[Biological screening of immuno-mediated marrow insufficiency by means of the CFU-GM assay].

We studied in agar growth behaviour of bone marrow granulocyte-macrophage progenitor cells (CFU-GM) in 16 patients with marrow failure in order to discriminate patients with cells inhibiting granulopoiesis both in bone marrow and peripheral blood. Our experimental design was based on: a) agar culture of bone marrow cells before and after treatment with antilymphocyte globulin (AGL); b) agar co-culture of marrow cells with autologous lymphocytes from peripheral blood. ALG treatment of marrow cells determined CFU-GM growth increase in 4 out of 10 patients; in the same patients co-culture with autologous lymphocytes showed a significant inhibition of CFU-GM growth. The growth enhancement induced by ALG treatment "in vitro" associated with growth inhibition in the coculture suggests the existence of a lymphocyte population suppressing the granulopoiesis both in bone marrow and peripheral blood. With this work we propose an experimental model in order to discriminate marrow failure based on cell-mediated suppression of CFU-GM growth in patient susceptible of immunosuppressive therapy with ALG.