Successful management of Epstein‑Barr virus‑associated severe checkpoint inhibitor‑related pneumonitis: A case report.

A novel current treatment, immunotherapy, is normally effective for pulmonary lymphoepithelial carcinoma (pLELC). However, it is frequently accompanied by responses such as immune checkpoint inhibitor-associated pneumonitis (CIP), a rare immune adverse reaction that may be fatal in severe cases. pLELC is known to be linked to Epstein-Barr virus (EBV), while associations between EBV and CIP in clinical settings have rarely been reported. A 57-year-old male patient with pLELC presented at our hospital with cough, expectoration, fever and dyspnea following his third course of immunotherapy at another hospital. Diagnosis of grade 4 CIP was confirmed. Simultaneously, a rapid increase in the EBV titer and response of CIP to corticosteroids were observed. The corticosteroids and antiviral drugs were then increased. In spite of his severe condition, the patient recovered within eight days. After discontinuing antiviral drugs, chest computed tomography indicated rapid lesion progression and significantly increased bilateral multiple metastases. To our knowledge, the present study was the first to report a case of CIP caused by EBV during immune checkpoint inhibitor treatment. It indicates that EBV may be associated with CIP development. As immunotherapy has off-target effects, clinicians should remain aware of combined corticosteroids and antivirals in similar cases.