Involvement of MHC-Linked Hemopoietic-Histocompatibility Genes in Allogeneic Bone Marrow Transplantation in Mice

Genes controlling resistance of irradiated mice of allogeneic hemopoietic cells were mapped within, or closely linked to the D region of MHC and were designated Hemopoietic-histocompatibility genes (Hha). Hhp genes responsible for resistance to parenteral hemopoietic cells had also previously been detected on the D-end of MHC. Hh genes are regarded as determinants of cell surface antigens (Hh antigens) phenotypically expressed, in contrast to Histocompatibility antigens (H antigens) only on blood-forming and leukemic cells. The inheritance of Hh genes is not codominant, unlike thformed on peripheral blood lymphocytes and platelets. Sixteen Tunisian families were typed with 37 patients and 108 relatives. Genetic transmission of the disease of the HLA system seemed to be independent in this study. Comparison of HLA gene frequencies (unrelated) parents of patients and a control population showed no difference, proving that there is no clear association in population between deleterious XP genes and a particular HLA gene. However, an excess of identical HLA among pairs of diseased siblings would suggest that the disease is polymorphic and a form of the XP could be linked to HLA.