COVID-19 Pneumonia Followed by Anti-signal Recognition Particle Antibody-positive Fibrosing Interstitial Lung Disease.

Coronavirus disease 2019 (COVID-19) pneumonia is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and is frequently accompanied by various sequelae. Interstitial lung diseases (ILDs) are observed in COVID-19 pneumonia patients after recovery, probably due to persistent inflammation in the lungs. We herein report a case of ILD with anti-signal recognition particle antibodies following severe COVID-19 pneumonia. The patient was diagnosed with ILD three months after COVID-19 pneumonia. Although the exact mechanism is unknown, the autoantibody-induced immune response might have been the pulmonary fibrosis trigger in this patient.

Association of SARS-CoV-2 RNA Copy Number with the COVID-19 Mortality Rate and Its Effect on the Predictive Performance of Mortality in Severe Cases.

Factors associated with mortality are important in the treatment of coronavirus disease 2019 (COVID-19). Polymerase chain reaction (PCR) is the gold standard for diagnosing COVID-19, which reflects the viral load in the upper respiratory tract. In total, 523 patients were enrolled in this study; of them, 441 and 75 patients underwent PCR testing of nasopharyngeal swabs and sputum samples, respectively, within 20 days from onset of COVID-19. We investigated the association between RNA copy number and the COVID-19 severity and mortality rate and its effect on the predictive performance for severity and mortality. RNA copy numbers in nasopharyngeal swabs were higher in the non-survivor group than in the survivor group. Multivariate logistic regression analysis identified that the high RNA copy number (≥9 log10 /swab) in nasopharyngeal swabs was a factor associated with mortality (odds ratio, 4.50; 95% confidence interval, 1.510-13.100; P = 0.008). Furthermore, adding RNA copy number (≥9 log10 /swab) in severe cases, adjusted by duration from onset to PCR, improved mortality predictive performance based on known factors. The RNA copy number is a factor associated with the mortality of patients with COVID-19 and can improve the predictive performance of mortality in severe cases.

Atypical lymphocytes in the peripheral blood of COVID-19 patients: A prognostic factor for the clinical course of COVID-19.

BACKGROUND: Clinical observations have shown that there is a relationship between coronavirus disease 2019 (COVID-19) and atypical lymphocytes in the peripheral blood; however, knowledge about the time course of the changes in atypical lymphocytes and the association with the clinical course of COVID-19 is limited. OBJECTIVE: Our purposes were to investigate the dynamics of atypical lymphocytes in COVID-19 patients and to estimate their clinical significance for diagnosis and monitoring disease course. MATERIALS AND METHODS: We retrospectively identified 98 inpatients in a general ward at Kashiwa Municipal Hospital from May 1st, 2020, to October 31st, 2020. We extracted data on patient demographics, symptoms, comorbidities, blood test results, radiographic findings, treatment after admission and clinical course. We compared clinical findings between patients with and without atypical lymphocytes, investigated the behavior of atypical lymphocytes throughout the clinical course of COVID-19, and determined the relationships among the development of pneumonia, the use of supplemental oxygen and the presence of atypical lymphocytes. RESULTS: Patients with atypical lymphocytes had a significantly higher prevalence of pneumonia (80.4% vs. 42.6%, p < 0.0001) and the use of supplemental oxygen (25.5% vs. 4.3%, p = 0.0042). The median time to the appearance of atypical lymphocytes after disease onset was eight days, and atypical lymphocytes were observed in 16/98 (16.3%) patients at the first visit. Atypical lymphocytes appeared after the confirmation of lung infiltrates in 31/41 (75.6%) patients. Of the 13 oxygen-treated patients with atypical lymphocytes, approximately two-thirds had a stable or improved clinical course after the appearance of atypical lymphocytes. CONCLUSION: Atypical lymphocytes frequently appeared in the peripheral blood of COVID-19 patients one week after disease onset. Patients with atypical lymphocytes were more likely to have pneumonia and to need supplemental oxygen; however, two-thirds of them showed clinical improvement after the appearance of atypical lymphocytes.