Analysis of Interacting Cell Populations

Utilizing an adherence separation pro- tion; studies on the remaining patient cedure, marrow cells from six neutropenic exhibited reduced CFU-C in the presence patients were studied in cell culture for of normal A-C function. The demonstration colony-forming ability (CFU-C), and for of these various abnormalities in marrow colony-stimulating function of the ad- cell culture from neutropenic patients herent cell (A-C) population. Assays on suggests that the in vitro techniques have two patients showed reduced CFU-C and relevance to the study of granulopoiesis A-C function, while assays on three pa- in vivo. tients yielded normal CFU-C and A-C func- G RANULOCYTIC COLONY FORMATION in culture by cells of normal human marrow is effected by two interacting cell populations separated on the basis of adherence to glass or plastic:' first, nonadherent committed granulopoietic progenitors (CFU-C),2 6 the cells of origin of the coloniesand second, adherent cells (A-C), which give rise to substances required for colony formation."7'8 The latter cell class may be replaced by one of their cellular products with colony-stimulating activity (CSA).6'9"#{176} Granulopoiesis in cell culture has been shown to require either CSA or CSA-producing cells, but an equivalent physiologic need in vivo has not been demonstrated. As an approach to this problem, we examined CFU-C and A-C in cultures of marrow from six patients with neutropenia. The finding of defective A-C function in two of these patients is consistent with the view that these cells may play a regulatory role in gran ulopoiesis.