Acute myelogenous leukaemia modulated by B₁₂ deficiency: a case with bone marrow blast cell assay corroboration

A patient is described who appeared to demonstrate modulation of acute myelogenous leukaemia with vitamin B₁₂ deprivation. Support for this observation was obtained via an in vitro bone marrow blast cell assay. The addition of B₁₂ to this patient's bone marrow in vitro significantly stimulated the colony forming ability of the blast cells. Patients with B₁₂ deficiency have an increased incidence of haematopoietic malignancies and excessive replacement of B₁₂ may in some cases have the potential of accelerating such disorders. Intensive B₁₂ replacement in refractory megaloblastic anaemias should be done with caution.