Effects of HLA-haploidentical blood transfusions on donor-specific immune responsiveness

Fifteen recipients of donor-specific blood transfusions (DST) from HLA haploidentical related donors were tested for changes in immune responsiveness following the transfusions. Three patients developed cytotoxic antibodies toward the donor, but no "broad" sensitization toward the panel cells was seen. The responsiveness to mitogens (PHA and con A) and soluble antigens (PPD and a mixture of antigens) was not changed. MLC responsiveness toward the donor, but not to third-party or pool-stimulating cells, was reduced. Evidence of specific MLC-suppressing cells was found in 11 of 15 patients following DST. The cell-mediated lympholysis response toward the donor increased in 50% of the patients after DST, including those who developed antibodies. The frequency of acute rejection episodes in the 11 grafted patients was not correlated with the changes in in vitro responsiveness.