Immunomodulation in allogeneic marrow transplantation: use of intravenous immune globulin to suppress acute graft-versus-host disease.

Intravenous immune globulin (IVIG) has been used with success to prevent and treat infection in patients with immunodeficiencies of humoral immune function. More recently, IVIG has been shown to modulate immune responses and to treat successfully several autoimmune disease. Initial trials in bone marrow transplant recipients were aimed at the prevention of cytomegalovirus (CMV) disease. Although most studies showed such a benefit, CMV prophylaxis is now commonly provided by use of CMV-negative blood products or ganciclovir prophylaxis in, respectively, CMV-seronegative and CMV-seropositive patients. Acute and chronic graft-versus-host disease (GVHD) and associated infections remain critical barriers to the wider application of allogeneic blood or marrow transplantation, especially among patients given HLA-disparate grafts. To date, four controlled clinical trials have shown a significant reduction in acute GVHD in patients given IVIG (500-1000 mg/kg) weekly until 90-120 days post-transplant. In addition, bacterial infection in the early transplant period appears reduced. Meta-analysis of controlled trials reporting acute GVHD endpoints in 379 patients found a relative risk of acute GVHD of 0.68 (95% CI, 0.45-1.02) in IVIG recipients compared to untreated controls. Overall mortality reported in 809 patients in these trials showed an odds ratio of mortality of 0.74 (0.55-0.99) in IVIG recipients compared to controls (values < 1.0 suggest that IVIG was effective in preventing the event). More recently it has been shown that in the absence of hypogammaglobulinaemia, IVIG (500 mg/kg) given monthly from day 90 to 360 did not reduce the incidence of chronic GVHD or late complications. Future research is aimed at characterizing the mechanism of action of suppression of acute GVHD with weekly IVIG prophylaxis and the role of IVIG prophylaxis in patients receiving unrelated marrow grafts.