Evaluation of the Screening Tests for the Diagnosis of Plasma Cell Neoplasm

BACKGROUND: Plasma cell neoplasm is diagnosed by performing bone marrow examination, serum- and urine-protein electrophoresis, and quantification of free light chains of immunoglobulins. We characterized and quantified monoclonal proteins typical of different diagnosed conditions to determine the best screening test(s). METHODS: We retrospectively reviewed diagnosis of and the characteristics of monoclonal proteins from 113 patients with monoclonal gammopathy. Monoclonal proteins were detected by agarose-gel electrophoresis and capillary electrophoresis, and if the results were ambiguous, they were confirmed by immunofixation electrophoresis. Free light chains were measured using nephelometry. RESULTS: The concentrations of monoclonal proteins in 113 patients with different conditions were as follows: multiple myeloma (MM) (67%), 2.66 (0.87-9.48) g/dL; monoclonal gammopathy of undetermined significance (MGUS) (26%), 0.62 (0.08-2.95) g/dL; lymphoma (3%), 3.65 (1.59-6.54) g/dL; Waldenstrom's macroglobulinemia (2%), 1.99 (1.08-2.90) g/dL; amyloidosis (2%), 0.61 g/dL; and POEMS syndrome (1%), 0.99 g/dL. There was a significant difference in the concentration and kappa/lambda ratio (which was based on the immunetype of the monoclonal proteins) of the monoclonal proteins in patients with MM and MGUS (P<0.001 and P=0.004, respectively). The diagnostic sensitivity of serum-protein electrophoresis, free-light-chain assay, and bone marrow analysis was 87.6%, 84.1%, and 84.5%, respectively. The sensitivity of a combination of 2 or 3 of these tests was higher at 100%. CONCLUSIONS: A combination of protein electrophoresis with immunotyping and serum free-light-chain assay may be the best screening method for detecting monoclonal proteins since its non-invasiveness.

Sole Trisomy 22 Not Associated with inv(16) in Myelodysplastic Syndrome / 이화의대지

Trisomy 22 is closely associated with inv(16) or t(16;16) and could be a marker of cryptic rearrangement of CBFB/MYH11 in acute myeloid leukemia (AML). Trisomy 22 not associated with CBFB/MYH11 rearrangement is a rare event. Here, we report a case diagnosed as refractory anemia with excess blasts-2 (RAEB-2) with sole trisomy 22 in the absence of CBFB/MYH11 rearrangement. The cytogenetic study of bone marrow cells disclosed trisomy 22 in 10% of metaphase cells analyzed. The other chromosomal abnormalities were not found. Fluorescence in situ hybridization (FISH) using CBFB/MYH11 probe to detect cryptic inv(16)(p13q22) showed negative result. We also excluded rearrangements of chromosome 5, 7, 8, 20, and ETV6 by FISH. Sole trisomy 22 not associated with inv(16) is a true entity.

Comparison of the AdvanSure Human Papillomavirus Screening Real-Time PCR, the Abbott RealTime High Risk Human Papillomavirus Test, and the Hybrid Capture Human Papillomavirus DNA Test for the Detection of Human Papillomavirus

BACKGROUND: We evaluated the performance of various commercial assays for the molecular detection of human papillomavirus (HPV); the recently developed AdvanSure HPV Screening real-time PCR assay (AdvanSure PCR) and the Abbott RealTime High Risk HPV PCR assay (Abbott PCR) were compared with the Hybrid Capture 2 HPV DNA Test (HC2). METHODS: All 3 tests were performed on 177 samples, and any sample that showed a discrepancy in any of the 3 tests was genotyped using INNO-LiPA HPV genotyping and/or sequencing. On the basis of these results, we obtained a consensus HPV result, and the performance of each test was evaluated. We also evaluated high-risk HPV 16/18 detection by using the 2 real-time PCR assays. RESULTS: Among the 177 samples, 65 were negative and 75 were positive in all 3 assays; however, the results of the 3 assays with 37 samples were discrepant. Compared with the consensus HPV result, the sensitivities and specificities of HC2, AdvanSure PCR, and Abbott PCR were 97.6%, 91.7%, and 86.9% and 83.9%, 98.8%, and 100.0%, respectively. For HPV type 16/18 detection, the concordance rate between the AdvanSure PCR and Abbott PCR assays was 98.3%; however, 3 samples were discrepant (positive in AdvanSure PCR and negative in Abbott PCR) and were confirmed as HPV type 16 by INNO-LiPA genotyping and/or sequencing. CONCLUSIONS: For HPV detection, the AdvanSure HPV Screening real-time PCR assay and the Abbott PCR assay are less sensitive but more specific than the HC2 assay, but can simultaneously differentiate type 16/18 HPV from other types.

Myelodysplastic Syndrome Mimicking Idiopathic Thrombocytopenic Purpura / 대한진단검사의학회지

BACKGROUND: In patients with isolated thrombocytopenia, but without significant dysplasia, diagnosis of idiopathic thrombocytopenic purpura (ITP) rather than myelodysplastic syndrome (MDS) may be taken into account. It is important to make an accurate diagnosis because different treatments are used for ITP and MDS. The purpose of this study was to investigate the clinical and hematologic features of patients who were initially diagnosed as ITP but had cytogenetic abnormalities. METHODS: We retrospectively reviewed cytogenetic studies of 100 patients who were diagnosed as ITP from 2004 to 2009 at Mokdong Hospital of Ewha Womans University based on clinical features and hematologic studies. Bone marrow pathology was re-evaluated based on 2008 WHO classification. Cytogenetic analysis was performed by 24-48 hr culture of bone marrow aspirates without using mitogens and 20 metaphases were analyzed. RESULTS: Of the 100 patients diagnosed as ITP initially, three patients (3%) had cytogenetic abnormalities. They had no thrombocytopenia-related symptoms and thrombocytopenia was found accidentally. The numbers of megakaryocytes in bone marrow were increased and dysplasia was not found in megakaryocyte, erythroid, and myeloid cell lineages. The proportion of blasts was within normal limits. Clonal chromosomal abnormalities found were der(1;7)(q10;p10), add(9)(q12), or t(7;11)(p22;q12). Presumptive diagnosis of MDS or diagnosis of idiopathic cytopenia of undetermined significance (ICUS) was made according to 2008 WHO classification. During the follow up, disease progression was not found. CONCLUSIONS: In patients with suspected ITP, cytogenetic analysis should be done. If specific clonal chromosomal abnormality is found, presumptive diagnosis of MDS has to be considered and close follow up is needed.

Evaluation of the Efficacies of Rapid Antigen Test, Multiplex PCR, and Real-time PCR for the Detection of a Novel Influenza A (H1N1) Virus / 대한진단검사의학회지

BACKGROUND: In April 2009, a novel influenza A (H1N1) virus was detected in the US, and at the time of conducting this study, H1N1 infection had reached pandemic proportions. In Korea, rapid antigen tests and PCR assays have been developed to detect the H1N1 virus. We evaluated the efficacies of rapid antigen test, multiplex PCR, and real-time PCR for detecting the H1N1 virus. METHODS: From August to September 2009, we tested 734 samples obtained from nasopharyngeal swab or nasal swab using rapid antigen test (SD Influenza Antigen, Standard Diagnostics, Inc., Korea) and multiplex PCR (Seeplex FluA ACE Subtyping, Seegene, Korea). We also tested 224 samples using the AdvanSure real-time PCR (LG Life Sciences, Korea) to compare the results obtained using real-time PCR with those obtained using multiplex PCR. Furthermore, 99 samples were tested using the AdvanSure real-time PCR and the AccuPower real-time PCR (Bioneer, Korea). RESULTS: In comparison with the results of multiplex PCR, the sensitivity and specificity of the rapid antigen test were 48.0% and 99.8%, respectively. The concordance rate for multiplex PCR and the AdvanSure real-time PCR was 99.6% (kappa=0.991, P=0.000), and that for the AdvanSure real-time PCR and the AccuPower real-time PCR was 97.0% (kappa=0.936, P=0.000). CONCLUSIONS: The rapid antigen test is significantly less sensitive than PCR assay; therefore, it is not useful for H1N1 detection; however multiplex PCR, the AdvanSure real-time PCR, and the Accu-Power real-time PCR can be useful for H1N1 detection.

The First Case of Antibiotic-associated Colitis by Clostridium difficile PCR Ribotype 027 in Korea

Clostridium difficile (C. difficile) is a common causative agent of pseudomembranous colitis (PMC). C. difficile-associated diarrhea (CDAD) ranges from mild diarrhea to life threatening PMC. Recently, a highly virulent strain of C. difficile polymerase chain reaction ribotype 027 was found in North America, Europe, and Japan. A 52-yr-old woman with anti-tuberculosis medication and neurogenic bladder due to traffic accident experienced five episodes of C. difficile PMC after taking antibiotics for pneumonia along with septic shock and acute renal failure. She was readmitted to the intensive care unit and treated with oral vancomycin with refractory of oral metronidazole, inotropics and probiotics for over 60 days. C. difficile isolated both at the first and the last admission was identified as C. difficile ribotype 027 by ribotyping, toxinotyping, and tcdC gene sequencing, which turned out the same pathogen as the epidemic hypervirulent B1/NAP1 strain. This is the first case of C. difficile PCR ribotype 027 in Korea. After discharge, she was maintained on probiotics and rifaximin for 3 weeks. She had no relapse for 6 months.