IntroductionIn light of the SARS-CoV-2 pandemic, protecting vulnerable groups has become a high priority. Persons at risk of severe disease, for example, those receiving immunosuppressive therapies for chronic inflammatory cdiseases (CIDs), are prioritised for vaccination. However, data concerning generation of protective antibody titres in immunosuppressed patients are scarce. Additionally, mRNA vaccines represent a new vaccine technology leading to increased insecurity especially in patients with CID.ObjectiveHere we present for the first time, data on the efficacy and safety of anti-SARS-CoV-2 mRNA vaccines in a cohort of immunosuppressed patients as compared with healthy controls.Methods42 healthy controls and 26 patients with CID were included in this study (mean age 37.5 vs 50.5 years). Immunisations were performed according to national guidelines with mRNA vaccines. Antibody titres were assessed by ELISA before initial vaccination and 7 days after secondary vaccination. Disease activity and side effects were assessed prior to and 7 days after both vaccinations.ResultsAnti-SARS-CoV-2 antibodies as well as neutralising activity could be detected in all study participants. IgG titres were significantly lower in patients as compared with controls (2053 binding antibody units (BAU)/mL ±1218 vs 2685±1102). Side effects were comparable in both groups. No severe adverse effects were observed, and no patients experienced a disease flare.ConclusionWe show that SARS-CoV-2 mRNA vaccines lead to development of antibodies in immunosuppressed patients without considerable side effects or induction of disease flares. Despite the small size of this cohort, we were able to demonstrate the efficiency and safety of mRNA vaccines in our cohort.

IL-9 acts as an autocrine amplifier of type 2 innate lymphoid cell function to promote tissue repair in the recovery phase of helminth-induced lung infection.

Bacterial-induced intestinal inflammation is crucially dependent on interleukin (IL)-23 and is associated with CD4(+) T helper type 1 (Th1) and Th17 responses. However, the relative contributions of these subsets during the induction and resolution of colitis in T-cell-sufficient hosts remain unknown. We report that Helicobacter hepaticus-induced typhlocolitis in specific pathogen-free IL-10(-/-) mice is associated with elevated frequencies and numbers of large intestinal interferon (IFN)-γ(+) and IFN-γ(+)IL-17A(+) CD4(+) T cells. By assessing histone modifications and transcript levels in IFN-γ(+), IFN-γ(+)IL-17A(+), and IL-17A(+) CD4(+) T cells isolated from the inflamed intestine, we show that Th17 cells are predisposed to upregulate the Th1 program and that they express IL-23R but not IL-12R. Using IL-17A fate-reporter mice, we further demonstrate that H. hepaticus infection gives rise to Th17 cells that extinguish IL-17A secretion and turn on IFN-γ within 10 days post bacterial inoculation. Together, our results suggest that bacterial-induced Th17 cells arising in disease-susceptible hosts contribute to intestinal pathology by switching phenotype, transitioning via an IFN-γ(+)IL-17A(+) stage, to become IFN-γ(+) ex-Th17 cells.

Interleukin 22 (IL-22) is a cytokine that regulates tissue homeostasis at barrier surfaces. A variety of IL-22 producing cell types are known, but identification on the single cell level remains difficult. We therefore generated a fate reporter mouse that would allow the identification of IL-22 producing cells and their fate mapping in vivo. To trace IL-22 expressing cells, a sequence encoding Cre recombinase was cloned into the Il22 locus and Il22Cre mice were crossed with reporter mice expressing enhanced yellow fluorescence protein (eYFP) under control of the endogenous Rosa26 promoter. In IL22CreR26ReYFP mice, the fluorescent reporter permanently labels cells that have switched on Il22 expression irrespective of cytokine production. Despite a degree of underreporting, eYFP expression was detectable in non-immune mice and restricted to innate lymphoid cells (ILC3) in the gut and γδ T cells in skin or lung. Upon skin challenge with imiquimod, eYFP+ γδ and CD4 T cells expanded in the skin. Infection with Citrobacter rodentium was initially controlled by ILC3, followed by expansion of eYFP+ CD4 T cells, which were induced in innate lymphoid follicles (ILF) in the colon. No eYFP expression was detected in small intestinal Th17 cells and they did not expand in the immune response. Colonic eYFP+ CD4 T cells exhibited plasticity during infection with expression of additional cytokines in contrast to ILC3, which remained largely stable. Single cell qPCR analysis of eYFP+ CD4 T cells confirmed their heterogeneity, suggesting IL-22 expression is not strictly confined to particular subsets or a dedicated Th22 subset.

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Summary Interleukin‐23 (IL‐23) plays an essential role in driving intestinal pathology in experimental models of both T‐cell‐dependent and innate colitis. Furthermore, genome‐wide association studies have identified several single‐nucleotide polymorphisms in the IL‐23 receptor (IL‐23R) gene that are associated with either susceptibility or resistance to inflammatory bowel disease in humans. Although initially found to support the expansion and maintenance of CD4+ T helper 17 (Th17) cells, IL‐23 is now recognized as having multiple effects on the immune response, including restraining Foxp3+ regulatory T‐cell activity and inducing the expression of Th17‐type cytokines from non‐T‐cell sources. Here we focus on Th17 cells and their associated cytokines IL‐17A, IL‐17F, IL‐21 and IL‐22. We review studies performed in mouse models of colitis where these effector cytokines have been shown to have either a pathogenic or a tissue‐protective function. We also discuss the heterogeneity found within the Th17 population and the phenomenon of plasticity of Th17 cells, in particular the ability of these lymphocytes to extinguish IL‐17 expression and turn on interferon‐γ production to become Th1‐like ‘ex‐Th17’ cells. Interleukin‐23 has been identified as a key driver in this process, and this may be an additional mechanism by which IL‐23 promotes pathology in the intestinal tract. These ‘ex‐Th17’ cells may contribute to disease pathogenesis through their secretion of pro‐inflammatory mediators.

BackgroundThe persistence of the SARS-CoV2 pandemic, partly due to the appearance of highly infectious variants, has made booster vaccinations necessary for vulnerable groups. Questions remain as to which cohorts require SARS-CoV2 boosters. However, there is a critical lack of data on the dynamics of vaccine responses in patients with chronic inflammatory diseases (CID) undergoing immunosuppressive/disease modifying anti-rheumatic (DMARD) treatment. Here, we present the first data regarding the decline of the vaccine-induced humoral immune responses in patients with CID.Methods23 patients with CID were monitored clinically and for anti-spike IgG and IgA levels, neutralization efficacy and antigen-specific CD4+ T cell responses over the first 6 months after SARS-CoV2 vaccination. 24 healthy individuals were included as controls.ResultsWhile anti-spike IgG-levels declined in CID patients and healthy controls, patients receiving anti-TNF treatment showed significantly greater declines at 6 months post second vaccination in IgG and especially neutralizing antibodies. IgA levels were generally lower in CID patients, particularly during anti-TNF therapy. No differences in SARS-CoV2 spike-specific CD4+ T-cell frequencies were detected.ConclusionAlthough the long-term efficacy of SARS-CoV2 vaccination in CID patients undergoing disease-modifying therapy is still not known, the pronounced declines in humoral responses towards SARS-CoV2 6 months after mRNA vaccination in the context of TNF blockade should be considered when formulating booster regimens. These patients should be considered for early booster vaccinations.

Type 17 helper T-cell cytokines have been implicated in the pathogenesis of inflammatory bowel disease, a chronic condition affecting the gastrointestinal tract, but information regarding their contribution to pathology in different regions of the gut is lacking. By using a murine model of bacteria-induced typhlocolitis, we investigated the role of IL-17A, IL-17F, and IL-22 in cecal versus colonic inflammation. Cecal, but not colonic, pathology in C57BL/6 mice inoculated with Helicobacter hepaticus plus antieIL-10 receptor (IL-10R) monoclonal antibody was exacerbated by co-administration of antieIL-17A monoclonal antibody, suggesting a disease-protective role for IL-17A in the cecum. In contrast, antieIL-17F had no effect on H. hepaticus-induced intestinal pathology. Neutralization of IL-22 prevented the development of colonic, but not cecal, inflammation in H. hepaticus-infected antieIL-10Retreated mice, demonstrating a pathogenic role for IL-22 in the colon. Analysis of transcript levels revealed differential expression of IL-22R, IL-22 binding protein, and IL-23R between cecum and colon, a finding that may help explain why these tissues respond differently after antieIL-22 treatment. Analysis of microarray data from healthy human intestine further revealed significant differences in cytokine receptor transcript levels (including IL-22RA1 and IL-23R) in distinct parts of the human gut. Together, our findings demonstrate that individual type 17 helper T-cell cytokines can have proinflammatory or anti-inflammatory effects in different regions of the intestine, an observation that may have implications for interventions against human inflammatory bowel disease. (Am J Pathol 2015, 185: 3290e3303; http://dx