Depression of the platelet count after inoculation of mice with L1210 or L5178Y cells.

The inoculation of L1210 or L5178Y leukaemia cells decreased the platelet count of the recipient mouse before extensive infiltration of marrow was expected by either tumour line. The decrease was more pronounced after intravenous inoculation of L1210 leukaemia than after intraperitoneal inoculation. Inoculation of L5178Y cells by both routes caused an initial decrease but the count recovered to 80% of normal before becoming markedly depressed prior to death of the host. Implantation of diffusion chambers containing L1210 cells also decreased the platelet count, which later returned to normal.