Chronic lung allograft dysfunction (CLAD) substantially limits long-term survival following lung transplantation. To identify potential targets for CLAD prevention, T cells from explanted CLAD lungs and lung-draining lymph nodes, as well as diseased and nondiseased controls were isolated and single-cell RNA sequencing and TCR sequencing were performed. TCR sequencing revealed a clonally expanded population of CD8+ tissue-resident memory T cells (TRMs) with high cytotoxic potential, including upregulation of KLRK1, encoding the co-receptor NKG2D. These cytotoxic CD8+ TRMs accumulated around the CLAD airways and had a 100-fold increase in clonal overlap with lung-draining lymph nodes when compared with non-CLAD lungs. Using a murine model of orthotopic lung transplantation, we confirmed that cytotoxic CD8+ TRM accumulation was due to chronic rejection and not transplantation alone. Furthermore, blocking NKG2D in vivo attenuated the airway remodeling following transplantation and diminished airway accumulation of CD8+ T cells. Our findings support NKG2D as a potential therapeutic target for CLAD, affecting cytotoxic CD8+ TRM accumulation.
Kaveh Moghbeli, Madeline A. Lipp, Marta Bueno, Andrew Craig, Michelle Rojas, Minahal Abbas, Zachary I. Lakkis, Byron Chuan, John Sembrat, Kentaro Noda, Daniel J. Kass, Kong Chen, Li Fan, Tim Oury, Zihe Zhou, Xingan Wang, John F. McDyer, Oliver Eickelberg, Mark E. Snyder