Yifang Gao

Role of Innate T Cells in Anti-Bacterial Immunity

Innate T cells are a heterogeneous group of αβ and γδ T cells that respond rapidly (<2 h) upon activation. These innate T cells also share a non MHC class I or II restriction requirement for antigen recognition. Three major populations within the innate T cell group are recognized, namely, invariant NKT cells, mucosal associated invariant T cells, and gamma delta T cells. These cells recognize foreign/self-lipid presented by non-classical MHC molecules, such as CD1d, MR1, and CD1a. They are activated during the early stages of bacterial infection and act as a bridge between the innate and adaptive immune systems. In this review, we focus on the functional properties of these three innate T cell populations and how they are purposed for antimicrobial defense. Furthermore, we address the mechanisms through which their effector functions are targeted for bacterial control and compare this in human and murine systems. Lastly, we speculate on future roles of these cell types in therapeutic settings such as vaccination.

Clinical and Biological Effects of an Agonist Anti-CD40 Antibody: A Cancer Research UK Phase I Study

Purpose: This phase I study aimed to establish the biologic effects and MTD of the agonistic IgG1 chimeric anti-CD40 antibody ChiLob7/4 in patients (pts) with a range of CD40-expressing solid tumors and diffuse large B-cell lymphoma, resistant to conventional therapy. Potential mechanisms of action for agonistic anti-CD40 include direct cytotoxic effects on tumor cells and conditioning of antigen-presenting cells. Experimental Design: ChiLob7/4 was given by IV infusion weekly for 4 doses at a range from 0.5 to 240 mg/dose. Validated ELISAs were used to quantify ChiLob7/4 in serum and test for anti-chimeric MAb (HACA) responses. Pharmacodynamic assessments included quantitation of T-cell, natural killer–cell, and B-cell numbers and activation in blood by flow cytometry and a panel of cytokines in plasma by Luminex technology. Planned dose escalation was in cohorts of 3 patients until MTD or biologic effect, defined as reduction of peripheral blood CD19+ B cells to 10% or less of baseline. Results: Twenty-nine courses of treatment were given to 28 subjects. The MTD was 200 mg × 4, with dose-limiting toxicity of liver transaminase elevations at 240 mg. At 200 mg (range between 2.1 mg/kg and 3.3 mg/kg based on patient body weight), the trough level pretreatment was above 25 μg/mL. Grade 1-2 infusion reactions were seen above the dose of 16 mg, but could be prevented with single-dose corticosteroid premedication. HACA responses were seen after doses between 1.6 mg and 50 mg, but not above this. There were dose-dependent falls in blood B-cell numbers accompanied by reduced expression of CD21, and transient reductions in NK cell numbers with increased CD54 expression from 50 mg upward. MIP-1β and IL12 plasma concentrations rose after doses above 16 mg. Fifteen of 29 treatments were accompanied by disease stabilization for a median 6 months, the longest for 37 months. Conclusions: ChiLob7/4 can activate B and NK cells at doses that can be administered safely, and should be tested in combination with other antibodies and chemotherapy agents. Clin Cancer Res; 21(6); 1321–8. ©2015 AACR.

The synthesis and in vivo evaluation of 2,2-difluoro KRN7000

The synthesis of 2′,2′‐difluoro KRN7000 is described. In vivo evaluation demonstrates that this fluorinated glycolipid induces CD1d‐dependent TCR activation of NKT cells, with a bias towards Th2 cytokine production.

Precision treatment with sirolimus in a case of activated phosphoinositide 3-kinase δ syndrome

• Activated phosphoinositide 3-kinase δ syndrome may be complicated by refractory autoimmune hemolytic anemia.

A novel FOXP3 mutation causing fetal akinesia and recurrent male miscarriages.

Potential reviewers may include; •Dr Stephen Jolles, University of Wales Hospital, jollessr@cardiff.ac.uk •Prof Magda Carneiro-Sampaio, Hospital da Clinicas sa FMUSP, magdascs@usp.br •Prof John Routes, Medical College of Wisconsin, jroutes@mcw.edu •Dr Eleonora Gambineri, University of Florence and Anna Meyer Childrens Hospital, eleonora.gambineri@unifi.it.

Corticosteroids and infliximab impair the performance of interferon-γ release assays used for diagnosis of latent tuberculosis

The impact of immunosuppression on interferon-γ release assays and novel cytokine biomarkers of TB infection, mycobacteria-specific IL-2, IP-10 and TNF-α responses was investigated in an ex vivo model. Cytokine responses in standard QuantiFERON-TB Gold in-Tube (QFT-GIT) assays were compared with duplicate assays containing dexamethasone or infliximab. Dexamethasone converted QFT-GIT results from positive to negative in 30% of participants. Antigen-stimulated interferon-γ, IL-2 and TNF-α responses were markedly reduced, but IP-10 responses were preserved. Infliximab caused QFT-GIT result conversion in up to 30% of participants and substantial reductions in all cytokine responses. Therefore, corticosteroids and anti-TNF-α agents significantly impair interferon-γ release assay performance. IP-10 may be a more robust TB biomarker than interferon-γ in patients receiving corticosteroids.

IL-10 production by CLL cells is enhanced in the anergic IGHV mutated subset and associates with reduced DNA methylation of the IL10 locus

Chronic lymphocytic leukemias (CLLs) with unmutated (U-CLL) or mutated (M-CLL) IGHV have variable features of immunosuppression, possibly influenced by those CLL cells activated to produce interleukin 10 (IL-10). The two subsets differ in their levels of anergy, defined by low surface immunoglobulin M levels/signaling capacity, and in their DNA methylation profile, particularly variable in M-CLL. We have now found that levels of IL-10 produced by activated CLL cells were highly variable. Levels were higher in M-CLL than in U-CLL and correlated with anergy. DNA methylation analysis of IL10 locus revealed two previously uncharacterized ‘variably methylated regions’ (CLL-VMRs1/2) in the gene body, but similarly low methylation in the promoter of both U-CLL and M-CLL. CLL-VMR1/2 methylation was lower in M-CLL than in U-CLL and inversely correlated with IL-10 induction. A functional signal transducer and activator of transcription 3 (STAT3) binding site in CLL-VMR2 was confirmed by proximity ligation and luciferase assays, whereas inhibition of SYK-mediated STAT3 activation resulted in suppression of IL10. The data suggest epigenetic control of IL-10 production. Higher tumor load may compensate the reduced IL-10 production in U-CLL, accounting for clinical immunosuppression in both subsets. The observation that SYK inhibition also suppresses IL-10 provides a potential new rationale for therapeutic targeting and immunological rescue by SYK inhibitors in CLL.

Environmental temperature impacts on the performance of QuantiFERON-TB Gold In-Tube assays

We read with interest the recent article by Pan et alwhich highlighted that a substantial proportion of patients with pulmonary and extrapulmonary tuberculosis (TB) have false-negative interferon-gamma release assay (IGRA) results, showing that a negative IGRA result does not rule out active TB. Unfortunately the authors excluded indeterminate assay results from the analyses, despite those results posing a considerable dilemma for clinical management, as they confer no information about the patients TB infection status

Genes implicated in thiopurine-induced toxicity: Comparing TPMT enzyme activity with clinical phenotype and exome data in a paediatric IBD cohort

The aim of our study was to assess the utility of next generation sequencing (NGS) for predicting toxicity and clinical response to thiopurine drugs in paediatric patients with inflammatory bowel disease. Exome data for 100 patients were assessed against biochemically measured TPMT enzyme activity, clinical response and adverse effects. The TPMT gene and a panel of 15 other genes implicated in thiopurine toxicity were analysed using a gene based statistical test (SKAT-O test). Nine patients out of 100 (Crohn’s disease- 67, ulcerative colitis- 23 and IBDU-10) had known TPMT mutations associated with deficient enzyme activity. A novel and a highly pathogenic TPMT variant not detectable through standard genotyping, was identified through NGS in an individual intolerant to thiopurines. Of the 14 patients intolerant to thiopurines, NGS identified deleterious TPMT variants in 5 individuals whereas the biochemical test identified 8 individuals as intolerant (sensitivity 35.7% and 57.14%; specificity 93.75% and 50% respectively). SKAT-O test identified a significant association between MOCOS gene and TPMT activity (p = 0.0015), not previously reported. Although NGS has the ability to detect rare or novel variants not otherwise identified through standard genotyping, it demonstrates no clear advantage over the biochemical test in predicting toxicity in our modest cohort.

Autoimmunity|[sol]|inflammation in a monogenic primary immunodeficiency cohort

Primary immunodeficiencies (PIDs) are rare inborn errors of immunity that have a heterogeneous phenotype that can include severe susceptibility to life‐threatening infections from multiple pathogens, unique sensitivity to a single pathogen, autoimmune/inflammatory (AI/I) disease, allergies and/or malignancy. We present a diverse cohort of monogenic PID patients with and without AI/I diseases who underwent clinical, genetic and immunological phenotyping. Novel pathogenic variants were identified in IKBKG, CTLA4, NFKB1, GATA2, CD40LG and TAZ as well as previously reported pathogenic variants in STAT3, PIK3CD, STAT1, NFKB2 and STXBP2. AI/I manifestations were frequently encountered in PIDs, including at presentation. Autoimmunity/inflammation was multisystem in those effected, and regulatory T cell (Treg) percentages were significantly decreased compared with those without AI/I manifestations. Prednisolone was used as the first‐line immunosuppressive agent in all cases, however steroid monotherapy failed long‐term control of autoimmunity/inflammation in the majority of cases and additional immunosuppression was required. Patients with multisystem autoimmunity/inflammation should be investigated for an underlying PID, and in those with PID early assessment of Tregs may help to assess the risk of autoimmunity/inflammation.