RAFT-VERSUS-HOST DISEASE OCCURRENCE AMONG CORD BLOOD TRANSPLANTATION RECIPIENTS IN RELATION TO HUMAN LEUKOCYTE ANTIGEN MATCH GRADE

Umbilical cord blood (UCB) transplantation has been consistently found to have low rates of graft-versus-host disease (GVHD), high rates of engraftment, and faster turnaround times in terms of finding suitable donors. In addition, it serves as a viable option for individuals with no matched donor options especially due to its flexible human leukocyte antigen matching criteria. Despite its advantages, there has been an overall decrease in UCB transplantation. However, its advantages emphasize the need for further research and investment in resources such as cord blood banking especially since pediatric populations are most likely to benefit from continued research due to them typically being the recipients of UCB transplantation. A retrospective cohort study was conducted to determine if recipients of a mismatched UCB transplantation were at higher risk of developing acute GVHD and failure to achieve engraftment. Other risk factors including cytomegalovirus (CMV) serology status, geographical origin of UCB unit, and primary disease were examined to determine if they were associated with an increased risk of acute GVHD and failure to achieve engraftment. The results for the following factors were shown to be not significant thus not considered as an increased risk of acute GVHD: mismatched cord blood units according to 6 loci matching criteria (RR 1.09; CI 95%, 0.28-4.24; p = 0.61), mismatched cord blood units according to 10 loci matching criteria (RR 0.86; CI 95%, 0.19-3.89; p = 0.57), malignant primary disease (RR 2.55; CI 95%, 0.65-9.94; p=0.54), international CBU origin (RR 0.63; CI 95% 0.08-4.73; p=0.54), and positive donor’s maternal CMV status (RR 0.82; CI 95%, 0.20-3.35; p=0.54). In addition, the following results for potential risk factors were not significant thus not considered as an increased risk of failure to achieve engraftment: mismatched cord blood units according to 6 loci matching criteria (RR 1.28; CI 95%, 0.12-13.54; p = 0.66), mismatched cord blood units according to 10 loci matching criteria (RR 0.56; CI 95%, 0.05-5.86; p = 0.53), and malignant primary disease (RR 0.74; CI 95%, 0.07-7.86; p=0.64). The non-significant results could be contributed to the fact that the small sample size did not meet the requirement for 80% power. Despite this major limitation, the study helped further understand how match grade is related to GVHD development especially since there is a limited number of studies on this topic to begin with. This study emphasizes the need for further large-scale research to gain a more comprehensive understanding of UCB transplantation. Further research has implications to improve the transplant-related diseases in the pediatric populations around the world