Newly recruited intraepithelial Ly6A+CCR9+CD4+ T cells protect against enteric viral infection.

The intestinal epithelium comprises the body's largest surface exposed to viruses. Additionally, the gut epithelium hosts a large population of intraepithelial T lymphocytes, or IELs, although their role in resistance against viral infections remains elusive. By fate-mapping T cells recruited to the murine intestine, we observed an accumulation of newly recruited CD4+ T cells after infection with murine norovirus CR6 and adenovirus type-2 (AdV), but not reovirus. CR6- and AdV-recruited intraepithelial CD4+ T cells co-expressed Ly6A and chemokine receptor CCR9, exhibited T helper 1 and cytotoxic profiles, and conferred protection against AdV in vivo and in an organoid model in an IFN-γ-dependent manner. Ablation of the T cell receptor (TCR) or the transcription factor ThPOK in CD4+ T cells prior to AdV infection prevented viral control, while TCR ablation during infection did not impact viral clearance. These results uncover a protective role for intraepithelial Ly6A+CCR9+CD4+ T cells against enteric adenovirus.

Compartmentalized gut lymph node drainage dictates adaptive immune responses.

The intestinal immune system has the challenging task of tolerating foreign nutrients and the commensal microbiome, while excluding or eliminating ingested pathogens. Failure of this balance leads to conditions such as inflammatory bowel diseases, food allergies and invasive gastrointestinal infections1. Multiple immune mechanisms are therefore in place to maintain tissue integrity, including balanced generation of effector T (TH) cells and FOXP3+ regulatory T (pTreg) cells, which mediate resistance to pathogens and regulate excessive immune activation, respectively1-4. The gut-draining lymph nodes (gLNs) are key sites for orchestrating adaptive immunity to luminal perturbations5-7. However, it is unclear how they simultaneously support tolerogenic and inflammatory reactions. Here we show that gLNs are immunologically specific to the functional gut segment that they drain. Stromal and dendritic cell gene signatures and polarization of T cells against the same luminal antigen differ between gLNs, with the proximal small intestine-draining gLNs preferentially giving rise to tolerogenic responses and the distal gLNs to pro-inflammatory T cell responses. This segregation permitted the targeting of distal gLNs for vaccination and the maintenance of duodenal pTreg cell induction during colonic infection. Conversely, the compartmentalized dichotomy was perturbed by surgical removal of select distal gLNs and duodenal infection, with effects on both lymphoid organ and tissue immune responses. Our findings reveal that the conflict between tolerogenic and inflammatory intestinal responses is in part resolved by discrete gLN drainage, and encourage antigen targeting to specific gut segments for therapeutic immune modulation.

[Insulin autoimmune syndrome : A rare, but important differential diagnosis of hypoglycemia]. / Insulinautoimmunsyndrom : Eine seltene, aber wichtige Differentialdiagnose der Hypoglykämie.

A 69-year-old female patient was referred to the Medical University of Hanover for further diagnostic evaluation of recurrent severe hypoglycemia. The patient had previously been started on clopidogrel after arterial stenting for peripheral arterial obstructive disease (PAOD). The presence of an insulinoma and paraneoplastic syndrome was excluded. Increased serum insulin and insulin autoantibodies levels were confirmed, despite normal to low blood sugar levels. An insulin autoimmune syndrome was diagnosed, most likely induced by the prior intake of clopidogrel. Treatment with immunoadsorption was initiated, achieving a significant reduction in hypoglycemic events and a lasting response to treatment over 3 months.

[Best supportive care in a young patient with locally advanced MSI-high colon cancer?] / Best supportive care bei einer jungen Patientin mit lokal fortgeschrittenem MSI-high-Kolonkarzinom?

Molecular diagnostics are increasingly important to guide treatment decisions in oncologic patients. For instance, the presence of high-grade microsatellite-instability (MSI-high) is considered to be one of the major positive predictors of therapy response to immune-checkpoint inhibitors in patients with solid tumors. Based on impressive results from several immune-oncology trials, the American Food and Drug Administration (FDA) granted approval to immunotherapy in any previously treated, MSI-high solid cancer in 2017. Here, we report the clinical case of a young patient with MSI-high colorectal cancer. The case illustrates, that insurance companies in Germany are still reluctant to cover the cost of immunotherapy in this specific patient subgroup, which, in our opinion, results in an ethically problematic therapeutic dilemma.

Dietary protein shapes the profile and repertoire of intestinal CD4 + T cells.

The intestinal immune system must tolerate food antigens to avoid allergy, a process requiring CD4 + T cells. Combining antigenically defined diets with gnotobiotic models, we show that food and microbiota distinctly influence the profile and T cell receptor repertoire of intestinal CD4 + T cells. Independent of the microbiota, dietary proteins contributed to accumulation and clonal selection of antigen-experienced CD4 + T cells at the intestinal epithelium, imprinting a tissue specialized transcriptional program including cytotoxic genes on both conventional and regulatory CD4 + T cells (Tregs). This steady state CD4 + T cell response to food was disrupted by inflammatory challenge, and protection against food allergy in this context was associated with Treg clonal expansion and decreased pro-inflammatory gene expression. Finally, we identified both steady state epithelium-adapted CD4 + T cells and tolerance-induced Tregs that recognize dietary antigens, suggesting that both cell types may be critical for preventing inappropriate immune responses to food.

Dietary protein shapes the profile and repertoire of intestinal CD4+ T cells.

The intestinal immune system must tolerate food antigens to avoid allergy, a process requiring CD4+ T cells. Combining antigenically defined diets with gnotobiotic models, we show that food and microbiota distinctly influence the profile and T cell receptor repertoire of intestinal CD4+ T cells. Independent of the microbiota, dietary proteins contributed to accumulation and clonal selection of antigen-experienced CD4+ T cells at the intestinal epithelium, imprinting a tissue-specialized transcriptional program including cytotoxic genes on both conventional and regulatory CD4+ T cells (Tregs). This steady state CD4+ T cell response to food was disrupted by inflammatory challenge, and protection against food allergy in this context was associated with Treg clonal expansion and decreased proinflammatory gene expression. Finally, we identified both steady-state epithelium-adapted CD4+ T cells and tolerance-induced Tregs that recognize dietary antigens, suggesting that both cell types may be critical for preventing inappropriate immune responses to food.

Immune Checkpoint Inhibitors for Child-Pugh Class B Advanced Hepatocellular Carcinoma: A Systematic Review and Meta-Analysis.

Importance: Immune checkpoint inhibitors (ICIs) are increasingly used in patients with advanced hepatocellular carcinoma (HCC). However, data on ICI therapy in patients with advanced HCC and impaired liver function are scarce. Objective: To conduct a systematic review and meta-analysis to determine the efficacy and safety of ICI treatment for advanced HCC with Child-Pugh B liver function. Data Sources: PubMed, Embase, Web of Science, and Cochrane Library were searched for relevant studies from inception through June 15, 2022. Study Selection: Randomized clinical trials, cohort studies, or single-group studies that investigated the efficacy or safety of ICI therapy for Child-Pugh B advanced HCC were included. Data Extraction and Synthesis: The Preferred Reporting Items for Systematic Reviews and Meta-Analysis guideline was followed to extract data. A random-effects model was adopted if the heterogeneity was significant (I2 > 50%); otherwise, a fixed-effect model was used. Main Outcomes and Measures: The objective response rate (ORR) and overall survival (OS) were considered to be the primary efficacy outcomes of ICI treatment for Child-Pugh B advanced HCC, and the incidence of treatment-related adverse events (trAEs) was set as the primary measure for the safety outcome. Results: A total of 22 studies including 699 patients with Child-Pugh B and 2114 with Child-Pugh A advanced HCC comprised the analytic sample (median age range, 53-73 years). Upon pooled analysis, patients treated with ICIs in the Child-Pugh B group had an ORR of 14% (95% CI, 11%-17%) and disease control rate (DCR) of 46% (95% CI, 36%-56%), with a median OS of 5.49 (95% CI, 3.57-7.42) months and median progression-free survival of 2.68 (95% CI, 1.85-3.52) months. The rate of any grade trAEs in the Child-Pugh B group was 40% (95% CI, 34%-47%) and of grade 3 or higher trAEs was 12% (95% CI, 6%-23%). Compared with the Child-Pugh A group, the ORR (odds ratio, 0.59; 95% CI, 0.43-0.81; P < .001) and DCR (odds ratio, 0.64; 95% CI, 0.50-0.81; P < .001) were lower in the Child-Pugh B group. Child-Pugh B was independently associated with worse OS in patients with advanced HCC treated with ICIs (hazard ratio, 2.72 [95% CI, 2.34-3.16]; adjusted hazard ratio, 2.33 [95% CI, 1.81-2.99]). However, ICIs were not associated with increased trAEs in the Child-Pugh B group. Conclusions and Relevance: The findings of this systematic review and meta-analysis suggest that although the safety of ICI treatment was comparable between patients with HCC with vs without advanced liver disease and the treatment resulted in a significant number of radiologic responses, survival outcomes are still inferior in patients with worse liver function. More study is needed to determine the effectiveness of ICI treatment in this population.

Atezolizumab and bevacizumab in patients with advanced hepatocellular carcinoma with impaired liver function and prior systemic therapy: a real-world experience.

Objective: Evaluation of the efficacy and safety of atezolizumab/bevacizumab in a real-world HCC cohort, including patients with impaired liver function and prior systemic therapy. Methods: Retrospective analysis of 147 HCC patients treated with atezolizumab/bevacizumab at six sites in Germany and Austria. Results: The overall response rate and disease control rate were 20.4% and 51.7%, respectively. Seventy-three patients (49.7%) met at least one major exclusion criterion of the IMbrave150 trial (IMbrave-OUT), whereas 74 patients (50.3%) were eligible (IMbrave-IN). Median overall survival (mOS) as well as median progression-free survival (mPFS) was significantly longer in IMbrave-IN versus IMbrave-OUT patients [mOS: 15.0 months (95% confidence interval (CI): 10.7-19.3] versus 6.0 months (95% CI: 3.2-8.9; p < 0.001) and mPFS: 8.7 months (95% CI: 5.9-11.5) versus 3.7 months (95% CI: 2.7-4.7; p < 0.001)]. Prior systemic treatment did not significantly affect mOS [hazard ratio (HR): 1.32 (95% CI: 0.78-2.23; p = 0.305)]. mOS according to ALBI grades 1/2/3 were 15.0 months (95% CI: not estimable), 8.6 months (95% CI: 5.4-11.7), and 3.2 months (95% CI: 0.3-6.1), respectively. ALBI grade and ECOG score were identified as independent prognostic factors [ALBI grade 2 versus 1; HR: 2.40 (95% CI: 1.34 - 4.30; p = 0.003), ALBI grade 3 versus 1; HR: 7.28 (95% CI: 3.30-16.08; p < 0.001), and ECOG ⩾2 versus 0; HR: 2.09 (95% CI: 1.03 - 4.23; p = 0.042)], respectively. Sixty-seven patients (45.6%) experienced an adverse event classified as CTCAE grade ⩾3. Patients in the IMbrave-OUT group were at increased risk of hepatic decompensation with encephalopathy (13.7% versus 1.4%, p = 0.004) and/or ascites (39.7% versus 9.5%; p < 0.001). Conclusion: In this real-world cohort, efficacy was comparable to the results of the IMbrave150 study and not affected by prior systemic treatment. ALBI grade and ECOG score were independently associated with survival. IMbrave-OUT patients were more likely to experience hepatic decompensation.

A conserved Bacteroidetes antigen induces anti-inflammatory intestinal T lymphocytes.

The microbiome contributes to the development and maturation of the immune system. In response to commensal bacteria, intestinal CD4+ T lymphocytes differentiate into functional subtypes with regulatory or effector functions. The development of small intestine intraepithelial lymphocytes that coexpress CD4 and CD8αα homodimers (CD4IELs) depends on the microbiota. However, the identity of the microbial antigens recognized by CD4+ T cells that can differentiate into CD4IELs remains unknown. We identified ß-hexosaminidase, a conserved enzyme across commensals of the Bacteroidetes phylum, as a driver of CD4IEL differentiation. In a mouse model of colitis, ß-hexosaminidase-specific lymphocytes protected against intestinal inflammation. Thus, T cells of a single specificity can recognize a variety of abundant commensals and elicit a regulatory immune response at the intestinal mucosa.

Differential Modulation of Mouse Heart Gene Expression by Infection With Two Trypanosoma cruzi Strains: A Transcriptome Analysis.

The protozoan Trypanosoma cruzi (T. cruzi) is a well-adapted parasite to mammalian hosts and the pathogen of Chagas disease in humans. As both host and T. cruzi are highly genetically diverse, many variables come into play during infection, making disease outcomes difficult to predict. One important challenge in the field of Chagas disease research is determining the main factors leading to parasite establishment in the chronic stage in some organs, mainly the heart and/or digestive system. Our group previously showed that distinct strains of T. cruzi (JG and Col1.7G2) acquired differential tissue distribution in the chronic stage in dually infected BALB/c mice. To investigate changes in the host triggered by the two distinct T. cruzi strains, we assessed the gene expression profiles of BALB/c mouse hearts infected with either JG, Col1.7G2 or an equivalent mixture of both parasites during the initial phase of infection. This study demonstrates the clear differences in modulation of host gene expression by both parasites. Col1.7G2 strongly activated Th1-polarized immune signature genes, whereas JG caused only minor activation of the host immune response. Moreover, JG strongly reduced the expression of genes encoding ribosomal proteins and mitochondrial proteins related to the electron transport chain. Interestingly, the evaluation of gene expression in mice inoculated with a mixture of the parasites produced expression profiles with both up- and downregulated genes, indicating the coexistence of both parasite strains in the heart during the acute phase. This study suggests that different strains of T. cruzi may be distinguished by their efficiency in activating the immune system, modulating host energy metabolism and reactive oxygen species production and decreasing protein synthesis during early infection, which may be crucial for parasite persistence in specific organs.