Could Mucosal TNF Transcript as a Biomarker Candidate Help Optimize Anti-TNF Biological Therapy in Patients With Ulcerative Colitis?

Feedback regulation of VISTA and Treg by TNF-α controls T cell responses in drug allergy

BACKGROUND

Severe cutaneous adverse reactions (SCARs) mediated by cytotoxic T lymphocytes are a series of life-threatening conditions with a mortality of 4%-20%. The clinical application of tumor necrosis factor-alpha (TNF-α) antagonist improves the outcome of some SCARs patients; however, this is complicated by the elusive and varied immunopathogenesis.

AIM

To investigate whether IgE antibody responses to HEMAs are associated with AD, its severity, and response to dupilumab.

METHODS

To clarify the precise process and optimize the therapy regimen of SCARs, we performed single-cell sequencing, in vitro functional and clinical analysis of patients with SCARs.

RESULTS

We observed that TNF-α breaks drug-specific T-cell tolerance by inhibiting the expression of V-type immunoglobulin domain-containing suppressor of T-cell activation (VISTA). Furthermore, TNF-α generated a positive feedback loop in the early phase of drug-specific T-cell activation, whereby B cells acted reciprocally on the corresponding T cells to reinforce TNF-α cytokine expression. In contrast, this pathway of TNF-α-VISTA signaling did not operate in memory effector T cells. Drug-specific memory effector T-cell responses were inhibited by increasing Treg cell expression in a negative feedback loop, with TNF-α antagonists preventing the inhibitory effect. These observations align with the clinical analysis that early but not late intervention with TNF-α antagonists significantly improved outcomes in SCARs patients.

CONCLUSION

Our findings defining feedback regulation of VISTA and Treg cells by TNF-α in different stages of the drug-specific T-cell response and, indicate that a Treg agonists, instead of TNF-α antagonists, could be used for treatment of patients with progressive SCARs.

Cytokine Signatures in Inflamed Mucosa of IBD Patients: State-of-the-Art

The process of development, recurrence, and exacerbation of the inflammatory process depends on the cytokine levels in IBD. For that reason, many cytokine therapies have been developed for treating IBD patients. Researchers employ various techniques and methodologies for cytokine profiling to identify cytokine signatures in inflamed mucosa. These include enzyme-linked immunosorbent assays (ELISA), multiplex immunoassays, flow cytometry, and gene expression analysis techniques (i.e., microarray, RNA-seq, single-cell RNA-seq (scRNA-seq), mass cytometry (CyTOF), Luminex). Research knowledge so far can give us some insights into the cytokine milieu associated with mucosal inflammation by quantifying cytokine levels in mucosal tissues or biological fluids such as serum or stool. The review is aimed at presenting state-of-the-art techniques for cytokine profiling and the various biomarkers for follow-up and treatment.

Inflammatory Bowel Disease Treatments and Predictive Biomarkers of Therapeutic Response

Inflammatory bowel disease (IBD) is a chronic immune-mediated inflammation of the gastrointestinal tract with a highly heterogeneous presentation. It has a relapsing and remitting clinical course that necessitates lifelong monitoring and treatment. Although the availability of a variety of effective therapeutic options including immunomodulators and biologics (such as TNF, CAM inhibitors) has led to a paradigm shift in the treatment outcomes and clinical management of IBD patients, some patients still either fail to respond or lose their responsiveness to therapy over time. Therefore, according to the recent Selecting Therapeutic Targets in Inflammatory Bowel Disease (STRIDE-II) recommendations, continuous disease monitoring from symptomatic relief to endoscopic healing along with short- and long-term therapeutic responses are critical for providing IBD patients with a tailored therapy algorithm. Moreover, considering the high unmet need for novel therapeutic approaches for IBD patients, various new modulators of cytokine signaling events (for example, JAK/TYK inhibitors), inhibitors of cytokines (for example IL-12/IL-23, IL-22, IL-36, and IL-6 inhibitors), anti-adhesion and migration strategies (for example, β7 integrin, sphingosine 1-phosphate receptors, and stem cells), as well as microbial-based therapeutics to decolonize the bed buds (for example, fecal microbiota transplantation and bacterial inhibitors) are currently being evaluated in different phases of controlled clinical trials. This review aims to offer a comprehensive overview of available treatment options and emerging therapeutic approaches for IBD patients. Furthermore, predictive biomarkers for monitoring the therapeutic response to different IBD therapies are also discussed.