Korean Journal of Laboratory Medicine最新文献

In B lymphoblastic leukemia/lymphoma (B-ALL/LBL), t(9;22)(q34;q11.2) and t(1;19)(q23;p13.3) are recurrent cytogenetic abnormalities. The concurrent occurrence of both abnormalities is very rare, and only 3 cases have been previously reported. Here, we report a case of adult B-ALL with ider(9)(q10)t(9;22)(q34;q11.2) and der(19)t(1;19)(q23;p13.3). A literature review revealed that ider(9) (q10)t(9;22) is a rare variant of t(9;22) with a deletion of the short arm of chromosome 9. Fifteen cases of ider(9)(q10)t(9;22) have been reported. This abnormality is specific to precursor B-lymphoid neoplasms, such as B-ALL or B-lymphoid blast phase of CML, and is associated with disease progression or short survival. The cytogenetic abnormality t(1;19) is also specific to B-ALL. In most instances of t(1;19), TCF3 is fused to PBX1; however, a few cases have identical translocations but no TCF3-PBX1 fusion, as was observed in our patient. We describe the first case of ider(9)(q10)t(9;22) in combination with TCF3-PBX1 negative t(1;19). The patient underwent imatinib therapy in addition to intensive chemotherapy, but failed to achieve remission.

Background: Accurate and early detection of vancomycin-resistant enterococci (VRE) is critical for controlling nosocomial infection. In this study, we evaluated the usefulness of a selective chromogenic agar medium and of multiplex PCR for detection of VRE, and both these techniques were compared with the conventional culture method for VRE detection.

Methods: We performed the following 3 methods for detecting VRE infection in stool specimens: the routine culture method, culturing in selective chromogenic agar medium (chromID VRE, bioMérieux, France), and multiplex PCR using the Seeplex® VRE ACE Detection kit (Seegene Inc., Korea) with additional PCR for vanC genes.

Results: We isolated 109 VRE strains from 100 stool specimens by the routine culture method. In chromID VRE, all the isolates showed purple colonies, including Enterococcus gallinarum and E. raffinosus, which were later identified using the Vitek card. All VRE isolates were identified by the multiplex PCR method; 100 were vanA-positive E. faecium, 8 were vanA- and vanC-1-positive E. gallinarum, and 1 was vanA-positive E. raffinosus.

Conclusions: For VRE surveillance, culturing the isolates in chromID VRE after broth enrichment appears to be an accurate, rapid, and easy method for routine screening test. Multiplex PCR is relatively expensive and needs skilled techniques for detecting VRE, but it can be an auxiliary tool for rapid detection of genotype during a VRE outbreak.

Background: Anti-double stranded DNA antibody (anti-dsDNA) test is useful for the diagnosis and monitoring of systemic lupus erythematosus (SLE). Although several methods are available, none of them is completely satisfactory and differences among them have been reported. We evaluated the diagnostic performance of 6 commercial kits for anti-dsDNA detection.

Methods: A total of 142 sera (SLE [N=74], other systemic rheumatic diseases [N=50], other diseases [N=18]) were tested by 6 different assay kits using different antigenic sources of DNA: Crithidia luciliae immunofluorescence test (CLIFT), salmon testes (immunoblot, IB), human (ELISA I), salmon testes with nucleosome linker (ELISA II), plasmid (ELISA III), and synthetic oligonucleotides (chemiluminescence immunoassay, CLIA).

Results: With manufacturers' cut-off values, 6 test kits showed sensitivities of 55.4-91.9%. ELISA I had a greater sensitivity than the other five assays (P<0.001). The specificities of ELISA II, ELISA III, CLIA, and CLIFT were higher than those of ELISA I and IB (P<0.05). In ROC curve analysis, 3 ELISA kits and CLIA showed AUC values of 0.845-0.893, and revealed no significant differences among them (P>0.05). With cut-off values set at 95% of specificity, ELISA II had a higher sensitivity than ELISA III (63.5% vs. 41.9%, P<0.05). IB had poor concordance rates with other assays (42.0-65.0%). Pearson correlation coefficients among 4 quantitative assays were 0.667-0.798.

Conclusions: Six different assays showed various performances depending on the methods and cut-off values used. Except IB, the other five assays can be used for the detection of anti-dsDNA.

The t(3;3)(q21;q26.2) is known to be mainly observed in hematologic myeloid malignancies, as a form of 3q21q26 syndrome. Cytogenetic abnormalities of 3q21q26 syndrome result in RPN1-EVI1 fusion transcripts involving ecotropic viral integration site-1 (EVI1) at 3q26.2 and ribophorin I (RPN1) at 3q21, and the fusion transcripts play an important role in leukemogenesis and disease progression. They are usually associated with dysplasia, especially of megakaryocytes. Patients with these cytogenetic abnormalities show extremely poor prognosis even with aggressive anti-leukemic therapy. We report a case of blastic crisis of CML with both t(3;3)(q21;q26.2) and t(9;22)(q34;q11.2) and associated severe multilineage dysplasia. The patient showed a poor response to imatinib, dasatinib and aggressive induction therapy. When both t(3;3)(q21;q26.2) and t(9;22)(q34;q11.2) are observed in cases of leukemia with increased blasts, they are best considered as aggressive phases of CML with t(3;3)(q21;q26.2), rather than AML with t(9;22)(q34;q11.2) by 2008 WHO classification.

Background: Total IgE levels in allergic patients tend to be higher than those in healthy individuals. We evaluated the usefulness of total IgE levels in predicting positive results of allergen specific IgEs in multiple allergen simultaneous tests.

Methods: A total of 133 patients with allergic symptoms were evaluated. Allergen specific IgEs were detected using 3 different kits: Allergy screen (R-biopharm, Germany), AdvanSure Allergy Screen (LG Life Science, Korea) and Polycheck allergy (Biocheck Co., Germany). Total IgE was measured by turbidoimmunometric assay (LX-2200, Eiken Chemical Co., Japan). The patients were divided into high (≥ 170 IU/mL) and low (<170 IU/mL) groups of total IgE level, and the positive rates and number of positive allergen specific IgEs were evaluated in each group. Positive concordance rates among different kits were also evaluated.

Results: High total IgE group showed significantly higher positive rates and number of positive allergen specific IgEs in all of the 3 test kits used compared to low total IgE group. Only two of the allergens, Dermatophagoides farinae and Dermatophagoides pteronyssinus had positive concordance rates of ≥ 50%. Allergen specific IgEs to these two allergens showed good correlation with total IgE (correlation coefficients >0.5).

Conclusions: Total IgE appears to be useful in predicting positive results in allergen specific IgE tests to common allergens. The specific IgEs to D. farinae and D. pteronyssinus showed good correlation with total IgE. However, for other allergens, significant differences were observed among different test kits, and the standardization of allergens in multiple allergen simultaneous tests is needed.

Background: In this study, we used high-resolution DNA typing to investigate the distribution of HLA alleles and haplotypes in Koreans.

Methods: HLA-A, -B, -C, and -DRB1 alleles were genotyped at the allelic (4-digit) level in 474 healthy Koreans. HLA genotyping was performed in two steps. Initially, serologic typing or generic-level DNA typing was performed using the PCR-sequence-specific oligonucleotide method, and then allelic DNA typing (exons 2 and 3 for class I, and exon 2 for DRB1) was carried out using the PCR-single-strand conformation polymorphism method or sequence-based typing. HLA allele and haplotype frequencies and linkage disequilibrium values were calculated by the maximum likelihood method using a computer program developed for the 11th International Histocompatibility Workshop.

Results: A total of 21 HLA-A, 40 HLA-B, 22 HLA-C, and 29 HLA-DRB1 alleles were found in Koreans. The most frequent alleles in each locus with frequencies of ≥ 10% were, in decreasing order of frequency, as follows: A*24:02, A*02:01, A*33:03; B*51:01; C*01:02, C*03:03; and DRB1*09:01. The numbers of two- and three-locus haplotypes with frequencies of >0.5% were as follows: 44 A-C, 42 B-C, 51 A-B, 52 B-DRB1, 42 A-C-B, and 34 A-B-DRB1. Thirteen A-B-DRB1 haplotypes with frequencies of ≥ 1.0% comprised 26.0% of the total haplotypes. The six most common haplotypes were as follows: A*33:03-B*44:03-DRB1*13:02 (3.7%), A*33:03-B*44:03-DRB1*07:01 (3.0%), A*33:03-B*58:01-DRB1*13:02 (3.0%), A*24:02-B*07:02-DRB1*01:01 (2.8%), A*30:01-B*13:02-DRB1*07:01 (2.3%), and A*11:01-B*15:01-DRB1*04:06 (2.2%).

Conclusions: The information obtained in this study can be used as basic data for Koreans in the fields of organ transplantation, disease association, and anthropologic studies.

Hypermethylation of the homeobox (HOX) gene promoter leads to decreased expression of the gene during tumor development and is thought to be correlated with the clinical outcome in leukemia. In this study, we performed pyrosequencing to quantify the methylation level of HOXA5 genes in the bone marrow samples obtained from 50 patients with AML and 19 normal controls. The methylation percentage of HOXA5 in AML patients (median=65.4%, interquartile range=35.9-72.3%) was higher than that of HOXA5 in control patients (median=43.1%, interquartile range=36.7-49.6%, Mann-Whitney U test, P=0.012). The patients of the AML group who had a high methylation percentage (>70%) had a good prognosis with a 3-yr overall survival (OS) of 82.5%, whereas the patients with a low methylation percentage (≤70%) showed a 3-yr OS of 40.5% (P=0.048). Cox proportional hazards regression showed that the methylation percentages of HOXA5 were independently associated with the 3-yr OS of AML patients, regardless of their karyotypes. We propose that the quantification of HOXA5 methylation by pyrosequencing may be useful for predicting short-term prognosis in AML. However, the limitations of our study are the small sample size and its preliminary nature. Thus, a larger study should be performed to clearly determine the relationships among HOXA5 methylation levels, cytogenetics, and prognosis in AML patients.

JAK2 V617F and MPL W515L/K mutations have been reported in approximately 50% and 5% of the patients with essential thrombocythemia (ET), respectively. We investigated the frequency of MPL W515L/K mutations in a series of consecutive patients with ET and post-essential thrombocythemia myelofibrosis (post-ET MF). The study subjects were 63 patients diagnosed either with ET (N=59) or post-ET MF (N=4) at our institution between June 2006 and February 2010. Among them, 35 (55.6%) had the JAK2 V617F mutation. MPL W515L/K mutations were detected by direct sequencing analyses of exon 10, and 2 patients were found to harbor the following MPL mutations: W515L in 1 patient with ET and W515K in 1 patient with post-ET MF. Neither of the patients had the JAK2 V617F mutation. Thus, the frequency of MPL W515L/K mutation in Korean patients with ET/post-ETMF was 3.2% (2/63) and that in JAK2 V617F-negative ET/post-ET MF was 7.1% (2/28) [corrected]. This is the first study to report the frequency of JAK2 V617F and MPL W515L/K mutations in Korean patients with ET/post-ET MF.

Background: The emergence of multidrug-resistant (MDR) Acinetobacter baumannii as an important opportunistic pathogen has given rise to significant therapeutic challenges in the treatment of nosocomial infections. In the present study, we assess the antibiotic resistance mechanisms of MDR A. baumannii strains by estimating the prevalence of antibiotic resistance determinants, including integrons, β-lactamases, str genes, and gyrA and parC mutations.

Methods: Thirty-five MDR A. baumannii clinical isolates were collected from 3 Korean university hospitals over a 2-yr period. A. baumannii was confirmed by rpoB gene analysis. For each isolate, the minimal inhibitory concentrations (MICs) of 9 antibiotics were determined by the agar dilution method. PCR and DNA sequencing were used to identify the genes that potentially contribute to each resistance phenotype.

Results: Of the 35 MDR A. baumannii isolates examined, 7 antibiotic resistance gene determinants were detected. These resistance gene determinants included the gene bla(OXA-23), with an upstream element ISAba1 to promote increased gene expression and subsequent resistance to carbapenems, in 8 isolates (22.9%); aacA4, located within class 1 integrons, in 7 isolates (20.0%); and fluoroquinolone resistance conferred by gyrA and parC sense mutations in 31 isolates.

Conclusions: Of the 35 MDR A. baumannii isolates, 26 (74.3%) from both outbreak and sporadic cases possessed at least 4 of the 7 antibiotic resistance gene determinants that give rise to the MDR phenotype. The co-occurrence of several resistance determinants may present a significant threat.