Increased IFN‐γ⁺ and TNF‐α⁺ mucosal‐associated invariant T cells in patients with aplastic anemia

Abstract

Background Aplastic anemia (AA) is known as an autoimmune disease in which T cell activation is aberrant. It has been reported that unconventional T cells, mucosal‐associated invariant T (MAIT) cells, play an important role in several autoimmune diseases, but it is unclear if they are involved in AA. Methods In this study, we for the first time analyzed the proportions, phenotypes, and cytokine properties of MAIT cells in AA by flow cytometry. Results We found that the percentage of circulating MAIT cells was generally higher for CD3+, CD8+, and CD8− T cells in AA patients compared with healthy individuals. Moreover, the percentage of IL‐18Rα‐, NKG2D‐, IFN‐γ‐, and TNF‐α‐ positive MAIT cells was also significantly higher in AA patients. In addition, the percentage of IFN‐γ+ CD3+ or TNF‐α+CD8− MAIT cells had a significant negative correlation with the absolute neutrophil count. Conclusions We present the first observation of MAIT cells in patients with AA. MAIT cells are associated with a higher frequency of IFN‐γ and TNF‐α production and may contribute to the pathogenesis of AA.

Mendelian randomization analysis identified tumor necrosis factor as being associated with severe COVID-19

“…Proteins circulating in the blood are critical for predicting human disease and are often used as biomarkers for clinical decision making (Folkersen et al, 2020). Previous studies have revealed the role of TNF superfamily members in cancer (Flieswasser et al, 2022;Curtis et al, 2023), autoimmune diseases (Tian et al, 2020;Chen et al, 2023), and respiratory diseases (Cho et al, 2020;Cross et al, 2023), which have been proven to be involved with severe COVID-19 (Zhang et al, 2021). Our genetic evidence suggests that FAS is positively associated with the severity of COVID-19 and that CD40 is protective against severe COVID-19.…”

Issue highlights—May 2023

“…The last article in this issue (Chen, Zhang, et al, 2023) studied mucosal‐associated invariant T cells (MAIT) (Godfrey et al, 2019) in aplastic anemia (AA), a type of bone marrow failure directly linked to abnormal immune responses. MAIT cells exhibit an effector‐memory phenotype and express several NK receptors such as NKG2D and CD161 and play an important role in the development of autoimmune diseases.…”

“…The last article in this issue (Chen, Zhang, et al, 2023) studied mucosal-associated invariant T cells (MAIT) (Godfrey et al, 2019)…”