Treatment Response of Donor Specific Antibodies and Forced Expiratory Volume in Lung Transplant Recipients With Antibody Mediated Rejection

Background. Antibody-mediated rejection (AMR) is an evolving diagnosis in lung transplantation. The presence of anti-human leukocyte antigen (HLA) donor-specific antibodies (DSAs) does not always correlate with clinical picture, leading to variation in treatment. This study sought to examine anti-HLA DSA response and lung allograft stabilization following AMR treatment. Methods. A single-center, retrospective case series was conducted in adult lung transplant recipients treated for clinical and subclinical AMR. The primary outcome was anti-HLA DSA reduction (>= 25% decrease in mean fl uorescence intensity [MFI]). The secondary outcome was forced expiratory volume (FEV1) stabilization (<= 10% decline) at peak FEV1 and at 6-months post-treatment. Results. Fifteen bilateral lung transplant recipients were included. Eight (53%) patients achieved the primary outcome with median MFI reduction of - 56.7% (interquartile range [IQR] = - 41.3 to - 69.5). Statistical significance was found on matched pairs analysis between 3 and 6 months post-treatment for anti-HLA DSA reduction. Of the subjects with available data, 7 of 9 (78%) patients had FEV1 stabilization from diagnosis to peak FEV1, and 5 of 7 (71%) patients had stabilization from diagnosis to 6 months post-treatment. A statistically significant decline was found from peak FEV1 post-treatment to 6 months post-treatment (-0.4 L 0.2, P = .05). Univariate analysis did not identify predictors affecting anti-HLA DSA response. Conclusions. Anti-HLA DSA response was achieved in approximately half the cohort. A statistically significant decline in FEV1 was seen from peak FEV1 post-treatment but stabilized in most patients by 6 months. These results highlight the difficulty of DSA management and recovering lung function once lost, however, the fi nding of FEV1 stabilization after treatment is notable.