Interferon production by human leukaemic leucocytes.

The Sendai virus-induced interferon (IF) production by partially purified human leucocyte suspensions of normal donors and of leukaemic patients have been investigated in vitro. (i) An increased production was observed with leucocytes taken from patients suffering from chronic myelogenous leukaemia (CML) during exacerbation, but the production was approximately normal with cells taken during remission. (ii) IF production was not influenced by large doses of cytostatics (DBM, 5-FU, FUDR, 5-HU, 6-MP, cyclophosphamide) irrespective of whether normal or CML leucocytes were used. (iii) In contrast, production was inhibited in both systems by inhibitors of RNA or protein synthesis (actinomycin D, puromycin, cycloheximide). (iv) CML leucocytes produced IF for a prolonged period of time as compared to normal leucocytes. (v) Leucocytes from children with acute blastic leukaemia and those from adults with chronic lymphoid or acute paramyeloblastic leukaemia produce, in contrast to normal leukocytes, approximately as much IF in the absence as in the presence of serum. It is concluded that the Sendai virus-induced IF synthesis in CML leucocytes requires de novo protein synthesis.