Exploration and practice of HLA antibody detection strategy at organ transplantation laboratoryies / 中华器官移植杂志

ABSTRACT

Objective:To compare the results of three detection methods, single antigen-bead assay(SAB), Luminex screening assay(LMX), and ELISA assay for detecting HLA antibody, and compares the two screening methods, LMX and ELISA with SAB detection as a reference method to provide a reference for organ transplantation laboratories to choose a reasonable HLA antibody test strategy.Methods:A lot of 124 consecutive samples were tested using SAB, ELISA, and LMX methods at the same time, and analyze the differences of these results. SAB testing was used as a reference method to analyze the sensitivity and specificity of the two screening assays. Chi-square analysis was used to compare the two methods, and P<0.05 was considered statistically significant. Results:Both ELISA and LMX methods showed low sensitivity of 34.4% and 31.3% for HLA class I, and 29.7% and 51.3% for class Ⅱ. Otherwise, the specificity of the ELISA and LMX method was much higher. For class, I both was 98.9%, and for class Ⅱ were 100% and 91.9% respectively. Out of 124 samples, the number of SAB(+ )ELISA(-)LMX(-) results was 17, and SAB(-)ELISA(+ )LMX(+ ) results was zero indicating that there were considerably screening assays probably with missed detection. In the cases of SAB(+ )ELISA(-)LMX(-), the distribution of MFI value of SAB assay ranges from 750 to 7000.Conclusions:Because the sensitivity of the two screening methods is relatively low, there is a greater risk of missed antibody detection in the scheme of testing for specific antibodies after the screening test is positive. This should be paid attention to, especially for patients with a history of sensitization. For negative screening test results, SAB or other assays should be considered to check the result. It could provide more accurate results when SAB which is recognized as higher sensitivity and specificity is directly used as an initial test. At the same time, the MFI value of the SAB test can serve as an indicator to determine whether to add other assays to check the ASB result.