Microchimerism decades after transfusion among combat-injured US veterans from the Vietnam, Korean, and World War II conflicts.
BACKGROUND
Blood transfusion after traumatic injury can result in microchimerism (MC) of donor white cells (WBCs) in the recipient as late as 2 to 3 years postinjury, the longest prospective follow-up to date. The purpose of this study was to determine how long transfusion-associated MC lasts after traumatic injury.


METHODS
A group of US combat veterans who received transfusions who responded to a recruitment notice was retrospectively evaluated. Their blood was sampled, and MC was assessed by quantitative allele-specific polymerase chain reaction detection of differences at the HLA-DR locus or a panel of insertion-deletion polymorphism loci. Results of veterans were compared to those from an age- and gender-matched blood donor control group, from whom WBCs were retrieved from leukoreduction filters.


RESULTS
Among 163 combat veterans who received transfusion and 150 control subjects who did not receive transfusions, 16 (9.8%) of the veterans and 1 (0.7%) control subject had evidence of MC (relative risk, 14.7; 95% confidence interval, 2.0-110). The veterans with MC included 3 who served in WWII (7% of subjects from that conflict), 5 in Korea (18%), and 6 in Vietnam (7%).


CONCLUSIONS
Transfusion for combat-related injury can result in MC that lasts for 60 years, suggesting that it may involve permanent engraftment. MC is rare among male blood donors who did not receive transfusions, who are probably representative of individuals who have not had postnatal allogeneic exposures.
Utter
Garth H
GH
Department of Surgery, University of California, Davis, Medical Center, Sacramento, California 95817, USA. garth.utter@ucdmc.ucdavis.edu
Lee
Tzong-Hae
TH
Rivers
Ryan M
RM
Montalvo
Lani
L
Wen
Li
L
Chafets
Daniel M
DM
Reed
William F
WF
Busch
Michael P
MP
D000368:Aged; D000369:Aged, 80 and over; D001803:Blood Transfusion; D046528:Chimerism; D005500:Follow-Up Studies; D006801:Humans; D047869:Korean War; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013997:Time Factors; D014481:United States; D014493:United States Department of Veterans Affairs; D014728:Veterans; D047829:Vietnam Conflict; D014857:Warfare; D047789:World War II; D014947:Wounds and Injuries / Q000628:therapy*