C3d Assay Result in Potential Transplant Recipients with HLA-DSA, AHG-CDC CxM Negative and FxM Positive or Negative with Their Potential Donors.
Transplantation Department, Instituto Nacional de Ciencias Medicas y Nutricion SZ, Mexico City, Mexico
Meeting: 2017 American Transplant Congress
Abstract number: A247
Keywords: Antibodies, Flowcytometry crossmatching, HLA antibodies
Session Information
Session Name: Poster Session A: Living Donor Kidney Transplant I
Session Type: Poster Session
Date: Saturday, April 29, 2017
Session Time: 5:30pm-7:30pm
Presentation Time: 5:30pm-7:30pm
Location: Hall D1
Background: In a previous study we searched the association between the flow cytometry cross-match assay (FXM) result and the results obtained in the analysis of the C1q-SAB assay in a group of kidney transplant candidates with DSA against their potential living donors and a negative CDC cross-match in all cases. We found that for FXM prediction: the combination of DSA and C1q+Ab was the most specific (95.8%, 85-100), and the combination of DSA-MFI > 2,300 and C1q+Ab, the most sensitive (92%, 79.1-100). In this study we analyze the performance of the C3d assay as an alternative to C1q assay in a new group of patients with a similar clinical profile. Aim: To establish the DSA MFI level with the best sensitivity and specificity in predicting FXM and compare it with the C3d assay's predictive capacity in patients with DSA(s) and AHG-CDC CxM negative. Methods: We used cryopreserved (-70C) sera from potential renal transplant recipients (PRT), containing DSA(s) against their respective donors- all had negative AHG-CDC CxM and either positive or negative FXM. Results: Of the 92 FXM performed, 27 were positive. The median MFI of the immunodominant DSA was 1684 (IQR 1038 – 3882). 31 patients (33.7%) have at least one C3d+ HLAab, and only 10 of them could be assigned as donor specific. The best predictive cutoff value of immunodominant DSA MFI was 2000. The diagnostic performance was summarized in table 1.
| HLAAb C3d+ | DSA C3d+ | DSA > 2000 MFI | DSA>2000 + C3d | |
| Sensitivity | 62.9 (42.9 – 83.1) | 25.9 (7.54 – 44.3) | 81.4 (64.9 – 97.9) | 92.5 (80.8 – 100) |
| Specificity | 78.4 (67.7 – 89.2) | 95.3 (89.5 – 100) | 70.7 (58.9 – 82.6) | 58.4 (45.7 – 71.2) |
| PPV | 54.8 (35.7 – 73.9) | 70 (36 – 100) | 53.6 (37.1 – 70.1) | 48.1 (33.5 – 62.6) |
| NPV | 83.6 (73.5 – 93.7) | 75.6 (65.7 – 85.5) | 90.2 (81.1 – 99.3) | 95 (87 – 100) |
Conclusions: The conjunction of the findings of low MFI DSA (< 2000) and the absence HLAab C3d+, have a high negative predictive value to FXM.
CITATION INFORMATION: Contreras A, Casillas A, Castelan N, Gonzalez-Tableros N, Lopez M, Arvizu A, De Santiago A, Alberu J, Arreola-Guerra J. C3d Assay Result in Potential Transplant Recipients with HLA-DSA, AHG-CDC CxM Negative and FxM Positive or Negative with Their Potential Donors. Am J Transplant. 2017;17 (suppl 3).
To cite this abstract in AMA style:
Contreras A, Casillas A, Castelan N, Gonzalez-Tableros N, Lopez M, Arvizu A, Santiago ADe, Alberu J, Arreola-Guerra J. C3d Assay Result in Potential Transplant Recipients with HLA-DSA, AHG-CDC CxM Negative and FxM Positive or Negative with Their Potential Donors. [abstract]. Am J Transplant. 2017; 17 (suppl 3). https://atcmeetingabstracts.com/abstract/c3d-assay-result-in-potential-transplant-recipients-with-hla-dsa-ahg-cdc-cxm-negative-and-fxm-positive-or-negative-with-their-potential-donors/. Accessed May 11, 2025.« Back to 2017 American Transplant Congress