Identifying the host genetic factors underlying severe COVID-19 is an emerging challenge1–5. Here we conducted a genome-wide association study (GWAS) involving 2,393 cases of COVID-19 in a cohort of Japanese individuals collected during the initial waves of the pandemic, with 3,289 unaffected controls. We identified a variant on chromosome 5 at 5q35 (rs60200309-A), close to the dedicator of cytokinesis 2 gene (DOCK2), which was associated with severe COVID-19 in patients less than 65 years of age. This risk allele was prevalent in East Asian individuals but rare in Europeans, highlighting the value of genome-wide association studies in non-European populations. RNA-sequencing analysis of 473 bulk peripheral blood samples identified decreased expression of DOCK2 associated with the risk allele in these younger patients. DOCK2 expression was suppressed in patients with severe cases of COVID-19. Single-cell RNA-sequencing analysis (n = 61 individuals) identified cell-type-specific downregulation of DOCK2 and a COVID-19-specific decreasing effect of the risk allele on DOCK2 expression in non-classical monocytes. Immunohistochemistry of lung specimens from patients with severe COVID-19 pneumonia showed suppressed DOCK2 expression. Moreover, inhibition of DOCK2 function with CPYPP increased the severity of pneumonia in a Syrian hamster model of SARS-CoV-2 infection, characterized by weight loss, lung oedema, enhanced viral loads, impaired macrophage recruitment and dysregulated type I interferon responses. We conclude that DOCK2 has an important role in the host immune response to SARS-CoV-2 infection and the development of severe COVID-19, and could be further explored as a potential biomarker and/or therapeutic target.

Systemic corticosteroid therapy is frequently used to treat coronavirus disease 2019 . However, its maximum duration without secondary infections remains unclear. We aimed to evaluate the utility of monitoring cytomegalovirus (CMV) infection in patients with COVID-19 and estimate the maximum duration of systemic corticosteroid therapy without secondary infections. We included 59 patients with severe COVID-19 without CMV infection on admission to the intensive care unit (ICU). All patients received systemic corticosteroid therapy under invasive mechanical ventilation, with examination for plasma CMV-deoxyribonucleic acid (DNA) levels during the ICU stay. We analyzed the correlations among patient characteristics, CMV infection, diseases, and patient mortality. CMV infections were newly identified in 15 (25.4%) patients; moreover, anti-CMV treatment was administered to six (10.2%) patients during the ICU stay. Four (6.8%) patients had secondary infection-related mortality. The cumulative incidences of CMV infection and anti-CMV treatment during the ICU stay were 26.8% (95% confidence interval [CI], 15.8%-39.0%) and 12.3% (95% CI, 4.8%-23.4%), respectively. Furthermore, the median duration of systemic corticosteroid therapy without CMV infection was 15 days (95% CI, 13-16 days). The presence of CMV infection was associated with mortality during the ICU stay (p = 0.003). Monitoring plasma CMV-DNA levels could facilitate the detection of secondary CMV infection due to prolonged systemic corticosteroid therapy. The duration of systemic corticosteroid therapy for COVID-19 should be limited.

Although the utility of oscillometry for predicting disease severity in idiopathic pulmonary fibrosis (IPF) had been researched, little has been reported on the mechanism of why respiratory impedance reflects the disease severity. In addition, traction bronchiectasis has been considered to reduce respiratory resistance and correlate negatively with airflow obstruction, but this hypothesis has not been validated. The present study aimed to investigate the correlations between oscillometric parameters and fibrosis-related lung abnormalities in IPF and to assess the utility of oscillometry as a surrogate marker for traction bronchiectasis and airflow obstruction.Eighty Japanese patients with IPF underwent high-resolution computed tomography (HRCT), spirometry, and oscillometry and were retrospectively investigated. Fibrosis-related HRCT findings were scored regarding airspace consolidation, honeycombing, architectural distortion, traction bronchiectasis, and fibrosis. Correlations between the HRCT scores, spirometric parameters, and oscillometric parameters were analysed.Respiratory reactance correlated positively with all fibrosis-related HRCT scores. Vital capacity and forced vital capacity (FVC) correlated negatively with oscillometric parameters and HRCT scores, reflecting the severity of restrictive ventilatory deficiency. Respiratory resistance was not related to any of the HRCT scores or forced expiration volume in 1 s/FVC. However, forced expiration volume in 1 s/FVC correlated positively with HRCT scores, which showed that airflow obstruction became milder as the disease progressed.In conclusion, respiratory reactance reflects fibrosis and restrictive ventilatory deficiency in IPF. Moreover, respiratory resistance is independent of traction bronchiectasis and airflow obstruction in patients with IPF, which implies that respiratory resistance might reflect different properties of the airways.

mRNA vaccines that protect against coronavirus disease (COVID-19) are widely used in many countries due to their high efficacy and safety profiles. Recently, some severe adverse events, such as anaphylaxis and myocarditis, were reported in healthy individuals. The safety of mRNA COVID-19 vaccines has not been adequately studied in patients with interstitial lung disease. We report two cases of acute exacerbation of pre-existing interstitial pneumonia associated with mRNA COVID-19 vaccination. In both cases, lung disease was stable prior to the vaccination. Initial responses to steroid therapy were unfavorable, and intravenous cyclophosphamide was administered in both cases. Both patients were diagnosed with vaccine-related exacerbation of interstitial pneumonia, based on laboratory results, radiological features, and the observed clinical course, which lacked other causative events. We suggest that clinicians should note the possibility of acute exacerbation of pneumonia after mRNA COVID-19 vaccination, and carefully monitor patients with interstitial lung disease.

The association between Mycobacterium avium complex pulmonary disease (MAC-PD) and pleuroparenchymal fibroelastosis (PPFE) has been reported previously, and interstitial pneumonia as a comorbidity is associated with a worse prognosis. However, no study has thoroughly reported on PPFE associated with MAC-PD. The present study investigated the prevalence, clinical characteristics, and prognostic impact of PPFE in patients with MAC-PD.A total of 224 patients, newly diagnosed with MAC-PD, were retrospectively reviewed. At the time of diagnosis, chest high-resolution computed tomography (HRCT), sputum examination, and clinical characteristics were collected. The extent of PPFE and MAC-PD was evaluated semi-quantitatively using HRCT scores. Risk factor analysis for clinical or radiological deterioration necessitating multidrug antimicrobial treatment within 3 years, and all-cause mortality within 5 years, from the initial diagnosis was performed based on the PPFE score.PPFE was observed in 59 out of 224 patients (26.3%). A higher PPFE score was a risk factor for dyspnoea, fatigue, and lower body mass index (BMI) (p<0.05). Although PPFE score did not correlate with clinical or radiological deterioration within 3 years (p=0.576), a higher PPFE score (adjusted OR 1.66, 95% CI 1.06–2.60, p=0.028) and lower BMI (adjusted OR 0.61, 95% CI 0.39–0.94, p=0.028) increased the risk of 5-year mortality.PPFE is a relatively common complication and an independent poor prognostic factor of MAC-PD. This study highlights the need for further studies investigating whether the presence of PPFE can be a clinical indicator for initiating treatment of MAC-PD.

The combination of rifamycin (RFP), ethambutol (EB), and macrolides is currently the standard regimen for treatment of Mycobacterium avium complex pulmonary disease (MAC-PD). However, poor adherence to the standardized regimens recommended by current guidelines have been reported. We undertook a single-centred retrospective cohort study to evaluate the long-term outcomes in 295 patients with MAC-PD following first line treatment with standard (RFP, EB, clarithromycin [CAM]) or alternative (EB and CAM with or without fluoroquinolones (FQs) or RFP, CAM, and FQs) regimens. In this cohort, 80.7% were treated with standard regimens and 19.3% were treated with alternative regimens. After heterogeneity was statistically corrected using propensity scores, outcomes were superior in patients treated with standard regimens. Furthermore, alternative regimens were significantly and independently associated with sputum non-conversion, treatment failure and emergence of CAM resistance. Multivariate cox regression analysis revealed that older age, male, old tuberculosis, diabetes mellitus, higher C-reactive protein, and cavity were positively associated with mortality, while higher body mass index and M. avium infection were negatively associated with mortality. These data suggest that, although different combination regimens are not associated with mortality, first line administration of a standard RFP + EB + macrolide regimen offers the best chance of preventing disease progression in MAC-PD patients.

Background Pirfenidone is an antifibrotic agent that is potentially effective for the treatment of idiopathic pulmonary fibrosis (IPF). However, no study has reported on its prophylactic value against chemotherapy‐associated acute IPF exacerbations when combined with chemotherapy for non‐small cell lung cancer (NSCLC). The present study assessed the safety and effectiveness of pirfenidone combined with carboplatin‐based chemotherapy or immune checkpoint inhibitors (ICIs) in patients with IPF and NSCLC. Methods A total of 14 patients with IPF and NSCLC who received treatment from 2013 to 2019 were included. Patients were treated with pirfenidone combined with carboplatin and nanoparticle albumin‐bound paclitaxel or S‐1 as first‐line chemotherapy. After confirming disease progression, patients received cytotoxic agents or ICIs, including nivolumab and pembrolizumab. Pirfenidone was continued regardless of chemotherapy changes. Overall survival (OS) and progression‐free survival (PFS) for lung cancer and IPF were calculated. Moreover, the cumulative incidence of acute exacerbation of IPF (AE‐IPF) within one year was evaluated. Results Median PFS for lung cancer was 110 days (95% confidence interval [CI]: 57–199 days), while the median OS was 362 days (95% CI: 220–526 days). Moreover, PFS for IPF was 447 days (95% CI: 286–indeterminate days), and the cumulative incidence of AE‐IPF within one year was 18%. Notably, none of the patients developed AE‐IPF associated with first‐line chemotherapy. Among the included patients, four received ICIs, none of whom developed ICI‐associated AE‐IPF. Conclusions The present study found that pirfenidone combined with carboplatin‐based regimens or ICIs might be safe first‐line chemotherapy for patients with IPF and NSCLC. Key points Significant findings of the study No patients with IPF and NSCLC who received pirfenidone in combination with first‐line carboplatin‐based chemotherapy or late‐line ICIs developed acute IPF exacerbations. What this study adds Pirfenidone might have a prophylactic effect against chemotherapy‐associated AE‐IPF.

Although the diagnostic value of impulse oscillometry (IOS) in bronchiectasis for the differential diagnosis of healthy subjects has been researched, the usefulness of each IOS parameter for predicting disease severity in bronchiectasis has not been thoroughly investigated. In addition, the usefulness of IOS in patients with nontuberculous mycobacteria (NTM) infection has not been reported. This study aimed to determine the predictive significance of respiratory impedance and detect the other most significant IOS parameters for predicting disease severity in bronchiectasis patients and to validate the usefulness of IOS in patients with NTM infection.A total of 206 patients with bronchiectasis who attended clinics at the National Hospital Organization Osaka Toneyama Medical Center were included. Chest high-resolution computed tomography, spirometry and IOS were performed. Hospital admissions, mortality and disease severity indices for bronchiectasis (Bronchiectasis Severity Index (BSI), FACED, and E-FACED scores) were calculated to assess disease severity. The patients were divided into subgroups with and without NTM infection, and subgroup analyses were performed.Respiratory reactance, especially resonant frequency (fres), correlated with both BSI and FACED score better than respiratory resistance. Inspiratory but not expiratory impedance was strongly correlated with BSI, FACED and E-FACED scores. Inspiratory fres was the most useful predictor, increasing as the disease became more severe. The usefulness of IOS was almost equivalent in patients both with and without NTM infection.Inspiratory reactance measured by IOS is useful for estimating disease severity in bronchiectasis. Inspiratory fres best predicts disease severity in bronchiectasis patients both with and without NTM infection.