| Abstract: | The influence of total-body irradiation (TBI) and autologous or allogeneic bone marrow transplantation on serum immunoglobulin subclasses was determined in a dog model. Only IgG1 levels decreased after low-dose (+/- 4.5 Gy) TBI, but levels of all immunoglobulin classes fell after high-dose TBI (8.5 GyX1 or 2X6.0 Gy). After autologous bone marrow transplantation IgM levels were the first and IgE levels were the last to return to normal. After successful allogeneic bone marrow transplantation prolonged low IgM and IgE levels were found but IgA levels increased rapidly to over 150% of pretreatment values. A comparison of dogs with or without clinical signs or graft-versus-host disease (GVHD), revealed no differences in IgM levels. Dogs with GVHD had higher IgA but lower IgE levels. Dogs that rejected their allogeneic bone marrow cells showed significant early rises in IgE and IgA levels in comparison with dogs with GVHD. These results differ from the observations made on Ig levels in human bone marrow transplant patients. No significant differences in phytohemagglutinin stimulation tests were found between dogs with or without GVHD or dogs receiving an autologous transplant for the first four months after TBI and transplantation. An early primary or secondary involvement of humoral immunity in GVHD and graft rejection in dogs is postulated. |
