PDCD1LG2 and lung disorder: Antibodies against PD‐1 inhibit binding of both PD‐L1 and PD‐L2 to PD‐1 expressed on activated T cells.3, 8, 12 This raises the possibility that blockade of PD‐1–PD‐L2 interaction by anti‐PD‐1 antibodies mediates Th2‐associated pulmonary diseases such as AEP: anti‐PD‐1 antibody activates Th2 cells and promotes the production of Th2‐type cytokines in the lung.