Measurement of C1q binding to Donor specific antibodies (DSA) gives transplantation chance to hypersensitive patients having non-binding high amount of anti-HLA antibodies. In our series of 409 patients having either Class I and/or Class II anti-HLA antibody positivity, 79% of Class I positive , 59% of Class II positive patients could have been transplanted by testing of C1q binding. However, increased number of hypersensitive patients require more detailed pretransplant immunological assessment. In order to test reciprocity of crossmatch results and C1q binding of alloantibodies, we have cross compared MFI values of C1q binding of anti HLA antibodies and flow cytometric cross match in 276 hypersensitive and high-risk 'patients as kidney transplantation candidates. All patients have at least one class of PRA positivity measured by single antigen beads (Sab). MFI value is greater than 1000 for donor specific antibodies (DSA) and 5000 for non DSA positivity were cut off values for the decission of C1q testing. All sera were pretreated with DTT. Calculated MFI values of both T and B crossmatches were compared to MFI values of PRA and C1q binding. Increased B and T cell crossmatch MFI values were found to be correlated to MFI value of C1q binding in general( CC: 0,28 for B cells and CC: 0,38 for T cells; p=0.01). Those correlations were found to be stronger when DSA binding C1q values were compared to crossmatch results (CC: 0,4 (p=0.01) for B cell; CC: 0,59 (p=0.001) for T cells). In comparison to PRA positivity of B and T cell cross matches, a weaker correlation was found [(CC: 1,12 (p=0.01) for B cell and CC:0,22 (p=0.01) for T cell] as well as a similar correlations were found when DSA PRA values were compared to C1q bindings. We conclude that, comparative evaluation of both flow cytometric cross match results and C1q MFI values provides double checking possibility of immunological assesment in hypersensitive patients. Therefore, more accurate donor selection would be possible in high risk patient groups.

CITATION INFORMATION: Eksioğlu-Demiralp E., Türkmen A., Yelken B., Görçin S., Elbasi O., Yalçin F., Koçak B., Karatas C., Tuncer M., Altinel M. Comparison of C1Q Binding and Flow Cytometric Crossmatch Results Provides an Accurate Evaluation of Hypersensitive Kidney Transplant Patients Am J Transplant. 2017;17 (suppl 3).

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