Endometriosis is a chronic disease affecting 6-10% of women of reproductive age. It is an important cause of infertility and chronic pelvic pain with poorly understood aetiology. CD8+ T (CD8 T) cells were shown to be linked to infertility and chronic pain and play a significant role in lesion clearance in other pathologies, yet their function in endometriosis is unknown. We systematically evaluated the literature on the CD8 T in peripheral blood and endometriosis-associated tissues to determine the current understanding of their pathophysiological and clinical relevance in the disease and associated conditions (e.g. infertility and pelvic pain).
Four databases were searched (MEDLINE, EMBASE, Web of Science, CINAHL), from database inception until September 2022, for papers written in the English language with database-specific relevant terms/free-text terms from two categories: CD8 T cells and endometriosis. We included peer-reviewed papers investigating CD8 T cells in peripheral blood and endometriosis-associated tissues of patients with surgically confirmed endometriosis between menarche and menopause, and animal models with oestrous cycles. Studies enrolling participants with other gynaecological pathologies (except uterine fibroids and tubal factor infertility used as controls), cancer, immune diseases, or taking immune or hormonal therapy were excluded.
28 published case-control studies and gene set analyses investigating CD8 T cells in endometriosis were included. Data consistently indicate that CD8 T cells are enriched in endometriotic lesions in comparison to eutopic endometrium, with no differences in peripheral blood CD8 T populations between patients and healthy controls. Evidence on CD8 T cells in peritoneal fluid and eutopic endometrium is conflicting. CD8 T cell cytotoxicity was increased in the menstrual effluent of patients, and genomic analyses have shown a clear trend of enriched CD8 T effector memory cells in the eutopic endometrium of patients.
Literature on CD8 T cells in endometriosis-associated tissues is inconsistent. Increased CD8 T levels are found in endometriotic lesions, however, their activation potential is understudied in all relevant tissues. Future research should focus on identifying clinically relevant phenotypes to support the development of non-invasive diagnostic and treatment strategies.
PROSPERO identifier CRD42021233304.

T cells are critical orchestrators of the adaptive immune response that optimally eliminate a specific pathogen. Aberrant T-cell development and function are implicated in a broad range of human disease including immunodeficiencies, autoimmune diseases, and allergic diseases. Accordingly, therapies targeting T cells and their effector cytokines have markedly improved the care of patients with immune dysregulatory diseases. Newer discoveries concerning T-cell-mediated antitumor immunity and T-cell exhaustion have further prompted development of highly effective and novel treatment modalities for malignancies, including checkpoint inhibitors and antigen-reactive T cells. Recent discoveries are also uncovering the depth and variability of T-cell phenotypes: while T cells have long been described using a subset-based classification system, next-generation sequencing technologies suggest an astounding degree of complexity and heterogeneity at the single-cell level.

Colorectal carcinoma is a leading cause of cancer-related death worldwide. There is significant prognostic heterogeneity in stages II and III tumours, necessitating the development of new biomarkers to more clearly identify patients at risk of disease progression. Recently, the tumour immune environment, particularly the type and quantity of T lymphocytes, has been shown to be a useful biomarker in predicting prognosis for patients with colorectal carcinoma. In this review, the significance of the immune response in colorectal carcinoma, including its influence on prognosis and response to therapy, will be detailed.

UNASSIGNED: Many COVID-19 patients reveal a marked decrease in their lymphocyte counts, a condition that translates clinically into immunodepression and is common among these patients. Outcomes for infected patients vary depending on their lymphocytopenia status, especially their T-cell counts. Patients are more likely to recover when lymphocytopenia is resolved. When lymphocytopenia persists, severe complications can develop and often lead to death. Similarly, IL-10 concentration is elevated in severe COVID-19 cases and may be associated with the depression observed in T-cell counts. Accordingly, this systematic review and meta-analysis aims to analyze T-cell subsets and IL-10 levels among COVID-19 patients. Understanding the underlying mechanisms of the immunodepression observed in COVID-19, and its consequences, may enable early identification of disease severity and reduction of overall morbidity and mortality.
UNASSIGNED: A systematic search was conducted covering PubMed MEDLINE, Scopus, Web of Science, and EBSCO databases for journal articles published from December 1, 2019 to March 14, 2021. In addition, we reviewed bibliographies of relevant reviews and the medRxiv preprint server for eligible studies. Our search covered published studies reporting laboratory parameters for T-cell subsets (CD4/CD8) and IL-10 among confirmed COVID-19 patients. Six authors carried out the process of data screening, extraction, and quality assessment independently. The DerSimonian-Laird random-effect model was performed for this meta-analysis, and the standardized mean difference (SMD) and 95% confidence interval (CI) were calculated for each parameter.
UNASSIGNED: A total of 52 studies from 11 countries across 3 continents were included in this study. Compared with mild and survivor COVID-19 cases, severe and non-survivor cases had lower counts of CD4/CD8 T-cells and higher levels of IL-10.
UNASSIGNED: Our findings reveal that the level of CD4/CD8 T-cells and IL-10 are reliable predictors of severity and mortality in COVID-19 patients. The study protocol is registered with the International Prospective Register of Systematic Reviews (PROSPERO); registration number CRD42020218918.
UNASSIGNED: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020218918, identifier: CRD42020218918.

Thanks to the growing knowledge about cancers and their interactions with the immune system, a huge number of therapeutic cancer vaccines have been developed in the past two decades. Despite encouraging results in pre-clinical models, cancer vaccines have not yet achieved significant clinical efficacy. Several factors may contribute to such poor results, including the difficulty of triggering a strong immune response and the immunosuppressive tumor microenvironment. Many strategies are currently being explored. Different types of adjuvants have been incorporated into vaccine formulations to improve their efficacy, as cancer antigens are usually poorly immunogenic. Nanoparticle systems are promising tools as they act as carriers for antigens and can be surface-modified so that they specifically target antigen-presenting cells in lymph nodes. Bioinspired nanomaterials are ideal candidates thanks to their biocompatibility. Recently, melanin-based nanoparticles were reported to efficiently localize into draining lymphoid tissues and trigger immune responses against loaded antigens. In addition, by virtue of their photochemical properties, melanin-based nanoparticles can also play an immunomodulatory role to promote anti-cancer responses in the context of photothermal therapy. In this review, we discuss the above-mentioned properties of melanin, and summarize the promising results of the melanin-based cancer vaccines recently reported in preclinical models.

Infections are most common and most severe at the extremes of age, the young and the elderly. Vaccination can be a key approach to enhance immunogenicity and protection against pathogens in these vulnerable populations, who have a functionally distinct immune system compared to other age groups. More than 50% of the vaccine market is for pediatric use, yet to date vaccine development is often empiric and not tailored to molecular distinctions in innate and adaptive immune activation in early life. With modern vaccine development shifting from whole-cell based vaccines to subunit vaccines also comes the need for formulations that can elicit a CD8+ T cell response when needed, for example, by promoting antigen cross-presentation. While our group and others have identified many cellular and molecular determinants of successful activation of antigen-presenting cells, B cells and CD4+ T cells in early life, much less is known about the ontogeny of CD8+ T cell induction. In this review, we summarize the literature pertaining to the frequency and phenotype of newborn and infant CD8+ T cells, and any evidence of induction of CD8+ T cells by currently licensed pediatric vaccine formulations. In addition, we review the molecular determinants of antigen cross-presentation on MHC I and successful CD8+ T cell induction and discuss potential distinctions that can be made in children. Finally, we discuss recent advances in development of novel adjuvants and provide future directions for basic and translational research in this area.

An expanding number of mind-body therapies are being used to reduce the psychological burden of peoples living with human immunodeficiency virus (HIV). However, the effects on the immune system and mental health varied among studies.
This meta-analysis was conducted to summarize the randomized controlled trials to draw comprehensive conclusions regarding the psycho-immunological efficacy.
Random-effects models were used to assess the outcome of interest. Egger\'s tests were used to identify publication bias. Subgroup and meta-regression were used to explore potential moderators. This review was registered on the PROSPERO database (CRD42019148118).
Nineteen randomized controlled trials with a total sample size of 1,300 were included in this meta-analysis. Regarding immune system outcome, mind-body therapy significantly improved CD4 T-cell counts (Cohen\'s d = 0.214, p = .027) and maintained (0.427, p = .049). In addition, baseline CD4 T-cell counts and years since HIV diagnosis significantly moderated the efficacy of mind-body practices on CD4 improvement (all ps < .001). Regarding mental health outcome, mind-body therapy significantly reduced stress, depression, and anxiety symptoms (0.422, p < .001; 0.506, p < .001, and 0.709, p < .001, respectively) while improving quality of life (0.67, p < .001).
Meditation/yoga intervention could result in potential benefits with regard to improved CD4 T-cell counts immediately after the intervention and at long-term follow-up, while also improving their mental health. The cost-effective meditation/yoga intervention should be integrated into routine care for people living with HIV, especially for those with lower CD4 baseline and fewer years since diagnosis.

For several years, it was believed that the thymus was entirely responsible for maintaining T cell homeostasis. Today, it is well-known that homeostatic peripheral mechanisms are essential in order to maintain T cell numbers and diversity constant in the periphery. Naïve and memory T cells require continual access to self-peptide MHC class I and II molecules and/or cytokines to survive in the periphery. Under normal conditions, homeostatic resources are low, and lymphocytes undergo very slow proliferation and survive. Following T cell depletion, the bioavailability of homeostatic resources is significantly increased, and T cell proliferation is dramatically augmented. The development of lymphopenic mouse models has helped our current understanding of factors involved in the regulation of peripheral T cell homeostasis. In this minireview, we will give a brief overview about basic techniques used to study peripheral T cell homeostasis in mice.

Primary cutaneous γδ T-cell lymphoma (CGD-TCL) is a rare form of primary cutaneous lymphoma. The histopathological features of CGD-TCL are still unclear because of its rarity. Here, we report a case of a 77-year-old Japanese man who presented with a 9-month history of erythematous plaques on his left forearm. Skin biopsy specimens revealed the infiltration of atypical medium/large-sized lymphocytes from the epidermis to the deep dermis. Atypical lymphocytes were positive for CD3, CD5, CD8 and Vδ1, and negative for CD4, CD7, CD56, EBER-ISH, intracellular antigen-1, granzyme B and perforin. CD30 was partially expressed. We also reviewed 246 cases of CGD-TCL from the published work. CD4- CD8- double-negative cases were 113 of 196 cases (57.6%), followed by CD4- CD8+ cases (52/196, 26.5%). CD5 was expressed in 25.8% of the cases (34/132). At least one cytotoxic molecule marker was expressed in 150 of 160 cases (93.8%). Some cases showed an indolent clinical course, especially in mycosis fungoides-like CGD-TCL cases. CD5 positivity and lack of cytotoxic molecule expression could be associated with a better prognosis. In addition, CD30 expression was found in approximately half of CGD-TCL cases (51/112 cases), suggesting that brentuximab vedotin could be a good treatment option for such patients. Further studies with more cases with detailed clinical and pathological information are necessary to elucidate the etiology and prognostic markers of this entity.

This report summarizes the discussions and conclusions from the \"Immunological Assays and Correlates of Protection for Next-Generation Influenza Vaccines\" meeting which took place in Siena, Italy, from March 31, 2019, to April 2, 2019.
Furthermore, we review current correlates of protection against influenza virus infection and disease and their usefulness for the development of next generation broadly protective and universal influenza virus vaccines.