Studies on antigens of C-type primate viruses and antibodies to them at patients with myeloid leukemia and potentially preleukemic hematological disorders.

: Peripheral leucocytes from patients with chronic myeloid leukemia were examined for the presence of oncornavirus p30 antigens by indirect cytoplasmic immunofluorescence. The leucocytes of patients who could be kept in balance by chemotherapy proved to be negative or contained the p30 antigen of baboon endogenous oncornavirus. In the leucocytes of patients being in blastoid crisis, an antigen related to the p30 antigen of simian sarcoma virus was detected. In five of six patients decrease in sensitivity to chemotherapy, or blastoid crisis, was preceded by expression of leukaemia-sarcoma virus p30 antigen(s). Plasma samples of patients with acute myeloid leukemia (AML) and potentially preleukemic hematological disorders were studied for the presence of anti-HL 23 virus antibodies by indirect membrane immunofluorescence. In patients with untreated AML, antibodies could be detected when the peripheral leucocyte count was low. After treatment of AML with cytostatic drugs the presence of high titer antibodies was connected with long lasting remission. Of twelve patients with potentially preleukemic disorders, five proved to be positive for the presence of HL 23-specific antibodies. In half a year period development of overt leukemic disease could be observed in four patients, who proved to be antibody negative in the preleukemic phase.