No abstract

26 Background: The SARS-CoV-2 virus emerged in December 2019 and caused a 27 pandemic associated with a spectrum of COVID-19 disease ranging from 28 asymptomatic to lethal infection. Serology testing is important for diagnosis of 29 infection, determining infection attack rates and immunity in the population. It also 30 informs vaccine development. Although several serology tests are in use, improving 31 their specificity and sensitivity for early diagnosis on the one hand and for detecting 32 past infection for population-based studies, are priorities. 33 Methods: We evaluated the anti-SARS-CoV-2 antibody profiles to 15 SARS-CoV-2 34 antigens by cloning and expressing 15 open reading frames (ORFs) in mammalian 35 cells and screened antibody responses to them in COVID-19 patients using the 36 Luciferase Immunoprecipitation System (LIPS). 37 Results: The LIPS technique allowed us to detect antibody responses in COVID-19 38 patients to 11 of the 15 SARS-CoV-2 antigens tested, identifying novel immunogenic 39 targets. This technique shows that antigens ORF3b and ORF8 allow detection of 40 antibody early in infection in a specific manner and reveals the immuno-dominance of 41 the N antigen in COVID-19 patients. 42 Conclusion: Our report provides an unbiased characterization of antibody responses 43 to a range of SARS-CoV-2 antigens. The combination of 3 SARS-CoV-2 antibody 44LIPS assays, i.e. N, ORF3b, and ORF8, is sufficient to identify all COVID-19 patients 45 of our cohort even at early time-points of illness, whilst Spike alone fails to do so. 46Furthermore, our study highlights the importance of investigating new immunogens 47

Spirometry is important in the diagnosis and management of chronic obstructive pulmonary disease (COPD), yet it is a common clinical observation that it is underused though the extent is unclear. This survey aims to examine the use of spirometry in the diagnosis and management of COPD patients in a district in Hong Kong. It is a cross-sectional survey involving four clinic settings: hospital-based respiratory specialist clinic, hospital-based mixed medical specialist clinic, general outpatient clinic (primary care), and tuberculosis and chest clinic. Thirty physician-diagnosed COPD patients were randomly selected from each of the four clinic groups. All of them had a forced expiratory volume in 1 second (FEV1) to forced vital capacity ratio less than 0.70 and had been followed up at the participating clinic for at least 6 months for COPD treatment. Of 126 patients who underwent spirometry, six (4.8%) did not have COPD. Of the 120 COPD patients, there were 111 males and mean post-bronchodilator FEV1 was 46.2% predicted. Only 22 patients (18.3%) had spirometry done during diagnostic workup, and 64 patients (53.3%) had spirometry done ever. The only independent factor predicting spirometry done ever was absence of old pulmonary tuberculosis and follow-up at respiratory specialist clinic. Age, sex, smoking status, comorbidities, duration of COPD, percentage predicted FEV1, body mass index, 6-minute walking distance, and Medical Research Council dyspnea score were not predictive. We conclude that spirometry is underused in general but especially by nonrespiratory physicians and family physicians in the management of COPD patients. More effort at educating the medical community is urgently needed.

Purpose Blood eosinophil is a readily available biomarker to reflect the eosinophilic inflammation in chronic obstructive pulmonary disease (COPD) patients, yet its association with exacerbation is inconclusive. It is uncertain which measurement, eosinophil percentage or absolute eosinophil count, should be used and what is the optimal cutoff for exacerbation prediction. Patients and Methods A total of 247 COPD patients were included in this retrospective cohort study. Blood eosinophil during stable disease state, baseline demographics, and clinical characteristics in 12 months after the index complete blood count (CBC) were recorded. Exacerbation frequencies were compared between patients with high and low blood eosinophil percentage using 2% as cut-off. Logistic regression and receiver operating characteristics (ROC) curve analyses were conducted. Results Patients with blood eosinophil ≥2% were associated with more frequent exacerbations than patients with eosinophil <2% in the 12 months after the index CBC (mean exacerbation 1.07 vs 0.34, p < 0.001). Higher blood eosinophil percentage conferred a higher risk of exacerbation. Adjusted odds ratio for exacerbation in 12 months after the index CBC for blood eosinophil ≥2% was 2.98 (95% confidence interval = 1.42–6.25). The area under the ROC curve of eosinophil percentage was significantly higher than that of absolute eosinophil count (0.678 vs 0.640, p = 0.010). The optimal cutoff of blood eosinophil percentage for exacerbation prediction was 2.8%. Conclusion Blood eosinophilia was associated with higher exacerbation risk in COPD patients. Further studies are required to elucidate the mechanism of eosinophilic inflammation in COPD and determine the optimal treatment strategy to reduce exacerbations.

In the version of this article initially published, the hyphen was missing from author Melanie Meyer-Luehmann's surname. The error has been corrected in the HTML and PDF versions of the article.