SARS-CoV-2 in pleural fluid in a kidney transplant patient.

Coronavirus disease 2019 (COVID-19), caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has quickly spread all over the globe from China. Pleural involvement is not common; around 5-10% of patients can develop pleural effusion and little is known about the involvement of pleural structures in this new infection.A 61-year-old male kidney transplant patient with a history of multiple biopsy-confirmed acute rejections and chronic allograft rejection was admitted to our COVID-19 Unit with dry cough, exertional dyspnea, oliguria, and abdominal distension. Lung ultrasound imaging, chest X-ray, and CT scan showed left pleural effusion and atelectasis of the neighboring lung parenchyma. RT-PCR was positive for SARS-CoV-2 in the pleural fluid and cytology showed mesothelial cells with large and multiple nuclei, consistent with a cytopathic effect of the virus.This is one of few reports describing detection of SARS-CoV-2 in the pleural fluid and to the best of our knowledge, is the first to document the simultaneous presence of a direct cytopathic effect of the virus on mesothelial cells in a kidney transplant patient with COVID-19 pneumonia. The pleura proved to be a site of viral replication where signs of a direct pathological effect of the virus on cells can be observed, as we report here. RT-PCR for SARS-CoV-2 should be part of routine examination of pleural effusion even in patients with mild respiratory symptoms or with comorbidities that seem to explain the cause of effusion.