HLA and Risk of Acute Graft Versus Host Disease in Allogeneic Bone Marrow Transplantation from an HLA-identical Sibling

Background-Recent reports have shown a probable association between certain HLA antigens and acute graft versus host disease (GVHD) after allogeneic bone marrow transplantation (BMT).Methods-Medical records of 162 patients who had undergone allogeneic BMT from an HLA-identical sibling in the Hematology, Oncology and Bone Marrow Transplantation Center of Shariati Hospital in Tehran between 1991 and 1999, were studied and analyzed by univariate and multivariate analyses. All factors including HLA antigens, age, sex and diagnosis were examined jointly using a logistic regression analysis. The relationship between HLA antigens and acute GVHD was re-examined within the regression setting. Results- The diagnosis was thalassemia in 81 (50%), CML in 27 (16.7%), AML in 16 (9.9%), ALL in 6 (3.7%) and aplastic anemia in 22 (13.6 %) cases. Overall, 36 (22.2%) patients developed clinical Grade III and IV acute GVHD. Univariate analysis confirmed an increased risk of severe acute Grade III and IV GVHD, which was associated with the diagnosis of AML, donor to recipient sex mismatch and probably with the allele HLA-DR7 (p=0.01, 0.051 and 0.07, respectively). The risk of GVHD was reduced in the presence of the HLA-B35 allele (p=0.04). Multivariate analysis confirmed a decreased risk of acute GVHD associated with HLA-B35 (p=0.01), while the risk was increased in patients with AML (p=0.009) and in those with a sex-mismatched donor.Conclusion-In this study, AML, donor-to-recipient sex mismatch and probably HLA-DR7 were found to be probable risk factors associated with GVHD, and HLA-B35 was found to be a protective factor against severe acute GVHD. These data might be useful as prognostic factors in predicting the risk of GVHD and also in defining risk-related methods for GVHD prophylaxis.