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DONOR ACTIVATING KIR INFLUENCE OUTCOME POST UNRELATED STEM CELL TRANSPLANTATION.
Amal Bishara, Dianne De Santis, Chaim Brautbar, Campbell Witt, Aaron Nagler, Shimon Slavin and Frank Christiansen. Jerusalem Israel, Hadassah University Hospital, Tissue Typing Unit; Perth Australia, Royal Perth Hospital, Clinical Immunology and Biochemical Genetics; Perth Australia, University of Western Australia, School of Surgery and Pathology; Jerusalem Israel, Hadassah University Hospital, Lautenberg Center for General and Tumor Immunology and Jerusalem Israel, Hadassah University Hospital, Dept. of Bone Marrow transplantation and Cancer Immunotherapy.

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This study evaluated the role of KIR activating receptors on outcome of stem cell transplantation (SCT) from unrelated donors. Sixty four recipients transplanted at Dept of BMT, Hadassah Medical Center, Israel were included in the study. All recipients and donors were typed for the presence or absence of 11 KIR genes. Recipients were analyzed for engraftment, rejection, occurrence of acute graft versus host disease (aGVHD), relapse and survival. Engraftment, rejection and relapse were not associated with the total number of donor activating receptor or the presence of any particular KIR. However, the incidence of severe aGVHD was less frequent in recipients whose donors had four or more activating receptors (p<0.05). In particular, the absence of KIR2DS2 was associated with a high incidence of grades III-IV aGVHD (p=0.002), and this was also true of KIR2DS1 (p=0.04). The overall survival was higher if the donor had KIR2DS2 (p=0.02) or KIR2DS1 (p=0.05). The effect of KIR2DS2 and KIR2DS1 appeared to be additive with 56% 3-year survival if the donor had both KIR2DS2 and KIR2DS1 versus 7% survival if the donor had neither receptor. These results demonstrate that donor KIR activating receptors influence outcome of unrelated SCT and therefore could be considered as a criteria for donor selection.