We developed a new and simplified donor-specific blood transfusion (DSBT) protocol for prospective kidney transplant recipients from one-haplotype-mismatched related donors. Prospective kidney donors gave 450 ml of blood in a quad-pack unit, and the blood was stored in a blood bank. Twenty-five patients were transfused with 100 ml of the respective donor's whole blood at 1, 8, and 15 days after its storage. After DSBT, only three (12%) developed donor-specific lymphocytotoxic antibodies. Following DSBT, donor-specific mixed lymphocyte culture (MLC) was significantly suppressed, without any accelerated (secondary-type) response in early MLC. In addition, sera obtained after DSBT also suppressed donor-specific MLC significantly. Sixteen recipients subsequently received a kidney transplant from the donor, and all had functioning grafts at three months, but one lost the graft thereafter (graft survival rate: 94% at 12 months). This study indicates that (1) 100 ml of stored whole-blood DSBT three times at weekly intervals is a practical, less immunizing, and effective approach to enhance graft survival in recipients of a one-haplotype-mismatched graft; and (2) immune consequences of DSBT include induction of donor-specific cellular and humoral adaptive responses that might be conducive to successful graft outcome.