Sung Ran Cho

Clinical and molecular biological analysis of a nosocomial outbreak of vancomycin-resistant enterococci in a neonatal intensive care unit

Lee HK, Lee WG, Cho SR. Clinical and molecular biological analysis of a nosocomial outbreak of vancomycin‐resistant enterococci in a neonatal intensive care unit. Acta Pædiatr 1999; 88: 651‐4. Stockholm. ISSN 0803‐5253

Comparison of multiplex reverse transcription polymerase chain reaction and conventional cytogenetics as a diagnostic strategy for acute leukemia

To clarify the usefulness of multiplex reverse transcription polymerase chain reaction (mRT‐PCR) in diagnosing acute leukemia, mRT‐PCR detecting 28 different translocations was performed on bone marrow aspirates of 156 patients with acute leukemia, and the results were compared with conventional chromosomal karyotypes. About 113 of 156 patients had acute myeloid leukemia (AML), and 36 had acute lymphoid leukemia (ALL) with patients’ ages ranging from 1 to 84 (median: 34.5). Concordance rate between karyotyping and mRT‐PCR was 50% (51% in AML and 44% in ALL). Karyotype revealed chromosomal abnormalities in 70 patients (45%) while mRT‐PCR showed some aberrations in 59 patients (38%). mRT‐PCR detected t(1;19), t(4;11), t(9;11), t(10;11), t(11;19), t(12;21), and TAL1d, which were not detected by G‐banding. In addition, 10 patients with t(15;17), one patient with t(8;21), and four patients with t(9;22) detected by mRT‐PCR revealed normal karyotypes. However, mRT‐PCR did not detect numerical abnormalities, deletions, and translocations other than the 28 translocations included in the assay as expected. In conclusion, although it cannot be a substitute of the conventional chromosome analysis, mRT‐PCR could be a complementary diagnostic strategy of acute leukemia.

[Two cases of acute myeloid leukemia with t(16;21)(p11;q22) and TLS/FUS-ERG fusion transcripts].

Many AML-associated chromosomal abnormalities, such as t(8;21), t(15;17), inv(16), t(9;11), t(9;22) and t(6;9) are well known. The chromosomal aberration of t(16;21)(p11;q22) in AML is rare and it is known to be associated with poor prognosis, young age (median age, 22 yr), and involvement of various subtypes of the French-American-British classification. We report here 2 AML patients with t(16;21)(p11;q22), proved by conventional cytogenetics and/or reverse transcription (RT)-PCR. Erythrophagocytosis by leukemic blasts was observed in both of the cases. One patient was a 24 yr-old male with acute myelomonocytic leukemia. His karyotype was 46,XY,t(16;21)(p11;q22),del(18)(p11.2) and RT-PCR revealed the TLS/FUS-ERG fusion transcripts. Although he received allogeneic peripheral blood stem cell transplantation after the first remission, he died 9 months after the initial diagnosis due to relapse of the disease and graft-versus-host disease. The other patient was a 72 yr-old male with acute myeloid leukemia without maturation. His karyotype was 45,XY,-16,add(21)(q22) and the presence of t(16;21)(p11;q22) was detected by RT-PCR. He was transferred to another hospital with no more follow-up. We suggest that the presence of t(16;21)(p11;q22) and/or TLS/FUS-ERG fusion transcripts has to be considered in cases of AML with erythrophagocytosis.

Change of platelet activation markers using flow cytometry in patients with hematology/oncology disorders after transfusion

In spite of the frequent need of platelet transfusions, there is limited information on the association of platelet activation markers, in transfused patients with hematology/oncology disorders, with platelet function using flow cytometry. The goal of this study was to evaluate the changes of PAC-1 binding and CD62P expression, with or without agonists in patients after transfusions. Twenty-eight whole blood samples were obtained from 24 patients admitted to the department of Hematology & Oncology and transfused with platelets; these samples were compared to 30 healthy controls. Whole blood samples, either with or without agonists, such as 20 µM adenosine diphosphate (ADP) or 100 µM thrombin receptor activating peptide (TRAP), were stained with the fluorescein conjugated monoclonal antibodies PAC-1 or CD62P. Then, the percent expression for each marker was analysed using flow cytometry. ADP and TRAP induced an increased percentage of CD62P expression and PAC-1 binding after platelet transfusions compared to the samples studied before transfusion, and these findings were lower than those of the healthy controls. However, the expression of platelets without the agonists was not significantly changed, despite the transfusions. Therefore, agonist-induced platelet activation markers, studied by flow cytometry, appear to be more useful for the evaluation of platelet function after transfusions than platelet activation markers without agonists.

Current Status and Proposal of a Guideline for Manual Slide Review of Automated Complete Blood Cell Count and White Blood Cell Dfferential

BACKGROUNDnManual slide review (MSR) is usually triggered by the results of automated hematology analyzers, but each laboratory has different criteria for MSR. This study was carried out to investigate the current status of MSR criteria of automated complete blood cell count (CBC) and white blood cell (WBC) differential results and to propose a basic guideline for MSR.nnnMETHODSnTotal 111 laboratories were surveyed regarding MSR using questionnaires. The questionnaire asked: kinds of automated hematology analyzers used and the presence of criteria triggering MSR in seven categories: 1) CBC results, 2) 5 differential WBC counts, 3) 3 differential WBC counts, 4) automated reticulocyte counts, 5) delta check, 6) instrument flags (or messages), 7) clinical information (wards or diseases). Based on the survey results, we determined basic and extended criteria for MSR. With these criteria, we consulted nine hematology experts to get a consensus.nnnRESULTSnAll 111 laboratories had their own MSR criteria. Among 111 laboratories, 98 (88.3%) used more than three criteria for MSR including CBC results and 5-part WBC differential count results and 95 (85.6%) had criteria of flags triggering MSR. For MSR criteria with numeric values, the 10th, 50th, and 90th percentiles of upper and lower threshold values were obtained. The basic guideline for MSR was made.nnnCONCLUSIONSnWe proposed a basic guideline for MSR. This guideline would be helpful to hematology laboratories for their daily operation and providing more rapid and accurate CBC and WBC differential results.

Nodular lymphoid hyperplasia of the stomach in a patient with multiple submucosal tumors.

Nodular lymphoid hyperplasia of the stomach is a rare lymphoproliferative disorder. Here, we report a 38-year-old man who presented with multiple submucosal tumors of the stomach. Histologically, the lesions were characterized by multiple discrete submucosal nodules of lymphoid cells. The infiltrates between the lymphoid follicles were composed mainly of medium-sized lymphoid cells with abundant clear cytoplasm, as well as a few large cells with vesicular nuclei. The gastric mucosa exhibited multifocal lymphoid aggregates and some of the epithelial cells were infiltrated by small lymphocytes mimicking lymphoepithelial lesions. Histopathology was consistent with mucosa-associated lymphoid tissue lymphoma. However, the infiltrating lymphoid cells were positive for CD2, CD3, CD5, and CD7. In addition, polymerase chain reaction analysis of the immunoglobulin heavy chain and T-cell receptor gene rearrangements demonstrated polyclonality. This case was diagnosed as reactive lymphoid hyperplasia of the stomach.

Current routine practice and clinico-pathological characteristics associated with acute promyelocytic leukemia in Korea

Background Acute promyelocytic leukemia (APL) can be life threatening, necessitating emergency therapy with prompt diagnosis by morphologic findings, immunophenotyping, cytogenetic analysis, or molecular studies. This study aimed to assess the current routine practices in APL and the clinico-pathologic features of APL. Methods We reviewed the medical records of 48 Korean patients (25 men, 23 women; median age, 51 (20-80) years) diagnosed with APL in 5 university hospitals between March 2007 and February 2012. Results The WBC count at diagnosis and platelet count varied from 0.4 to 81.0 (median 2.0)×109/L and 2.7 to 124.0 (median 54.5)×109/L, respectively. The median values for prothrombin time and activated partial thromboplastin time were 14.7 (11.3-44.1) s and 29 (24-62) s, respectively. All but 2 patients (96%) showed a fibrin/fibrinogen degradation product value of >20 µg/mL. The D-dimer median value was 5,000 (686-55,630) ng/mL. The t(15;17)(q22;q12 and PML-RARA fusion was found in all patients by chromosome analysis and/or multiplex reverse transcriptase-polymerase chain reaction (RT-PCR), with turnaround times of 8 (2-19) d and 7 (2-13) d, respectively. All patients received induction chemotherapy: all-trans retinoic acid (ATRA) alone (N=11, 26%), ATRA+idarubicin (N=25, 58%), ATRA+cytarabine (N=3, 7%), ATRA+idarubicin+cytarabine (N=4, 9%). Conclusion Since APL is a medical emergency and an accurate diagnosis is a prerequisite for prompt treatment, laboratory support to implement faster diagnostic tools to confirm the presence of PML-RARA is required.

Clinical significance of cryptic chromosomal translocations detected by multiplex RT‐PCR in patients with acute leukemia

Sir, Chromosomal aberrations of leukemic cells in patients with acute leukemia are strongly associated with clinical course of the disease, and cytogenetic analysis at diagnosis is believed to be the most powerful prognostic factor in acute leukemia. However, identification of prognosis remains problematic, particularly for patients with normal karyotype because standard cytogenetic analysis has limitations for patients with insufficient metaphases, or those with cryptic chromosomal translocations. Recently, alternative molecular techniques such as reverse transcription polymerase chain reaction (RTPCR), fluorescence in situ hybridization, and comparative genomic hybridization have been able to provide accurate information, in addition to conventional cytogenetic results, for patients with leukemia [1, 2]. Furthermore, multiplex reverse transcription polymerase chain reaction (mRT-PCR) was introduced for identifying all translocation-positive patients by detecting 29 different translocations simultaneously [3, 4]. A matter of concern is the concordance between conventional G-banding results and the above-mentioned advanced techniques. In the same context, it is to be answered whether AML patients with normal karyotype should be considered as a single homogeneous population who have the same prognosis or should be separated into different groups according to mRT-PCR results. We performed mRT-PCR (Hemavision kit, Bio-Rad Laboratories, Hercules, CA, USA) technique together with cytogenetic study in detecting cryptic translocations on 299 patients with acute leukemia to investigate appropriate risk stratification at diagnosis on the basis of our previous study [5]. G-band analysis was carried out, and karyotypes were described according to the International System for Human Cytogenetic Nomenclature, 2009 Edition [6]. Multiplex RT-PCR (mRT-PCR) was performed using the mDx HemavisionTM kit according to the manufacturer’s instructions, with slight modification of the previous mRT-PCR method as described earlier [4]. Patients with favorable or unfavorable aberrations, detected either by conventional cytogenetics or by mRT-PCR, were separately divided into independent subgroups or compared with double normal (normal karyotype and normal mRT-PCR) patients with regard to overall survival (OS). Comparison of clinical variables across groups was made using Fisher’s exact test for categorical data. OS was calculated using the Kaplan– Meier method, and a log-rank test was used to compare differences between survival curves. OS was measured from the diagnosis. The concordance rate between conventional cytogenetic and mRT-PCR was 76.5% (150/197) (76.4% in AML, 74.1% in ALL, 75% in BAL, and 100% in acute leukemia with dysplasia). mRT-PCR missed each case of inv(16), inv(9), t(3;5), t(6;11), t(9;12), t(16;21), and