The prognosis for patients with AML is improving, but mortality due to bleeding and infection remains significant. HLA compatibility has been the cornerstone of matching for prophylactic platelet transfusion; while HLA matched platelets are often of benefit, we have observed that HLA matching does not reliably predict transfusion responses. The platelet migration inhibition assay is, however, consistently predictive. The matching problem may be circumvented by the use of frozen autologous platelets, which circulate and function hemostatically. In the granulocytopenic patient with de novo fever (frequently due to bacterial sepsis), the immediate empiric use of broad spectrum antibiotics is mandatory. If the marrow begins to recover from chemotherapy shortly after the onset of infection, such that the peripheral granulocyte count will approach normal within 10 days, the likelihood of survival from an episode of septicemia after antibiosis now approaches 80%. If the marrow does not recover shortly, however, the likelihood of survival with antibiosis alone is poor. In this setting, survival is improved if patients are given granulocyte transfusions in addition to antibiotics. Patients who receive chemotherapy in a laminar air-flow room (LAFR) experience fewer severe infections than do patients in a conventional ward. However, most patients who are unresponsive to initial chemotherapy remain so in spite of protection from infection. Thus, the available results do not suggest that the LAFR is likely to improve appreciably the rate or duration of remission. Using malignant lymphoma as a model, we have found that cryopreserved autologous marrow infusions can hasten hematopoietic recovery in man after high-dose chemotherapy, and earlier reconstitution may be of clinical benefit to the patient; techniques are at hand that might permit the application of this concept to AML.Cancer 42:883-894, 1978.ESPITE SIGNIFICANT IMPROVEMENT in the D complete remission induction rate of patients with acute myelogenous leukemia (AML), and the gradual prolongation of survival, most patients with AML die of their disease.14 Death is primarily due to bleeding and/ or infection, and thus the major efforts in supportive therapy have been directed toward these two complications.26 While it is true that the majority of patients die of these complications only after they have exhausted the opportunities for remission afforded by the premier chemotherapeutic regimens, it is impor-