BACKGROUND: We evaluated the effect of antithymocyte globulin (ATG) on anti-human leukocyte antigen (HLA) antibody assays. METHODS: We tested sera from six in vivo ATG-treated kidney transplant patients after measuring serum concentrations, as well as six nonsensitized sera with ATG added in vitro. T- and B-cell complement-dependent cytotoxicity (CDC), flow cytometric (FXM), and solid-phase HLA class I and II assays based on antigen-coated microspheres and enzyme-linked immunosorbent assay (ELISA) were studied. Sera were then retested after treatment to remove ATG. RESULTS: We found that ATG affects test results differently depending on whether sera is obtained from in vivo treated patients or added in vitro. In vitro treated sera produced ATG concentration-dependent positive results for T/B CDC, FXM, and flow bead testing for HLA I/II, while the ELISA-based assay was unaffected. In vivo treated sera from ATG-treated patients produced positive test results for T CDC and T/B FXM, while the B-cell CDC crossmatch remained negative. Solid phase assays were minimally affected using in vivo treated sera. After ATG extraction, all tests became negative. CONCLUSION: We conclude that ATG produces positive results in anti-HLA antibody testing, and treatment to remove ATG abolishes this effect. This treatment allows ATG-treated patients to be monitored for anti-HLA antibodies.
BACKGROUND: We evaluated the effect of antithymocyte globulin (ATG) on anti-human leukocyte antigen (HLA) antibody assays. METHODS: We tested sera from six in vivo ATG-treated kidney transplant patients after measuring serum concentrations, as well as six nonsensitized sera with ATG added in vitro. T- and B-cell complement-dependent cytotoxicity (CDC), flow cytometric (FXM), and solid-phase HLA class I and II assays based on antigen-coated microspheres and enzyme-linked immunosorbent assay (ELISA) were studied. Sera were then retested after treatment to remove ATG. RESULTS: We found that ATG affects test results differently depending on whether sera is obtained from in vivo treated patients or added in vitro. In vitro treated sera produced ATG concentration-dependent positive results for T/B CDC, FXM, and flow bead testing for HLA I/II, while the ELISA-based assay was unaffected. In vivo treated sera from ATG-treated patients produced positive test results for T CDC and T/B FXM, while the B-cell CDC crossmatch remained negative. Solid phase assays were minimally affected using in vivo treated sera. After ATG extraction, all tests became negative. CONCLUSION: We conclude that ATG produces positive results in anti-HLA antibody testing, and treatment to remove ATG abolishes this effect. This treatment allows ATG-treated patients to be monitored for anti-HLA antibodies.
Authors: M Mengel; B Sis; M Haas; R B Colvin; P F Halloran; L C Racusen; K Solez; L Cendales; A J Demetris; C B Drachenberg; C F Farver; E R Rodriguez; W D Wallace; D Glotz Journal: Am J Transplant Date: 2012-02-02 Impact factor: 8.086