Peptide library-based evaluation of T-cell receptor breadth detects defects in global and regulatory activation in human immunologic diseases.

The ability of T-cells to respond to foreign antigens and to appropriately regulate this response is crucial for maintaining immune homeostasis. Using combinatorial peptide libraries, we functionally measured broad T-cell reactivity and observed impaired reactivity in established models of T-cell receptor repertoire restriction and in previously unrecognized disease contexts. By concurrently analyzing T-regulatory and T-effector cells, we show strong functional correlation between these subsets in healthy individuals and, strikingly, that alterations of this balance are associated with T helper type 2 (Th2)-mediated disease in a lymphopenic setting. Finally, we demonstrate that peptide-based priming of polyclonal naive cells with relatively low concentrations skews toward Th2 differentiation. These findings provide unique insight into the pathophysiology and functional consequences of abnormal T-cell repertoires and into differentiation of human naive T-cells.

Correlation of rapid point-of-care vs send-out fecal calprotectin monitoring in pediatric inflammatory bowel disease.

AIM: To assess the correlation between the send-out enzyme-linked immuno sorbent assay (ELISA) and the point-of-care (POC) calprotectin test in pediatric inflammatory bowel disease (IBD) patients. METHODS: We prospectively collected stool samples in pediatric IBD patients for concomitant send-out ELISA analysis and POC calprotectin testing using the Quantum Blue® (QB) Extended immunoassay. Continuous results between 17 to 1000 µg/g were considered for comparison. Agreement between the two tests was measured by a Bland-Altman plot and statistical significance was determined using Pitman's test. RESULTS: Forty-nine stool samples were collected from 31 pediatric IBD patients. The overall means for the rapid and ELISA tests were 580.5 and 522.87 µg/g respectively. Among the 49 samples, 18 (37.5%) had POC calprotectin levels of ≤ 250 µg/g and 31 (62.5%) had levels > 250 µg/g. Calprotectin levels ≤ 250 µg/g show good correlation between the two assays. Less correlation was observed at quantitatively higher calprotectin levels. CONCLUSION: In pediatric IBD patients, there is better correlation of between ELISA and POC calprotectin measurements at clinically meaningful, low-range levels. Future adoption of POC calprotectin testing in the United States may have utility for guiding clinical decision making in real time.

Cost-effectiveness of adalimumab, infliximab or vedolizumab as first-line biological therapy in moderate-to-severe ulcerative colitis.

BACKGROUND: There are no head-to-head randomised controlled trials (RCTs) comparing the effectiveness of biologics in ulcerative colitis (UC). We aimed to assess the cost-effectiveness of adalimumab, infliximab and vedolizumab as first-line agents to induce clinical remission and mucosal healing (MH) in UC. METHODS: We constructed a decision tree based on a payer's perspective in the USA to estimate the first year costs of adalimumab, infliximab or vedolizumab to achieve clinical remission and MH in patients with moderate-to-severe UC. Transition probabilities were derived from ACT, ULTRA and GEMINI RCT data. Costs were derived from Medicare reimbursement rates and wholesale drug prices. RESULTS: Assuming a biological-naïve cohort, infliximab 5 mg/kg every 8 weeks was more cost-effective ($99 171 per MH achieved) than adalimumab 40 mg every other week ($316 378 per MH achieved) and vedolizumab every 8 weeks ($301 969 per MH achieved) at 1 year. Non-drug administration cost of infliximab exceeding $1974 per infusion would make adalimumab more cost-effective. First-line UC therapy with vedolizumab would be cost-effective if the drug acquisition price was <$2537 for each 300 mg administration during the 1-year time horizon. CONCLUSIONS: If non-drug costs of infliximab administration are not excessive (<$2000), infliximab is the most cost-effective first-line biologic for moderate-to-severe UC. Exceeding this threshold infusion-related cost would make adalimumab the more cost-effective therapy. Considering its drug costs in the USA, vedolizumab appears to be appropriately used as a second-line biologic after antitumour necrosis factor failure.

Exo-endocytic trafficking and the septin-based diffusion barrier are required for the maintenance of Cdc42p polarization during budding yeast asymmetric growth.

Cdc42p plays a central role in asymmetric cell growth in yeast by controlling actin organization and vesicular trafficking. However, how Cdc42p is maintained specifically at the daughter cell plasma membrane during asymmetric cell growth is unclear. We have analyzed Cdc42p localization in yeast mutants defective in various stages of membrane trafficking by fluorescence microscopy and biochemical fractionation. We found that two separate exocytic pathways mediate Cdc42p delivery to the daughter cell. Defects in one of these pathways result in Cdc42p being rerouted through the other. In particular, the pathway involving trafficking through endosomes may couple Cdc42p endocytosis from, and subsequent redelivery to, the plasma membrane to maintain Cdc42p polarization at the daughter cell. Although the endo-exocytotic coupling is necessary for Cdc42p polarization, it is not sufficient to prevent the lateral diffusion of Cdc42p along the cell cortex. A barrier function conferred by septins is required to counteract the dispersal of Cdc42p and maintain its localization in the daughter cell but has no effect on the initial polarization of Cdc42p at the presumptive budding site before symmetry breaking. Collectively, membrane trafficking and septins function synergistically to maintain the dynamic polarization of Cdc42p during asymmetric growth in yeast.