Sulfamethoxazole-trimethoprim was administered prophylactically to 786 patients judged to be at sufficient risk for development of Pneumocystis carinii pneumonitis. The selection of patients, administration of the agents, and surveillance for compliance were the responsibility of the attending oncologists rather than specialists in infectious diseases, as in an earlier trial at this center. The recommended dosage was trimethoprim, 150 mg/sq m/day, and sulfamethoxazole, 750 mg/sq m/day. Over a three-year study period, nine cases of P carinii pneumonitis occurred at this institution, with none attributable to drug failure. Adverse reactions, skin rashes mainly, were noted in 43 patients, and one patient died with Stevens-Johnson syndrome. These results confirm the efficacy of sulfamethoxazole-trimethoprim in preventing P carinii pneumonitis in childhood cancer patients and illustrate the feasibility of large-scale unstructured delivery of the combination to patients with malignant diseases frequently associated with this pneumonia.

Adolescent↗

PubMed1980

Aplastic anemia: lack of inhibitory effect of bone marrow lymphocytes on in vitro granulopoiesis.

Prompted by previous reports that in certain patients with aplastic anemia, cell-mediated autoimmune suppression of myeloid stem cell proliferation may be demonstrable in vitro, we studied the effects of bone marrow lymphocytes from 18 patients with myeloid aplasia on the proliferation of committed granulocytic-monocytic progenitor cells (CFU-C). When assayed in soft agar cultures, marrow suspensions from 10 patients with aplastic anemia contained significantly fewer viable CFU-C than similar cell preparations from control subjects. To deplete marrow cell suspensions of lymphocytes, we employed rabbit anti-human thymocyte serum (ATS), which after multiple adsorptions exhibited marked cytotoxicity for human B and T lymphocytes but had negligible effect on normal CFU-C proliferation. Preincubation of marrow samples from 12 patients with ATS and complement resulted in no inhibition or enhancement of CFU-C growth. In further experiments, marrow cells from 8 patients were incubated with marrow from control subjects prior to CFU-C culture. No suppression of donor CFU-C proliferation was observed in any of these studies, and in 4 cocultures, mixture of the 2 marrow suspensions resulted in stimulation of CFU-C growth. Using these assays, we detected no evidence of cell-mediated inhibition of CFU-C proliferation in any of the 18 patients that we evaluated. Our data support the conclusion that in the majority of patients with aplastic anemia, an absolute deficiency of hemopoietic stem cells is present within the marrow that does not appear to be effected or sustained by suppressor lymphocytes. Whether the reduction of viable stem cells is the cause or the consequence of the process that leads to marrow failure remains unknown.

Anemia, Aplastic↗

PubMed1979