[Immune-related pneumonitis caused by programmed death-1 inhibitor Pembrolizumab: a case report and literature review].

Objective To investigate the risk factors, clinical manifestations, radiological features, diagnosis, treatment and prognosis of immune-related pneumonitis caused by programmed death-1(PD-1)/PD-L1 inhibitors. Methods The clinical data of immune-related pneumonitis caused by PD-1 inhibitor Pembrolizumab in a patient with advanced esophageal carcinoma admitted to the 307th Hospital of Chinese People′s Liberation Army was retrospectively analyzed and the related literatures were reviewed. We searched Medline database using the keywords"PD-1 inhibitor","PD-L1 inhibitor","Pembrolizumab","Nivolumab","Atezolizumab"combined with"Pneumonitis"by Mar 31, 2017. Results The patient was a 60-year-old male presented with progression disease after surgery, local radiation and couples of chemotherapy for his esophageal carcinoma. Then pembrolizumab, a kind of PD-l inhibitors, was given intravenously every 3 weeks with the average dosage 3 mg per kg. After six cycles of pembrolizumab, the patient began to have fever, cough and dyspnea, which aggravated gradually. Chest CT showed diffuse ground glass opacity, exudation and consolidation in both lungs and little pleural effusion in the right side. Cellular interstitial pneumonitis was confirmed by pathological examination. The patient′s symptoms were alleviated after enough steroids and chest CT showed pulmonary infiltration was also absorbed. But the pneumonitis reoccurred twice after stopping or tapering steroids quickly and could also be controlled by using steroids again. Now the patient was still given steroids treatment and the primary esophageal cancer remained stable. 14 articles were retrieved and 88 cases of immune-related pneumonitis caused by PD-1/PD-L1 inhibitors were reported. Among these 89 cases with immune-related pneumonitis, both male and female could attack and the median age was 67 years old. Most cases were grade 1 or 2. The common clinical manifestations were dyspnea, cough, fever and other immune-related damages. And about 20% patients had no symptoms. Ground glass opacities, reticular opacities, consolidation and centrilobular nodules were the common radiological features. The commonest histologic pattern of pneumonitis associated with anti-PD-1/PD-L1 therapy on lung biopsy was organizing pneumonia. Adequate steroid and tapering slowly is the standard treatment. Immunosuppressive agents could be added in some serious cases. The prognosis was relatively good. Most patients were alleviated but few patients died of progression disease or infections during treatment. Conclusions Immune-related pneumonitis associated with PD-l/PD-L1 inhibitor should be aware of; early detection, early treatment, and the prognosis could be better. Key words: Immune-related pneumonitis; Programmed cell death-1 inhibitor; Clinical characteristics; Treatment