From 1979 to 1988, 82 allogeneic and 2 syngeneic bone marrow transplants (BMT) were performed in 78 patients (age range 13-49 years) with the following diagnoses: acute myelogenous leukemia (AML) (21 patients); acute lymphoblastic leukemia (ALL) (15 patients); chronic myelocytic leukemia in chronic, accelerated, or blastic phase (CML-CP, AP or BC) (25 patients); myelodysplastic syndrome (MDS) (1 patient); multiple myeloma (MM) (1 patient); Hodgkin's disease (HD) (1 patient); diffuse poorly differentiated lymphoma (DPDL) (1 patient); aplastic anemia (AA) (13 patients). Univariant analyses were carried out to determine factors of importance in predicting outcome. AML patients receiving transplants in remission had 12/19 (63%) survivors. Only one of seven ALL patients receiving transplants in remission survives free of disease, and none of eight patients receiving transplants in relapse survived. Six ALL patients relapsed. In CML, 6 of 16 (40%) patients receiving transplants in CP survive; two of nine patients (22%) in AP or BC survive. Of the 13 aplastic anemias, 8 (62%) survive. Graft-vs.-host disease (GVHD) was evaluated in 75 patients, 24 of 33 (73%) who developed GVHD died, compared to 24 of 44 (55%) who did not develop GVHD. Of the 30 patients given the combination of methotrexate (MTX) plus cyclosporine (CSP), only 23% developed GVHD, compared to 58% of those not given the combination. Interstitial pneumonia (IP) occurred in 16 patients and was fatal in 15. The introduction of daily acyclovir and weekly intravenous gamma globulin in 1985 was associated with little reduction in the frequency of IP (from 20% to 18%). However, survival increased from 21% to 47%.(ABSTRACT TRUNCATED AT 250 WORDS)