Detection of donor-specific HLA antibodies: A retrospective observation in 350 renal transplant cases.

Background: The main objective of this study was to determine the results of the cell-based assay (CDC-XM and FC-XM), and correlate with the results of solid phase assay (L-SAB). Methods. In this retrospective study, 350 prospective renal transplant recipients were tested for the presence of HLA antibodies by CDC-XM, FC-XM and L-SAB screening with their corresponding donor. Results: T-cell-FC-XM showed a sensitivity of 71.43% and a specificity of 91.50% for detecting class I L-SAB (+), while B-cell-FCXM showed a sensitivity of 94.94% and a specificity of 61.99% for detecting class II L-SAB (t). On the other hand, T-CDC-XM showed a sensitivity of 32.14% and a specificity of 98.64% for detecting class I L-SAB (-4-), while B-CDC-XM showed a sensitivity of 44.30% and a specificity of 94.83% for detecting class H L-SAB (-). In this study, the results indicated that DSA class I MFI value of 2845 and above significantly (p 50.001) correlated with T-cell-FC-XM positivity, while MFI value of 4585 and above (p 50.001) showed strong predictive accuracy of a positive T-cell-CDC-XM. However, DSA class II MFI cut-off of 1988 and above significantly (p 50.001) correlated with B-cell-FC-XM positivity, while MFI value of 5986 and above (p %0.001) showed strong predictive accuracy of a positive B-cell-CDC-XM. Conclusions: Our study showed that CDC-XM has poor sensitivity, while FC-XM has poor specificity to detect DSA. L-SAB has good correlation with T-cell-FC-XM (p < 0.0001) but not with B-cell-FC-XM (P = 0.31). DSA strength >2845 and > 1988 significantly correlated with T-cell-FC-XM positivity and B-cell-FC-XM positivity, respectively. While, a MFI value of >4585 and > 5986 significantly correlated with T-tell-CDC-XM posilivity and Bcell- CDC-XM positivity, respectively. These MFI cut-off values could serve as a surrogate marker for CDC-XMl and FC-XM tests and may help in resolving the limitations of cell-based techniques. Iii conclusion, we found that LSAB is more sensitive and specific than CDC-XM and FC-XM and therefore may be used as a test of choice. [ABSTRACT FROM AUTHOR]