P126 Exression of killer cell immunoglobulin like receptors among Arabs from the Kuwait national stem cell registy

Abstract

Hematopoietic stem-cell transplantation (HSCT) is the curative approach for many patients with hematological malignancies. Despite improvements in HLA typing, it is unfortunately still impossible to prevent graft versus host disease (GVHD) in all cases and therefore can reduce the chances of achieving the curable goals of HSCT. An important immunological factor that influences the success of HSCT is the function of natural killer (NK) cells. NK cells are closely controlled by killer-cell immunoglobulin-like receptor (KIRs) which interact with specific HLA class I molecules. The presence or absence of individual KIR genes varies within and between populations, creating a diverse pool of KIR genotypes. Aim of this study was to investigate the KIR gene frequencies among 600 healthy Kuwaiti Arab unrelated volunteers donors. Methods KIR SSO genotyping was performed using the Luminex reverse SSO DNA. The study was performed on 600 random Kuwaiti individuals from the National Stem Cell Registry. Results The percentage for the presence of the KIR genes was found to be: KIR2DL1 95%, KIR2DL2 81%, KIR2DL3 91.5%, KIR2DL4 96%, KIR2DL5 62%, KIR2DP1 97%, KIR2DS1 34.3%, KIR2DS2 97.7%, KIR2DS3 53.1%, KIR2DS4 93.0%, KIR2DS5 67%, KIR3DL1 94.4%, KIR3DL2 99%, KIR3DL3 97%, KIR3DP1 98%, KIR3DS1 36%. The framework genes were present in almost 100% of the volunteers as expected. The donors were classified based on the number of B haplotype genes and A haplotype genes. Only 2% of the Kuwaiti subjects were of AA haplogroup genotype, making 98% Bx haplogroup genotype. Conclusion Findings of this study are crucial to characterize and to provide a new data on KIR genotype of the Kuwaiti Arab population. Ultimately it may improve HSCT matching outcome by choosing an HLA matched donor with NK-cell alloreactivity versus a non-alloreactive donor.