Korean Journal of Laboratory Medicine最新文献

Background: Myelomatous pleural effusion (MPE) is rare in myeloma patients. We present a consecutive series of patients with MPE in a single institution.

Methods: We retrospectively reviewed the medical records of 19 patients diagnosed with MPE between 1989 and 2008 at the Asan Medical Center. Diagnoses were confirmed by cytologic identification of malignant plasma cells in the pleural fluid.

Results: Our patients showed dominance of IgA (36.8%) and IgD (31.6%) subtypes. Of 734 myeloma patients, the incidence of MPE was remarkably high for the IgD myeloma subtype (16.7%), compared to the other subtypes (1.4% for IgG and 4.6% for IgA). At the time of diagnosis of MPE, elevated serum β2-microglobulin, anemia, elevated serum lactate dehydrogenase, and elevated creatinine levels were found in 100%, 89.5%, 83.3%, and 57.9% of the patients, respectively. Approximately one-third (31.3%) of the patients had adenosine deaminase (ADA) activities in their pleural fluid exceeding the upper limit of the reported cutoff values for tuberculous pleural effusion (55.8 U/L). Chromosome 13 abnormality was seen in 77.8% of the tested patients. The median survival period from the development of MPE was 2.8 months.

Conclusions: Patients with MPE have aggressive clinical and laboratory characteristics. The preponderance of IgD myeloma in MPE patients is a noteworthy finding because IgD myeloma is a rare subtype. Elevated ADA activity in the pleural fluid is also noteworthy, and may be helpful for detecting MPE. Physicians treating myeloma patients should monitor the development of MPE and consider the possibility of a worse clinical course.

Alpha 1-antitrypsin (AAT) deficiency is a genetic disorder that primarily affects the lungs and liver. While AAT deficiency is one of the most common genetic disorders in the Caucasian population, it is extremely rare in Asians. Here, we report the case of a 36-year-old Korean woman with AAT deficiency who visited the emergency department of our hospital for the treatment of progressive dyspnea that had begun 10 years ago. She had never smoked. Chest computed tomography revealed panlobular emphysema in both lungs, which suggested AAT deficiency. The serum AAT level was 33 mg/dL (reference interval: 90-200 mg/dL). Four exons of the SERPINA1 gene, which is responsible for AAT deficiency, and their flanking regions were analyzed by PCR-direct sequencing. The patient was found to have 1 missense mutation (c.230C>T, p.Ser77Phe; S(iiyama)) and 1 frameshift mutation (c.1158dupC, p.Glu387ArgfsX14; QO(clayton)). This is the first Korean case of AAT deficiency confirmed by genetic analysis and the second case of a compound heterozygote of S(iiyama) and QO(clayton), the first case of which was reported from Japan.

Background: We assessed the efficacy of serial interferon-gamma release assays (IGRAs) for the diagnosis of latent tuberculosis infection (LTBI) in patients receiving immunosuppressive agents for treatment of rheumatic diseases in Korea.

Methods: Of 276 patients who underwent consecutive screening with one of two IGRAs [QuantiFERON-TB Gold or QuantiFERON-TB Gold In-Tube], 66 patients were evaluated by the serial IGRA for detection of LTBI during therapy with immunosuppressive agents. Information on clinical diagnosis, medication, previous TB, blood cell count, tuberculin skin test, and interferon-gamma (IFN-γ) level measured by IGRA was collected.

Results: Of the 66 patients, the initial IGRA was positive in 24.2%, negative in 65.2%, and indeterminate in 10.6%. Forty-six patients (69.7%) showed consistent IGRA results during follow-up, and 13 patients (19.7%) had consistently positive results. IGRA conversion rate was 12.1% (8/66) and reversion rate was 4.5% (3/66). Conversion of IGRA results was only observed in ankylosing spondylitis patients, and the median interval between the two tests in patients with conversion was 8.5 months. The mean IFN-γ level in the group of patients with consistently positive IGRA results was higher than that in the group with inconsistently positive results, although this trend was not statistically significant (P=0.293). Indeterminate results were observed most frequently in patients with systemic lupus erythematosus.

Conclusions: In patients receiving immunosuppressive agents, both IGRA conversions and reversions were observed. Serial IGRA testing may not be needed in patients with a positive initial IGRA result showing high IFN-γ levels, because of high consistency in the test results.

Background: β-thalassemia is primarily found in individuals of Mediterranean and Southeast Asian ancestry. With rapid growth in the Southeast Asian segments of the Korean population, the geographic distribution of hemoglobinopathies is expected to become significantly different from what it is today. In this study, Hb fractions were measured in patients with hypochromic microcytosis to detect thalassemia and Hb variants. To evaluate the feasibility of replacing cellulose acetate electrophoresis (CA) with capillary electrophoresis (CE) in a clinical laboratory, both techniques were performed and the outcomes were compared.

Methods: To evaluate hemoglobinopathies, complete blood cell counts (CBC), CA, and CE were carried out on samples from healthy and microcytic hypochromic groups. The microcytic hypochromic group consisted of 103 patients whose mean corpuscular volume (MCV) was less than 75 fL and mean corpuscular hemoglobin (MCH) was less than 24 pg. Quantitative analysis of Hb fractions was performed on 143 whole blood samples.

Results: There was a good correlation for measurements of HbA (r=0.9370, P<0.0001), HbA(2) (r=0.8973 P<0.0001), and HbF (r= 0.8010, P=0.0304) between the two methods. In the microcytic hypochromic group, there were 29 cases (28.2%) with decreased HbA(2), 2 cases (1.9%) with increased HbA(2), 3 cases (2.9%) with increased HbF, and 2 cases (1.9%) with increased HbA(2) and HbF.

Conclusions: CE is comparable to CA for reliable measurement of Hb fractions. It is suitable for screening of hemoglobinopathies in many clinical laboratories.

Background: Members of the Acinetobacter calcoaceticus-baumannii (Acb) complex are important opportunistic bacterial pathogens and present significant therapeutic challenges in the treatment of nosocomial infections. In the present study, we investigated the integrons and various genes involved in resistance to carbapenems, aminoglycosides, and fluoroquinolones in 56 imipenem-nonsusceptible Acb complex isolates.

Methods: This study included 44 imipenem-nonsusceptible A. baumannii, 10 Acinetobacter genomic species 3, and 2 Acinetobacter genomic species 13TU strains isolated in Daejeon, Korea. The minimum inhibitory concentrations (MICs) were determined by Etest. PCR and DNA sequencing were used to identify the genes that potentially contribute to each resistance phenotype.

Results: All A. baumannii isolates harbored the bla(OXA-51)-like gene, and 21 isolates (47.7%) co-produced OXA-23. However, isolates of Acinetobacter genomic species 3 and 13TU only contained bla(IMP-1) or bla(VIM-2). Most Acb complex isolates (94.6%) harbored class 1 integrons, armA, and/or aminoglycoside-modifying enzymes (AMEs). Of particular note was the fact that armA and aph(3')-Ia were only detected in A. baumannii isolates, which were highly resistant to amikacin (MIC(50)≥256) and gentamicin (MIC(50)≥1,024). In all 44 A. baumannii isolates, resistance to fluoroquinolones was conferred by sense mutations in the gyrA and parC. However, sense mutations in parC were not found in Acinetobacter genomic species 3 or 13TU isolates.

Conclusions: Several differences in carbapenem, aminoglycoside, and fluoroquinolone resistance gene content were detected among Acb complex isolates. However, most Acb complex isolates (87.5%) possessed integrons, carbapenemases, AMEs, and mutations in gyrA. The co-occurrence of several resistance determinants may present a significant threat.

The aminoglycoside 6'-N-acetyltransferases of type Ib (aac(6')-Ib) gene confers resistance to amikacin, tobramycin, kanamycin, and netilmicin but not gentamicin. However, some isolates harboring this gene show reduced susceptibility to amikacin. The European Committee on Antimicrobial Susceptibility Testing (EUCAST) recommends a revision of the phenotypic description for isolates harboring the aac(6')-Ib gene. In this study, we determined the aminoglycoside susceptibility profiles of 58 AAC(6')-Ib-producing Enterobacter cloacae isolates. On the basis of the CLSI and EUCAST breakpoints, a large proportion (84.5% and 55.2%, respectively) of these 58 isolates were found to be susceptible to amikacin. However, among the isolates that were shown to be anikacin-susceptible according to the CLSI and EUCAST breakpoints, only 30.6% and 18.8% isolates, respectively, could be considered to have intermediate resistance on the basis of the EUCAST expert rules. Further studies should be conducted to determine the aminoglycoside susceptibility profiles of aac(6')-Ib-harboring isolates from various geographic regions and to monitor the therapeutic efficacy of amikacin in infections caused by these isolates.

We report a rare case of multiple myeloma with biclonal gammopathy (IgG kappa and IgA lambda type) in a 58-year-old man with prostate cancer who presented with lower back pain. Through computed tomography (CT) imaging, an osteolytic lesion at the L3 vertebra and an enhancing lesion of the prostate gland with multiple lymphadenopathies were found. In the whole body positron emission tomography-computed tomography (PET-CT), an additional osteoblastic bone lesion was found in the left ischial bone. A prostate biopsy was performed, and adenocarcinoma was confirmed. Decompression surgery of the L3 vertebra was conducted, and the pathologic result indicated that the lesion was a plasma cell neoplasm. Immunofixation electrophoresis showed the presence of biclonal gammopathy (IgG kappa and IgA lambda). Bone marrow plasma cells (CD138 positive cells) comprised 7.2% of nucleated cells and showed kappa positivity. We started radiation therapy for the L3 vertebra lesion, with a total dose of 3,940 cGy, and androgen deprivation therapy as treatment for the prostate cancer.

Carbapenem-resistant Klebsiella pneumoniae isolates producing K. pneumoniae carbapenemases (KPC) were first reported in the USA in 2001, and since then, this infection has been reported in Europe, Israel, South America, and China. In Korea, the first KPC-2-producing K. pneumoniae sequence type (ST) 11 strain was detected in 2010. We report the case of a patient with a urinary tract infection caused by KPC-2-producing K. pneumoniae. This is the second report of a KPC-2-producing K. pneumoniae infection in Korea, but the multilocus sequence type was ST258. The KPC-2-producing isolate was resistant to all tested β-lactams (including imipenem and meropenem), amikacin, tobramycin, ciprofloxacin, levofloxacin, and trimethoprim-sulfamethoxazole, but was susceptible to gentamicin, colistin, polymyxin B, and tigecycline. The KPC-2-producing isolate was negative to phenotypic extended-spectrum β-lactamase (ESBL) and AmpC detection tests and positive to modified Hodge test and carbapenemase inhibition test with aminophenylboronic acid.