- Email: [email protected]
22-P: Univeristy of Chicago Medical Center AHG-CDC crossmatch validation experience
Abstracts
S19
22-P
UNIVERISTY OF CHICAGO MEDICAL CENTER AHG-CDC CROSSMATCH VALIDATION EXPERIENCE. J.G. Weidner, W.F. Herczyk, J.R. Meade, S.R. Marino. Transplant Immunology & Immunogenetics Laboratory, University of Chicago Medical Center, Chicago, IL, USA. Aim: The University of Chicago Medical Center (UCMC) laboratory performs solid-phase antibody (Ab) testing. The final crossmatches (XMs) are flow crossmatch (FXM) and AHG-CDC XM. Methods: The UCMC validated T and B cell AHG-CDC XM using sera from 4 ASHI accredited laboratories; Medstar Research Institute, Ohio State University Medical Center, Duke University Heath System, and DCI. Sera provided had specificities to 5 cells of known HLA. Ab testing was performed at the original laboratories by CDC or solid phase methods. When solid-phase methods were used, efforts were made to select samples with high levels of Ab reactivity. Twenty-nine sera were crossmatched against 5 cells providing 32 T and 28 B cell AHG-CDC XMs. Serum/cell combinations for parallel testing were selected to provide a range of positive and negative results. Results: The AHG-CDC validation showed T cell concordance of 84% (27/32) and B cell concordance of 82% (23/28). All predicted negative T (17) and B cell (9) XMs correlated. Predicted T cell positive XMs were in concordance 67% (10/15). Predicted B cell positive XMs were in concordance 74% (14/19). Five predicted positive T and B cell XMs were negative. These XM pairs were predicted positive using solid phase and not CDC specificity. Six FXMs were performed with the AHG-CDC XMs on sera tested by non-CDC methods. Five of 6 FXMs were positive. The results demonstrate that the sera provided had specificities that would be XM positive when the XM and PRA method have comparable sensitivity. Conclusions: The UCMC laboratory validation experience shows that even samples with strong solid-phase detectable Ab do not always result in a positive AHG-CDC XM. Therefore, solid-phase Ab testing cannot be used to predict all AHG-CDC XM outcomes.
23-P
POTENTIAL RELEVANCE OF HLA-E SPECIFIC ANTIBODIES IN RENAL TRANSPLANTATION. Yvonne M. Zoet,1 Erik Pereira,1 Marrie Franke,1 Chantal Eijsink,1 Vera Rebmann,2 Peter vd Elsen,1 Elisabeth Weiss,3 Arend Mulder,1 Frans H.J. Claas,1 Ilias I.N. Doxiadis.1 1Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, Netherlands; 2Institut of Immunology, University Hospital Esse-GHS, Essen, Germany; 3Institute of Anthropology, University of Munich, Munich, Germany. Aim: Allo antibodies against the classical HLA-A and –B antigens have been implicated in hyperacute, acute and chronic renal allograft rejection. Since HLA-E is constitutively expressed on endothelial cells, we examined whether antibodies against HLA-E do also play a role in renal transplantation. Methods: HLA-ER (HLA-E*0101) transfected K562 cells and HLA-EG (HLA-E*0103) transfected K562 cells were used as targets for flow cytometric cross matches with a panel of 94 locally produced human monoclonal antibodies (human mAbs, reactive with HLA-A, B and C allelic products). Sera of multiparous women (donors, whose lymphocytes were used for human mAb development) and sera from renal patients awaiting a primary or re-transplant were also tested. Results: Out of 94 human mAbs, four mAbs and the sera from the donors, who were the source of these mAbs cross reacted with the HLA-E transfectants. Sera from 13/43 retransplant candidates, but only 2/21 sera from patients waiting for their first transplant showed positive reactions as well (p⬍0.05). Conclusions: HLA-E turns out to be recognized by human alloantisera especially in patients who have rejected a renal allograft. These results are indicative of a humoral immune response towards these gene products. HLA-E typing of recipients and donors should reveal whether this reactivity is due to auto- or allo antibodies.
S19
22-P
UNIVERISTY OF CHICAGO MEDICAL CENTER AHG-CDC CROSSMATCH VALIDATION EXPERIENCE. J.G. Weidner, W.F. Herczyk, J.R. Meade, S.R. Marino. Transplant Immunology & Immunogenetics Laboratory, University of Chicago Medical Center, Chicago, IL, USA. Aim: The University of Chicago Medical Center (UCMC) laboratory performs solid-phase antibody (Ab) testing. The final crossmatches (XMs) are flow crossmatch (FXM) and AHG-CDC XM. Methods: The UCMC validated T and B cell AHG-CDC XM using sera from 4 ASHI accredited laboratories; Medstar Research Institute, Ohio State University Medical Center, Duke University Heath System, and DCI. Sera provided had specificities to 5 cells of known HLA. Ab testing was performed at the original laboratories by CDC or solid phase methods. When solid-phase methods were used, efforts were made to select samples with high levels of Ab reactivity. Twenty-nine sera were crossmatched against 5 cells providing 32 T and 28 B cell AHG-CDC XMs. Serum/cell combinations for parallel testing were selected to provide a range of positive and negative results. Results: The AHG-CDC validation showed T cell concordance of 84% (27/32) and B cell concordance of 82% (23/28). All predicted negative T (17) and B cell (9) XMs correlated. Predicted T cell positive XMs were in concordance 67% (10/15). Predicted B cell positive XMs were in concordance 74% (14/19). Five predicted positive T and B cell XMs were negative. These XM pairs were predicted positive using solid phase and not CDC specificity. Six FXMs were performed with the AHG-CDC XMs on sera tested by non-CDC methods. Five of 6 FXMs were positive. The results demonstrate that the sera provided had specificities that would be XM positive when the XM and PRA method have comparable sensitivity. Conclusions: The UCMC laboratory validation experience shows that even samples with strong solid-phase detectable Ab do not always result in a positive AHG-CDC XM. Therefore, solid-phase Ab testing cannot be used to predict all AHG-CDC XM outcomes.
23-P
POTENTIAL RELEVANCE OF HLA-E SPECIFIC ANTIBODIES IN RENAL TRANSPLANTATION. Yvonne M. Zoet,1 Erik Pereira,1 Marrie Franke,1 Chantal Eijsink,1 Vera Rebmann,2 Peter vd Elsen,1 Elisabeth Weiss,3 Arend Mulder,1 Frans H.J. Claas,1 Ilias I.N. Doxiadis.1 1Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, Netherlands; 2Institut of Immunology, University Hospital Esse-GHS, Essen, Germany; 3Institute of Anthropology, University of Munich, Munich, Germany. Aim: Allo antibodies against the classical HLA-A and –B antigens have been implicated in hyperacute, acute and chronic renal allograft rejection. Since HLA-E is constitutively expressed on endothelial cells, we examined whether antibodies against HLA-E do also play a role in renal transplantation. Methods: HLA-ER (HLA-E*0101) transfected K562 cells and HLA-EG (HLA-E*0103) transfected K562 cells were used as targets for flow cytometric cross matches with a panel of 94 locally produced human monoclonal antibodies (human mAbs, reactive with HLA-A, B and C allelic products). Sera of multiparous women (donors, whose lymphocytes were used for human mAb development) and sera from renal patients awaiting a primary or re-transplant were also tested. Results: Out of 94 human mAbs, four mAbs and the sera from the donors, who were the source of these mAbs cross reacted with the HLA-E transfectants. Sera from 13/43 retransplant candidates, but only 2/21 sera from patients waiting for their first transplant showed positive reactions as well (p⬍0.05). Conclusions: HLA-E turns out to be recognized by human alloantisera especially in patients who have rejected a renal allograft. These results are indicative of a humoral immune response towards these gene products. HLA-E typing of recipients and donors should reveal whether this reactivity is due to auto- or allo antibodies.