Evidence to Support a Contribution of Polyreactive Antibodies to HLA Serum Reactivity.
BACKGROUND
Assessing the serum reactivity to HLA is essential for the evaluation of transplant candidates and the follow-up of allograft recipients. In this study, we look for evidence at the clonal level that polyreactive antibodies cross-reactive to apoptotic cells and multiple autoantigens can also react to HLA and contribute to the overall serum reactivity.


METHODS
We immortalized B cell clones from the blood of 2 kidney transplant recipients and characterized their reactivity to self-antigens, apoptotic cells as well as native, denatured, and cryptic HLA determinants using enzyme-linked immunosorbent assay (ELISA), immunofluorescence, flow cytometry and Luminex assays. We also assessed the reactivity of 300 pretransplant serum specimens to HLA and apoptotic cells.


RESULTS
We report here 4 distinct B cell clones cross-reactive to self and HLA class I. All 4 clones reacted to numerous HLA class I alleles but did not appear to target canonical "shared" epitopes. In parallel experiments, we observed a strong correlation between IgG reactivity to HLA and apoptotic cells in pretransplant serum samples collected from 300 kidney transplant recipients. Further analysis revealed that samples with higher reactivity to apoptotic cells displayed significantly higher class I percent panel-reactive antibodies compared to samples with low reactivity to apoptotic cells.


CONCLUSIONS
We provide here (1) proof of principle at the clonal level that human polyreactive antibodies can cross-react to HLA, multiple self-antigens and apoptotic cells and (2) supportive evidence that polyreactive antibodies contribute to overall HLA reactivity in the serum of patients awaiting kidney transplant.
1 Department of Surgery, Transplant Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA. 2 Transplant Center, The First Hospital of Jilin University, Changchun, China. 3 The Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China. 4 Division of Nephrology, New York Presbyterian Hospital, Columbia University Medical Center, New York, NY. 5 Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA.
Baoshan
B
Gao
Chunshu
C
Rong
Fabrice
F
Porcheray
Carolina
C
Moore
Timothy C
TC
Girouard
Susan L
SL
Saidman
Waichi
W
Wong
Yaowen
Y
Fu
Emmanuel
E
Zorn
D017209:Apoptosis; D001324:Autoantigens; D001402:B-Lymphocytes / Q000276:immunology*; D001900:Boston; D002999:Clone Cells; D018920:Coculture Techniques; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes; D061252:Feeder Cells; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D050438:Genes, Immunoglobulin Heavy Chain; D057809:HEK293 Cells; D006680:HLA Antigens / Q000276:immunology*; D006648:Histocompatibility; D006650:Histocompatibility Testing; D006801:Humans; D007135:Immunoglobulin Variable Region / Q000235:genetics; D007518:Isoantibodies / Q000097:blood*; D019169:Jurkat Cells; D016030:Kidney Transplantation; D015458:Leukemia, T-Cell / Q000276:immunology / Q000473:pathology; D066027:Transplant Recipients
D001324:Autoantigens; D000939:Epitopes; D006680:HLA Antigens; D007135:Immunoglobulin Variable Region; D007518:Isoantibodies