| Abstrakt: |
Patients awaiting renal transplantation over the 6‐month period from October 1988 to March 1989 were tested for autoreactive lymphocytotoxic antibodies (ALCA) by autologous crossmatch. All patient sera had previously been screened for lymphocytotoxic antibodies against a 40‐member cell panel, and only those with panel reactivity of 10% or more were included in the study (63/88). Lymphocytotoxic crossmatch was performed against autologous B and T lymphocytes using peak and current sera and other historical sera if available. A total of 167 sera from the 63 patients were tested. Fourteen of the 63 patients (22%) had ALCA, 10 of whom were available for further study. There was no apparent difference between race, age and peak or current panel reactivity among the 14 patients with and the 49 without ALCA. A second autocrossmatch was performed using 11 selected sera from the 10 patients with ALCA. Sera used for this crossmatch were depleted of ALCA using three methods; (1) autologous absorption (AA) with EBV‐transformed B‐lymphoblastoid cells. (2) treatment with dithiothreitol (DTT) which dissociates IgM, and (3) absorption with Staphylococcal protein A (PrA) for IgG depletion. In 7 sera, ALCA were removed by AA and DTT treatment but not PrA absorption, inferring an IgM antibody. In 1 serum ALCA was removed by AA and PrA absorption but not DTT treatment, inferring an IgG antibody. In 2 sera, ALCA activity remained after DTT treatment and PrA absorption and was only removed after AA. Alloantibodies were detected by screening AA, DTT‐treated and PrA‐absorbed sera from each patient against a 30‐member lymphocyte panel typed for HLA‐A and ‐B loci. Sera with persisting panel reactivity after AA were considered to contain alloantibodies. These were classified as IgM or IgG on the basis of their reduction or non‐reduction with DTT. Four reaction patterns were observed which identified ALCA (IgM and IgG) and alloantibodies (IgM and IgG). Alloantibodies were present in 5 of the 10 patients with ALCA. All patients identified as having alloantibodies had either a failed kidney graft and/or multiple transfusions (> 10 units). Two of these sera contained IgG alloantibodies alone, and 3 contained mixtures of IgG and IgM alloantibodies. HLA class I‐specific antibodies could be recognized in 3 patients and in each case appeared to be IgG. Some sera remain highly reactive after AA, indicating that high panel reactivity cannot be presumed to be due to ALCA in patients with a positive autocrossmatch. Five patients from this study were transplanted on the basis of a negative crossmatch using AA serum. Four grafts have good function at between 8 and 28 months after transplantation. One patient died with a functioning graft 12 months after transplantation. No patient experienced acute rejection in the 1st week. |
