Korean J Transplant.  2020 Dec;34(Supple 1):S48. 10.4285/ATW2020.OP-1158.

The clinical utility of preformed C1q-binding donor-specific anti-HLA antibodies in kidney transplantation

• Lee S
• Yang CW
• Chung BH

• KMID: 2509182
• DOI: http://doi.org/10.4285/ATW2020.OP-1158

Abstract

Background
The role of C1q-binding donor-specific antibody (DSA) in antibody-mediated rejection (AMR) is considered important. De novo C1q-binding DSA is well known as an associated factor for increased risk of AMR and graft loss. However, the impact of preformed C1q-binding DSA is not yet clear. We investigated the clinical utility of identification of preformed C1q-binding DSA for predicting graft outcomes in kidney transplantation (KT).
Methods
From December 2016 to December 2019, 373 recipients underwent living-donor KT at St. Mary's Hospital. If the result of panel reactive antibody was positive in the pre-transplant, DSA and C1q-binding DSA were performed using Luminex single antigen bead assay. According to the presence of C1q-binding DSA, recipients were classified as C1q-positive and C1q-negative groups. Primary outcome was biopsy-proven acute AMR.
Results
Of 373, 75 recipients (20.1%) had preformed DSA. Among them, 16 recipients (4.3%) had preformed C1q-binding DSA. C1q-positive group had more positive panel reactive antibody (PRA) class II and DSA class II with statistical significance (P=0.036 and P=0.050, respectively). DSA class II mean fluorescence intensity in C1q-positive group was significantly higher than in C1q-negative group (median [interquartile range], 13,796 [10,746–22,883] vs. 5,055 [1,247–7,697]; P<0.001). The incidence of acute rejection in C1q-positive group was significantly higher than in C1q-negative group, especially acute AMR (P=0.037 and P=0.040, respectively). In Kaplan-Meier analysis, the cumulative incidence of acute AMR in C1q-positive group was significantly higher than in C1q-negative group (P=0.012). In univariate logistic regression analysis, C1q-binding DSA was related with an increased risk of acute AMR (hazard ratio, 3.81; P=0.023).
Conclusions
Preformed C1q-binding DSA would be associated with an increased risk of acute AMR. Surveillance, such as protocol allograft biopsy, can help to detect acute AMR early in recipients with preformed C1q-binding DSA.