Effects of Recombinant a and ‘y Interferons on the In Vitro Growth of Circulating Hematopoietic Progenitor Cells (CFU-GEMM, CFU-Mk, BFU-E, and CFU-GM) From Patients With Myelofibrosis With Myeloid Metaplasia

Myeloflbrosis with myeloid metaplasia (MMM) is a chronic myeloproliferative disorder due to clonal expansion of a pluripotent hematopoietic progenitor cell with secondary marrow fibrosis. No definitive treatment has as yet been devised for this condition, which shows a marked variability in clinical course. To evaluate whether excessive hematopoietic progenitor cell proliferation could be controlled by recombinant human interferon a (rIFN-a) and “y (rlFN-’y). we studied the effects of these agents on the in vitro growth of pluripotent and lineage-restricted circulating hematopoietic progenitor cells in i 8 patients with MMM. A significant increase in the growth (mean ± i SEM) per milliliter of peripheral blood of CFU-GEMM (594 ± 253). CFU-Mk (i,033 ± 4i0). BFU-E (4.799 ± 2.020) and CFUGM (5.438 ± 2,505) was found in patients as compared with normal controls. Both rlFN-a and rlFN-’y (iO to 10” U/mi) produced a significant dose-dependent suppression of CFU-GEMM. CFU-Mk. BFU-E. and CFU-GM growth.