OR31. Characterization of the CCR5 delta 32 mutation by race in unrelated donors listed on the national marrow donor program’s be the match registry

Aim Donors homozygous for the CCR5 delta 32 deletion are of interest in hematopoietic stem cell transplantation (HCT) for patients infected by both HIV-1 and a hematologic malignancy. The mutation has been published to confer natural HIV resistance to individuals carrying two copies, while heterozygous individuals show increased resistance and lower viral loads compared to wild type. The aim of this study was to characterize the CCR5 delta 32 deletion frequency in the diverse unrelated donor populations listed on the National Marrow Donor Program’s Be The Match Registry. Methods Next Generation Sequencing by the Illumina MiSeq was used to target the 32 base pair deletion in the CCR5 gene for 495,530 URDs between 2016-2018. The frequency of donors identified as homozygous, heterozygous and wild type for the mutation was calculated for each of broad race/ethnic groups; Black, Asian/Pacific Islander, White, Hawaiian, Hispanic and Native American Indian. Results Overall, .73% URDs were identified as CCR5 delta 32 homozygous in our cohort. The frequency of homozygotes found in unrelated registry donors self-identified as race group of White was similar (.95%) to previously published data on European individuals (1%). The frequency of homozygotes in the remaining populations was low with .04% observed in Black, .01% in Asian/Pacific Islander, .21% in Hispanic and .24% in Native American. Within donors carrying the homozygous genotype, the population was highly homogeneous, with 98.9% self-identifying as White, given predominate donor recruitment numbers and higher frequency. Conclusions The frequency of self-identified White U.S. registry donors homozygous for the CCR5 delta 32 deletion is consistent with previous studies on individuals of European descent. Given the low frequency of homozygous CCR5 delta32 genotypes in the unrelated donor population, additional treatment methods using multiply mismatched donors can extend the feasibility of this use case for concurrent HCT and infection therapy in HIV patients. Download high-res image (283KB) Download full-size image