Despite strict guidelines for coronavirus disease 2019 (COVID-19), South Korea is facing its fourth pandemic wave. In this study, by using an automated electrochemiluminescence immunoassay assay, we tracked anti-spike protein receptor-binding domain (anti-S-RBD) antibody titer from the second dose to 2 weeks after the booster dose vaccination. After the second dose, 234 participants had their anti-S-RBD antibody titers decrease over time. We also showed the booster dose (the third dose) increased antibody titer by average 14 (min–max, 2–255)-fold higher compared to the second dose among the 211-booster group participants, therefore, the booster dose could be recommended for low responders to the second dose. Our findings showed a distinct humoral response after booster doses of BNT162b2 mRNA vaccines and may provide further evidence of booster vaccination efficacy. These data will also be helpful in vaccination policy decisions that determine the need for the booster dose.

Background: Whole genome sequencing (WGS) is an increasingly useful tool for tuberculosis (TB) diagnosis and disease management. In this study, we evaluated the utility of userfriendly WGS tools in reporting resistance profiles and identifying lineages of clinical TB isolates from South Korea. Methods: Forty clinical samples from TB patients showing discrepancies between their rapid molecular and conventional drug susceptibility tests were used in this study. Among these clinical isolates, 37 strains were successfully evaluated via WGS software, using the GenTB, TB Profiler, PhyResSE, CASTB, and Mykrobe. Results: More accurate and faster susceptibility results could be obtained with isoniazid than with rifampin. Using the phenotypic test as the gold standard, the isoniazid concordance rate between phenotypic drug susceptibility test (DST) and WGS (GenTB: 45.9%, TB profiler: 40.5%, PhyResSE: 40.5%, CASTB: 48.6%, and Mykrobe: 43.2%) was much higher than between phenotypic DST and rapid molecular genotypic DST (18.9%) among the 37 strains.In contrast, the rifampin concordance rate between phenotypic DST and WGS and that between phenotypic DST and rapid molecular genotypic DST was similar (81.1–89.2%). We also found novel mutations associated with INH in katG and ahpC gene region, not covered by the line probe assay. In addition, lineage analysis identified 81.1% of these samples as L2 East Asian lineage strains, and 18.9% as L4 Euro-American lineage strains. Conclusion WGS may play a pivotal role in TB diagnosis and the detection of drug resistance, genetic diversity, and transmission dynamics in the near future because of its accuracy, speed, and extensibility.

Background/Aims: Adjuvant chemotherapy is the standard of care for resected stage II-IIIA non-small cell lung cancer (NCSLC). The efficacy of adjuvant chemotherapy in stage IB (< 4 cm) NSCLC with high-risk factors is controversial. Methods: This retrospective multicenter study included 285 stage IB NSCLC patients with high-risk factors according to the 8th edition tumor, node, metastasis (TNM) classification from four academic hospitals. High-risk factors included visceral pleural invasion, vascular invasion, lymphatic invasion, lung neuroendocrine tumors, and micropapillary histology patterns. Results: Of the 285 patients, 127 (44.6%) were included in the adjuvant chemotherapy group and 158 (55.4%) were included in the non-adjuvant chemotherapy group. The median follow-up was 41.5 months. Patients in the adjuvant chemotherapy group had a significantly reduced recurrence rate and risk of mortality than those in the non-adjuvant chemotherapy group (hazards ratio, 0.408; 95% confidence interval, 0.221 to 0.754; p = 0.004 and hazards ratio, 0.176; 95% confidence interval, 0.057 to 0.546; p = 0.003, respectively). Adjuvant chemotherapy should be particularly considered for the high-risk factors such as visceral pleural involvement or vascular invasion. Based on the subgroup analysis, adjuvant chemotherapy should be considered when visceral pleural involvement is present, even if the tumor size is < 3 cm. Conclusions Adjuvant chemotherapy may be useful for patients with stage IB NSCLC with high-risk factors and is more relevant for patients with visceral pleural involvement or vascular invasion.

The antibody titer of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was observed in 289 healthy healthcare workers who had completed the second dose of the Pfizer-BioNTech coronavirus disease 2019 (COVID-19) vaccine. Antibody tests were performed using both the automated electrochemiluminescence immunoassay (ECLIA) and the chromatographic lateral flow immunoassay (LFIA). All subjects had antibodies against the receptor binding domain of the spike protein of SARS-CoV-2 only one week after completing the vaccination, and the antibody titer became significantly higher after another week (P < 0.001). Since there was a large amount of antibody formation within two weeks after completion of vaccination, the less sensitive method, LFIA, also showed high sensitivity.There was no significant difference between whole blood and serum in detecting SARS-CoV-2 antibodies after vaccination. This is an early study of vaccinations among Koreans and is expected to contribute to the establishment of national guidelines on COVID-19 vaccination.

The antibody titer of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was observed in 289 healthy healthcare workers who had completed the second dose of the Pfizer-BioNTech coronavirus disease 2019 (COVID-19) vaccine. Antibody tests were performed using both the automated electrochemiluminescence immunoassay (ECLIA) and the chromatographic lateral flow immunoassay (LFIA). All subjects had antibodies against the receptor binding domain of the spike protein of SARS-CoV-2 only one week after completing the vaccination, and the antibody titer became significantly higher after another week (P < 0.001). Since there was a large amount of antibody formation within two weeks after completion of vaccination, the less sensitive method, LFIA, also showed high sensitivity.There was no significant difference between whole blood and serum in detecting SARS-CoV-2 antibodies after vaccination. This is an early study of vaccinations among Koreans and is expected to contribute to the establishment of national guidelines on COVID-19 vaccination.

Background: In the coronavirus disease 2019 (COVID-19) pandemic era, the simultaneous detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza virus (Flu), and respiratory syncytial virus (RSV) is important in the rapid differential diagnosis in patients with respiratory symptoms. Three multiplex real-time reverse transcription polymerase chain reaction (rRT-PCR) assays have been recently developed commercially in Korea: PowerChek™ SARS-CoV-2, Influenza A&B Multiplex Real-time PCR Kit (PowerChek; KogeneBiotech); STANDARD™ M Flu/SARS-CoV-2 Real-time Detection Kit (STANDARD M; SD BioSensor); and Allplex™ SARS-CoV-2/FluA/FluB/RSV Assay (Allplex; Seegene). We evaluated the analytical and clinical performances of these kits. Methods: A limit of detection tests were performed and cross-reactivity analysis was executed using clinical respiratory samples. Ninety-seven SARS-CoV-2-positive, 201 SARS-CoV-2-negative, 71 influenza A-positive, 50 influenza B-positive, 78 RSV-positive, and 207 other respiratory virus-positive nasopharyngeal swabs were tested using the three assays. The AdvanSure™ respiratory viruses rRT-PCR assay (AdvanSure; LG Life Sciences) was used as a comparator assay for RSV. Results: Except in influenza B, in SARS-CoV-2 and influenza A, there were no significant differences in detecting specific genes of the viruses among the three assays. All three kits did not cross-react with common respiratory viruses. All three kits had greater than 92% positive percent agreement and negative percent agreement and ≥ 0.95 kappa value in the detection of SARS-CoV-2 and flu A/B. Allplex detected RSV more sensitively than AdvanSure. Conclusion The overall performance of three multiplex rRT-PCR assays for the concurrent detection of SARS-CoV-2, influenza A/B, and RSV was comparable. These kits will promote prompt differential diagnosis of COVID-19, influenza, and RSV infection in the COVID-19 pandemic era.

Background: The presence of telomerase reverse transcriptase (TERT) promoter mutations have been associated with a poor prognosis in patients with papillary thyroid carcinomas (PTC). The frequency of TERT promoter mutations varies widely depending on the population and the nature of the study. Methods: Data were prospectively collected in 724 consecutive patients who underwent thyroidectomy for PTC from 2018 to 2019. Molecular testing for BRAF V600E and TERT promoter mutations was performed in all cases. Results: TERT promoter alterations in two hotspots (C228T and C250T) and C216T were found in 16 (2.2%) and 4 (0.6%) of all PTCs, respectively. The hotspot mutations were significantly associated with older age at diagnosis, larger tumor size, extrathyroidal extension, higher pathologic T category, lateral lymph node metastasis, and higher American Thyroid Association recurrence risk. The patients with C216T variant were younger and had a lower American Thyroid Association recurrence risk than those with hotspot mutations. Concurrent BRAF V600E was found in 19 of 20 cases with TERT promoter mutations. Of 518 microcarcinomas measuring ≤1.0 cm in size, hotspot mutations and C216T variants were detected in five (1.0%) and three (0.6%) cases, respectively. Conclusions Our study indicates a low frequency of TERT promoter mutations in Korean patients with PTC and supports previous findings that TERT promoter mutations are more common in older patients with unfavorable clinicopathologic features and BRAF V600E. TERT promoter mutations in patients with microcarcinoma are uncommon and may have a limited role in risk stratification. The C216T variant seems to have no clinicopathologic effect on PTC.

Facklamia hominis is a facultative anaerobic Gram-positive coccus generally displaying weak alpha-hemolysis and negativity for catalase and oxidase. Facklamia species are part of the normal flora of the female genitourinary tract and have been reported in invasive diseases such as meningitis and infective endocarditis, albeit rarely. A 67 year-old-man presented to hospital with a tender, erythematous epidermal cyst on the right side of his upper back. Simple excision of the cyst was performed and the pus was taken with a sterile swab for culture, yielding no growth. One week later, discharge was observed in the patient's wound site and a sterile swab for culture was taken. The colonies grown were identified as F. hominis by the Vitek 2 system (bioMérieux, France), and the result was then reported to clinicians, and later confirmed by 16S rRNA gene sequencing and matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry. To the best of our knowledge, this is the first reported case of F. hominis isolation from a clinical specimen in Korea.
Catalase ; Endocarditis ; Epidermal Cyst ; Female ; Genes, rRNA ; Humans ; Korea ; Mass Spectrometry ; Meningitis ; Oxidoreductases ; Suppuration ; Wounds and Injuries

BACKGROUND: Cord blood (CB) is a reliable source of hematopoietic stem cells, and its utilization in stem cell transplantation is increasing continuously. The CD34+ cell count is arguably one of the most important parameters for evaluating the quality of a cord blood unit (CBU), but there is little evidence on the post-genetic modifications that can affect the CD34+ cell counts. In this study, the difference in the miRNA expression profiles between low and high CD34+ CBU was evaluated. METHODS: Paired CB and maternal samples with low (<0.06%) and high CD34+ cell counts (>0.9%) were selected for analysis. MicroRNA profiling was performed, and differentially expressed miRNA were identified. In addition, gene ontology analysis was conducted on the miRNA to elucidate the genes that could potentially affect the CD34+ cell count. RESULTS: Ten miRNA were identified to show significantly different expression between the low and high CD34+ groups. Four of the 10 miRNA were hematopoiesis-related (miR-199a-5p, miR-22-5p, miR-140-5p, and miR-181b-5p). From a total of 119 associated genes, nine (CALCA, FARP2, FSHR, ITGAM, MELK, MLF1, PRG4, TREM2 and VCAM1) were associated with two or more of the aforementioned miRNA. CONCLUSION: This is the first study that examined the difference in the miRNA expression profiles between high and low CD34+ CB cells and revealed the relevant genes associated with hematopoiesis. These results provide basic insight into the genetic processes involving hematopoietic stem cell proliferation.
Cell Count ; Fetal Blood ; Gene Ontology ; Genetic Processes ; Hematopoiesis ; Hematopoietic Stem Cells ; MicroRNAs ; Stem Cell Transplantation ; Stem Cells