Activation, Impaired Tumor Necrosis Factor-alpha Production, and Deficiency of Circulating Mucosal-Associated Invariant T Cells in Patients with Scrub Typhus

作者：Kang Seung Ji; Jin Hye Mi; Won Eun Jeong; Cho Young Nan; Jung Hyun Ju; Kwon Yong Soo; Kee Hae Jin; Ju Jae Kyun; Kim Jung Chul; Kim Uh Jin; Jang Hee Chang; Jung Sook In; Kee Seung Jung; Park Yong Wook

来源：PLoS Neglected Tropical Diseases, 2016, 10(7): e0004832.

DOI：10.1371/journal.pntd.0004832

Background
Mucosal-associated invariant T (MAIT) cells contribute to protection against certain microorganism infections. However, little is known about the role of MAIT cells in Orientia tsutsugamushi infection. Hence, the aims of this study were to examine the level and function of MAIT cells in patients with scrub typhus and to evaluate the clinical relevance of MAIT cell levels.
Methodology/Principal Findings
Thirty-eight patients with scrub typhus and 53 health control subjects were enrolled in the study. The patients were further divided into subgroups according to disease severity. MAIT cell level and function in the peripheral blood were measured by flow cytometry. Circulating MAIT cell levels were found to be significantly reduced in scrub typhus patients. MAIT cell deficiency reflects a variety of clinical conditions. In particular, MAT cell levels reflect disease severity. MAIT cells in scrub typhus patients displayed impaired tumor necrosis factor (TNF)-alpha production, which was restored during the remission phase. In addition, the impaired production of TNF-alpha by MAIT cells was associated with elevated CD69 expression.
Conclusions
This study shows that circulating MAIT cells are activated, numerically deficient, and functionally impaired in TNF-a production in patients with scrub typhus. These abnormalities possibly contribute to immune system dysregulation in scrub typhus infection.

• 出版日期2016-7