Multicenter Evaluation of the Cepheid Xpert® HBV Viral Load Test.

Accurate measurement of the hepatitis B virus (HBV) DNA is important for the management of patients with chronic HBV infection. Here, the performance of the Xpert® HBV Viral Load test (Xpert HBV Viral Load) versus the Roche COBAS® Ampliprep/COBAS® TaqMan® system (CAP/CTM HBV) HBV test v2.0 was evaluated. From September 2017 to December 2017, a total of 876 prospectively collected or archived serum or EDTA plasma specimens from subjects chronically infected with HBV were tested using the Xpert HBV Viral Load and the CAP/CTM HBV v2.0 assays. Of the 876 specimens tested, 560 were within the quantitative range of both assays. The agreement between the two methods was 90.0%. No difference in plasma or serum samples was observed. Deming regression analysis showed a good correlation of the Xpert HBV Viral Load assay with the CAP/CTM HBV v2.0 assay. The Bland-Altman analysis showed a good agreement between the results of the Xpert HBV Viral Load assay and the CAP/CTM HBV assay, with a mean difference (±1.96 standard deviation) of 0.0091 ± 0.3852 Log IU/mL. Comparing the two assays, only nineteen specimens (2.1%) had a difference greater than 1.96 times the standard deviation. The Xpert® HBV Viral Load test is suitable for monitoring patients with HBV infection and is useful in diagnostic settings.

Accuracy to 2nd International HIV-1 RNA WHO Standard: assessment of three generations of quantitative HIV-1 RNA nucleic acid amplification tests.

BACKGROUND: Standardization of quantitative HIV-1 tests to a global primary standard is required by regulatory authorities to ensure comparability of test results across different assays and platforms of different manufacturers. OBJECTIVES AND STUDY DESIGN: Three generations of quantitative HIV-1 tests, the COBAS(®) AMPLICOR(®) HIV-1 Monitor Test, v1.5 (HIV-1 Monitor test v1.5); the COBAS(®) AmpliPrep/COBAS(®) TaqMan(®) HIV-1 Test (HIV-1 TaqMan(®) test v1.0); and the dual-target-based COBAS(®) AmpliPrep/COBAS(®) TaqMan(®) HIV-1 Test, v2.0 (HIV-1 TaqMan(®) test v2.0), were assessed for accuracy to World Health Organization (WHO) 2nd International Standard for human immunodeficiency virus 1 (HIV-1) RNA (NIBSC code 97/650) at concentration levels below 1667 IU/mL including relevant medical decision points. RESULTS: With the 2nd WHO Standard the mean difference across all concentrations was -0.07 log(10) for the HIV-1 Monitor test v1.5; +0.12 log(10) for the HIV-1 TaqMan(®) test v1.0; and +0.09 log(10) for the HIV-1 TaqMan(®) test v2.0. Linearity, including concentrations below the claimed limit of quantitation, was demonstrated for HIV-1 TaqMan(®) test v2.0. The HIV-1 TaqMan(®) test v1.0 showed a trend towards higher quantitation at very low concentration levels and the HIV-1 Monitor test v1.5 had a tendency towards lower quantitation at low concentration levels. CONCLUSIONS: All three assays are closely traceable to the primary WHO HIV-1 RNA standard for in vitro diagnostic IVD assays. Compared to the other two assays, the HIV-1 TaqMan(®) test v2.0 showed better linearity around the limit of detection and below.

Acquisition of antibiotic-resistant Enterococcus faecium strains during long-term hospitalization and fast adaptation of enterococcal flora to antibiotic treatment: a case report.

Recently, it has been suspected that long durations of hospitalization might be a possible risk factor to get colonized by multiple VRE strains. Here we present the case of a patient who underwent stem cell transplantation and subsequently stayed at the hospital for about 4 months until death. At least four different Enterococcus faecium strains were identified from routinely taken microbiological specimens as demonstrated by pulsed-field gel-electrophoresis. Additionally, these strains showed variable susceptibility to quinupristine/dalfopristine, vancomycin, and/or linezolid depending on different antibiotic administrations. These findings indicate that patients might be colonized with multiple Enterococcus faecium strains and that the enterococcal flora quickly adapts due to antibiotic exposure.

Evaluation of host stem cell-derived cardiac myocytes in consecutive biopsies in long-term cardiac transplant patients.

BACKGROUND: Bone marrow-derived stem cells are involved in tissue formation in transplanted organs. In human renal cell transplants, recipient-specific cells have been shown to participate in regeneration of interstitial tissue. In hepatic transplants, hepatocytes with a recipient sex chromosome pattern have been observed. Recruitment of stem cells in repair and regeneration of cardiac myocytes has been demonstrated in experimental ischemia. Recently, cardiac antral myocytes of recipient origin have been shown to populate transplanted hearts in gender-mismatched transplants. METHODS: Using the fluorescence in situ hybridization (FISH) technique we examined serial post-transplant right ventricular biopsies and sections of ventricle (at time of autopsy) of 4 gender-mismatched female-to-male transplanted hearts (graft survival 0.5 to 10 years, mean 5.1 years) for Y chromosomes within cardiac myocytes. RESULTS: We detected recipient-specific sex chromosomal patterns in single rare cardiac myocytes in 1 case in a serial biopsy after 7 years of transplant survival. The other serial biopsies, as well as the final sections at autopsy, showed no recipient pattern chromosomes within the myocytes. In addition, 2 cases demonstrated Y chromosomes in the smooth muscle of intracardiac arteries. CONCLUSION: Development of recipient marrow-derived stem cells into functional myocytes in the ventricle of transplanted hearts is a rare feature. The higher percentage of stem cell population in the cardiac atria may be a feature of tissue repair and/or an early feature of transplant physiology. Similar to other transplant organs, recipient stem cells are involved in tissue neovascularization.

HER2 status in non-small cell lung cancer: results from patient screening for enrollment to a phase II study of herceptin.

PURPOSE: For the first time a large number (563) of non-small cell lung cancer (NSCLC) samples was used to compare three different technologies for the assessment of HER2 status. Fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) were used for tumor tissue samples, and ELISA for serum samples. The results were compared with other tumor entities, mainly breast. EXPERIMENTAL DESIGN: Samples (563) from patients suffering from primary advanced or metastatic NSCLC were evaluated. RESULTS: HER2 overexpression was demonstrated using IHC in 20% (83 of 410) of the specimens, whereas 2% (7 of 378) were positive by FISH and 6% (31 of 511) showed elevated serum HER2 levels (>15 ng/ml) by ELISA. Sixty-six specimens were positive by IHC only and 13 by ELISA only, whereas none of the specimens was positive only by FISH. Concordance between all of the techniques was seen for only 3 specimens. Of 7 IHC 3+ specimens, 4 showed gene amplification by FISH, and 3 were positive by ELISA (>15 ng/ml), whereas of 76 IHC 2+ cases only 2 were amplified by FISH, and 4 were positive by ELISA. HER2 positivity by at least one of the three techniques was most common in adenocarcinomas, at 29% (42 of 143). CONCLUSION: Gene amplification and HER2 protein overexpression at the 3+ level appear to be uncommon in NSCLC. The concordance between FISH and IHC 3+ disease was good in this study, in addition, ELISA would have detected several patients without IHC/FISH-positive disease.

Pancreatic mucinous noncystic (colloid) carcinomas and intraductal papillary mucinous carcinomas are usually microsatellite stable.

Pancreatic mucinous noncystic (colloid) carcinomas (MNCC) differ from the usual ductal adenocarcinomas in their mucin expression profile and share with many extrapancreatic mucinous carcinomas the expression of MUC2. Because mucinous carcinomas are frequently associated with mutations of the DNA mismatch repair genes, causing them to exhibit the so-called mutator phenotype, we decided to investigate whether MNCCs of the pancreas are characterized by microsatellite instability (MSI). Twelve carcinomas with a mucinous phenotype (8 mucinous noncystic carcinomas, 3 intraductal papillary-mucinous carcinomas with an invasive muconodular component, and 1 ductal adenocarcinoma with an extensive mucinous noncystic component) and 11 ductal adenocarcinomas were immunostained with monoclonal antibodies to the mismatch repair gene products hMLH1, hMSH2, and hMSH6. For MSI analysis, DNA was isolated from microdissected tissue, and five primary microsatellites (BAT 25, BAT 26, D5S346, D17S250, and D2S123) were analyzed. MSI was diagnosed in case a novel allele was found, compared with the normal tissue. The criterion for LOH was a 75% signal reduction. All carcinomas tested exhibited nuclear expression of mismatch repair gene products, except for one MNCC that also showed MSI at the molecular level. The data suggest that pancreatic carcinomas with a mucinous phenotype (MUC2+/MUC1-) do not appear to normally exhibit mutations in the mismatch repair genes and therefore differ in their carcinogenesis from those in other organs.

Recipient-derived hepatocytes in liver transplants: a rare event in sex-mismatched transplants.

Bone marrow-derived stem cells have been shown to engraft and populate native tissues during repair and in transplanted animal tissues. Very few studies have been performed in humans to evaluate the possibility of stem cell engraftment in transplanted tissues. In human renal transplants, recipient cells have been demonstrated within vascular and interstitial structures. In a previous study of patients with hepatic transplants, hepatocytes with XY chromosome patterns have been detected in sex-mismatched female to male transplanted livers in a small number of cases. Because of the possibility of Y chromosome microchimerism of females with male offspring, we analyzed the presence of X and Y chromosomes in liver biopsies of 13 patients with sex-mismatched liver transplants (8 female to male, 5 male to female) and long transplant to biopsy intervals (1.2 to 12 years; mean, 4.5 years). We were able to detect recipient-specific sex chromosomal patterns in inflammatory cells by fluorescent in situ hybridization/immunohistochemistry combination within the liver parenchyma but not within hepatocytes. In conclusion, recipient engraftment of stem cells may be an early feature in liver transplant but may be an infrequent persistent feature in long-term grafts.

T-cell factor-4 frameshift mutations occur frequently in human microsatellite instability-high colorectal carcinomas but do not contribute to carcinogenesis.

Colorectal carcinomas with microsatellite instability accumulate errors in short repetitive DNA repeats, especially mono and dinucleotide repeats. One such error-prone A(9) monorepeat is found in exon 17 of the TCF-4 gene. TCF-4 and beta-catenin form a transcription complex, which is important for both maintenance of normal epithelium and development of colorectal tumors. To elucidate the relevance of frameshift mutations in the TCF-4 in colorectal carcinogenesis, a variety of investigations in human tumors and cell lines was performed. It was found that mutations in the TCF-4 A(9) repeat do not contribute to tumorigenesis and seem to be passenger mutations.