Representative QAS-PCR results of short-term survival kinetics of male donor leukocyte subsets in female transfusion recipients 1 and 2 (A and B). The pre- (pre-tx) and post-tx (post-tx) serial frozen whole-blood samples collected from female recipients were subjected to the enrichment of leukocyte subpopulations including CD4, CD8, CD15, and CD19 cells, followed by amplification and quantitation using Y-chromosome–specific primers.