Acceleration of myeloid recovery from cyclophosphamide-induced leukopenia by pretreatment with Bacillus Calmette-Guérin.

Treatment of C57BL/6 mice with Bacillus Calmette-Guérin i.p. 8 days prior to the induction of leukopenia by cyclophosphamide (300 mg/kg i.p.) significantly (p less than 0.002) increased peripheral granulocyte counts on each day during the recovery from leukopenia. The recovery of lymphocyte counts was unaffected by Bacillus Calmette-Guérin treatment. Further experiments indicated that the accelerated granulocyte recovery was the result of an earlier initiation of the recovery process rather than of the release of stored granulocytes. Bacillus Calmette-Guérin may have clinical value as a stimulator of myelopoiesis in patients rendered leukopenic by antineoplastic chemotherapy.