Conditioning Regimen Protects Against Graft-Versus-Host Disease

NEW YORK SEP 28, 2005 (Reuters Health) - A conditioning regimen that combines total lymphoid irradiation with antithymocyte serum reduces the risk of acute graft-versus-host disease (GVHD) after hematopoietic-cell transplantation, new research indicates.

This strategy was shown to prevent GVHD in mice, but it was unclear if the same applied to humans, senior author Dr. Samuel Strober, from Stanford University School of Medicine in California, and colleagues note. 

As reported in The New England Journal of Medicine for September 29, the researchers assessed the outcomes of 37 patients with leukemia or lymphoma who received 10 doses of total lymphoid irradiation plus antithymocyte globulin before undergoing HLA-matched hematopoietic-cell transplantation.

Only two of the patients experienced GVHD, the authors report.  By contrast, previous reports have described GVHD rates of up to 65%.

Use of the conditioning regimen was also tied to potent antitumor effects in patients with lymphoid malignancies as indicated by a shift from partial to complete remission.

Compared with control subjects who only received a single dose of total-body irradiation before transplantation, those who received the special conditioning regimen showed an increase in the fraction of IL-4-producing donor CD4+ T cells and a drop in the proliferative response to alloantigens in vitro.

In a related editorial, Dr. Gerard Socie, from Hopital Saint Louis in Paris, comments that "the low incidence of GVHD in this study is impressive," but the study is not without its limitations.  For example, "the small number of patients precludes a definitive conclusion," he notes.

Also, the crude incidence of acute GVHD that was used makes it difficult to compare with the cumulative incidence rates used by most other researchers. 

SOURCE:

• N Engl J Med 2005;353:1321-1331,1396-1397.