An in vitro studAn in vitro study of basophil production in chronic myeloproliferative disorders.

An examination was carried out of certain parameters of basophil production in semisolid agar cultures by granulomonocyte precursors (CFU-C) from normal subjects and from patients with chronic myeloproliferative disorders. Basophils were rare in the first four days of culture, after which their number increased gradually to reach a plateau on about the 12th day. Pure basophil colonies were frequent only in cultures from a patient with marked basophilia. In the other cases the colonies also included other cells of the granulomonocyte pathway. There was a linear correlation between basophilia in vivo and basophil production in vitro. The latter, however, was influenced by the type of colony-stimulating activity (CSA) used. Different CSA sources, inducing the production of a comparable number of colonies, did not stimulate basophilic differentiation in the same way. Serum from patients with chronic myelocytic leukemia and varying degrees of basophilia did not have a significant effect on autologous in vitro basophilopoiesis, nor did it increase that of normal CFU-C.