Seven human coronaviruses (HCoVs) have been isolated and identified as of February 2020 ; among these, HCoV-229E is known as a common causative organism of seasonal cold, however, a few cases of severe pneumonia caused by this virus in immunocompromised patients have also been reported. Previous reports have suggested that the majority of pneumonia cases labelled as being of unknown origin have a viral cause, including this virus.
Herein, we report a case of pneumonia caused by Human Coronavirus 229E in a 78-year-old man with chronic obstructive pulmonary disease (COPD) who had been undergoing medical treatment for Behcetʼs disease as an outpatient. He presented to our hospital complaining of chills, excessive sputum, and cough. At the time of consultation, we suspected the possibility of viral pneumonia caused by SARS-CoV-2 (COVID-19),which had sporadically occurred in Japan by that time. Chest x-ray showed ground glass opacities in the periphery of the middle and lower right lung field and computed tomographic images showed ground-glass opacities in the right middle and lower lobes ; therefore, the patient was admitted to our hospital for treatment and observation in a depressurized room. Urinary rapid antigen tests for Streptococcus pneumoniae and Legionella pneumophila, the rapid influenza diagnostic test, sputum culture, and blood culture were all negative. Further, the PCR test for SARS-CoV-2 PCR was also negative. However, examination of a nasopharyngeal swab sample by nested multiplex PCR (nmPCR) revealed Coronavirus 229E ; we thus diagnosed the patient as having Coronavirus 229E-related pneumonia. He received supportive care with supplemental oxygen, his symptoms gradually improved, and he was discharged on Day 16. The few cases reported in the past had severe immunodeficiency due to hematological tumors, whereas a case like ours appears to be extremely rare. On the other hand, Coronavirus 229E-related pneumonia, which could have occurred in a larger population in the past may have remained unidentified due to a lack of suitable tests. Reports of cases of viral pneumonia in the future are expected to increase with the increased use of nmPCR tests.