T-Cell Exhaustion (Other (Not Listed) Sample)

T-Cell Exhaustion Abstract Background: T cell function in the immune system makes it a critical subject in the medical field. It mediates adaptive immune response, which is crucial in fighting antigens and chronic infections. However, T cell exhaustion limits its capacity to bind and destroy foreign substances in the body.   Aims: This report provides insights into the connection between T cell exhaustion and chronic diseases. It also articulates the role of T cell exhaustion in chronic inflammation. The paper contributes to the body of knowledge on T cell exhaustion.  Materials and methods:  This study is subject to a systematic review of recent findings on T cell exhaustion. 40 articles published within the past decade 2021 [ n=6], 2020 [ n=8], 2019 [ n=8], 2018 [ n=4], 2017 [ n=3], 2016 [ n=2], 2015 [ n=7], and 2014[ n=2] were explored. The review identified themes and patterns that resonated with the research subject.   Results: The findings indicate a connection between T cell exhaustion, chronic illnesses, and inflammation. T cell exhaustion is subject to prolonged antigen stimulation due to chronic infections. Furthermore, T cell’s Th1 subset mediates autoimmune diseases and, therefore, exacerbates vascular inflammations when the lymphocytes dysfunction.  Discussion: The articles resonate with the study subject since they indicate that T cell exhaustion plays a central role in chronic diseases and inflammations. T cell exhaustion results from pathogen overload due to chronic infections causing persistent antigen-specific stimulation.  Conclusion: Immunology experts agree that T cell exhaustion contributes to the exacerbation of chronic illnesses. The prolonged exposure to antigens causes T cell hyporesponsiveness, which limits the lymphocytes’ pathogen clearance capabilities.  Introduction Also known as lymphocytes, T cells are white blood cells that originate from the bone marrow and proliferate in the thymus. They play a pivotal role in the adaptive immune response [1-6].In this lymphatic gland, T cells differentiate into memory, regulatory, and cytotoxic T lymphocytes. The evolved T cells operate in the peripheral tissues and the blood or lymphatic systems. Here, they play an integral role in the adaptive immune response. Cytotoxic T lymphocytes respond to specific antigens and kill virally infected cells. Also known as helper T cells, regulatory T cells are vital in activating other immune responses [2-4], [5], [6]. According to Amezquita and Kaech [1] helper T cells also release cytokines, and stimulate B cells to produce antibodies. Memory T cells, on the other hand, are long-lived antigen-specific lymphocytes that develop after an infection. They retain memories against previously encountered antigens activating the immune system upon re-exposure. T cell exhaustion occurs due to the progressive loss of lymphocytes' effector function due to prolonged exposure to antigens [3], [4], [7]. It is a common dysfunction synonymous with chronic infections and cancer [8], [9-11].This report outlines the role of T-cell exhaustion in chronic diseases and chronic inflammation based on a systematic review of articles published over the last decade. The manuscript summarizes what experts know so far concerning the relationship between T cell exhaustion and chronic illnesses. Material and methods This paper summarizes studies providing insights into the connection between chronic diseases, chronic inflammation, and T-cell exhaustion. Choosing articles that would answer the research question was essential to obtaining viable evidence. PubMed was the primary database for this review; it contains reliable medical sources. It entailed searching the terms T-cell exhaustion, chronic inflammation, chronic diseases, and a combination of these phrases. The results provided 116 studies conducted to understand the role of T cells in chronic illnesses. The next phase entailed examining the articles to select those that aligned with the research topic. In this regard, the inclusion and exclusion criterion was used as part of the search strategy. The review included articles published in the last ten years, written in English, peer-reviewed, and focusing on T cell exhaustion. It excluded studies that paid attention to T cell function, lymphocyte therapy, and B cells. In addition, the search strategy eliminated reports issued more than ten years ago. Reading every source's abstract, introduction, and conclusion was crucial to ensure that the review explored the most appropriate studies. Furthermore, establishing the author's credibility on the subject was vital. These steps helped identify 40 relevant, timely, credible, and accurate sources essential in answering the research question. Results The applied search strategy was vital in identifying articles that resonate with the research subject. The timeliness of the chosen articles was crucial given that the oldest report was published in 2014 while the most recent was issued last year. Six sources were produced in 2021, eight in 2020, eight in 2019, four in 2018, three in 2017, two in 2016, seven in 2015, and two in 2014. Their relevance is up to par since 29 of the 40 articles were published in the last five years. Most of these studies were issued in immunology journals, which augment their credibility and reliability. 48% of the studies (19 out of 40) focused on T cell exhaustion as it relates to immunity. Seven articles highlighted the lymphocytes' role in cancer development, while three articulated T cell exhaustion in relation to cell death and disease. The rest of the reports (11) were issued in the Nature and Nature communications journals, highly regarded publishers of natural science research. The 40 studies align with the research subject since they provide insights into the connection between chronic diseases and T cell exhaustion. 95% of the studies (38 out of 40) focus on T cell exhaustion and the elements exacerbating its occurrence. Cancer is a notable chronic illness associated with the illness; it accounts for 25% (10 studies) of the articles used in this review. Covid-19, tumor, tuberculosis, old age, and obesity also contribute to T cell exhaustion. Nine studies are based on primary research, while 31 are subject to recent findings in T cell biology. Therefore, qualitative research accounts for 78% of the literature used in this review. Three articles use randomized clinical trials, four utilized controlled experiments, and two applied quantitative research techniques. The data collection and analysis techniques used in the selected studies augment their accuracy and relevance. They provide in-depth information from an array of sources, thus eliminating bias. The combination of primary and secondary data underpins the articles’ reliability and credibility.     The systematic review provided several notable concepts in relation to what experts know so far regarding the role of T cell exhaustion in chronic diseases and inflammations. As mentioned earlier, T cells proliferate into regulatory, cytotoxic, and memory lymphocytes [10-12]. They play a critical role in responding to antigens as each carries different receptors. The helper T cells are especially vital in differentiating B cells into the antibody-producing nucleus [13-19], [20], [21]. In retrospect, the T cells determine the specificity of the body’s response to foreign substances. They, therefore, protect the body from infections and help fight cancer. One of the most notable functions of the lymphocytes is directly killing infected host cells [14- 16], [17], [18], [19-23]. The cytotoxic T cells secrete cytokines that bind to and destroy cancer cells. Helper T cells are vital in activating other immune cells, thus ensuring the body adapts appropriately to the antigen in question. On the other hand, the regulatory T cells keep the immune response in check ensuring there is optimal antigen specific reaction to pathogens [17, 20]. Scholars agree that T-cell exhaustion limits the body’s ability to counter chronic conditions [15-19], [20], [21-26]. It leaves the body susceptible to multiple infections since the adaptive immune response is compromised [16-21], [22-24]. However, contemporary techniques of reinvigorating immunity outline viable approaches to revitalizing T cells.  T cell exhaustion contributes to sustained inflammations. They produce proinflammatory cytokines in response to the up-regulation of inflammatory reactions. The T cells activate macrophages which secret IL-1β, IL-6, and TNF-α cytokines, critical elements of pathological pain [17-19]. In this process, the role of synovial CD8+ T cells is crucial; they contain significant frequencies of IFN-γ producing effector cells that are alert to inflammatory antigen invasion [8], [18], [19], [20]. The T cells secrete immunoregulatory cytokines in response to the infectious antigens. These antibodies amplify the inflammation as the lymphocytes activate immune responses to counter the infection [21], [22]. Other studies indicate that T cells are central mediators of vascular inflammation, as seen in their response to autoimmune diseases [23-28], [29], [30]. They posit that T cell dysfunction promotes autoimmunity-associated cardiovascular diseases. It is vital to note that once CD4 T cells get activated with antigen-specific, they differentiate into theTh1 or Th2 subset. The Th1 is crucial in cellular immunity and, therefore, involved in autoimmune diseases [24], [25]. Conversely, Th2 cells respond to allergic reactions as they mediate humoral immunity [26], [27]. Therefore, the Th1 subset of the T cells promotes vascular inflammation due to their cellular activity.  Chronic infections such as cancer, tuberculosis, and Covid-19 overload pathogens in the body. The increase in foreign substances causes an equal response from the adaptive immune response [28], [29]. The T cells swing into full ge...