Jang Su Kim

Human Bocavirus in Patients with Respiratory Tract Infection

Background Human bocavirus (HBoV) is a newly identified viral pathogen, and its clinical epidemiology and significance in respiratory infections have not yet been completely elucidated. We investigated the prevalence of HBoV infection and the association between viral (HBoV) load and clinical features of the infection in patients of all age-groups. Methods Nasopharyngeal aspirates from patients with symptoms of respiratory infection were tested for presence of HBoV by using real-time polymerase chain reaction. HBoV-positive patients were categorized into low- and high-viral-load groups using 1.0×106 copies/mL as the threshold value of viral load. Results Detection rate of HBoV was 4.8% (N=93) in a total of 1,926 samples with peak incidence of infection being observed in patients aged 6-12 months. HBoV infection was more frequently observed in young children, especially, in children aged less than 5 yr, and the HBoV load decreased with increase in age. HBoV was codetected with other respiratory viruses in 17 (18.3%) of the 93 HBoV-positive patients and 15 patients (88.2%) belonged to the low-viral-load group. Patients infected with HBoV alone showed a higher viral load than those patients in whom HBoV was codetected with other respiratory viruses (median load, 3.78×105 copies/mL vs. 1.94×104 copies/mL, P=0.014). Higher pulse rate (P=0.007) and respiratory rate (P=0.021) were observed in patients with a high-viral-load. Conclusions Our results suggest that HBoV may be the causative agent of respiratory infection in the high-viral-load group.

Enhanced detection of respiratory viruses using cryopreserved R-Mix ReadyCells

BACKGROUND R-Mix, which contains a fresh mixture of two cell lines, Mv1Lu (mink lung cells) and A549 cells, has shown good sensitivity and specificity for respiratory virus culture. However, it has until recently only been available in North America, in part due to the shipping constraints associated with cell aging and the difficulty in providing these cells to hard to reach regions. Recently, cryopreserved R-Mix ReadyCells for longer storage were developed. These cells, which are shipped on dry ice and have a shelf life as long as 6 months from date of manufacture, can be thawed and used as needed with minimal addition of refeeding media. OBJECTIVE Assess the potential for cryopreserved R-Mix ReadyCells to replace conventional culture. STUDY DESIGN Two hundred and twenty-three nasopharyngeal aspirates confirmed as respiratory virus-positive by conventional culture were inoculated into cryopreserved R-Mix ReadyCells and re-inoculated into conventional culture cells simultaneously. After 1 and 3 days of incubation cryopreserved R-Mix ReadyCells and conventional culture cells were screened using a respiratory virus fluorescent antibody pool for the detection of seven major respiratory viruses (influenza A and B viruses, parainfluenza 1, 2 and 3 viruses, respiratory syncytial virus and adenovirus). Positive pool results were further differentiated with specific monoclonal antibodies against the individual viruses. RESULTS After 1 day of incubation detection rates for conventional culture were 25%, 39%, 39%, 49%, and 10% for influenza A virus, influenza B virus, parainfluenza viruses, respiratory syncytial virus, and adenovirus, respectively. Corresponding detection rates for cryopreserved R-Mix ReadyCells were 78%, 91%, 72%, 81%, and 65%. Average detection rates of cryopreserved R-Mix ReadyCells for all respiratory viruses were 80% after 1 day incubation and 95% after 3 days incubation, compared to 35% and 70% by conventional culture. CONCLUSION The cryopreserved R-Mix ReadyCells system offers a highly sensitive and rapid method for detection of respiratory viruses that may allow it to replace conventional cell culture systems.

Evaluation of a malaria antibody enzyme immunoassay for use in blood screening

Transfusion-transmitted malaria is rare, but it may produce severe problem in the safety of blood transfusion due to the lack of reliable procedure to evaluate donors potentially exposed to malaria. Here, we evaluated a new enzyme-linked immunosorbent assay malaria antibody test (ELISA malaria antibody test, DiaMed, Switzerland) to detect antibodies to Plasmodium vivax (the indigenous malaria) in the blood samples in the Republic of Korea (ROK). Blood samples of four groups were obtained and analyzed; 100 samples from P.vivax infected patients, 35 from recovery patients, 366 from normal healthy individuals, and 325 from domestic travelers of non-endemic areas residents to risky areas of ROK. P.vivax antibody levels by ELISA were then compared to the results from microscopic examination and polymerase chain reaction (PCR) test. As a result, the ELISA malaria antibody test had a clinical sensitivity of 53.0% and a clinical specificity of 94.0% for P.vivax. Twenty out of 325 domestic travelers (6.2%) were reactive and 28 cases (8.6%) were doubtful. Of the reactive and doubtful cases, only two were confirmed as acute malaria by both microscopy and PCR test. Thus we found that the ELISA malaria antibody test was insufficiently sensitive for blood screening of P.vivax in ROK.

Genetic variability in Plasmodium vivax aldolase gene in Korean isolates and the sensitivity of the Binax Now malaria test

Introduction of rapid malaria diagnostic tests (RDT) initiated numerous field evaluations in various epidemiologic settings. But the efficiency of some RTD kits based on aldolase raised reservations for direct implementation of RDT into clinical settings. We performed Binax Now malaria test in 84 Korean Plasmodium vivax isolates and compared it with the traditional Giemsa stain microscopy test as the reference standard. The sensitivity of Binax Now was 62.0% for P. vivax cases (52/84, 95% CI 51.2–71.6%) with 100.0% specificity (50/50, 95% confidence interval 92.9–100%). After the aldolase gene sequence analysis of 84 isolates, two synonymous mutations in aldolase gene were identified in both Binax Now positive and negative samples. No significant association between the mutations and Binax Now malaria tests was found. Thus, the genetic variability would not explain the poor performance of P. vivax RDTs by detecting aldolase in ROK isolates.

Alteration of platelet counts and lipid profiles after treatment of acute Plasmodium vivax

During malaria infections, thrombocytopenia and low cholesterol levels are frequently observed changes. We compared these changes in patients admitted with fevers and infected with Plasmodium vivax, patients admitted with fevers with respiratory/urinary infections and afebrile normal (control) non-infected volunteers. Changes in the platelet count and lipid parameters are reported for malaria patients after treatment with hydroxychloroquine and primaquine for acute P. vivax malaria. Of a total 141 participants, 55 patients were diagnosed with malaria (positive blood smear) prior to treatment. Compared to the normal (n=52) and non-malaria fever groups (n=34), there was a significant decrease in five hematologic indices (white blood cell, red blood cell, hemoglobin, hematocrit and platelet) and three lipid parameters (total cholesterol, HDL-c and LDL-c) in the vivax malaria group at day 0 (pre-treatment). Following treatment, the platelet counts returned to normal limits (P<0.05) from 91,058/microL on day 0 to 246,833/microL by day 17 after treatment. However, changes in the lipid parameters of malaria patients showed a slow recovery to normal limits compared to the platelet counts. The HDL-c and LDL-c remained low for 1 month after treatment but increased at 3 and 6 months post-treatment. At 12 months after treatment, the levels of two lipid parameters had fully recovered to the normal limits. Thus, special attention should be applied when interpreting laboratory blood profiles of malaria patients, especially platelet and lipid based tests, until full recovery after treatment.

Familial hemiplegic migraine with prolonged coma and cerebellar atrophy: CACNA1A T666M mutation in a Korean family.

We report the first Korean patient with familial hemiplegic migraine type 1, with clinical and multimodal imaging findings. A 43-yr-old man was admitted for right hemianopia and aphasia, followed by coma. MRI showed only cerebellar atrophy. CT angiography showed mild vasodilation of intracranial blood vessels and increased vascularity in the left hemisphere and perfusion-weighted imaging showed elevated cerebral blood flow. Gene analysis of the patient and his mother led to the identification of a heterozygous point mutation (1997C→T, T666M) in exon 16 of the CACNA1A gene. Familial hemiplegic migraine should be considered in patients with episodic neurological dysfunction with cerebellar atrophy.

Comparison of the automated fluorescence microscopic viability test with the conventional and flow cytometry methods

The cell viability test is an essential tool in any laboratory, performing cell‐based studies and clinical laboratory tests. The trypan blue exclusion method is the most popular assay for its simple concept among various diagnostic tools. However, several disadvantages include time‐consuming and labor‐intensive steps with low precision. In this study, we evaluated a new technique for the automatic cell viability measurement with microscopic cell counter and microchip. Upon blood draw from 11 healthy volunteers, Mononuclear cells were separated immediately from the heparinized whole blood, and the viable cells were diluted from 100 to 1%. The cell viability tests were performed simultaneously with following three methods: the conventional manual trypan blue exclusion method; the flow cytometry measurement with propidium iodide stain; and the newly developed microscopic cell counter with microchip. Linearities, precisions, and correlations from three methods were analyzed and compared. The correlations data from the microscopic cell counter were in good agreement with both the conventional trypan blue method (r=0.99, P<0.05) and the flow cytometry (r=0.99, P<0.05), respectively. The precision (2.0–6.2%) and linearity from the microscopic cell counter method with microchip were superior in comparison with the conventional method. The microscopic cell counter with microchip performed well with high precision, linearity, and efficient running time than both the manual trypan blue and the flow cytometry methods. J. Clin. Lab. Anal. 25:90–94, 2011.

Acute myeloid leukemia (AML-M2) associated with variant t(8;21): report of three cases

Variants of the t(8;21)(q22;q22) involving chromosome 8, 21, and other chromosomes account for approximately 3% of all t(8;21)(q22;q22) found in patients with acute myeloid leukemia (AML). The clinicopathologic features of AML with the variant t(8;21) have not been well established. We report three cases of AML with variants of t(8;21) characterized, respectively, by derivative 8 with the interstitial inverted insertion of 21q and concurrent monosomy 21, t(8;18;21)(p22;q11.3;q22), and t(2;21;8)(q11.2;q22;q22). Fluorescence in situ hybridization or reverse transcriptase-polymerase chain reaction assay confirmed the presence of RUNX1-RUNX1T1 gene (previously AML1-ETO) rearrangements. Among these cases, three-way breakpoints 18p11.3 and 2q11.2 have not been previously reported. The present report deals with the results of hematologic, immunophenotypic, cytogenetic, fluorescence in situ hybridization, and molecular analyses of these variants. The possible role of the genes in this region in leukemogenesis, response to treatment, and clinical implications are discussed.

Standardization of Terminology in Laboratory Medicine II

Standardization of medical terminology is essential in data transmission between health care institutes and in maximizing the benefits of information technology. The purpose of this study was to standardize medical terms for laboratory observations. During the second year of the study, a standard database of concept names for laboratory terms that covered those used in tertiary health care institutes and reference laboratories was developed. The laboratory terms in the Logical Observation Identifier Names and Codes (LOINC) database were adopted and matched with the electronic data interchange (EDI) codes in Korea. A public hearing and a workshop for clinical pathologists were held to collect the opinions of experts. The Korean standard laboratory terminology database containing six axial concept names, components, property, time aspect, system (specimen), scale type, and method type, was established for 29,340 test observations. Short names and mapping tables for EDI codes and UMLS were added. Synonym tables were prepared to help match concept names to common terms used in the fields. We herein described the Korean standard laboratory terminology database for test names, result description terms, and result units encompassing most of the laboratory tests in Korea.

Evaluation of Plasmodium vivax ELISA for the blood screen

Plasmodium vivax malaria is the indigenous strain in the Republic of Korea (ROK). Plasmodium vivax can be transmitted through the transfusions of various blood components, which became a severe problem with the safety of blood transfusions and blood‐related products in ROK. We evaluated a P. vivax‐specific enzyme‐linked immunosorbent assay (Genedia Malaria Ab ELISA 2.0, Green Cross, ROK) with blood samples from four groups: 251 samples from P. vivax‐infected patients, 39 samples from post‐treatment patients upon follow‐up, 200 samples from healthy volunteers and 421 samples from domestic travellers to and from high endemic areas of ROK. The positive cases from the ELISA test were confirmed by both Giemsa microscopic and polymerase chain reaction methods. The clinical sensitivity and specificity of detecting P. vivax with ELISA test were 94.4% and 99.0%, respectively. Thirteen of 421 domestic travellers (3.0%) to endemic areas tested positive. The results indicate the effectiveness of detecting antibodies against P. vivax in blood with Genedia Malaria Ab ELISA 2.0 test in a large blood screen setting.