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Summary: Background: When used proactively, drug‐tolerant anti‐tumour necrosis factor (TNF) antibody assays provide early opportunity to suppress immunogenicity. Aim: To validate positivity thresholds of IDKmonitor drug‐tolerant anti‐infliximab and ‐adalimumab antibody assays. Methods: We applied positivity thresholds, defined by testing sera from 498 anti‐TNF naive healthy adults, from the Exeter Ten Thousand study to data from our therapeutic drug monitoring (TDM) service and Personalised Anti‐TNF Therapy in Crohn's disease (PANTS) cohort to explore associations with drug level and treatment outcomes. Results: The 80% one‐sided lower confidence interval of the 99th centile concentration for anti‐infliximab and –adalimumab antibodies were lower than the manufacturers threshold of 10 arbitrary units (AU)/mL; 9 and 6 AU/mL, respectively. Using these new thresholds in the TDM cohort, more adalimumab‐ than infliximab‐ (11.2% [814/7272] vs 3.1% [390/12 683] P < 0.0001) treated patients were reclassified as antibody‐positive. Adalimumab drug concentrations in this reclassified group (median 8.1, interquartile range [IQR] 5.5‐11.0 mg/L) were lower than those below the new threshold (<5AU/mL) (median 9.9, IQR 7.1‐13.0 mg/L; P < 0.0001), but higher than at the manufacturer's threshold (10‐29 AU/mL) (median 5.9 mg/L, IQR 3.5‐8.7; P < 0.0001). No difference in infliximab drug concentration was observed using the new or manufacturer's positivity threshold (P = 0.11). In the PANTS cohort, patients with anti‐adalimumab antibody concentrations at or above the new threshold were more likely to be in primary non‐response (25/68 [37%] vs. 64/332 [19%], P = 0.0035), and non‐remission at week 54 (51/62 [82%] vs. 168/279 [60%], P = 0.0011), than patients with anti‐drug antibody concentrations in the group below the new threshold (0‐5 AU/mL); this was not seen for anti‐infliximab antibodies. Conclusion: Laboratories should derive antibody positivity thresholds for assays they use. For adalimumab, low‐concentration anti‐drug antibodies were associated with lower drug levels and treatment failure. [ABSTRACT FROM AUTHOR]

Objective: To determine the diagnostic accuracy of calprotectin to diagnose inflammatory bowel disease (IBD) in children in whom general practitioners (GPs) suspected IBD.Design: Prospective observational cohort study of a new calprotectin-based primary care referral pathway.Setting: 48 GP practices and gastroenterology secondary care services at the Royal Devon and Exeter NHS Foundation Trust in the South-West of England, UK.Patients: 195 children aged between 4 and 18 years referred on the pathway between January 2014 and August 2017 for investigation of gastrointestinal symptoms were included.Interventions: Primary-care-driven faecal calprotectin testing. Primary and secondary care records over 12 months from the point of calprotectin testing were used as the reference standard.Main Outcome Measures: Diagnostic accuracy of calprotectin testing to detect IBD.Results: 7% (13/195) tested patients were diagnosed with IBD. Using our prespecified cut-off of 100 µg/g, calprotectin had a diagnostic accuracy of 91% (95% CI 86% to 95%) with a sensitivity for distinguishing IBD from non-IBD of 100% (95% CI 75% to 100%), a specificity of 91% (95% CI 85% to 94%), a positive predictive value of 43% (95% CI 25% to 63%) and a negative predictive value of 100% (95% CI 98% to 100%). Calprotectin testing had no effect on the time to diagnosis, but a negative test contributed to saved referrals and was associated with fewer diagnostic tests in secondary care.Conclusions: Calprotectin testing of children with suspected IBD in primary care accurately distinguishes IBD from a functional gut disorder, reduces secondary care referrals and associated diagnostic healthcare utilisation. [ABSTRACT FROM AUTHOR]

Anti–tumor necrosis factor (anti-TNF) therapies are the most widely used biologic drugs for treating immune-mediated diseases, but repeated administration can induce the formation of anti-drug antibodies. The ability to identify patients at increased risk for development of anti-drug antibodies would facilitate selection of therapy and use of preventative strategies. We performed a genome-wide association study to identify variants associated with time to development of anti-drug antibodies in a discovery cohort of 1240 biologic-naïve patients with Crohn's disease starting infliximab or adalimumab therapy. Immunogenicity was defined as an anti-drug antibody titer ≥10 AU/mL using a drug-tolerant enzyme-linked immunosorbent assay. Significant association signals were confirmed in a replication cohort of 178 patients with inflammatory bowel disease. The HLA-DQA1*05 allele, carried by approximately 40% of Europeans, significantly increased the rate of immunogenicity (hazard ratio [HR], 1.90; 95% confidence interval [CI], 1.60–2.25; P = 5.88 × 10–13). The highest rates of immunogenicity, 92% at 1 year, were observed in patients treated with infliximab monotherapy who carried HLA-DQA1*05; conversely the lowest rates of immunogenicity, 10% at 1 year, were observed in patients treated with adalimumab combination therapy who did not carry HLA-DQA1*05. We confirmed this finding in the replication cohort (HR, 2.00; 95% CI, 1.35–2.98; P = 6.60 × 10–4). This association was consistent for patients treated with adalimumab (HR, 1.89; 95% CI, 1.32–2.70) or infliximab (HR, 1.92; 95% CI, 1.57–2.33), and for patients treated with anti-TNF therapy alone (HR, 1.75; 95% CI, 1.37–2.22) or in combination with an immunomodulator (HR, 2.01; 95% CI, 1.57–2.58). In an observational study, we found a genome-wide significant association between HLA-DQA1*05 and the development of antibodies against anti-TNF agents. A randomized controlled biomarker trial is required to determine whether pretreatment testing for HLA-DQA1*05 improves patient outcomes by helping physicians select anti-TNF and combination therapies. ClinicalTrials.gov ID: NCT03088449. [ABSTRACT FROM AUTHOR]

The article discusses a study which compared the R-Biopharm and Immundiagnostik enzyme-linked immunosorbent assay (ELISA) assays to determine infliximab drug levels. Topics include information on infliximab, major studies which both aimed to address the diagnostic utility of anti-TNF drug monitoring in the management of inflammatory bowel disease (IBD), and correlation between the assays.

The herbicide linuron is used worldwide, and has been detected in surface waters as well as in food and drinking water. Toxicological studies have reported that linuron acts as an antiandrogen in vitro and in vivo and disrupts mammalian male reproductive function. However, global mechanisms of linuron toxicity are poorly documented. We used RNA-seq to characterize the hepatic transcriptional response of mature male brown trout exposed for 4 days to 1.7, 15.3, and 225.9 μg/L linuron. We identified a striking decrease in the expression of transcripts encoding the majority of enzymes forming the cholesterol biosynthesis pathway. We also measured a very significant decrease in total hepatic cholesterol in fish exposed to 225.9 μg/L linuron and a negative correlation between total cholesterol and linuron treatment concentration. We hypothesize that inhibition of cholesterol biosynthesis may result from the disruption of androgen signaling by linuron. Additionally, there was increased expression of a number of transcripts involved in cellular stress responses, including cypla (up to 560-fold), molecular chaperones, and antioxidant enzymes. We found some evidence of similar patterns of transcriptional change in fish exposed to an environmentally relevant concentration of linuron, and further research should investigate the potential for adverse effects to occur following chronic environmental exposure. [ABSTRACT FROM AUTHOR]

Introduction: C-peptide and insulin measurements in blood provide useful information regarding endogenous insulin secretion. Conflicting evidence on sample stability and handling procedures continue to limit the widespread clinical use of these tests. We assessed the factors that altered the stability of insulin and C-peptide in blood. Methods: We investigated the impact of preservative type, time to centrifugation, storage conditions and duration of storage on the stability of C-peptide and insulin on three different analytical platforms. Results: C-peptide was stable for at least 24 hours at room temperature in both centrifuged and whole blood collected in K+-EDTA and serum gel tubes, with the exception of whole blood serum gel, which decreased to 78% of baseline at 24 hours, (p = 0.008). Insulin was stable at room temperature for 24 hours in both centrifuged and whole blood collected in K+-EDTA tubes. In contrast insulin levels decreased in serum gel tubes both centrifuged and whole blood (66% of baseline, p = 0.01 and 76% of baseline p = 0.01, by 24 hours respectively). C-peptide and insulin remained stable after 6 freeze-thaw cycles. Conclusions: The stability of C-peptide and insulin in whole blood K+-EDTA tubes negates the need to conform to strict sample handling procedures for these assays, greatly increasing their clinical utility. [ABSTRACT FROM AUTHOR]

Introduction: The biologic anti-tumour necrosis factor alpha (anti-TNFα) agents infliximab and adalimumab are monoclonal antibodies with binding specificity to TNFα, which are used for the treatment of Crohn's disease. Clinical response is varied from complete with mucosal healing, to primary non-response, loss of response and adverse drug reactions. Measuring trough blood levels of infliximab and adalimumab may guide clinical management. The sample handling requirements for infliximab and adalimumab were previously unknown.Aim: The aim of this study was to determine the in vitro stability of infliximab and adalimumab in samples stored for up to seven days at room temperature.Methods: Samples were stored as clotted whole blood or serum at room temperature for up to seven days, before being frozen (-20℃) and analysed as a batch for either infliximab or adalimumab.Results: No significant difference between the concentration of infliximab and adalimumab measured in samples stored as serum or whole blood for seven days at room temperature, as compared to baseline was found (t-test; infliximab: P = .35 [serum], P = .38 [whole blood]; adalimumab: P = .12 [serum], P = .49 [whole blood]).Conclusion: The stability of infliximab and adalimumab at room temperature for seven days allows samples to be posted direct from clinics and research centres to the analysing laboratory. [ABSTRACT FROM AUTHOR]

Abstract: A 19year old male attended his GP with a history of “fluid retention”, lack of libido and erectile dysfunction. He was found to have a high serum testosterone, and a raised luteinising hormone. After further investigations, the patient admitted to taking a supplement called ActivaTe Xtreme™, obtained from an internet source, to address his low libido. ActivaTe Xtreme™ contains active ingredients which increase serum testosterone levels by several independent mechanisms that are not associated with luteinising hormone suppression. Urine analyses for synthetic anabolic steroids were negative, and urinary testosterone, epitestosterone and other androgens were normal. This biochemical pattern is not the same as that seen with anabolic steroids (i.e. raised testosterone, suppressed luteinising hormone and abnormal urine steroid profile). The issue of self medication with performance enhancing compounds needs to be carefully considered in order to avoid expensive and invasive investigations, missing an underlying pathology or misdiagnosing a patient. This case also raises the spectre of yet another “performance enhancing” product that may cause difficulty for those trying to ensure that sport remains on a “hormonally” equal basis. [Copyright &y& Elsevier]