Bronchiectasis and Recurrent Respiratory Infections with a De Novo STAT1 Gain-of-Function Variant: First Case in Korea

허희재,전병우,최새롬,김예진,윤선애,Eliel Nham,공태환,기창석,고원중 연세대학교의과대학 2018 Yonsei medical journal Vol.59 No.8

Bronchiectasis is a chronic disease characterized by airway infection and inflammation, leading to permanent dilation of the bronchi. Evaluation of underlying etiology is important in managing young bronchiectasis patients with recurrent infections caused byunusual pathogens. The signal transducer and activator of transcription 1 (STAT1) protein plays a key role in STAT signaling andimmune system regulation. Heterozygotes for gain-of-function (GOF) alleles of the STAT1 gene usually display autosomal dominantchronic mucocutaneous candidiasis (CMC) and a wide range of clinical features, such as bronchiectasis. Here, we report on apatient with CMC and bronchiectasis with various types of infections who carried a pathogenic variant of the STAT1 gene. The24-year-old female presented with recurrent respiratory bacterial and nontuberculous mycobacterial infections complicated by severebronchiectasis and CMC. Whole-exome sequencing revealed a c.800C>T (p.Ala267Val) heterozygous mutation in the STAT1gene. Further analysis by Sanger sequencing of STAT1 from the patient and her parents revealed the patient had a de novo occurrenceof the variant. This is the first report of a Korean patient with a GOF pathogenic variant in STAT1. Physicians should be awareof the existence of this variant as a genetic factor associated with CMC and bronchiectasis complicated by recurrent infection.

Performance of the Real-Q EBV Quantification Kit for Epstein-Barr Virus DNA Quantification in Whole Blood

허희재,박종은,김지연,윤선애,이명근,이남용,김종원,기창석 대한진단검사의학회 2017 Annals of Laboratory Medicine Vol.37 No.2

There has been increasing interest in standardized and quantitative Epstein-Barr virus (EBV) DNA testing for the management of EBV disease. We evaluated the performance of the Real-Q EBV Quantification Kit (BioSewoom, Korea) in whole blood (WB). Nucleic acid extraction and real-time PCR were performed by using the MagNA Pure 96 (Roche Diagnostics, Germany) and 7500 Fast real-time PCR system (Applied Biosystems, USA), respectively. Assay sensitivity, linearity, and conversion factor were determined by using the World Health Organization international standard diluted in EBV-negative WB. We used 81 WB clinical specimens to compare performance of the Real-Q EBV Quantification Kit and artus EBV RG PCR Kit (Qiagen, Germany). The limit of detection (LOD) and limit of quantification (LOQ) for the Real-Q kit were 453 and 750 IU/mL, respectively. The conversion factor from EBV genomic copies to IU was 0.62. The linear range of the assay was from 750 to 106 IU/mL. Viral load values measured with the Real-Q assay were on average 0.54 log10 copies/mL higher than those measured with the artus assay. The Real-Q assay offered good analytical performance for EBV DNA quantification in WB.

신문사 콘텐츠의 현황과 과제

허희재 한국조사기자협회 2005 조사연구 Vol.17 No.-

Performance Evaluation of the PowerChek MERS (upE & ORF1a) Real-Time PCR Kit for the Detection of Middle East Respiratory Syndrome Coronavirus RNA

허희재,김지연,권현정,윤선애,이명근,기창석,이남용,김종원 대한진단검사의학회 2017 Annals of Laboratory Medicine Vol.37 No.6

Background: Molecular detection of Middle East respiratory syndrome coronavirus (MERS-CoV) using real-time reverse transcription (rRT)-PCR assays is the method of choice for diagnosis of MERS. We evaluated the performance of the PowerChek MERS (upE & ORF1a) real-time PCR Kit (PowerChek MERS assay; Kogene Biotech, Korea) a one-step rRT-PCR assay for the qualitative detection of MERS-CoV. Methods: We evaluated PowerChek MERS assay performance in comparison with nested RT-PCR and sequencing of the RNA-dependent RNA polymerase (RdRp) and N genes. To evaluate diagnostic sensitivity and specificity, 100 clinical specimens (50 positive and 50 negative for MERS-CoV) were simultaneously tested by using the PowerChek MERS and sequencing assays. Assay performance, including limit of detection and precision, was evaluated in vitro by using MERS-CoV RNA transcripts. Analytical specificity was evaluated with a diverse collection of 16 respiratory virus–positive clinical specimens and 14 respiratory bacterial isolates. Results: The 95% limits of detection of the PowerChek MERS assay for the upE and the open rading frame (ORF)1a were 16.2 copies/μL and 8.2 copies/μL, respectively. No cross-reactivity was observed. The diagnostic sensitivity and specificity of the PowerChek MERS assay were both 100% (95% confidence interval, 91.1–100%). Conclusions: The PowerChek MERS assay is a straightforward and accurate assay for detecting MERS-CoV RNA. The assay will be a useful tool for the rapid diagnosis of MERS and could prove especially important for MERS outbreak control.

The First Korean Case of Mucopolysaccharidosis IIIC (Sanfilippo Syndrome Type C) Confirmed by Biochemical and Molecular Investigation

허희재,서자영,조성윤,기창석,이수연,김종원,박형두,진동규 대한진단검사의학회 2013 Annals of Laboratory Medicine Vol.33 No.1

Mucopolysaccharidosis (MPS) III has 4 enzymatically distinct forms (A, B, C, and D), and MPS IIIC, also known as Sanfilippo C syndrome, is an autosomal recessive lysosomal storage disease caused by a deficiency of heparan acetyl-CoA:alpha-glucosaminide N-acetyltransferase (HGSNAT). Here, we report a case of MPS IIIC that was confirmed by molecular genetic analysis. The patient was a 2-yr-old girl presenting with skeletal deformity, hepatomegaly, and delayed motor development. Urinary excretion of glycosaminoglycan (GAG) was markedly elevated (984.4 mg GAG/g creatinine) compared with the age-specific reference range (<175 mg GAG/g creatinine), and a strong band of heparan sulfate was recognized on performing thin layer chromatography. HGSNAT enzyme activity in leukocytes was 0.7 nmol/17 hr/mg protein, which was significantly lower than the reference range (8.6-32 nmol/17 hr/mg protein). PCR and direct sequencing of the HGSNAT gene showed 2 mutations: c.234+1G>A (IVS2+1G>A) and c.1150C>T (p.Arg384*). To the best of our knowledge, this is the first case of MPS IIIC to be confirmed by clinical, biochemical, and molecular genetic findings in Korea.

Importance of Specimen Type and Quality in Diagnosing Middle East Respiratory Syndrome

허희재,고재훈,김영은,박창훈,홍지혜,최리화,유신애,조선영,강지만,이명근,기창석,강은숙,이남용,김종원,김예진,하영은,강철인,정두련,백경란,송재훈 대한진단검사의학회 2017 Annals of Laboratory Medicine Vol.37 No.1

Dear Editor, From May to July 2015, there was a hospital-associated outbreak in South Korea reporting 186 laboratory-confirmed cases. Highly sensitive and specific laboratory diagnostic tests are important for the control of Middle East respiratory syndrome coronavirus (MERS-CoV) outbreaks. Clinical guidelines for the molecular diagnosis of MERS-CoV are based on the interim recommendations from the WHO, the United States Centers for Disease Control and Prevention (US CDC), and other available resources [1-4]. To date, only a few studies have reported the molecular detection of this disease during an outbreak [5-8]. To validate the current guidelines for MERS-CoV laboratory testing, we retrospectively reviewed the results of MERS-CoV real-time reverse transcription (rRT)-PCR assays in the Korean tertiary care hospital with the largest number of MERS cases (Samsung Medical Center). The Institutional Review Board of the Samsung Medical Center (IRB #2015-06-201) approved this study.

Comparative Evaluation Between the RealStar Pneumocystis jirovecii PCR Kit and the AmpliSens Pneumocystis jirovecii (carinii)-FRT PCR Kit for Detecting P. jirovecii in Non-HIV Immunocompromised Patients

허희재,임경리,기창석,허경민,심향진,송동준,김예진,정두련,이남용 대한진단검사의학회 2019 Annals of Laboratory Medicine Vol.39 No.2

Background: Real-time PCR is more sensitive than microscopic examination for detecting Pneumocystis jirovecii. We compared the performance of two assays for detecting P. jirovecii DNA: the RealStar Pneumocystis jirovecii PCR Kit 1.0 CE (Altona Diagnostics, Hamburg, Germany) and the AmpliSens Pneumocystis jirovecii (carinii)-FRT PCR kit (InterLabService Ltd., Moscow, Russia). Methods: We used 159 samples from the lower respiratory tract (112 bronchoalveolar lavage [BAL] fluid, 37 sputum, and 10 endotracheal aspirate [ETA] samples) of non-HIV immunocompromised patients. Nested PCR and sequencing were used to resolve discordant results. The performance of the two assays was evaluated according to clinical categories (clinical Pneumocystis pneumonia [PCP], possible PCP, or unlikely PCP) based on clinical and radiological observations. Results: The positive and negative percent agreement values were 100% (95% confidence interval [CI], 85.4–100%) and 96.6% (95% CI, 90.9–98.9%), respectively, and kappa was 0.92 (95% CI, 0.84–0.99). P. jirovecii DNA load was significantly higher in the clinical PCP group than in the other groups (P<0.05). When stratified by sample type, the positive rate for BAL fluids from the clinical PCP group was 100% using either assay, whereas the positive rate for sputum/ETA samples was only 20%. Conclusions: The two assays showed similar diagnostic performance and detected low P. jirovecii burden in BAL fluids. Both assays may be useful as routine methods for detecting P. jirovecii DNA in a clinical laboratory setting, though their results should be interpreted considering sample type.

Therapy-Related Myeloid Neoplasms in 39 Korean Patients: A Single Institution Experience

허희재,이수현,유건희,성기웅,구홍회,김기현,장준호,정철원,김선희,김희진,최윤라 대한진단검사의학회 2013 Annals of Laboratory Medicine Vol.33 No.2

Background: Therapy-related myeloid neoplasms (t-MN) occur as late complications of cytotoxic therapy. This study reviewed clinical and cytogenetic characteristics of patients with t-MN at a single institution in Korea. Methods: The study subjects included 39 consecutive patients diagnosed with t-MN. Each subject’s clinical history of previous diseases, treatments, and laboratory data was reviewed, including cytogenetics. The primary diagnosis was hematologic malignancy in 14 patients and solid tumor in 25 patients. Results: Therapy-related acute myeloid leukemia (t-AML, 66.7%) was found to be more common than therapy-related myelodysplastic syndrome (t-MDS). Primary hematologic malignancies that were commonly implicated included mature B-cell neoplasm and acute leukemia. Breast cancer was the most common primary solid tumor. The mean time interval from cytotoxic therapy initiation to t-MN detection was 49 months. Chromosomal aberrations were observed in 35 patients, and loss of chromosome 5, 7, or both accounted for 41% of all cases. Balanced rearrangements occurred in 13 patients; these patients showed shorter latency intervals (mean, 38 months) than patients with loss of chromosome 5 or 7(mean, 61 months). Conclusions: In this study, we determined the clinical and cytogenetic characteristics of Korean patients with t-MN. Although our results were generally consistent with those of previous reports, we found that t-MN resulting from de novo leukemia was common and that t-AML was more common than t-MDS at presentation. Multi-institutional studies involving a larger number of patients and additional parameters are required to investigate the epidemiology, genetic predisposition, and survival rate of t-MN in Korea.

Evaluation of the iNtRON VRE vanA/vanB Real-Time PCR Assay for Detection of Vancomycin-Resistant Enterococci

허희재,장미애,서자영,김지윤,기창석,김종원,이남용 대한진단검사의학회 2015 Annals of Laboratory Medicine Vol.35 No.1

Background: Recently, the iNtRON VRE vanA/vanB real-time PCR (iNtRON; iNtRON Biotechnology, Korea) assay, a multiplex real-time PCR method, was introduced. In this prospective study, we compared the iNtRON assay with the Seeplex VRE ACE detection kit (Seeplex; Seegene, Korea), a conventional multiplex PCR assay. Methods: A chromogenic agar-based culture, in which pre-selected vancomycin-resistant enterococci (VRE) was grown and subsequently plated on blood agar with vancomycin disks, was regarded as the reference method. A total of 304 consecutive rectal swab specimens were tested for VRE by culture and by iNtRON and Seeplex PCR assays. For the PCR assays, specimens were enriched for 16-24 hr before PCR. Results: VRE were isolated from 44 (14.5%) specimens by chromogenic agar-based culture. The clinical sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the iNtRON assay were 100% (95% confidence interval: 89.8%-100%), 99.2% (96.9%-99.9%), 95.6% (83.6%-99.2%), and 100% (98.2%-100%), respectively, while those of the Seeplex assay were 97.7% (86.2%-99.9%), 99.6% (97.5%-99.9%), 97.7% (86.2%-99.9%), and 99.6% (97.5%-99.9%), respectively. The iNtRON assay had a detection limit of 3,159 copies/μL and 13,702 copies/μL for the vanA and vanB genes, respectively. No cross-reactivity was observed in 11 non-VRE bacterial culture isolates. Conclusions: The overall performance of the iNtRON assay was comparable to that of a chromogenic agar-based culture method for prompt identification of VRE-colonized patients in hospitals. This assay could be an alternative or supportive method for the effective control of nosocomial VRE infection.

Identification of Erysipelothrix rhusiopathiae by DNA Sequencing in a Culture-Negative Intra-Abdominal Abscess

허희재,김현영,하영은,기창석,이남용 대한임상미생물학회 2014 Annals of clinical microbiology Vol.17 No.4

Erysipelothrix rhusiopathiae is a Gram-positive bacillus that causes infections primarily in animals. In humans, the bacteria usually cause localized or generalized cutaneous infections. A 75-year-old man with chronic alcoholism presented with abdominal pain. Abdominal computed tomography and laboratory findings suggested an intra-abdominal abscess in the periaortic soft tissue. While no definitive infectious source was identified, E. rhusiopathiae was identified by 16S rRNA-based gene sequencing from culture-negative, periaortic necrotic tissue, subsequent to empiric antibiotic treatment. It is suggested that E. rhusiopathiae has the potential to cause intra-abdominal abscesses. This case report highlights the usefulness of DNA sequencing to identify pathogens in patients pretreated with antibiotics. (Ann Clin Microbiol 2014;17:-135)