplantation, in whom pulmonary complications are relatively common.

Pathogenesis of "transplant lung". I. Interstitial pulmonary edema

Images

Non-specific induction of cytotoxicity in normal human lymphocytes in vitro: studies of mechanism and specificity of the reaction

The cytotoxic effect of non-immunized human lymphocytes was investigated in a system where the lymphocytes were applied to fibroblast monolayers of different genotypes. Non-immunized lymphocytes were not cytotoxic, disregarding the target cell genotype provided that the lymphocyte suspensions were free from contaminating granulocytes. By adding phytohaemagglutinin (PHA) to the culture, the lymphocytes became strongly cytotoxic and exerted their effect already after 4–8 hr. Cytotoxicity was shown to develop independently of other expressions of PHA-stimulation of the lymphocyte, such as RNA-, protein- and DNA-syntheses and morphological transformation. Living lymphocytes were required for cytotoxicity to occur and heating the lymphocytes to 48·5°C, ultrasound disintegration or freezing-thawing abolished their ability to damage the target cells. The PHA-induced cytotoxicity was equally expressed on allogeneic and autochthonous fibroblasts. Analogous results were obtained when the lymphocytes were stimulated by streptolysin O or anti-lymphocyte serum. The results suggest that expression of cytotoxicity is an immunologically non-specific process, caused by stimulated lymphocytes. When the lymphocytes have acquired a cytotoxic potential they do not discriminate between the target cell genotype or the event triggering lymphocyte cytotoxicity. The specificity of the cellular immune reactions is probably confined to the immunological recognition step initiating the cytotoxic potential. This recognition step is by-passed if the lymphocytes are stimulated by PHA or other non-specific stimulators.