Gammadelta T-cells alterations in the peripheral blood of high risk diabetes type 1 subjects with subclinical pancreatic B-cells impairment

γδ T cells: origin and fate, subsets, diseases and immunotherapy

The intricacy of diseases, shaped by intrinsic processes like immune system exhaustion and hyperactivation, highlights the potential of immune renormalization as a promising strategy in disease treatment. In recent years, our primary focus has centered on γδ T cell-based immunotherapy, particularly pioneering the use of allogeneic Vδ2+ γδ T cells for treating late-stage solid tumors and tuberculosis patients. However, we recognize untapped potential and optimization opportunities to fully harness γδ T cell effector functions in immunotherapy. This review aims to thoroughly examine γδ T cell immunology and its role in diseases. Initially, we elucidate functional differences between γδ T cells and their αβ T cell counterparts. We also provide an overview of major milestones in γδ T cell research since their discovery in 1984. Furthermore, we delve into the intricate biological processes governing their origin, development, fate decisions, and T cell receptor (TCR) rearrangement within the thymus. By examining the mechanisms underlying the anti-tumor functions of distinct γδ T cell subtypes based on γδTCR structure or cytokine release, we emphasize the importance of accurate subtyping in understanding γδ T cell function. We also explore the microenvironment-dependent functions of γδ T cell subsets, particularly in infectious diseases, autoimmune conditions, hematological malignancies, and solid tumors. Finally, we propose future strategies for utilizing allogeneic γδ T cells in tumor immunotherapy. Through this comprehensive review, we aim to provide readers with a holistic understanding of the molecular fundamentals and translational research frontiers of γδ T cells, ultimately contributing to further advancements in harnessing the therapeutic potential of γδ T cells.

A Distinctive γδ T Cell Repertoire in NOD Mice Weakens Immune Regulation and Favors Diabetic Disease

Previous studies in mice and humans suggesting that γδ T cells play a role in the development of type 1 diabetes have been inconsistent and contradictory. We attempted to resolve this for the type 1 diabetes-prone NOD mice by characterizing their γδ T cell populations, and by investigating the functional contributions of particular γδ T cells subsets, using Vγ-gene targeted NOD mice. We found evidence that NOD Vγ4+ γδ T cells inhibit the development of diabetes, and that the process by which they do so involves IL-17 production and/or promotion of regulatory CD4+ αβ T cells (Tregs) in the pancreatic lymph nodes. In contrast, the NOD Vγ1+ cells promote diabetes development. Enhanced Vγ1+ cell numbers in NOD mice, in particular those biased to produce IFNγ, appear to favor diabetic disease. Within NOD mice deficient in particular γδ T cell subsets, we noted that changes in the abundance of non-targeted T cell types also occurred, which varied depending upon the γδ T cells that were missing. Our results indicate that while certain γδ T cell subsets inhibit the development of spontaneous type 1 diabetes, others exacerbate it, and they may do so via mechanisms that include altering the levels of other T cells.

Effect of photopheresis on lymphocyte population in children with newly diagnosed type 1 diabetes

In recent years photopheresis has been claimed to be an effective form of immunomodulation. It has also been shown to have an effect on the disease process at the onset of type 1 diabetes. In a double-blind, placebo-controlled randomized study, we analyzed if the effect of photopheresis in children with newly diagnosed diabetes is related to changes in the balance of lymhocyte populations. We also analyzed if lymphocyte subsets were related to recent infection, mild or aggressive disease manifestations, heredity, or gender. Nineteen children received active treatment with photopheresis, while 21 children received sham pheresis (placebo group). No influence of a history of previous infection, heredity, or certain clinical parameters on lymphocyte subsets was found. At the onset of type 1 diabetes, girls showed a higher proportion and a larger number of T cells (CD3+) and T-helper cells (CD4+) and a higher proportion of naïve CD4+ CD45RA+ cells. In the placebo group, an increase in the number of subsets with the activated phenotype in both the CD4(CD29+) and the CD8 (CD11a+) compartments was noted during the course of the study. These changes did not occur in the photopheresis group. No relation between lymphocyte subsets and clinical outcome was found 1 year after the treatment with photopheresis. In conclusion, we found no major effect of photopheresis on lymphocyte populations in a group of children with newly diagnosed type 1 diabetes. However, in the placebo group the proportions of activated CD4 and CD8 cells increased over time. Since these changes did not occur in the actively treated group, our findings suggest that photopheresis may have some suppressive effects.

CD3 bright lymphocyte population reveal ?? T cells

BACKGROUND

In routine CD3/CD4/CD8 T-cell analysis, a CD3 bright population of lymphocytes is frequently observed. The aim of the present study was to identify the immunological significance of such CD3 bright lymphocytes.

METHODS

We analyzed samples from 31 healthy adult volunteers, 78 human immunodeficiency virus (HIV)-positive, and 78 renal transplanted patients.

RESULTS

A clearly distinct CD3 bright (frequently CD4-/CD8-) T-cell fraction was observed in 84% of donors and was directly correlated with the fraction of gammadelta T cells (r2 = 0.64). CD3 overexpression on gammadelta T cells was confirmed by a combination of monoclonal antibody staining (CD3-ECD, gammadeltaTCR-FITC, and alphabetaTCR-PE-Cy5) or immunomagnetic purification of gammadelta T cells (i.e., MdFI 20 vs 8.86). The gammadelta T cells expressed CD8 polypeptide chains (alpha and beta) in all possible combinations. The largest proportion, surprisingly, were cells expressing CD8betabeta homodimers (43.8 +/- 16.5%). CD8alphaalpha homodimers were expressed on 14.2% (+/- 12.3) of total gammadelta T cells, whereas CD8alphabeta heterodimers were expressed on 12.2% (+/- 7.5). We also observed a bimodal distribution of the intensity of CD3 fluorescence of gammadelta T cells in immunocompromised patients with a threshold at 105 cell/microl. CD3 bright gammadelta T cells were more frequently observed in HIV patients (29%) compared with renal transplant patients (11%) and healthy donors (3%; chi2 test: P = 0.0007).

CONCLUSIONS

The simple observation of a CD3 bright T-cell subset on CD3/CD4/CD8 routine analysis suggests a high gammadelta T-cell fraction and, in our opinion, should be followed by a complementary analysis to determine precisely the number of gammadelta T cells and to identify their CD8alpha/beta phenotype. When CD3 bright T cells/microl were more than 40%, high gammadelta T cells were detected in more than 87% of cases, with a specificity of 76%. Occasionally, the CD3 bright subset appeared to be strongly homogeneous, suggesting an oligoclonal proliferation that could possibly reveal a chronic localized stimulation or an early lymphoproliferative disorder. Because the gammadelta T cells have interesting immunological peculiarities, the clinical significance of their quantitative abnormality should be clarified in diseases such as HIV, organ transplantation, autoimmunity and lymphoma.

Phenotypic and functional characterization of blood gammadelta T cells in sleep apnea

Hypoxia-induced lymphocyte dysfunction may be implicated in endothelial cell damage in obstructive sleep apnea (OSA) syndrome. gammadelta T cells' unique migration, cytotoxic features, and accumulation in atherosclerotic plaques are considered critical in cardiovascular disorders. We characterized the phenotype, cytokine profile, adhesion properties, and cytotoxicity of gammadelta T cells in patients with OSA and control subjects. The following is a summary of our major findings regarding OSA gammadelta T cells: (1) a significant increase in the expression of the inhibitory natural killer B1 receptors was found; (2) the intracellular content of proinflammatory cytokines tumor necrosis factor (TNF)-alpha and interleukin-8 was increased, and the content of the antiinflammatory cytokine interleukin-10 was decreased; (3) gammadelta T cells of patients with OSA adhered significantly more avidly to nonactivated endothelial cells in culture than those of control subjects; (4) L-selectin expression was higher; (5) anti-E/P-selectin antibodies and anti-TNF-alpha antibodies decreased the adhesion index of OSA gammadelta T lymphocytes/endothelial cells but not of control subjects; and (6) cytotoxicity of OSA gammadelta T lymphocytes against endothelial cells in culture was 2.5-fold higher than that of control subjects and could be prevented by pretreatment with anti-TNF-alpha. Collectively these data implicate gammadelta T lymphocyte function in atherogenic sequelae in OSA.

Hepatosplenic gammadelta T-cell lymphoma presenting with immune-mediated thrombocytopenia and hemolytic anemia (Evans' syndrome)

We describe an unusual case of hepatosplenic T-cell lymphoma in a 61-year-old man who presented with fever, hepatosplenomegaly, anemia, and thrombocytopenia. A spleen biopsy was consistent with T-cell lymphoma. Cytogenetic studies did not reveal chromosome abnormalities. Using the polymerase chain reaction approach, clonality of the T-cell receptor gamma-chain gene rearrangement could be demonstrated, while Southern blot analysis disclosed only a germline configuration of the T-cell receptor beta chain genes. Of interest, an immune-mediated mechanism was demonstrated and was most likely responsible for erythrocyte and platelet destruction; this is, therefore, the first report of gamma T-cell lymphoma in association with Evans' syndrome. Initial steroid treatment was efficacious in limiting autoimmunity but constitutional symptoms did not subside. Chemotherapy (MACOP-B) was successful in obtaining complete clinical remission. Finally, thrombocytopenia in gammadelta T-cell lymphoma patients should be routinely evaluated for platelet autoantibodies.