Association of antiidiotypic antibody with successful second transplant of a kidney sharing HLA antigens with the previous hyperacutely rejected first kidney.

The evolution of HLA antibodies and autoantiidiotypic antibodies (AB2) were studied during an 18-month period in a patient who hyperacutely rejected an HLA-A2-positive kidney, but tolerated a second HLA-A2-positive kidney one year later. Following rejection of the first kidney, the patient's serum contained an HLA-A2 antibody that reacted with 100% of HLA-A2-positive panel cells. After several months, the HLA-A2 antibody activity was precipitously lost over a one-month period and could no longer be identified by sensitive lymphocytotoxicity procedures. Approximately one year later, the patient received a second HLA-A2-positive kidney that has survived for a 2-year period and was not associated with significant rejection episodes during the early posttransplantation period. Prior to and episodically following the second transplant, the patient's sera contained antiidiotypic-like antibodies that specifically inhibited HLA alloantibodies directed against HLA-A2. AB2, with specificity for a putative idiotype on HLA-A2 alloantibodies, existed concurrently with other HLA alloantibodies in the patient's serum that had not been lost over the course of several months. This case study demonstrates a temporal association between the loss of a specific HLA antibody and the development of an AB2 with inhibitory specificity for the antibody. The study also confirms that anamnestic responses to donor-specific antigens do not always occur in previously alloimmunized patients rechallenged with the same HLA antigens.