Hyojin Chae

Screening of sepsis using leukocyte cell population data from the Coulter automatic blood cell analyzer DxH800

Introduction:  We determined the utility of leukocyte cell population data (CPD) for the screening of sepsis and fungemia.

Comparative evaluation of three chromogenic media combined with broth enrichment and the real-time PCR-based Xpert MRSA assay for screening of methicillin-resistant Staphylococcus aureus in nasal swabs.

Background We evaluated the performance of three chromogenic media (Brilliance agar I [Oxoid, UK], Brilliance agar II [Oxoid], and ChromID MRSA [Biomérieux, France]) combined with broth enrichment and the Xpert MRSA assay for screening of methicillin-resistant Staphylococcus aureus (MRSA). Methods We obtained 401 pairs of duplicate nasal swabs from 321 patients. One swab was suspended overnight in tryptic soy broth; 50-µL aliquots of suspension were inoculated on the three chromogenic media. Brilliance agar I and II were examined after 24 hr, and ChromID MRSA, after 24 and 48 hr. The paired swab was processed directly using real-time PCR-based Xpert MRSA assay. Results True positives, designated as MRSA growth in any of the culture media, were detected with the prevalence of 17% in our institution. We report the sensitivity, specificity, positive predictive value, and negative predictive value of MRSA growth as follows: 92.3%, 94.0%, 75.9%, and 98.4% in Brilliance agar I (24 hr); 92.7%, 97.9%, 90.0%, and 98.5% in Brilliance agar II (24 hr); 95.6%, 95.8%, 82.3%, and 99.1% in ChromID MRSA (24 hr); 100%, 92.5%, 73.1%, and 100% in ChromID MRSA (48 hr); 92.6%, 96.7%, 85.1%, and 98.5% in Xpert MRSA assay. The agreement between the enriched culture and Xpert MRSA assay was 96.0%. Conclusions Three chromogenic culture media combined with enrichment and Xpert MRSA assay demonstrated similar capabilities in MRSA detection. The Xpert MRSA assay yielded results comparable to those of culture methods, saving 48-72 hr, thus facilitating earlier detection of MRSA in healthcare settings.

Impact of genetic abnormalities on the prognoses and clinical parameters of patients with multiple myeloma.

Background We reviewed patients with multiple myeloma (MM) in order to assess the incidence of genetic abnormalities and their associations with clinical parameters, risk groups, and prognosis. Methods A total of 130 patients with MM were enrolled. The incidences of genetic abnormalities were determined in all patients. The relationships of the genetic abnormalities and clinical parameters were investigated. In addition, a survival analysis was performed. Results Abnormal karyotypes were detected in 42.3% (N=55) of the patients, and this was increased to 63.1% (N=82) after including the results determined with interphase FISH. Hypodiploidy was observed in 7.7% (N=10) of the patients, and all were included in the group with complex karyotypes (30.8%, N=40). The 14q32 rearrangements were detected in 29.2% (N=38) of the patients, and these most commonly included t(11;14), which was followed by t(4;14) and t(14;16) (16.2%, 11.5%, and 0.8%, respectively). Abnormal karyotypes and complex karyotypes were associated with disease progression markers, including low hemoglobin levels, low platelet counts, high plasma cell burden, high β2-microglobulin, and high international staging system stages. A high free light chain (FLC) ratio and FLC difference were associated with abnormal karyotypes, complex karyotypes, and higher plasma cell burden. Hypodiploidy and low platelet counts were significant independent prognostic factors and were more important in patient outcome than any single abnormality. Conclusions Genetic abnormalities were associated with disease progression markers and prognosis of MM patients.

Sensitive detection and accurate monitoring of Plasmodium vivax parasites on routine complete blood count using automatic blood cell analyzer (DxH800TM)

Introduction:  Plasmodium vivax malaria is one of the most important infectious diseases plaguing humanity and causes significant mortality and morbidity worldwide. The gold standard of P. vivax malaria diagnosis is the microscopy of blood smears. Although microscopy is a rapid, cost‐effective, and readily applicable method, it has many disadvantages, including low sensitivity, specificity, and precision. Therefore, there is a clear need for an effective screening test for P. vivax malaria detection both in high‐prevalence areas and developed countries.

Novel method to dissociate platelet clumps in EDTA-dependent pseudothrombocytopenia based on the pathophysiological mechanism.

Abstract Background: EDTA-dependent pseudothrombocytopenia (EDTA-PTCP) is an in vitro phenomenon of platelet clumping that leads to spuriously low platelet counts by automatic hematology analyzers. The mechanism is not clearly defined, but is known as an immunologically mediated phenomenon due to the presence of EDTA-dependent antiplatelet auto-antibodies that induce platelet clumping. The purpose of this study was to identify antiplatelet antibodies in EDTA-PTCP samples and to design a method to dissociate platelet clumps based on the pathophysiological mechanism. Methods: The antiplatelet antibody was investigated using direct and indirect immunofluorescent flow cytometric methods in 23 EDTA-anticoagulated whole blood (WB) samples and 12 serum samples of EDTA-PTCP patients, respectively. A novel mixture containing 9 mmol/L CaCl2and 0.1 unit/L sodium heparin, that provides calcium replacement while curbing coagulation, was designed to dissociate platelet clumps. The effect on dissociation was demonstrated in 26 samples of EDTA-PTCP and compared with the established method of kanamycin supplementation. Results: The direct test was positive for IgM and IgG antiplatelet antibody in 60.9% and 4.4% of patients, respectively [mean median fluorescence intensity (MFI) of 223.9 and 128.4, respectively]. The indirect test was positive for IgM antiplatelet antibody in 58.3% of patients (mean MFI of 123.4). The novel method dissociated the platelet clumps with a mean increased platelet count of 242.3% and was equivalent in efficiency to kanamycin supplementation. Conclusions: The novel method is an easily applicable and efficient measure that allows dissociation of platelet clumps, based on the pathophysiological mechanism of EDTA-PTCP.

Genotype and phenotype heterogeneity in perrault syndrome.

BACKGROUND The hallmarks of Perrault syndrome are progressive sensorineural hearing loss and ovarian dysgenesis, but the disorder is both clinically and genetically heterogenous. CASE We report a 15-year-old girl with gonadal dysgenesis, unilateral sensorineural deafness, cataracts in both eyes, and Marfanoid body proportions diagnosed Perrault syndrome. We detected 14 single nucleotide variations including 2 homozygous missense change of c.317G>A (p.Arg106His) and c.1675A>G (p.Ile559Val) in HSD17B4. No significant mutation in HARS2 and PSMC3IP, and gene copy number variant were found as the cause of Perrault syndrome. SUMMARY AND CONCLUSION Mutations in HARS2, HSD17B4, and PSMC3IP genes do not explain Perrault syndrome in our patient, indicating that other critical genes remain to be identified.

FANCA and FANCG are the major Fanconi anemia genes in the Korean population

Fanconi anemia (FA) is a rare disorder characterized by physical abnormalities, bone marrow failure (BMF), increased risk of malignancies, and cellular hypersensitivity to DNA cross‐linking agents. This study evaluated the genetic alterations in three major Fanconi genes (FANCA, FANCC, and FANCG) in 30 FA patients using multiplex ligation‐dependent probe amplification and direct sequencing. Thirteen BMF patients were genetically classified as FA‐A (n = 6, 46%) and FA‐G (n = 7, 54%). Four common founder mutations were identified and included two FANCA mutations (c.2546delC and c.3720_3724delAAACA) and two FANCG mutations (c.307+1G>C and c.1066C>T), which had previously been commonly observed in a Japanese FA population. We also detected four novel deleterious mutations: c.2778+1G>C and c.3627‐1G>A of FANCA, and c.1589_1591delATA and c.1761‐1G>A of FANCG. This study shows that mutations in FANCA and FANCG are common in Korean FA patients and the existence of four common founder mutations in an East Asian FA population. Mutation screening workflow that includes these common mutations may be useful in the creation of an international database, and to better understand the ethnic characteristics of FA.

Differential Blast Counts Obtained by Automated Blood Cell Analyzers

BACKGROUND Automated blood cell analyzers often read leukemic blasts as normal cells. In this study, we evaluated the 5-part differential patterns of blasts using automated analyzers to determine if they can differentiate among blast types. METHODS Blood samples containing 10% or more blasts were collected from patients with acute leukemia (N=175). The 5-part differential count was conducted using DxH 800 (Beckman Coulter, USA) and XE-2100 analyzers (Sysmex Co., Japan), and the results were compared with manual differential counts, which was used as a reference method. RESULTS The DxH 800 reported the 5-part white blood cell differential count in 98.9% of the cases. The XE-2100 provided an invalid automated differential count in 72% of the cases. Both analyzers counted most lymphoblasts as lymphocytes and most myeloblasts as monocytes. In 11 cases, the DxH 800 reported a 5-part differential count without a blast flag. CONCLUSIONS Some automated analyzers are able to recognize and count blasts according to their characteristic cell types. Therefore, complete blood counts obtained automatically can provide valuable data for making provisional decisions regarding the lineage of leukemia cells before further investigation.

X-linked spondyloepiphyseal dysplasia tarda: identification of a TRAPPC2 mutation in a Korean pedigree.

Spondyloepiphyseal dysplasia (SED) comprises a heterogeneous group of skeletal dysplasias that primarily affect the epiphyses and vertebral bodies. Patients affected by SED usually exhibit short stature and experience early development of degenerative osteoarthritis. SED is subdivided into congenita and tarda forms according to the age at onset and clinical severity, and further subdivided into genetically different forms according to the mode of inheritance and the gene involved. We report a 14-yr-old Korean male who presented with a disproportionately short stature and a short trunk. A pedigree analysis of 3 generations with 6 affected persons revealed an X-linked recessive mode of inheritance. Mutation analysis of the TRAPPC2 (previously called SEDL) gene, the only gene associated with X-linked spondyloepiphyseal dysplasia tarda (X-linked SEDT; MIM 313400), was performed, and a splice-donor site mutation in intron 3 of the TRAPPC2 gene (c.93+5G>A) was identified in the proband and in his unaffected mother (a heterozygote). This mutation is one of the 2 most frequent mutations reported in the medical literature, and is known to result in exon 3 skipping. This is the first report of a genetically confirmed X-linked SEDT case in Korea and highlights the importance of recognizing the mode of inheritance in the diagnosis of X-linked SEDT.

Prenatal diagnosis of autosomal recessive polycystic kidney disease by molecular genetic analysis

A 27‐year‐old primigravida was referred for evaluation of severe oligohydramnios at 22 weeks of gestation. For a more accurate diagnosis and detection of other fetal anomalies, complementary fetal magnetic resonance imaging (MRI) was performed. Findings of fetal MRI evaluation were consistent with autosomal recessive polycystic kidney disease (ARPKD). Parental mutation analysis in the PKHD1 gene was performed. By PKHD1 mutation analysis, we were able to identify a heterozygous missense mutation in exon 20 (K626R) in the father. Molecular genetic analysis can be helpful for an early and reliable prenatal diagnosis of ARPKD. Herein, we present a case of ARPKD that was diagnosed at 22 weeks of gestation by ultrasonographic examination and MRI and verified by PKHD1 mutation analysis and array‐based genetic deletion analysis.