Increased leucocyte alkaline phosphatase and transcobalamin III in chronic myeloid leukaemia associated with lithium therapy.

A 38-year-old woman developed chronic myeloid leukaemia after 2 years of lithium carbonate therapy. A peculiar feature of her leukaemia, as well as of the 5 patients previously reported in whom CML has developed in the course of lithium therapy, was the unusually high degree of granulocyte maturation manifested in normal leucocyte alkaline phosphatase (LAP) score and, in 1 case, selective increase of transcobalamin III. Although a cause and effect relation between lithium therapy and CML has not yet been established, in view of the stimulatory effect of lithium on granulocyte proliferation, such treatment should be avoided in patients with established myeloproliferative disorders, or in patients at high risk of developing leukaemia.