102-P

Abstract

Aim Umbilical Cord Blood is validated as an alternative stem cell source allowing less HLA restriction for patients with malignant diseases. Besides the classical HLA matching, KIR genes form an independent diverse immunogenetic system that seems to have a significant influence on the outcome of allogeneic HSCT, especially the presence of B genotypes in the donor. Thus, the question rises on the possible value of KIR genotyping of prospective donors as an additional selection criterion. The aim of this study was to examine the diversity of the KIR repertoire of the HCBB (Hellenic Cord Blood Bank) inventory in comparison to previously documented favorable gene content (Cooley et al, 2010). Methods For this reason KIR genotyping of 320 CBU, for the presence of 14 KIR genes was performed, by PCR-SSO/SSP. Results The results revealed that 72.8% (233/320) of the donors had a Bx KIR genotype, while the remainder had the AA, which agreed with previously published KIR haplotype frequencies of the Greek population. When Bx KIR genotype content was further analyzed, 82.4% (192/233) of the CBUs had both KIR 2DL2/2DS2 (which may be independently advantageous), while 17.6% (41/233) had neither. On the other hand, the great variability of Bx genotypes observed in our inventory, indicates that units could be classified on the basis of a KIR B content score, in order to find a matching unit with the most favorable KIR gene content for a given patient. Conclusions In conclusion, adopting KIR genotyping could maximize the chance of identifying the optimal unit, out of several HLA-matched CBUs in our inventory, and would also be very attractive to incorporate in a unit selection algorithm in the future. It could become an additional service offered by the HCBB, which already offers high quality units that meet the highest standards in regards to TNC dose, CD34+ and CFU counts, HLA typing for HLA-A,-B,-DRB1 of both CBUs and mothers (making matching for NIMAs possible) and undergo all the required testing.