Serum Immune Profiling in Paediatric Crohn's Disease Demonstrates Stronger Immune Modulation With First-Line Infliximab Than Conventional Therapy and Pre-Treatment Profiles Predict Clinical Response to Both Treatments

BACKGROUND: Despite its efficacy, rational guidance for starting/stopping first-line biologic treatment in individual paediatric Crohn's disease [CD] patients is needed. We assessed how serum immune profiles before and after first-line infliximab [FL-IFX] or conventional [CONV] induction therapy associate with disease remission at week 52. METHODS: Pre- [n = 86], and 10-14-week post-treatment [n = 84] sera were collected from patients with moderate-to-severe paediatric CD in the TISKids trial, randomized to FL-IFX [n = 48; five 5-mg/kg infusions over 22 weeks] or CONV [n = 43; exclusive enteral nutrition or oral prednisolone]; both groups received azathioprine maintenance. The relative concentrations of 92 inflammatory proteins were determined with Olink Proteomics; fold changes [FC] with |log2FC| &gt; 0.5 after false discovery rate adjustment were considered significant. RESULTS: FL-IFX modulated a larger number of inflammatory proteins and induced stronger suppression than CONV; 18/30 proteins modulated by FL-IFX were not regulated by CONV. Hierarchical clustering based on IFX-modulated proteins at baseline revealed two clusters of patients: CD-hi patients had significantly higher concentrations of 23/30 IFX-modulated proteins [including oncostatin-M, TNFSF14, HGF and TGF-α], and higher clinical disease activity, C-reactive protein and blood neutrophils at baseline than CD-lo patients. Only 24% of CD-hi FL-IFX-treated patients maintained remission without escalation at week 52 vs 58% of CD-lo FL-IFX-treated patients. Similarly, 6% of CD-hi CONV-treated patients achieved remission vs 20% of CONV-treated CD-lo patients. Clustering based on immune profiles post-induction therapy did not relate to remission at week 52. CONCLUSION: FL-IFX leads to stronger reductions and modulates more immune proteins than CONV. Stratification on pre-treatment profiles of IFX-modulated proteins directly relates to maintenance of remission without treatment escalation. TRIAL REGISTRATION NUMBER: NCT02517684.</p

CD8⁺ T Cell Activation Leads to Constitutive Formation of Liver Tissue-Resident Memory T Cells that Seed a Large and Flexible Niche in the Liver

Liver tissue-resident memory T (Trm) cells migrate throughout the sinusoids and are capable of protecting against malaria sporozoite challenge. To gain an understanding of liver Trm cell development, we examined various conditions for their formation. Although liver Trm cells were found in naive mice, their presence was dictated by antigen specificity and required IL-15. Liver Trm cells also formed after adoptive transfer of in vitro-activated but not naive CD8+ T cells, indicating that activation was essential but that antigen presentation within the liver was not obligatory. These Trm cells patrolled the liver sinusoids with a half-life of 36 days and occupied a large niche that could be added to sequentially without effect on subsequent Trm cell cohorts. Together, our findings indicate that liver Trm cells form as a normal consequence of CD8+ T cell activation during essentially any infection but that inflammatory and antigenic signals preferentially tailor their development. Holz et al. demonstrate that tissue-resident memory T (Trm) cells routinely develop in the liver after T cell activation. Within the liver, IL-15, antigen, and inflammation aid Trm cell formation, but only IL-15 is essential. Newly formed Trm cells do not displace existing populations, demonstrating a flexible liver niche

Evaluation of exclusive enteral nutrition and corticosteroid induction treatment in new-onset moderate-to-severe luminal paediatric Crohn's disease

To induce remission in luminal paediatric Crohn's disease (CD), the ESPGHAN/ECCO guideline recommends treatment with exclusive enteral nutrition (EEN) or oral corticosteroids. In newly diagnosed moderate-to-severe paediatric CD patients, we determined the proportion of patients in which EEN or corticosteroids induced remission and maintained remission on azathioprine monotherapy. We included patients from the "TISKids" study assigned to the conventional treatment arm. Patients were aged 3-17 years and had new-onset, untreated luminal CD with weighted paediatric CD activity index (wPCDAI)> 40. Induction treatment consisted of EEN or oral corticosteroids; all received azathioprine maintenance treatment from start of treatment. The primary outcome of this study was endoscopic remission defined as a SES-CD score Conclusion: In children with moderate-to-severe newly diagnosed CD, induction treatment with EEN or CS regularly is insufficient to achieve endoscopic remission without treatment escalation at week 10.Peer reviewe

Plasmodium berghei Hsp90 contains a natural immunogenic I-A^b-restricted antigen common to rodent and human Plasmodium species

Thorough understanding of the role of CD4 T cells in immunity can be greatly assisted by the study of responses to defined specificities. This requires knowledge of Plasmodium-derived immunogenic epitopes, of which only a few have been identified, especially for the mouse C57BL/6 background. We recently developed a TCR transgenic mouse line, termed PbT-II, that produces CD4+ T cells specific for an MHC class II (I-Ab)-restricted Plasmodium epitope and is responsive to both sporozoites and blood-stage P. berghei. Here, we identify a peptide within the P. berghei heat shock protein 90 as the cognate epitope recognised by PbT-II cells. We show that C57BL/6 mice infected with P. berghei blood-stage induce an endogenous CD4 T cell response specific for this epitope, indicating cells of similar specificity to PbT-II cells are present in the naïve repertoire. Adoptive transfer of in vitro activated TH1-, or particularly TH2-polarised PbT-II cells improved control of P. berghei parasitemia in C57BL/6 mice and drastically reduced the onset of experimental cerebral malaria. Our results identify a versatile, potentially protective MHC-II restricted epitope useful for exploration of CD4 T cell-mediated immunity and vaccination strategies against malaria

Age profiles of sport participants.

Background: Participation in sport has many health benefits, and is popular amongst children. However participation decreases with age. While the membership records of peak sports organisations have improved markedly in recent years, there has been little research into sport participation trends across the lifespan. This study investigates age profiles of participation in sport and compares these trends between genders and residential locations. Methods: De-identified 2011 participant registration data for seven popular Australian sports (Australian Football, Basketball, Cricket, Hockey, Lawn Bowls, Netball and Tennis) were obtained and analysed according to age, gender and geographical location (metropolitan v non-metropolitan) within the state of Victoria, Australia. All data were integrated and sports were analysed collectively to produce broadly based participation profiles while maintaining confidentiality of membership data for individual sports. Results: The total number of registered participants included in the data set for 2011 was 520,102. Most participants (64.1 %) were aged less than 20 years. Nearly one third (27.6 %) of all participants were aged 10–14 years, followed by the 5–9 year age group (19.9 %). Participation declined rapidly during adolescence. A higher proportion of males than female participants were young children (4–7 years) or young adults 18–29 years; this pattern was reversed among 8–17 year-olds. A higher proportion of metropolitan participants were engaged between the ages of 4–13 and 19–29, whereas a higher proportion of non-metropolitan participants played during adolescence (14–18 years) and throughout mature adulthood (30+ years). Conclusions: Increasing participation in sport is an objective for both government and sporting organisations. In order to have both mass population-based participation, from a health policy and elite performance perspective, we need to further explore the findings arising from the analysis of this extensive data set. Such an examination will lead to better understand of the reasons for attrition during adolescence to inform program and policy developments to retain people participating in sport, for a healthy and sport performing nation

Evolution of Linked Avirulence Effectors in Leptosphaeria maculans Is Affected by Genomic Environment and Exposure to Resistance Genes in Host Plants

Brassica napus (canola) cultivars and isolates of the blackleg fungus, Leptosphaeria maculans interact in a ‘gene for gene’ manner whereby plant resistance (R) genes are complementary to pathogen avirulence (Avr) genes. Avirulence genes encode proteins that belong to a class of pathogen molecules known as effectors, which includes small secreted proteins that play a role in disease. In Australia in 2003 canola cultivars with the Rlm1 resistance gene suffered a breakdown of disease resistance, resulting in severe yield losses. This was associated with a large increase in the frequency of virulence alleles of the complementary avirulence gene, AvrLm1, in fungal populations. Surprisingly, the frequency of virulence alleles of AvrLm6 (complementary to Rlm6) also increased dramatically, even though the cultivars did not contain Rlm6. In the L. maculans genome, AvrLm1 and AvrLm6 are linked along with five other genes in a region interspersed with transposable elements that have been degenerated by Repeat-Induced Point (RIP) mutations. Analyses of 295 Australian isolates showed deletions, RIP mutations and/or non-RIP derived amino acid substitutions in the predicted proteins encoded by these seven genes. The degree of RIP mutations within single copy sequences in this region was proportional to their proximity to the degenerated transposable elements. The RIP alleles were monophyletic and were present only in isolates collected after resistance conferred by Rlm1 broke down, whereas deletion alleles belonged to several polyphyletic lineages and were present before and after the resistance breakdown. Thus, genomic environment and exposure to resistance genes in B. napus has affected the evolution of these linked avirulence genes in L. maculans

FONZIE: An optimized pipeline for minisatellite marker discovery and primer design from large sequence data sets

<p>Abstract</p> <p>Background</p> <p>Micro-and minisatellites are among the most powerful genetic markers known to date. They have been used as tools for a large number of applications ranging from gene mapping to phylogenetic studies and isolate typing. However, identifying micro-and minisatellite markers on large sequence data sets is often a laborious process.</p> <p>Results</p> <p>FONZIE was designed to successively 1) perform a search for markers via the external software Tandem Repeat Finder, 2) exclude user-defined specific genomic regions, 3) screen for the size and the percent matches of each relevant marker found by Tandem Repeat Finder, 4) evaluate marker specificity (i.e., occurrence of the marker as a single copy in the genome) using BLAST2.0, 5) design minisatellite primer pairs via the external software Primer3, and 6) check the specificity of each final PCR product by BLAST. A final file returns to users all the results required to amplify markers. A biological validation of the approach was performed using the whole genome sequence of the phytopathogenic fungus <it>Leptosphaeria maculans</it>, showing that more than 90% of the minisatellite primer pairs generated by the pipeline amplified a PCR product, 44.8% of which showed agarose-gel resolvable polymorphism between isolates. Segregation analyses confirmed that the polymorphic minisatellites corresponded to single-locus markers.</p> <p>Conclusion</p> <p>FONZIE is a stand-alone and user-friendly application developed to minimize tedious manual operations, reduce errors, and speed up the search for efficient minisatellite and microsatellite markers departing from whole-genome sequence data. This pipeline facilitates the integration of data and provides a set of specific primer sequences for PCR amplification of single-locus markers. FONZIE is freely downloadable at: <url>http://www.versailles-grignon.inra.fr/bioger/equipes/leptosphaeria_maculans/outils_d_analyses/fonzie</url></p

CD8+ T cells from a novel T cell receptor transgenic mouse induce liver-stage immunity that can be boosted by blood-stage infection in rodent malaria

To follow the fate of CD8+ T cells responsive to Plasmodium berghei ANKA (PbA) infection, we generated an MHC I-restricted TCR transgenic mouse line against this pathogen. T cells from this line, termed PbT-I T cells, were able to respond to blood-stage infection by PbA and two other rodent malaria species, P. yoelii XNL and P. chabaudi AS. These PbT-I T cells were also able to respond to sporozoites and to protect mice from liver-stage infection. Examination of the requirements for priming after intravenous administration of irradiated sporozoites, an effective vaccination approach, showed that the spleen rather than the liver was the main site of priming and that responses depended on CD8&alpha;+ dendritic cells. Importantly, sequential exposure to irradiated sporozoites followed two days later by blood-stage infection led to augmented PbT-I T cell expansion. These findings indicate that PbT-I T cells are a highly versatile tool for studying multiple stages and species of rodent malaria and suggest that cross-stage reactive CD8+ T cells may be utilized in liver-stage vaccine design to enable boosting by blood-stage infections