Transfusion-associated graft-versus-host disease in an immunocompetent patient following cardiac surgery

We determined which of the 22 blood components obtained from unrelated donors and transfused to an apparently immunocompetent patient following open heart surgery caused transfusion-associated graft-versus-host disease (TA-GVHD).

Serologic and molecular methods were used to type the donors, the patient's family members, and the patient's postmortem tissues for HLA and a genetic marker on chromosome 17.

Two donors were homozygous for the HLA class I antigens A1 B8, for which the patient was heterozygous. Both donors were heterozygous, not homozygous as expected, for the class II alleles. One of them had the same class II alleles as the patient (DRB1*0301, DRB3*0101/DRB1*0404, DRB4*0103). The patient's tissues were chimeric for restriction fragments at 17p13 of this donor.

One-way HLA match leading to TA-GVHD can be caused by donor blood that is homozygous for class I and heterozygous for class II alleles. Two blood components given to our patient had such one-way HLA match. Class II alleles of the lymphocytes in one component were identical with those of the recipient and caused TA-GVHD. Class II alleles of the lymphocytes in the other component differed from those of the recipient and were eliminated either by the immune system of the patient or the lymphocytes that caused the TA-GVHD (graft versus graft).