Respiratory virus infections of the lower respiratory tract elevate bronchoalveolar lavage eosinophil fraction: a clinical retrospective study and case review.

BACKGROUND: Eosinophilic airway inflammation caused by respiratory virus infection has been demonstrated in basic research; however, clinical investigations are lacking. To clarify the extent to which respiratory virus infection induces airway eosinophilic inflammation, we reviewed the results of bronchoalveolar lavage (BAL) and respiratory virus testing performed at our hospital. METHODS: Among the BAL procedures performed at the University of the Ryukyu Hospital from August 2012 to September 2016, we collected cases of acute respiratory disease in which multiplex polymerase chain reaction (PCR) was used to search for respiratory viruses. The effect of respiratory virus detection on BAL eosinophil fraction was analyzed using statistical analysis. A case study was conducted on respiratory virus detection, which showed an elevated BAL eosinophil fraction. RESULTS: A total of 95 cases were included in this study, of which 17 were PCR-positive. The most common respiratory virus detected was parainfluenza virus (eight cases). The PCR-positive group showed a higher BAL eosinophil fraction than the PCR-negative group (p = 0.030), and more cases had a BAL eosinophil fraction > 3% (p = 0.017). Multivariate analysis revealed that being PCR-positive was significantly associated with BAL eosinophil fraction > 1% and > 3%. There were nine PCR-positive cases with a BAL eosinophil fraction > 1%, of which two cases with parainfluenza virus infection had a marked elevation of BAL eosinophil fraction and were diagnosed with eosinophilic pneumonia. CONCLUSIONS: Cases of viral infection of the lower respiratory tract showed an elevated BAL eosinophil fraction. The increase in eosinophil fraction due to respiratory virus infection was generally mild, whereas some cases showed marked elevation and were diagnosed with eosinophilic pneumonia. Respiratory virus infection is not a rare cause of elevated BAL eosinophil fraction and should be listed as a differential disease in the practice of eosinophilic pneumonia.

Characteristics of patients with viral infections of the lower respiratory tract: A retrospective study.

While the impact of respiratory virus infections has been well researched in some respiratory diseases, no clinical studies have discussed the subject of who would be more likely to develop respiratory virus infections among patients with various respiratory illnesses who come from different backgrounds. This study aimed to identify respiratory diseases that are frequently associated with respiratory virus infections along with the characteristics of patients who develop such infections in clinical settings. Tested specimens were obtained from the lower respiratory tract by bronchoscopy to provide more accurate data. Data of bronchoscopies at Ryukyu University Hospital between August 2012 and September 2016 were reviewed, and patients who underwent multiplex polymerase chain reaction (PCR) tests for detecting respiratory viruses in bronchoscopy specimens were retrospectively recruited for descriptive statistics. Differences among patients' primary pulmonary diseases and backgrounds were compared between the PCR-positive and -negative patients, and multivariate statistical analysis was performed to analyze factors associated with a positive PCR test result. Overall, 756 bronchoscopies were performed during the study period and PCR tests were performed for 177 patients. Of them, 27 tested positive for respiratory viruses, mainly parainfluenza virus and rhinovirus, and out of those, 7 were hospitalized for >1 month. Overall, all patients did not experience typical upper respiratory infection symptoms. In positive patients, 13 and 7 had diagnoses of interstitial lung disease and bacterial pneumonia, respectively. The diagnoses of 3 bacterial pneumonia cases were changed to viral pneumonia after receiving their PCR-positive tests. Respiratory virus infections were confirmed in 14 patients on immunosuppressant therapy and 4 on maintenance dialysis. Multivariate analysis revealed that immunosuppressant therapy and maintenance dialysis were independently associated with respiratory virus infections. Viruses were commonly detected in patients with interstitial lung diseases and bacterial pneumonia, while few patients were diagnosed with pure viral pneumonia. These illnesses were considered to be induced by respiratory infections. Immunosuppressant therapy and maintenance dialysis were associated with respiratory virus infections. Multiplex PCR testing is an essential diagnostic tool for respiratory virus infections in immunocompromised patients.

False-positive for SARS-CoV-2 antigen test in a man with acute HIV infection.

Although rapid antigen tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is convenient, some articles have demonstrated their low sensitivity indicating false-negative results should always be considered. Here, we raise the issue of false-positive on rapid antigen tests for SARS-CoV-2 with the first case of acute HIV infection who repeatedly positive for the rapid antigen test. A 39-year-old man was admitted to our hospital complaining of high-grade fever, dry cough, general fatigue, and anorexia. The rapid antigen test performed on a nasopharyngeal swab sample was positive, therefore the patient was separated in an isolated room apart from the COVID-19 ward while awaiting the confirmatory RT-PCR result. However, the RT-PCR for SARS-CoV-2 performed on nasopharyngeal swabs was repeatedly negative (three times), while the antigen test was repeatedly positive (three times in total). This patient was eventually diagnosed with acute human immunodeficiency virus (HIV) infection based on a high titer of HIV-RNA and absence of plasma HIV-1/2 antibodies. Physicians should consider the possibility of false-positive results in addition to false-negative results when using a rapid antigen test for SARS-CoV-2, and keep in mind that nucleic acid amplification tests are needed to confirm the diagnosis.