CFU‐C Populations in Blood and Bone Marrow of Dogs after Lethal Irradiation and Allogeneic Transfusion with Cryopreserved Blood Mononuclear Cells

Abstract

Colony forming units in agar (CFU‐C) were assayed in both bone marrow and peripheral blood of dogs during haemopoietic recovery after lethal total‐body irradiation (1200 R) and allogeneic transfusion of blood mononuclear cells (MNC) from histocompatible donors. MNC had been collected from the peripheral blood by continuous‐flow centrifugation leucapheresis and cryopreserved at ‐196°C until transfusion.Two groups of dogs were studied. Group 1 dogs (n = 12) were given between 0.39 and 2.76 times 10⁹ MNC per kg body wt. Group 2 dogs (n = 14) were transfused with a similar number of MNC, ranging from 0.51 to 1.87 times 10⁹ per kg body wt., but in addition underwent immuno‐suppressive therapy with methotrexate. In group 1 dogs, there was a rather good correlation between the number of CFU‐C in the regenerating bone marrow and the recovery of the peripheral blood granulocyte values. The regeneration of the CFU‐C population in the bone marrow of methotrexate‐treated dogs showed a somewhat more heterogeneous picture than in dogs of group 1 and in dogs that, in a previous study, were transfused with autologous MNC. The minimum time interval required for the reconstitution of peripheral blood CFU‐C to normal levels was 2–4 weeks but usually took from 4–14 weeks.