C1q-Fixing Human Leukocyte Antigen Antibodies Identified by a C1q Assay Are Associated with Acute and Chronic Rejection in HLA-IgG Positive Kidney Transplant Recipients
Laboratory Medicine, Catholic University, Seoul, Republic of Korea
Medical Cell Biology, Department of Biomedical Science, Graduate School, Catholic University, Seoul, Republic of Korea
Internal Medicine, Catholic University, Seoul, Republic of Korea
Meeting: 2013 American Transplant Congress
Abstract number: A636
Background: Although donor-specific HLA antibodies (DSA) are associated with antibody-mediated rejection (AMR) and poor clinical outcome in kidney transplantation, not all DSAs are harmful to graft function. Because complement activation is involved in AMR, distinguishing the complement-fixing is important. The C1q assay on single antigen beads (SAB) is sensitive and specific method to identify complement-fixing HLA antibodies. The aim of this study was to investigate the additional significance of C1q-fixing HLA antibodies for the prediction or diagnosis of rejection over IgG-DSA.
Method: This study included 53 renal transplant patients who had HLA-IgG antibodies by SAB assays. 27 of 53 recipients had biopsy-proven acute or chronic rejection (Rej). We retrospectively tested C1q-fixing HLA antibodies pretransplant and at the time of biopsy using C1q assay.
Results: Of 53 recipients, IgG-DSA class I or class II were detected in 34 (64%) sera, and C1q-fixing HLA antibodies were found in 18 (34.0%) sera. There was no significant difference of IgG-DSA frequencies between Rej(+) and Rej(-) recipients (14(51.9%) vs. 20(76.9%), P=0.106). However, the recipients with rejection had higher frequency of C1q-fixing HLA antibodies than Rej(-) patients (14 (51.9%) vs. 4 (15.4%), P=0.008). In comparison of mean fluorescence intensity (MFI) values on SAB assay with C1q-positivity, high MFI values were associated with C1q-fixation. Sera with high MFI (> 5000) had higher frequency of C1q positivity than sera with low MFI (<5000) (anti-HLA class I, 8/11 (72.7%) vs. 1/21 (4.8%), P<0.001 ; anti-HLA class II, 10/18(55.6%) vs. 1/9 (11.1%), P=0.042, respectively)
Conclusions: Since complement fixing is involved in AMR pathogenesis, a sensitive and specific assay detecting complement-fixing and HLA-specific antibodies would be useful to predict poor clinical outcome in kidney transplant patients.
To cite this abstract in AMA style:
Oh E, Park K, Kim Y, Chung B, Yang C. C1q-Fixing Human Leukocyte Antigen Antibodies Identified by a C1q Assay Are Associated with Acute and Chronic Rejection in HLA-IgG Positive Kidney Transplant Recipients [abstract]. Am J Transplant. 2013; 13 (suppl 5). https://atcmeetingabstracts.com/abstract/c1q-fixing-human-leukocyte-antigen-antibodies-identified-by-a-c1q-assay-are-associated-with-acute-and-chronic-rejection-in-hla-igg-positive-kidney-transplant-recipients/. Accessed October 9, 2024.« Back to 2013 American Transplant Congress