Background The current gold standard in coronavirus disease (COVID-19) diagnostics is the real-time reverse transcription–polymerase chain reaction (RT-PCR) assay for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in nasopharyngeal swab (NPS) samples. Alternatively, nasal swab (NS) or saliva swab (SS) specimens are used, although available data on test accuracy are limited. We examined the diagnostic accuracy of NPS/NS/SS samples for this purpose. Methods Ten patients were included after being tested positive for SARS-CoV-2 RT-PCR in NPS samples according to the National Institute of Infectious Disease guidelines. In comparison with this conventional diagnostic method, NPS/NS/SS samples were tested using the cobas 6800 systems RT-PCR device. To investigate the usefulness of the cobas method and the difference among sample types, the agreement and sensitivity were calculated. Five to six samples were collected over a total period of 5–6 d from each patient. Results Fifty-seven sets of NPS/NS/SS samples were collected, of which 40 tested positive for COVID-19 by the conventional method. Overall, the concordance rates using the conventional method were 86.0%/70.2%/54.4% for NPS/NS/SS samples (cobas); however, for samples collected up to and including on Day 9 after disease onset (22 negative and one positive specimens), the corresponding rates were 95.7%/87.0%/65.2%. The overall sensitivity estimates were 100.0%/67.5%/37.5% for NPS/NS/SS samples (cobas). For samples up to 9 d after onset, the corresponding values were 100.0%/86.4%/63.6%. Conclusions NS samples are more reliable than SS samples and can be an alternative to NPS samples. They can be a useful diagnostic method in the future.

Endobronchial ultrasound (EBUS) features with B-, power/color Doppler, and elastography modes help differentiate between benign and malignant lymph nodes (MLNs) during transbronchial needle aspiration (TBNA); however, only few studies have assessed them simultaneously. We evaluated the diagnostic accuracy of each EBUS feature and aimed to establish a scoring system to predict MLNs. EBUS features of consecutive patients and final diagnosis per lymph node (LN) were examined retrospectively. In total, 594 LNs from 301 patients were analyzed. Univariable analyses revealed that EBUS features, except for round shape, could differentiate MLNs from benign LNs. Multivariable analysis revealed that short axis (>1 cm), heterogeneous echogenicity, absence of central hilar structure, presence of coagulation necrosis sign, and blue-dominant elastographic images were independent predictors of MLNs. At three or more EBUS features predicting MLNs, our scoring system had high sensitivity (77.9%) and specificity (91.8%). The area under the receiver operating curve (AUC) was 0.894 (95% confidence interval (CI): 0.868–0.920), which was higher than that of B-mode features alone (AUC: 0.840 (95% CI: 0.807–0.873)). The novel scoring system could predict MLNs more accurately than B-mode features alone. Multi-EBUS features may increase EBUS-TBNA efficiency for LN evaluation.

Corticosteroids are widely used to treat severe COVID-19, but in immunocompromised individuals, who are susceptible to persistent infection, long term corticosteroid use may delay viral clearance. We present a case of prolonged SARS-CoV-2 infection in a man with significantly impaired B-cell immunity due to non-Hodgkin lymphoma which had been treated with rituximab. SARS-CoV-2 shedding persisted, despite treatment with remdesivir. Viral sequencing confirmed the persistence of the same viral strain, ruling out the possibility of reinfection. Although SARS-CoV-2 IgG, IgA and IgM remained negative throughout the treatment period, after reduction of the corticosteroid dose, PCR became negative. Long-term corticosteroid treatment, especially in immunocompromised individuals, may result in suppression of cell-mediated immunity and prolonged SARS-CoV-2 infection.

A 62‐year‐old woman with rheumatoid arthritis and a history of receiving immunosuppressant therapy had a recurrence of lung adenocarcinoma with EGFR L858R mutation. Following 14 months of treatment with erlotinib, computed tomography (CT) findings revealed the presence of small diffuse nodules. Bronchoscopy was performed as metastasis was suspected; however, this was not detected on lung biopsy with forceps. Transbronchial lung cryobiopsy (TBLC) succeeded in detecting metastatic adenocarcinoma, and T790M and L858R gene mutations. Pathological examination revealed a cluster of tumor cells in the intralobular interstitial areas, which was consistent with the CT findings. This report provides important information regarding the role of TBLC in diagnosing metastatic cancer, such as diffuse small miliary nodules, and its genetic mutations.

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