Incompatibility for CD31 and human platelet antigens and acute graft-versus-host disease after bone marrow transplantation

Bone marrow transplantation (BMT) is often complicated by acute graft-versu s-host disease (aGVHD), In patients transplanted with an HLA-matched donor the occurrence of this complication is believed to be favoured by dispariti es at the minor histocompatibility antigens (mHA). However, few of these po lymorphic molecules have been identified. We sought to determine whether do nor/ recipient incompatibility for HPA-1, HPA-2, HPA-3. HPA-5 or CD31 (codo n 125) antigens represented a risk factor for aGVHD and genotyped these ant igens in 70 bone marrow donors and their HLA-identical recipients. All pati ents were children who received BMT for haematological malignancies at a si ngle institution according to well-defined therapy protocols. Statistical a nalysis showed that incompatibility for CD31 (codon 125) was a risk factor for grade II-IV aGVHD in the overall patient population, whereas HPA-3 inco mpatibility predicted aGVHD occurrence in HLA-A2 patients only. The magnitu de of the aGVHD risk was directly related to the number of HPA/CD31 incompa tibilities. No correlation was found between non-identity for HPA/CD31 and aGVHD. Since incompatibility but not non-identity for CD31 or HPA-3 was a r isk factor for aGVHD, we suggest that allelic variants of these molecules c an serve as mHA in BMT recipients from HLA-identical donors.