Coexisting suppressor cells for myeloid colony formation in the bone marrow of patients with aplastic anaemia.

Suppressor cells for colony forming cells (CFUC) were found in the bone marrow of 1 of 6 patients with aplastic anaemia. The assay applied was based on the fact that coexisting suppressor cells are more sensitive to dilution than CFUC, as long as adequate stimulation is provided by a source of colony stimulating activity. In the patient with suppressor cells, a 4 d trial of 1000 mg methylprednisolone per d failed to improve the blood cell production and had to be discontinued due to gastric irritation.