Development of bronchiolitis obliterans syndrome despite blood chimerism in human lung transplant recipients

Bronchiolitis Obliterans Syndrome (BOS) remains the overwhelming obstacle to the success of lung transplantations (LTx). The presence of donor-specific microchimerism (DSM) and its association with lung allograft function is not well defined. To investigate the relationship between chimerism and BOS, blood was obtained from 21 LTx recipients. Genomic DNA was isolated from patient blood, and PCR-based techniques were used to identify recipient and donor HLA-DR. Fifty percent of the LTx recipients with BOS exhibited DSM at "T1" time post transplant, and 40% at one year follow-up (T2). However, 54% exhibited DSM in the BOS-free group at T1, and 44% at T2. Of the BOS-free, DSM-positive patients at T1, 29% developed BOS by T2. In contrast, 50% of BOS-free DSM-negative patients 50% developed BOS (P > 0.05). Double LTx had a higher prevalence of DSM (73%) and a lower prevalence of BOS (46%) than single LTx (50% and 80% respectively, P > 0.05). One-HLA-DR-antigen-matched LTx recipients show a low prevalence of DSM compared to non-matched (P < 0.05). This study demonstrates that the development of BOS in LTx recipients could also occur in the presence of blood chimerism.