Characteristics of Donor-Specific Antibodies Associated With Antibody-Mediated Rejection in Lung Transplantation

Abstract

Although donor-specific anti-human leukocyte antigen (HLA) antibodies (DSAs) are frequently found in recipients after lung transplantation (LT), the characteristics of DSA which influence antibody-mediated rejection (AMR) in LT are not fully defined. We retrospectively analyzed 206 consecutive LT patients of our center (2010-2013). DSAs were detected by using luminex single antigen beads assay and mean fluorescence intensity was assessed. Within the study population, 105 patients had positive DSA. Patients with and without AMR (AMR^Pos, n = 22, and AMR^Neg, n = 83, respectively) were compared. AMR^Pos patients had significantly greater frequencies of anti-HLA DQ DSA (DQ DSA) than AMR^Neg patients (95 vs 58%, respectively, p < 0.0001). Compared to AMR^Neg patients, AMR^Pos patients had higher DQ DSA sum MFI [7,332 (2,067-10,213) vs 681 (0-1,887), p < 0.0001]. DQ DSA when associated with AMR, had more frequent graft loss and chronic lung allograft dysfunction (CLAD). These data suggest (i) that DSA characteristics clearly differ between AMR^Pos and AMR^Neg patients and (ii) the deleterious impact of DQ DSA on clinical outcome.

Keywords: HLA; antibody mediated rejection; clinical outcome; donor-specific antibodies; lung transplant.

Figure 1

Flow chart and analysis summary.

Figure 2

Mean fluorescence intensity (MFI) of immunodominant donor-specific antibody (DSA) at peak according to antibody-mediated rejection (AMR) status. Peak was defined as the time point of DSA with the highest sum MFI for AMR^Neg (DSA^PosAMR^Neg) patients, or as the time of AMR diagnosis for AMR^Pos patients. (A) Each patient’s immunodominant DSA is a circle. Circles inside broken line ellipse (n = 7) represent patients with AMR despite an immunodominant DSA MFI < 5,000, whose characteristics are detailed in panel (C) (Mann–Whitney test). (B) ROC curve for use of immunodominant DSA MFI as a predictor of AMR diagnosis, and the specificity/sensitivity according to different MFI cut-offs. (C) Characteristics of the 7 AMR^Pos patients with immunodominant DSA MFI < 5,000. Significance values are denoted above lines over compared groups.

Figure 3

Sum mean fluorescence intensity (MFI) of donor specific antibody (DSA) at peak according to antibody-mediated rejection (AMR) status. Peak was defined as the time point of DSA with the highest sum MFI for AMR^Neg (DSA^PosAMR^Neg) patients, or as the time of AMR diagnosis for AMR^Pos patients. (A) The sum MFI of each patient’s DSA is indicated by each circle. The table below lists the number of patients, median and mean sum MFI, and number of specificities for each patient group. (B) ROC curve for use of sum MFI as a predictor of AMR diagnosis and the specificity/sensitivity according to MFI different cutoffs. Significance values are denoted above lines over compared groups.

Figure 4

DQ mean fluorescence intensity (MFI) of donor specific antibody (DSA) at peak according to antibody-mediated rejection (AMR) status. Peak was defined as the time point of DSA with the highest sum MFI for AMR^Neg (DSA^PosAMR^Neg) patients, or as the time of AMR diagnosis for AMR^Pos patients. (A) Frequency and number of patients with DQ DSA at the peak. (B) Frequency and number of patients with immunodominant DQ DSA at the peak. (C) Each patient’s DQ DSA MFI are represented as a circle. Comparison of number of patients, as well as median and mean DQ DSA MFI, for AMR^Pos and AMR^Neg patients is in the table below. (D) ROC curve for use of DQ DSA MFI as a predictor of AMR diagnosis and the specificity/sensitivity according to different MFI cutoffs. Groups were compared using Chi-square (A,B) and Mann–Whitney tests (C) and significance values are denoted above lines over compared groups.

Figure 5

Clinical outcome associated with anti-HLA DQ donor-specific antibody (DQ DSA). Patients were categorized as DQ DSA if they had at least once DSA directed against one DQ antigen. Patients were categorized as non DQ DSA if they had DSA but never directed against DQ antigen. (A) Graft survival conditioned by 3-month survival compared between DSA negative, non-DQ DSA and DQ DSA patients. Global comparison was statistically significant, but non-DQ DSA and DQ DSA comparison did not reach significance. (B) CLAD occurrence between DSA negative, non-DQ DSA, and DQ DSA patients. Again, global comparison was statistically significant, but non-DQ DSA and DQ DSA comparison did not reach significance. (C) Graft survival conditioned by 3-month survival compared between non DQ DSA AMR^neg, DQ DSA AMR^neg, and DQ DSA AMR^pos patients. The only non-DQ DSA AMR^pos patient was exclude of the analysis. Both global and DQ DSA AMR^neg and DQ DSA AMR^pos comparison were highly significant.