Studies on graft versus host (GvH) reactions. I. Impairment of hemopoietic stroma in mice suffering from GvH disease.

The hematologic changes were described in the adult (C57BL/6 x C3H/He) F1 hybrid mice suffering from graft versus host (GvH) disease induced with 10(8) parental (C3H/He) lymph node (PLN) cells. Progressive decreased in numbers of leucocytes, granulocytes, erythrocytes and reticulocytes was observed from day 7 to 14 of GvH disease. Thrombocytopenia was not so remarkable. A histologic study revealed and extremely hypoplastic marrow. The number of colony forming units (CFUs)/femur decreased progressively from day 5 to 14. When the femurs, removed from the diseased mice at various intervals after the PLN cell injection, were implanted subcutaneously into other hosts for 7 weeks in order to evaluate the hemopoietic stroma to support the hemopoietic stem cells, the progressive decrease in CFUs number in the implanted femurs was also observed from day 5 to 14. There was a dose relation between the number of PLN cells injected and the reduction of CFUs number either in the femurs in situ or the implanted femurs. It is thus concluded that the impairment of hemopoietic stroma results form F1 hybrid disease, i.e., GvH disease and can be one of the major causes of the depletion of hemopoietic cells resulting in pancytopenia.