Rescue from canine graft-versus-host reaction by autologous or DL-A-compatible marrow¹

The present study is concerned with the termination of chimerism in canine marrow recipients threatened by lethal graft-versus-host (GVH) disease with use of an infusion of stored autologous marrow cells or cells from serotypically histocompatible littermates. All recipients were given 1,200 R of total body irradiation followed by a hemopoietic graft from a histoincompatible unrelated donor. Methotrexate was given on days 1, 3, 6, and 9 to delay the onset of GVH disease. Five dogs given no additional therapy died be¬tween 16 and 39 days with GVH disease. An attempt at rescue was made in 10 dogs by giving an infusion of stored autologous marrow on day 14 either with or without expo¬sure of the recipient to 400 R. Rescue failed, and dogs died between 18 and 37 days either with GVH disease or marrow aplasia. Rescue was successful in three of seven dogs given 600 R on day 14 followed by infusion of marrow from a compatible littermate. The re¬maining four dogs either rejected the littermate marrow or died of infection. In conclu¬sion, attempts at rescue from canine GVH disease are exceedingly difficult, and only pos¬sible in the present study after renewed exposure of the recipient to a high dose of total body irradiation followed by large numbers of hemopoietic cells from a compatible littermate.