Immune checkpoint inhibitor‐induced asthma and chronic obstructive pulmonary disease overlap in patient with adenocarcinoma

A 67‐year‐old current smoker Japanese man, with no history of asthma, was diagnosed with lung adenocarcinoma. He received first‐line chemotherapy with carboplatin, pemetrexed, ipilimumab, and nivolumab in July 20XX‐1, and subsequently a maintenance therapy with nivolumab. In October 20XX, he became aware of wheezy dyspnoea, and chest computed tomography demonstrated worsening bronchial wall thickenings. Eosinophilia was noted, and a pulmonary function test showed obstructive dysfunction insufficiently responding to beta‐agonists, with 130 mL increase of forced expiratory volume in one second and high fractional exhaled nitric oxide level (85 ppb). He was clinically diagnosed with asthma and chronic obstructive pulmonary disease overlap, secondary to immune checkpoint inhibitors (ICIs). The inhibition of binding between programmed cell death‐protein‐1 (PD‐1), expressed on T cells, and programmed cell death‐ligand‐2 (PD‐L2), expressed on tumour and dendritic cells, can induce airway hyperresponsiveness. Physicians should be wary of asthmatic symptoms and chest image findings during ICIs therapy.