IL-21 plays an important role in modulating “Th17-Treg” cell axis in leprosy Type 1 reactions

The role of Interleukin-21 in autoimmune Diseases: Mechanisms, therapeutic Implications, and future directions

IL-21 is a multifunctional cytokine that regulates the functional activity of various immune cells. Initial studies have shown that IL-21 can influence the differentiation, proliferation and function of T and B cells, as well as promote the maturation and increase the cytotoxicity of CD8 + T cells and NK cells. During humoral immune responses, IL-21 has significant effects on B cell activation, differentiation and apoptosis. In addition, IL-21 promotes the differentiation of both naive and memory B cells, ultimately leading to the activation of plasma cells. The function of IL-21 in the immune system is complex, as it has the ability to either stimulate or inhibit immune responses. in addition, IL-21 facilitates the differentiation of naive and memory B cells into plasma cells. The functionality of IL-21 in the immune system is diverse, as it has the ability to stimulate or inhibit immune responses. This cytokine has been implicated in several diseases including cancer, allergies and autoimmune diseases. Research has suggested that this cytokine is involved in the development of autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis. Several studies have suggested that inhibition of IL-21 has a therapeutic effect on autoimmune diseases. Therefore, targeting both the cytokine's receptor and IL-21 in autoimmune diseases may be an effective approach to reduce the severity of the disease or to treat it. This review will examine the biological effects of IL-21 on various immune cells and the role of the cytokine in autoimmune diseases.

Th17 Cells and Cytokines in Leprosy: Understanding the Immune Response and Polarization

While there are conflicting data concerning interleukin (IL)-17 levels in the serum of patients with leprosy compared with those in healthy controls, higher levels have been more evident in the tuberculoid clinical form of leprosy and type 1 reactions. This review aimed to highlight the role of Th17 cells and their cytokines in leprosy. Cytokines such as IL-1β and IL-23 induce Th17, while transforming growth factor beta and IL-10 inhibit Th17, indicating that the balance between Th17 and regulatory T cells is crucial for leprosy polarization. However, more comprehensive paired studies are required to better elucidate the role of Th17 cells in leprosy.

Interleukin-21 modulates balance between regulatory T cells and T-helper 17 cells in chronic hepatitis B virus infection

BACKGROUND

Chronic HBV infection is always accompanied by differences in the balance between regulatory T cells (Tregs) and T-helper 17 (Th17) cells in infection phases. IL-21 plays an important role in the progression of chronic HBV infection. Thus, the aim of our study was to investigate the role of the regulatory function of IL-21 in maintaining the balance between Tregs and Th17 cells in chronic HBV infection.

METHODS

Twenty-five chronic HBV-infected patients in the immune-tolerant (IT) phase and 23 chronic hepatitis B (CHB) patients were recruited in this study. Cytokines production was measured by ELISA. The mRNA expression levels were determined by qPCR. CD4+T cells were stimulated with or without IL-21. Tregs and Th17 cells were measured by flow cytometry. pSTAT3 and STAT3 expression was assessed by Western blotting.

RESULTS

The concentration of IL-21 in the serum of CHB were significantly higher than that in the serum from IT patients, and IL-21 and IL-21R levels in the PBMCs from CHB were higher than those from IT patients. IL-21 promoted Th17 cells differentiation and function but inhibited Treg cells differentiation and function by activating STAT3 signaling pathways, upregulating RORγt expression, downregulating Foxp3 expression, by increasing IL-17and IL-22 secretion, and decreasing TGF-β secretion in chronic HBV infection. The proportion of Tregs and TGF-β concentrations in CHB was significantly lower than that in IT patients. Furthermore, the percentage of Th17 cells and the IL-17 concentration in CHB was markedly higher than that in IT patients, causing a reduction in the Tregs/Th17 ratio in CHB patients.

CONCLUSIONS

Our results suggest that IL-21 may contribute to inflammation in chronic HBV infection by modulating the balance between Treg and Th17 cells.

Risk of candidiasis associated with interleukin-17 inhibitors: Implications and management

The application of interleukin-17 (IL-17) inhibitors, including secukinumab, ixekizumab, brodalumab, and bimekizumab, are associated with elevated risk of candidiasis. These medications interfere with the IL-17 pathway, which is essential for maintaining mucosal barriers and coordinating the immune response against Candida species. The observational data and clinical trials demonstrate the increased incidence of candidiasis in individuals treated with IL-17 inhibitors. Brodalumab and bimekizumab pose a greater risk than secukinumab in eliciting candidiasis, whereas the data regarding ixekizumab are equivocal. Higher doses and prolonged treatment duration of IL-17 inhibitors increase the risk of candidiasis by compromising the immune response against Candida species. Prior to prescribing IL-17 inhibitors, healthcare professionals should comprehensively evaluate patients' medical histories and assess their risk factors. Patients should be educated on the signs and symptoms of candidiasis to facilitate early detection and intervention. Future research should focus on identifying the risk factors associated with candidiasis in patients receiving IL-17 inhibitors. Prospective studies and long-term surveillance are required to explore the impact of specific inhibitors on the incidence and severity of candidiasis and to evaluate the effectiveness of combination therapies, such as concurrent use of IL-17 inhibitors and prophylactic antifungal agents.

Where do T cell subsets stand in SARS-CoV-2 infection: an update

An outbreak of coronavirus disease 2019 (COVID-19) emerged in China in December 2019 and spread so rapidly all around the globe. It’s continued and spreading more dangerously in India and Brazil with higher mortality rate. Understanding of the pathophysiology of COVID-19 depends on unraveling of interactional mechanism of SARS-CoV-2 and human immune response. The immune response is a complex process, which can be better understood by understanding the immunological response and pathological mechanisms of COVID-19, which will provide new treatments, increase treatment efficacy, and decrease mortality associated with the disease. In this review we present a amalgamate viewpoint based on the current available knowledge on COVID-19 which includes entry of the virus and multiplication of virus, its pathological effects on the cellular level, immunological reaction, systemic and organ presentation. T cells play a crucial role in controlling and clearing viral infections. Several studies have now shown that the severity of the COVID-19 disease is inversely correlated with the magnitude of the T cell response. Understanding SARS-CoV-2 T cell responses is of high interest because T cells are attractive vaccine targets and could help reduce COVID-19 severity. Even though there is a significant amount of literature regarding SARS-CoV-2, there are still very few studies focused on understanding the T cell response to this novel virus. Nevertheless, a majority of these studies focused on peripheral blood CD4+ and CD8+ T cells that were specific for viruses. The focus of this review is on different subtypes of T cell responses in COVID-19 patients, Th17, follicular helper T (TFH), regulatory T (Treg) cells, and less classical, invariant T cell populations, such as δγ T cells and mucosal-associated invariant T (MAIT) cells etc that could influence disease outcome.