Innate-like T lymphocytes are a recently defined group of T cells comprising mainly mucosa-associated invariant T (MAIT) cells. The relationship between MAIT cells and childhood asthma is controversial. In this study, we aimed to determine the role of MAIT cells in patients with allergic asthma (AA) and nonallergic asthma (NAA). This is the first study to compare the ratios of these cells in patients with AA and NAA.
The study included children aged 6-18 years with AA (n = 41) or NAA (n = 30) and healthy control subjects (n = 36). The control group consisted of children who presented to the outpatient clinic without chronic disease, malnutrition, or acute or chronic infection. The proportions of MAIT, TH17, MAIT-17, and Th17-17 cells were investigated by flow cytometry and compared among the AA, NAA, and control groups.
When the AA and NAA patient groups were compared, the mean MAIT cell ratio was significantly lower in NAA patients (median: 0.45, p < 0.05). MAIT cell ratios were also substantially lower in NAA patients compared to the control group (mean: 0.504, p < 0.05). TH17, MAIT-17, and TH17-17 cell values were not statistically significant among the groups.
Our study found that MAIT cell ratios were lower in the NAA patient group compared to the control group and AA patients. It has been predicted that MAIT cell depletion may have a role in the development of NAA. Our study is the first on this subject in the literature and further studies are needed.
© TÜBİTAK.

Induction immunosuppressive therapy for kidney transplant recipients (KTRs) primarily includes interleukin-2 receptor antagonists, such as basiliximab (BXM) or lymphocyte-depleting agents, and anti-thymocyte globulin (ATG). This study aimed to investigate their effects on T cell dynamics during the early post-transplantation period. This prospective observational study included 157 KTRs. Peripheral blood samples were collected from each patient within 5 days before and 4 and 12 weeks after transplantation. Flow cytometric analysis was performed to assess various T cell subsets whose changes were then analyzed. In the ATG group, CD4+ T cell expression decreased significantly compared with that in the BXM group. However, CD4+CD161+ and CD4+CD25+CD127low T cell expression levels increased significantly. In the CD8+ T cell subset, a decrease in CD8+CD28nullCD57+ and CD8+CCR7+ T cell expression was observed in the ATG group. However, among patients diagnosed with biopsy-proven acute rejection, T cell subset expression did not significantly differ relative to non-rejection cases. In conclusion, ATG induction therapy resulted in more pronounced changes in T lymphocyte subsets than BXM induction, with increased CD4+CD161+ and CD4+CD25+CD127low T cells and an early decrease in CD8+CD28nullCD57+ and CD8+CCR7+ T cells, some of which are associated with acute rejection.

γδ T cells are a rare and unique prototype of T cells that share properties with natural killer cells in secondary lymphoid organs. Although many studies have revealed the function and importance of adult-derived γδ T cells in cancer biology and regenerative medicine, the low numbers of these cells hamper their application as therapeutic cell sources in the clinic. To solve this problem, pluripotent stem cell-derived γδ T cells are considered alternative cell sources; however, few studies have reported the generation of human pluripotent stem cell-derived γδ T cells. In the present study, we investigated whether lymphoid lineage γδ T cells were successfully generated from human pluripotent stem cells via hemogenic endothelium under defined culture conditions. Our results revealed that pluripotent stem cells successfully generated γδ T cells with an overall increase in transcriptional activity of lymphoid lineage genes and cytolytic factors, indicating the importance of the optimization of culture conditions in generating lymphoid lineage γδ T cells. We uncovered an initial step in differentiating γδ T cells that could be applied to basic and translational investigations in the field of cancer biology. Based on our result, we will develop an appropriate method to purify γδ T cells with functionality and it helpful for the study of basic mechanism of γδ T cells in pathophysiologic condition as well as clinic application.

Mucosal-associated invariant T (MAIT) cells are unconventional T lymphocytes with a semi-conserved TCRα, activated by the presentation of vitamin B metabolites by the MHC-I related protein, MR1, and with diverse innate and adaptive effector functions. The role of MAIT cells in acute intestinal infections, especially at the mucosal level, is not well known. Here, we analyzed the presence and phenotype of MAIT cells in duodenal biopsies and paired peripheral blood samples, in patients during and after culture-confirmed Vibrio cholerae O1 infection. Immunohistochemical staining of duodenal biopsies from cholera patients (n = 5, median age 32 years, range 26-44, 1 female) identified MAIT cells in the lamina propria of the crypts, but not the villi. By flow cytometry (n = 10, median age 31 years, range 23-36, 1 female), we showed that duodenal MAIT cells are more activated than peripheral MAIT cells (p < 0.01 across time points), although there were no significant differences between duodenal MAIT cells at day 2 and day 30. We found fecal markers of intestinal permeability and inflammation to be correlated with the loss of duodenal (but not peripheral) MAIT cells, and single-cell sequencing revealed differing T cell receptor usage between the duodenal and peripheral blood MAIT cells. In this preliminary report limited by a small sample size, we show that MAIT cells are present in the lamina propria of the duodenum during V. cholerae infection, and more activated than those in the blood. Future work into the trafficking and tissue-resident function of MAIT cells is warranted.

Mucosal-associated invariant T (MAIT) cells are a subset of innate-like T cells that regulate the immune response via rapidly releasing inflammatory factors, including during progression of some tumors. However, the immunological role of MAIT cells is still unclear in lung cancer. We measured percentage, partial function, and clinical correlation of circulating MAIT cells from lung cancer patients through flow cytometry. Lung cancer patients displayed a high concentration of CD4+, CD8+, and activated CD38+CD8+MAIT cells, and a decrease of PD1+ double negative (DN) MAIT cells in peripheral blood. Meanwhile, increased levels of interferon-γ, interleukin (IL)-6, and 8 were examined in the serum of lung cancer patients. Importantly, we discovered a statistically positive association between accumulation of CD38+CD8+MAIT cells and reduced progression-free survival of lung cancer patients. While preliminary, the altering frequency of MAIT cells might be involved in dysfunctional immune response in lung cancer.
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