Mismatches of minor histocompatibility antigen (mHag) between HLA identical stem cell donor and host are known as a major risk factor for graft-versus-host disease (GVHD). We determined the alleles of 4 polymorphic molecules including HA-1 and 3 adhesion molecules; CD62L, CD31 codon563 and CD31 codon125 in 114 patients transplanted HLA identical stem cell grafts and investigated the association of mismatches as rates of relapse and GVHD. All 114 recipients underwent stem cell transplantation after myeloablative conditioning between 1985 and 2004. Risk ststus of the disease at SCT was standard (n=71) and high (n=43). After SCT, 36, 57 and 35 developed acute GVHD (≥2), chronic GVHD and relapsed, respectively. Our patients relapsed at rates of 14.3% and 38.0% with one or more and without incompatibilities (P=0.011). In standard risk group, the relapse rates of 20 and 51 patients with and without mHag incompatibilities were 5.0% and 39.2%, respectively (P=0.011). The relapse rates of patients with CD62L, CD31 codon563, HA-1, CD31 codon125 incompatibilities were 5.3%, 11.8%, 16.7%, 23.1% respectively. The frequency of acute GVHD (≥2) did not differ regardless of incompatibilities.

The probability of 10 year survival rates were 84.0% with incompatibility and 54.3% without incompatibility patients (P=0.009). Our data suggests that incompatibilities of at least one of 4 polymorphic molecules contribute to GVL effect rather than to GVHD, resulting in prolonged survival after HLA identical SCT.

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