Hepatitis delta virus (HDV) infection increases the risk of liver complications compared to hepatitis B virus (HBV) alone, particularly among persons with human immunodeficiency virus (HIV). However, no studies have evaluated the prevalence or determinants of HDV infection among people with HIV/HBV in the US. We performed a cross-sectional study among adults with HIV/HBV coinfection receiving care at eight sites within the Center for AIDS Research Network of Integrated Clinical Systems (CNICS) between 1996 and 2019. Among patients with available serum/plasma specimens, we selected the first specimen on or after their initial HBV qualifying test. All samples were tested for HDV IgG antibody and HDV RNA. Multivariable log-binomial generalized linear models were used to estimate prevalence ratios (PRs) with 95% CIs of HDV IgG antibody-positivity associated with determinants of interest (age, injection drug use [IDU], high-risk sexual behaviour). Among 597 adults with HIV/HBV coinfection in CNICS and available serum/plasma samples (median age, 43 years; 89.9% male; 52.8% Black; 42.4% White), 24/597 (4.0%; 95% CI, 2.4%-5.6%) were HDV IgG antibody-positive, and 10/596 (1.7%; 95% CI, 0.6%-2.7%) had detectable HDV RNA. In multivariable analysis, IDU was associated with exposure to HDV infection (adjusted PR = 2.50; 95% CI, 1.09-5.74). In conclusion, among a sample of adults with HIV/HBV coinfection in care in the US, 4.0% were HDV IgG antibody-positive, among whom 41.7% had detectable HDV RNA. History of IDU was associated with exposure to HDV infection. These findings emphasize the importance of HDV testing among persons with HIV/HBV coinfection, especially those with a history of IDU.

Diagnostic assays that can simultaneously determine the presence of infection with multiple pathogens are key for diagnosis and surveillance. Current multiplex diagnostic assays are complex and often have limited availability. We developed a simple, multianalyte, pathogen detection assay for screening and serosurveillance using the Luminex Magpix platform that is high throughput and can be helpful in monitoring multiple diseases. The Luminex bead-based 10-plex immunoassay for the detection of HIV-1, HIV-2, Treponema pallidum, hepatitis B virus (HBV), hepatitis C virus (HCV), herpes simplex virus 1 (HSV-1), and HSV-2 infections was accomplished by coupling beads with specific antigens to detect IgG antibodies in plasma or serum samples. Each coupled antigen was systematically optimized, and the performance was evaluated using a panel of well-characterized specimens (n=417) that contained antibodies to HIV-1, HIV-2, T. pallidum, HBV, HCV, HSV-1, and HSV-2. The multiplex assay had a sensitivity of 92.2% (95% Clopper-Pearson confidence interval [CI], 90.2 to 94.0%) and a specificity of 98.1% (95% CI, 97.6 to 98.7%). The sensitivities and specificities for disease-specific biomarker detection ranged from 68.7 to 100% and 95.6 to 100%, respectively. The results showed that the 10-plex immunoassay had an overall agreement of 96.7% (95% CI, 96.7 to 97.3%) with reference tests and a corresponding kappa value of 0.91 (95% CI, 0.90 to 0.93). Kappa values for the individual pathogens ranged from 0.69 to 1.00. The assay is robust and allows the simultaneous detection of antibodies to multiple antigens using a small sample volume in a high-throughput format. This assay has the potential to simplify disease surveillance by providing an alternative to expensive and highly specialized individual tests.

OBJECTIVES: The burden of hepatitis B virus (HBV) and hepatitis D virus (HDV) infections is unknown in Georgia. This analysis describes the prevalence of hepatitis B and coinfection with HDV and the demographic characteristics and risk factors for persons with HBV infection in Georgia. STUDY DESIGN: This is a cross-sectional seroprevalence study. METHODS: A cross-sectional, nationwide survey to assess hepatitis B prevalence among the general adult Georgian population (age ≥18 years) was conducted in 2015. Demographic and risk behavior data were collected. Blood specimens were screened for anti-hepatitis B core total antibody (anti-HBc). Anti-HBc-positive specimens were tested for hepatitis B surface antigen (HBsAg). HBsAg-positive specimens were tested for HBV and HDV nucleic acid. Nationally weighted prevalence estimates and adjusted odds ratios (aORs) for potential risk factors were determined for anti-HBc and HBsAg positivity. RESULTS: The national prevalence of anti-HBc and HBsAg positivity among adults were 25.9% and 2.9%, respectively. Persons aged ≥70 years had the highest anti-HBc positivity (32.7%), but the lowest HBsAg positivity prevalence (1.3%). Anti-HBc positivity was associated with injection drug use (aOR = 2.34; 95% confidence interval [CI] = 1.46-3.74), receipt of a blood transfusion (aOR = 1.68; 95% CI = 1.32-2.15), and sex with a commercial sex worker (aOR = 1.46; 95% CI = 1.06-2.01). HBsAg positivity was associated with receipt of a blood transfusion (aOR = 2.72; 95% CI = 1.54-4.80) and past incarceration (aOR = 2.72; 95% CI = 1.25-5.93). Among HBsAg-positive persons, 0.9% (95% CI = 0.0-2.0) were HDV coinfected. CONCLUSIONS: Georgia has an intermediate to high burden of hepatitis B, and the prevalence of HDV coinfection among HBV-infected persons is low. Existing infrastructure for hepatitis C elimination could be leveraged to promote hepatitis B elimination.

Biotin taken orally can interfere with some diagnostic immunoassays, including those for thyroid hormones, ferritin, and markers of infectious disease. Assays affected are ones that use streptavidin-biotin in their design. The goal of our study was to examine the effect of biotin concentrations of up to 1200 ng/ml on three serological assays performed on VITROS 3600 system, IgM anti-HAV, total anti-HAV, and IgM anti-HBc, by spiking serum samples with variable amounts of biotin. No false negative results were generated with either concentration of biotin for total anti-HAV (65/65). Likewise, biotin caused no false positive IgM anti-HAV results (59/59) with either concentration of biotin; however, 6.7% false negativity was found for IgM anti-HAV when samples were spiked with 1200 ng/mL of biotin. Conversely, 100% false positivity (30/30) was produced by biotin interference in total anti-HAV negative specimens with both concentrations of biotin. False negativity rate was 87.5% in IgM anti-Hbc positive samples when biotin levels were at 1200 ng/mL. These data show that individuals taking biotin-containing supplements may test false-positive in some serologic assays using streptavidin-biotin chemistries. Further studies are warranted to determine the extent of biotin interference resulting in false positive and negative results and their impact, if any, on surveillance and diagnostic settings. This article is protected by copyright. All rights reserved.

BACKGROUND: Dissolvable microneedle patches (dMNPs) provide ease of deployment and eliminate need for hypodermic needle disposal after conventional vaccinations. In this study, immunogenicity of dMNP delivery of adjuvant-free monovalent hepatitis B surface antigen (HBsAg) vaccine (AFV) to standard intramuscular (IM) injection of monovalent aluminum-adjuvanted monovalent hepatitis B vaccine (AAV) were compared in rhesus macaques. METHODS: Sixteen macaques were immunized twice in 4 groups: dMNP delivery of 24 +/- 8microg (n=4) or 48 +/- 14microg (n=4) AFV; IM injection of 10microg AFV (IM AFV, n=4); and IM injection of 10microg AAV (IM AAV, n=4). Levels of hepatitis B surface antibody and HBsAg-specific T-cell responses were analyzed. RESULTS: Six of 8 animals with dMNP delivery of AFV had anti-HBs levels >/=10 mIU/ml after the first vaccine dose. After dMNP delivery of AFV, IFN-gamma, IL-2, and IL-4 production by HBsAg-specific T-cells were detected. A statistically significant positive correlation was detected between anti-HBs levels and HBsAg-specific IFN-gamma and IL-2 (Th1-type cytokine) and IL-4 (Th2-type cytokine) producing cells in all anti-HBs positive animals. CONCLUSIONS: dMNP delivery of AFV can elicit seroprotective anti-HBs levels in rhesus macaques that correlate in human seroprotection, and could be particularly promising for hepatitis B vaccine birth dose delivery in resource-constrained regions.

An estimated 41,200 people were newly infected with hepatitis C virus (HCV) in 2016 in the United States. Screening tests for antibodies to HCV may generate up to 32% false positivity in low-risk populations. Current Centers for Disease Control and Prevention (CDC) screening recommendations do not require confirmatory testing of a screening anti-HCV positive test, however confirmation is valuable for surveillance in the absence of HCV RNA testing. Recombinant Immunoblot Assay (RIBA) was used as a confirmatory assay for anti-HCV reactive samples but was discontinued in 2013. Another anti-HCV confirmatory assay, INNO-LIA, is commercially available in Europe but not approved by the Food and Drug Administration (FDA) in the United States. We report the development of an anti-HCV assay performed on an automated immunoblot platform using a fourth generation HCV recombinant fusion protein. Based on testing of 70 well characterized samples of which 40 were HCV RNA and anti-HCV positive, 15 HCV RNA positive/anti-HCV negative and 15 HCV RNA and anti-HCV negative, the specificity and sensitivity of the HCV-WES assay was 100% and 95%, respectively. Concordance between INNO-LIA and HCV WES, was determined by testing 205 HCV RNA negative/anti-HCV positive samples, of which 149 (72.7%) were positive by HCV-WES, while 146 (71.2%) were positive by INNO-LIA. We have shown proof of concept for the use of this test for confirmation of screening anti-HCV results. The HCV-WES assay is advantageous over manual western blot assays and INNO-LIA including ease of use, low cost and reduced hands-on time.

Chronic Hepatitis B virus infection remains a major global public health problem, accounting for about 887,000 deaths in 2015. Perinatal and early childhood infections are strongly associated with developing chronic hepatitis B. Adding a birth dose of the hepatitis B vaccine (HepB BD) to routine childhood vaccination can prevent over 85% of these infections. However, HepB BD coverage remains low in many global regions, with shortages of birth attendants trained to vaccinate and limited HepB BD supply at birth. To address the challenges, we developed coated metal microneedle patches (cMNPs) and dissolvable microneedle patches (dMNPs) that deliver adjuvant-free hepatitis B vaccine to the skin in a simple-to-administer manner. The dMNP contains micron-scale, solid needles encapsulating vaccine antigen and dissolve in the skin, generating no sharps waste. We delivered HepB BD via cMNP to BALB/c mice and via dMNP to both mice and rhesus macaques. Both cMNP and dMNP were immunogenic, generating hepatitis B surface antibody levels similar to human seroprotection. Biomechanical analysis showed that at high forces the microneedles failed mechanically by yielding but microneedles partially blunted by axial compression were still able to penetrate skin. Overall, this study indicates that with further development, dMNPs could offer a method of vaccination to increase HepB BD access and reduce needle waste in developing countries.

Real-time PCR assays for nucleic acid testing (NAT) of hepatitis viruses A-E and for HIV-1 and HIV-2 have been developed; however, a multiplex assay that can simultaneously detect all of these agents is not yet available. Standardized TaqMan assays for detection of hepatitis viruses A-E have been described and applied to TaqMan Array Cards (TAC) which are capable of multiple pathogen detection using a single set of optimized PCR conditions. Assays for three gene regions of HIV-1 (long-terminal repeat (LTR), gag, and polymerase) and HIV-2 (overlap of LTR and gag, protease and integrase) were designed using the hepatitis assay conditions. Nucleic acid extracts of HIV-1-infected samples (44 plasma, 41 whole blood, 20 HIV-1 viral stocks) were tested on the TAC cards; 98 were reactive (92%) with 70 in multiple gene regions. Twenty-four of the 27 (89%) HIV-2 specimens (10 plasma, 1 PBMC lysate, 6 whole blood and 10 plasmids containing HIV-2 polymerase) were detected on TAC. No HIV or hepatitis virus sequences were detected in 30 HIV-negative samples (specificity 100%). Three HBV and 18 HCV co-infections were identified in the HIV-1-infected specimens. Multi-pathogen detection using TAC could provide a rapid, sensitive and more efficient method of surveying for a variety of infectious disease nucleic acids.

The prevalence of hepatitis C virus (HCV) infection in the Kenyan population has not been previously determined. We estimated the Kenyan HCV prevalence in HIV-negative persons aged 15-64 years. This is a retrospective cross-sectional study using data from the 2007 Kenya AIDS Indicator Survey-a nationally representative sample of 15,853 persons aged 15-64 years who completed a health interview and provided a blood specimen. Of the 1,091 randomly selected participants, 50 tested positive for HCV antibody using the automated chemiluminescence immunoassay, corresponding to a weighted HCV antibody positivity rate of 4.4% (95% confidence interval: 3.3-5.9%) or 848,000 (range: 634,000-1,100,000) persons. Hepatitis C virus RNA, a marker for current infection, was not detected in any of the tested antibody-positive specimens. The high HCV antibody prevalence together with no current infection suggests that some HCV antibody serologic testing in Kenya may result in false positives whereas others may be because of spontaneous viral clearance.

Diagnosis of hepatitis C virus (HCV) infection is based on testing for antibodies to HCV (anti-HCV), hepatitis C core antigen (HCV cAg) and HCV RNA. To ensure quality control (QC) and quality assurance (QA), proficiency panels are provided by reference laboratories and various international organizations, requiring costly dry ice shipments to maintain specimen integrity. Alternative methods of specimen preservation and transport can save on shipping and handling and help in improving diagnostics by facilitating QA/QC of various laboratories especially in resource limited countries. Plasma samples positive for anti-HCV and HCV RNA were either dried using dried tube specimens (DTS) method or lyophilization for varying durations of time and temperature. Preservation of samples using DTS method resulted in loss of anti-HCV reactivity for low-positive samples and did not generate enough volume for HCV RNA testing. Lyophilized samples tested positive for anti-HCV even after storage at 4 degrees C and 25 degrees C for 12 weeks. Further, HCV RNA was detectable in 5 of 5 (100%) samples over the course of 12 week storage at 4, 25, 37 and 45 degrees C. In conclusion, lyophilization of specimens maintains integrity of plasma samples for testing for markers of HCV infection and can be a potent mode of sharing proficiency samples without incurring huge shipping costs and avoids challenges with dry ice shipments between donor and recipient laboratories.

Hepatitis D virus (HDV), the etiologic agent of hepatitis D or delta hepatitis, is a unique human virus that requires the hepatitis B surface antigen (HBsAg) of hepatitis B virus (HBV) for its replication and to establish infection. HDV, the only member of its own separate genus, Deltavirus, is the smallest known infectious viral agent of humans.1 The HDV virion, which measures 35‐37 nm in diameter, contains a single‐stranded circular ∼1,700‐nucleotide RNA genome of negative polarity, which encloses only a single functional open reading frame encoding the sole viral protein, the hepatitis delta antigen (HDAg). The HDAg is associated with the genomic RNA to form a ribonucleoprotein complex which is encapsulated by a lipid envelope containing the small, middle, and large HBsAg proteins.2 HDV exhibits a high degree of genetic heterogeneity, with estimated mutation rates between 3 × 10–2 and 3 × 10–3 base substitutions per genomic site per year.1 The virus has a wide geographic distribution with eight distinct genotypes. HDV genotype 1 is the most common genotype, being prevalent in North America, Europe, the Middle East, and North Africa; genotypes 2 and 4 are found predominantly in East Asia; genotype 3 is found exclusively in the Amazon basin in South America; and genotypes 5‐8, also known as African genotypes, are predominantly found in West and central Africa.3

Hepatitis E is a major public health problem in developing countries and is increasingly being recognized as a cause of substantial sporadic viral hepatitis infections in industrialized countries. Variable rates of hepatitis E seroprevalence have been reported from the same geographic regions depending on the assay used. In this study, we evaluated the performance characteristics of four assays which included two commercial assays, Wantai HEV-IgG ELISA kit (Wantai, China) and DS-EIA-ANTI-HEV-G kit (DSI, Italy), one NIH-developed immunoassay (NIH-55K, Kuniholm et al. 2009. JID 200:48-56) previously used in several major seroprevalence studies and one in-house western blot assay (CDC-WB). The limit of detection of IgG anti-HEV is 100 mIU/ml for Wantai assay, 200 mIU/ml for CDC-WB assay, 1000 mIU/ml for DSI assay and 40 mIU/ml for NIH-55K assay. Pairwise concordance between the four assays ranged from 56 to 87%. The concordance among all four assays was observed in 52% of the samples, while the concordance among three assays was observed in 37% of the samples. These data show a wide discordance between various IgG anti-HEV assays and warrant a comprehensive evaluation of all the assays using well characterized global serum reference panels.

Several commercial assays are now available to detect the nucleic acid of multiple respiratory pathogens from a single specimen. Head-to-head comparisons of such assays using a single set of standard specimens provide additional information about key assay parameters such as sensitivity, specificity and lower limits of detection, and help to inform the decision regarding which method to use. We evaluated two real-time PCR platforms: the Fast-track Diagnostics(R) (FTD) multiplex respiratory panel and a TaqMan array card (TAC) for simultaneous uniplex detection of multiple respiratory pathogens. Two sets of samples were used to evaluate the assays. One set was created by spiking pooled nasal wash or phosphate buffered saline with specified volumes of known concentrations of virus and/or bacteria. Clinical nasal wash specimens from children with lower respiratory tract illness comprised the other set. Thirteen pathogen targets were compared between the two platforms. Testing with a validation panel of spiked samples revealed a sensitivity of 96.1% and 92.9% for the FTD and TAC assays, respectively. Specificity could not be reliably calculated due to a suspected contamination of the sample substrate. Inter-assay agreement was high (>95%) for most targets. Previously untested clinical specimens tested by both assays revealed a high percent agreement (>95%) for all except rhinovirus, enterovirus and Streptococcus pneumoniae. Limitations of this evaluation included extraction of the validation samples by two different methods and the evaluation of the assays in different laboratories. However, neither of these factors significantly impacted inter-assay agreement for these sets of samples, and it was demonstrated that both assays could reliably detect clinically relevant concentrations of bacterial and viral pathogens.

BACKGROUND: Five viruses have been etiologically associated with viral hepatitis. Nucleic acid testing (NAT) remains the gold standard for diagnosis of viremic stages of infection. NAT methodologies have been developed for all hepatitis viruses; however, a NAT-based assay that can simultaneously detect all five viruses is not available. OBJECTIVES: We designed TaqMan card-based assays for detection of HAV RNA, HBV DNA, HCV RNA, HDV RNA and HEV RNA. STUDY DESIGN: The performances of individual assays were evaluated on TaqMan Array Cards (TAC) for detecting five viral genomes simultaneously. Sensitivity and specificity were determined by testing 329 NAT-tested clinical specimens. RESULTS: All NAT-positive samples for HCV (n=32), HDV (n=28) and HEV (n=14) were also found positive in TAC (sensitivity, 100%). Forty-three of 46 HAV-NAT positive samples were also positive in TAC (sensitivity, 94%), while 36 of 39 HBV-NAT positive samples were positive (sensitivity, 92%). No false-positives were detected for HBV (n=32), HCV (n=36), HDV (n=30), and HEV (n=31) NAT-negative samples (specificity 100%), while 38 of 41 HAV-NAT negative samples were negative by TAC (specificity 93%). CONCLUSIONS: TAC assay was concordant with corresponding individual NATs for hepatitis A-E viral genomes and can be used for their detection simultaneously. The TAC assay has potential for use in hepatitis surveillance, for screening of donor specimens and in outbreak situations. Wider availability of TAC-ready assays may allow for customized assays, for improving acute jaundice surveillance and for other purposes for which there is need to identify multiple pathogens rapidly.

Hepatitis D virus (HDV) is a defective virus which requires hepatitis B virus (HBV) surface antigen (HBsAg) for its assembly. Hepatitis B infected individuals co-infected or superinfected with HDV often present with more severe hepatitis, progress faster to liver disease, and have a higher mortality rate than individuals infected with HBV alone. Currently, there are no commercially available clinical tests for the detection and quantitation of HDV RNA in the United States. A one-step TaqMan quantitative reverse transcription-polymerase chain reaction (qRT-PCR) assay was developed for detection of HDV RNA, designing primers located in the region located just downstream from the HDV antigen gene. The assay has the potential to detect all eight HDV genotypes. A quantifiable synthetic RNA control was also developed for use in the determination of HDV RNA titers in clinical samples. The limit of detection of this assay is 7.5x102 HDV RNA copies/ml with a dynamic range of six logs. Most clinical specimens tested (40/41) fell within the linear range of the assay. The median HDV RNA titer of the tested specimens was 6.24x106 copies/ml, with a range of 8.52x103 to 1.79x109 copies/ml. Out of 132 anti-HDV-positive specimens 41 (31.1%) were positive for HDV RNA.

During a pneumococcal disease outbreak in a pediatric psychiatric unit in a hospital in Rhode Island, USA, 6 (30%) of 20 patients and staff were colonized with Streptococcus pneumoniae serotype 15A, which is not included in pneumococcal vaccines. The outbreak subsided after implementation of antimicrobial drug prophylaxis and enhanced infection control measures.

Human enterovirus 68 (EV68) infections are rarely reported. We describe a respiratory outbreak associated with EV68 among 18 children admitted to a remote Indian Health Service facility during August 11-September 14, 2010. Clinical illness was characterized by pneumonia and wheezing. EV68 should be considered as an etiology in outbreaks of lower respiratory tract illness.

Members of the Gram-negative genus Legionella are typically found in freshwater environments, with the exception of L. longbeachae, which is present in composts and potting mixes. When contaminated aerosols are inhaled, legionellosis may result, typically as either the more serious pneumonia Legionnaires' disease or the less severe flu-like illness Pontiac fever. It is presumed that all species of the genus Legionella are capable of causing disease in humans. As a followup to a prior clinical study of legionellosis in rural Thailand, indigenous soil samples were collected proximal to cases' homes and workplaces and tested for the presence of legionellae by culture. We obtained 115 isolates from 22/39 soil samples and used sequence-based methods to identify 12 known species of Legionella represented by 87 isolates.

Recently, we evaluated a custom TaqMan Array Card (TAC) detection system, formerly known as TaqMan(R) Low Density Array (TLDA) card, for simultaneous real-time PCR identification of 21 pathogens and three control targets in duplicate from respiratory specimens (Kodani, M., et al. 2011. J Clin Microbiol 49:2175-2182). We engineered an adaptable and expandable system of in-vitro RNA transcripts to serve as a combined positive control for both DNA and RNA targets in multiple pathogen detection technologies based on real-time reverse-transcription PCR.

The large and growing number of viral and bacterial pathogens responsible for respiratory infections poses a challenge for laboratories to provide rapid and comprehensive pathogen identification. We evaluated a novel application of the TaqMan(R) Low Density Array (TLDA) cards for real-time PCR detection of 21 respiratory pathogen targets. TLDA performance was compared to individual real-time PCR (IRTP) assays with the same primers and probes using 1) nucleic acids extracted from the 21 pathogen strains and 66 closely-related viruses and bacteria and 2) 292 clinical respiratory specimens. Using spiked samples, TLDA cards were about ten-fold less sensitive than the IRTP assays. Using 292 clinical specimens to generate 2238 paired individual assays, TLDA exhibited 89% sensitivity (95% confidence interval [CI] 86-92; 47-100 range per target) and 98% specificity (95% CI 97-99; 85-100 range per target) overall compared to IRTP real-time assays as the gold standard with a Ct cut-off of 43. The TLDA card approach offers promise for rapid and simultaneous identification of multiple respiratory pathogens for outbreak investigations and disease surveillance.

This study compared six automated nucleic acid extraction systems and one manual kit for their ability to recover nucleic acids from human nasal wash specimens spiked with five respiratory pathogens, representing Gram-positive bacteria (Streptococcus pyogenes), Gram-negative bacteria (Legionella pneumophila), DNA viruses (adenovirus), segmented RNA viruses (human influenza virus A), and non-segmented RNA viruses (respiratory syncytial virus). The robots and kit evaluated represent major commercially available methods that are capable of simultaneous extraction of DNA and RNA from respiratory specimens, and included platforms based on magnetic-bead technology (KingFisher mL, Biorobot EZ1, easyMAG, KingFisher Flex, and MagNA Pure Compact) or glass fiber filter technology (Biorobot MDX and the manual kit Allprep). All methods yielded extracts free of cross-contamination and RT-PCR inhibition. All automated systems recovered L. pneumophila and adenovirus DNA equivalently. However, the MagNA Pure protocol demonstrated more than 4-fold higher DNA recovery from the S. pyogenes than other methods. The KingFisher mL and easyMAG protocols provided 1- to 3-log wider linearity and extracted 3- to 4-fold more RNA from the human influenza virus and respiratory syncytial virus. These findings suggest that systems differed in nucleic acid recovery, reproducibility, and linearity in a pathogen specific manner.

BACKGROUND: Recent studies have indicated that prostate cancer patients with the TMPRSS2-ERG gene fusion have a higher risk of recurrence. To identify markers associated with TMPRSS2-ERG fusion and prognostic of biochemical recurrence, we analysed a cohort of 139 men with prostate cancer for 502 molecular markers. METHODS: RNA from radical prostatectomy tumour specimens was analysed using cDNA-mediated, annealing, selection, extension and ligation (DASL) to determine mRNAs associated with TMPRSS2-ERG T1/E4 fusion and prognostic of biochemical recurrence. Differentially expressed mRNAs in T1/E4-positive tumours were determined using significance analysis of microarrays (false discovery rate (FDR) <5%). Univariate and multivariate Cox regression determined genes, gene signatures and clinical factors prognostic of recurrence (P-value <0.05, log-rank test). Analysis of two prostate microarray studies (GSE1065 and GSE8402) validated the findings. RESULTS: In the 139 patients from this study and from a 455-patient Swedish cohort, 15 genes in common were differentially regulated in T1/E4 fusion-positive tumours (FDR <0.05). The most significant mRNAs in both cohorts coded ERG. Nine genes were found prognostic of recurrence in this study and in a 596-patient Minnesota cohort. A molecular recurrence score was significant in prognosticating recurrence (P-value 0.000167) and remained significant in multivariate analysis of a mixed clinical model considering Gleason score and TMPRSS2-ERG fusion status. CONCLUSIONS: TMPRSS2-ERG T1/E4 fusion-positive tumours had differentially regulated mRNAs observed in multiple studies, the most significant one coded for ERG. Several mRNAs were consistently associated with biochemical recurrence and have potential clinical utility but will require further validation for successful translation.