Jonghyeon Choi

Comparison of the Abbott RealTime High-Risk Human Papillomavirus (HPV), Roche Cobas HPV, and Hybrid Capture 2 Assays to Direct Sequencing and Genotyping of HPV DNA

ABSTRACT Infection with high-risk (HR) human papillomavirus (HPV) genotypes is an important risk factor for cervical cancers. We evaluated the clinical performances of two new real-time PCR assays for detecting HR HPVs compared to that of the Hybrid Capture 2 test (HC2). A total of 356 cervical swab specimens, which had been examined for cervical cytology, were assayed by Abbott RealTime HR and Roche Cobas HPV as well as HC2. Sensitivities and specificities of these assays were determined based on the criteria that concordant results among the three assays were regarded as true-positive or -negative and that the results of genotyping and sequencing were considered true findings when the HPV assays presented discrepant results. The overall concordance rate among the results for the three assays was 82.6%, and RealTime HR and Cobas HPV assays agreed with HC2 in 86.1% and 89.9% of cases, respectively. The two real-time PCR assays agreed with each other for 89.6% of the samples, and the concordance rate between them was equal to or greater than 98.0% for detecting HPV type 16 or 18. HC2 demonstrated a sensitivity of 96.6% with a specificity of 89.1% for detecting HR HPVs, while RealTime HR presented a sensitivity of 78.3% with a specificity of 99.2%. The sensitivity and specificity of Cobas HPV for detecting HR HPVs were 91.7% and 97.0%. The new real-time PCR assays exhibited lower sensitivities for detecting HR HPVs than that of HC2. Nevertheless, the newly introduced assays have an advantage of simultaneously identifying HPV types 16 and 18 from clinical samples.

Characteristics of clinical isolates of Acinetobacter genomospecies 10 carrying two different metallo-β-lactamases

Acquired metallo-beta-lactamase (MBL) production is an important mechanism of carbapenem resistance. To our knowledge, carriage of two different MBLs has not been described previously in Acinetobacter spp. We present the characteristics of five Acinetobacter isolates carrying two different MBL genes. The species of all five Acinetobacter isolates with two different MBL genes were Acinetobacter genomospecies 10, and bla(IMP-1), bla(VIM-2) and bla(SIM-1) may coexist in this species. Minimum inhibitory concentrations (MICs) of imipenem for all five isolates with two different MBLs were >or=32 microg/mL, whilst those for two segregants that lost both MBLs were 0.5 microg/mL. The presence of MBL gene-carrying integrons with identical structures suggested the easily transferable nature of the elements, whilst instability of the MBL genes indicated potentially erroneous phenotypic and genetic characterisation.

Urinary iodine and sodium status of urban Korean subjects: a pilot study.

OBJECTIVES We estimated iodine status of Korean population by determining the concentration of spot urinary iodine (UI) with a reliable method based on the Sandell-Kolthoff reaction. MATERIALS AND METHODS A total of 540 urine samples from apparently healthy subjects were collected, and UI, urinary sodium (UNa), and urinary creatinine (UCr) were determined from those samples and analyzed with age. RESULTS There were significant decreases in either UI (P<0.0001), UI/UCr ratio (P=0.0001), UNa (P<0.0001), or UNa/Cr ratio (P=0.0001) in younger subjects than older ones. The median value of UI was 267.6 μg/L, but the median UI of the younger group (191.8 μg/L) was significantly decreased compared to that of the older group (383.9 μg/L). CONCLUSIONS This study showed that the median of UI in Korean urban population was in a more than adequate iodine nutritional state, but UI was significantly different between the younger age group and the older age group.

Subcutaneous Phaeohyphomycosis Caused by Phaeoacremonium Species in a Kidney Transplant Patient: The First Case in Korea

Phaeohyphomycosis is a subcutaneous infection caused by dark pigmented fungi, including fungi of the species Phaeoacremonium, Alternaria, Exophiala, and Pyrenochaeta. In August 2005, a 54-yr-old man who had received a renal transplant 5 yr ago was admitted to our hospital with a subcutaneous mass on the third finger of the right hand; the mass had been present for several months. He had been receiving immunosuppressive agents for several years. He underwent excision of the mass, which was followed by aspiration of the wound for bacterial and fungal cultures. Many fungal hyphae were observed on the histology slide treated with periodic acid-Schiff stain. A few white waxy colonies with a woolly texture grew on the Sabouraud dextrose agar at 30℃ and changed to dark brown in color. Nucleotide sequencing of internal transcribed spacer regions revealed 100% homology to the Phaeoacremonium aleophilum anamorph and Togninia minima teleomorph (514 bp/514 bp). The patient completely recovered after wide surgical excision. Here, we report the first case of phaeohyphomycosis caused by Phaeoacremonium species in a kidney transplant patient in Korea.

Evaluation of automated serum des-gamma-carboxyprothrombin (DCP) assays for detecting hepatocellular carcinoma

OBJECTIVES We evaluated two new autoanalyzers, μTAS and Lumipulse for des-γ-carboxyprothrombin (DCP) assay. MATERIAL AND METHODS Analytical performance was evaluated, and the upper reference limit of the 97.5th percentile for DCP was re-established using sera from 140 healthy individuals. DCP levels were determined by the two autoanalyzers and EIA in a total of 239 sera from HCC patients (n=120) and those without HCC (n=119). RESULTS Total imprecision of the two automated assays was <5% CV. Analytical measurement ranges (AMRs) were verified to be linear. The new reference limits were 29.5 mAU/mL for μTAS and 35.0 mAU/mL for Lumipulse. There were proportional and constant biases between the results from the autoanalyzers and those from EIA. CONCLUSION The two newly developed DCP assays showed high analytical performance, but re-establishment of reference limits would be necessary. The new analyzers could be useful for clinical laboratories because of convenience of operation and wide AMRs.

Detection and genotyping of human papillomavirus by five assays according to cytologic results

Five assays for the detection of human papillomavirus (HPV) with different assay principles were evaluated. A total of 230 cervical swab specimens were collected from subjects according to the cytologic results. All specimens were tested by the following assays: hybrid capture 2 (HC2), two real-time PCR assays (Abbott RealTime HR and AdvanSure RealTime), liquid beads microarray (GeneFinder) and peptide nucleic acid-based array (PANArray). The HPV DNA of 99 samples was sequenced to identify genotypes. Concordance rates between the results for the identification of 14 high risk HPV genotypes by any two of the evaluated assays, except for AdvanSure RealTime, ranged from 83.0% to 88.3%, and those for the identification of genotypes 16 and 18, except for HC2, were 93.0% and 96.1%, respectively. The results for the evaluation of high risk HPV genotypes by HC2 agreed with those of the other assays in 76.5-86.5% of cases. Identification of HPV genotype by GeneFinder and PANArray corresponded with that by direct sequencing in 88.9% and 84.8% of sequenced samples. This study demonstrated that HC2 and the two real-time PCR assays could be used for routine HPV screening, and the other genotyping assays can be applied for epidemiologic surveillance.

Evaluation of revisited fucosylated alpha-fetoprotein (AFP-L3) with an autoanalyzer μTAS in a clinical laboratory.

BACKGROUND We assessed clinical and analytical performances of AFP and fucosylated AFP (AFP-L3) assays by a newly developed automated analyzer based on liquid-phase binding (micro-total analysis systems, μTAS). METHODS A total of 239 serum samples were obtained from 120 patients with hepatocellular carcinoma (HCC) and 119 without HCC. Precision of assays by the μTAS was evaluated, and the correlation between AFP-L3 and AFP levels was analyzed. Receiver operating characteristics curve-area under the curve (ROC-AUC) value was calculated to measure the diagnostic performance. RESULTS Imprecision for AFP (ng/ml), AFP-L3 (ng/ml), and AFP-L3 (%) with 2 levels of QC materials was all within 5% coefficient of variation. AFP levels measured by the μTAS were correlated well with those by the UniCel DxI 800 Access (r=0.83). AFP-L3 concentrations in HCC patients were higher than those in control group (median 379.2 ng/ml in HCC, 1.0 ng/ml in non-HCC, P<0.05). AUC of AFP-L3 was 0.91 which was significantly higher than that of AFP (0.88 by μTAS; 0.84 by UniCel DxI 800, P<0.05 for both). CONCLUSION AFP-L3 in HCC was significantly higher than that of control group. The μTAS showed good performances for routine uses in clinical laboratories for measuring AFP and AFP-L3.

Performance evaluation of the Vitros anti-hepatitis C virus antibody assay for use in clinical laboratories

OBJECTIVES We evaluated the performance of Vitros anti-HCV assay. DESIGN AND METHODS Precision performance was assessed for 20 days. A total of 1011 sera were tested for anti-HCV with Vitros and Elecsys assays. Specimens positive for any of the two assays were retested with Architect assay. Discrepant results were evaluated with recombinant immunoblot assay (RIBA) and HCV RNA quantification. RESULTS Total imprecision of Vitros assay was 11.6% and 3.3% CV for negative and positive QC. Among the 1011 sera, 17 showed discrepant results between the three assays. Six were positive and three negative for RIBA. HCV RNA was not detected from all discrepant cases. Sensitivity and specificity were 99.5% and 99.5% for the Vitros, and 100.0% and 99.9% for the Elecsys assay. CONCLUSIONS Sensitivities and specificities of the anti-HCV assays were sufficiently high for use in clinical laboratories, but retesting of weak positive results may be necessary.

Anaphylactic Transfusion Reaction in a Patient with Anhaptoglobinemia: The First Case in Korea

Anaphylactic transfusion reactions are rare complications of blood transfusions. Anhaptoglobinemia, a condition that has high incidence in Asia, can cause allergic transfusion reactions or anaphylaxis in severe cases. A 50-yr-old Korean woman was diagnosed with relapsed acute promyelocytic leukemia. She developed thrombocytopenia during chemotherapy and an anaphylactic transfusion reaction on the 4th and 5th platelet transfusions immediately after the transfusion of the platelet concentrates was initiated. Blood analysis showed no detectable serum haptoglobin. We examined her genetic phenotype and detected anhaptoglobinemia, which occurs because of an allelic deletion in the Hp gene cluster. The presence of an antibody against haptoglobin was detected by performing ELISA. To prevent anaphylactic reactions, apheresis platelets were transfused after washing. Consequently, anaphylactic transfusion reactions did not develop. Here, we report the first case of anhaptoglobinemia causing anaphylactic transfusion reaction in Korea.

Prognostic significance of trisomy 6 in an adult acute myeloid leukemia with t(8;21)

In the diagnosis of acute myeloid leukemia (AML) according to World Health Organization classifications declared on 2008, the importance of recurrent cytogenetic abnormalities such as t(8;21)(q22;q22), inv(16)(p13.1q22), t(15;17)(q24;q21), and t(9;11)(p22;q23) are being increasingly emphasized. Among these cytogenetic abnormalities, t(8;21) is a favorable marker detected in approximately 5% of AML and in 10% of the prior AML with maturation (M2) category in the FrencheAmericaneBritish classification [1]. However, in recent studies, AML patients with t(8;21) are reported to show an adverse outcome with concurrent CD56 expression or KIT gene mutation [2,3]. Trisomy 6 as a sole chromosomal abnormality is relatively rare in patients with AML, myelodysplastic syndrome, and bone marrow hypoplasia, and the prognostic significance of trisomy 6 in AML harboring t(8;21) needs to be elucidated [4]. Herein, we report an AML patient with the karyotypic abnormalities including trisomy 6, t(8;21), and Y chromosome loss at the time of diagnosis coinciding with a negative result of KIT gene mutation study. A 49-year-old Korean man with a chief complaint of general weakness and anemia was admitted to the Severance Hospital of Yonsei University. Complete blood count revealed a hemoglobin level of 3.5 g/dL, platelet count of 44,000/mL, and white blood cell count of 17,390/mL with 71% segmented neutrophils, 20% lymphocytes, 2% monocytes, 1% myelocytes, 2% atypical lymphocytes, and 4% blasts. A bone marrow study revealed hypercellular marrow filled with blasts with maturation, consistent with AML-M2 morphology. Initial chromosome study showed 46,X, Y,þ6,t(8;21)(q22;q22) in all 20 metaphase cells analyzed (Fig. 1A). Flow cytometry analysis showed the blasts to be positive for CD13, CD19, CD33, CD117, HLA-DR, and MPO, and negative for CD3, CD7, CD10, CD 14, CD20, cCD22, CD79a, and TdT. Fluorescence in situ hybridization with the AML panel and reverse transcriptaseepolymerase chain reaction showed a RUNX1-RUNXT1 fusion, consistent with the t(8;21) identified in the chromosome studies (Fig. 1B).