Assessing Antibody Strength: Comparison of MFI, C1q, and Titer Information.
The presence of donor-specific HLA antibodies before or after transplantation may have different implications based on the antibody strength. Yet, current approaches do not provide information regarding the true antibody strength as defined by antigen-antibody dissociation rate. To assess currently available methods, we compared between neat mean fluorescence intensity (MFI) values, C1q MFI values, ethylenediaminetetraacetic acid (EDTA)-treated samples, as well as titration studies and peak MFI values of over 7000 Luminex-based single-antigen HLA antibody data points. Our results indicate that neat MFI values do not always accurately depict antibody strength. We further showed that EDTA treatment (6%) does not always remove all inhibitory factors compared with C1q or titration studies. In this study of patients presenting with multiple antibody specificities, a prozone effect was observed in 71% of the cohort (usually not affecting all antibody specificities within a single serum sample, though). Similar to titration studies, the C1q assay was able to address the issue of potential inhibition; however, its limitation is its low sensitivity and inability to detect the presence of weak antibodies. Titration studies are the only method among the approaches used in this study to provide information suggesting antigen-antibody dissociation rates and are, therefore, likely to provide better indication of true antibody strength.
Transplant Immunology Laboratory, Northwestern University Feinberg School of Medicine, Chicago, IL.|Comprehensive Transplant Center, Northwestern University Feinberg School of Medicine, Chicago, IL.
A R
AR
Tambur
Transplant Immunology Laboratory, Northwestern University Feinberg School of Medicine, Chicago, IL.|Comprehensive Transplant Center, Northwestern University Feinberg School of Medicine, Chicago, IL.
N D
ND
Herrera
Transplant Immunology Laboratory, Northwestern University Feinberg School of Medicine, Chicago, IL.|Comprehensive Transplant Center, Northwestern University Feinberg School of Medicine, Chicago, IL.
K M K
KM
Haarberg
Transplant Immunology Laboratory, Northwestern University Feinberg School of Medicine, Chicago, IL.|Comprehensive Transplant Center, Northwestern University Feinberg School of Medicine, Chicago, IL.
M F
MF
Cusick
Division of Cardiology, Northwestern University Feinberg School of Medicine, Chicago, IL.|Comprehensive Transplant Center, Northwestern University Feinberg School of Medicine, Chicago, IL.
R A
RA
Gordon
Department of Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL.|Comprehensive Transplant Center, Northwestern University Feinberg School of Medicine, Chicago, IL.
J R
JR
Leventhal
Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL.|Comprehensive Transplant Center, Northwestern University Feinberg School of Medicine, Chicago, IL.
J J
JJ
Friedewald
Nephrology and Transplantation Service, Hôpital Saint-Louis, Paris, France.
D
D
Glotz
D000328:Adult; D000918:Antibody Specificity; D015922:Complement C1q / Q000276:immunology*; D005260:Female; D005453:Fluorescence; D006680:HLA Antigens / Q000276:immunology*; D006650:Histocompatibility Testing; D006801:Humans; D007518:Isoantibodies / Q000097:blood*; D016030:Kidney Transplantation; D008297:Male; D011379:Prognosis; D014019:Tissue Donors
D006680:HLA Antigens; D007518:Isoantibodies; D015922:Complement C1q
Antibody biology; desensitization; major histocompatibility complex (MHC); rejection: antibody-mediated (ABMR)