HLA CLASS I AND CLASS II ANTIBODIES OF BROAD SPECIFICITY IDENTIFIED IN PATIENTS RELISTED FOR KIDNEY TRANSPLANTS.

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HLA CLASS I AND CLASS II ANTIBODIES OF BROAD SPECIFICITY IDENTIFIED IN PATIENTS RELISTED FOR KIDNEY TRANSPLANTS.
Deborah A. Sesok-Pizzini, MD , Eline T. Luning Prak, MD PhD , Brad Johnson MD PhD , Stephen Master MD PhD , Jane Kearns MT CHS and Malek Kamoun MD PhD . Philadelphia PA, USA, University of Pennsylvania Medical Center, 19104-4283, Pathology and Laboratory Medicine .

Introduction: Patients relisted for a kidney transplant often spend more time on the waiting list compared to those waiting for their first transplant. This is in part due to an increased difficulty in obtaining crossmatch compatible organs because of HLA antibodies formed from mismatched antigens in the first donor. We have therefore examined the frequency and characteristics of the HLA antibodies present in these patients who were relisted for a kidney transplant.
Methods: Sera from 105 patients listed for kidney retransplant were examined for Class I and Class II antibodies using a combination of CDC and flow cytometry technique. Antibody specificities for HLA Class I and Class II antigens from a small subset of 20 of these patients were also studied using a sensitive single antigen bead flow cytometry assay (One Lambda, Inc.)
Results: Our results showed that 68 of the 105 patients (65%) had both Class I and Class II antibodies and 14 (13%) had Class II antibodies. In the subset of 20 patients where HLA antibody specificities were examined, 15 patients (75%) showed HLA Class I antibodies directed toward mismatched donor antigens from the first graft. Furthermore, these antibodies were of broader specificities. The other 25% of patients showed no antibodies directed against mismatched antigens from the first donor.
Conclusion: In this study, the majority of kidney transplant patients have developed both HLA Class I and Class II antibodies. These patients were more likely to have HLA Class I antibodies of broad specificity directed against mismatched antigens from the first graft. Thus, the development of new methods for defining acceptable mismatches in presensitized kidney transplant patients are needed.