title: Activation, Impaired Tumor Necrosis Factor-α Production, and Deficiency of Circulating Mucosal-Associated Invariant T Cells in Patients with Scrub Typhus.
abstract: 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.
  
  
  
  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)-α production, which was restored during the remission phase. In addition, the impaired production of TNF-α by MAIT cells was associated with elevated CD69 expression.
  
  
  
  This study shows that circulating MAIT cells are activated, numerically deficient, and functionally impaired in TNF-α production in patients with scrub typhus. These abnormalities possibly contribute to immune system dysregulation in scrub typhus infection.
authors.affiliation: Department of Infectious Diseases, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea.
authors.forename: Seung-Ji
authors.initials: SJ
authors.lastname: Kang
authors.affiliation: Department of Rheumatology, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea.
authors.forename: Hye-Mi
authors.initials: HM
authors.lastname: Jin
authors.affiliation: Department of Laboratory Medicine, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea.
authors.forename: Eun Jeong
authors.initials: EJ
authors.lastname: Won
authors.affiliation: Department of Rheumatology, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea.
authors.forename: Young-Nan
authors.initials: YN
authors.lastname: Cho
authors.affiliation: Department of Rheumatology, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea.
authors.forename: Hyun-Ju
authors.initials: HJ
authors.lastname: Jung
authors.affiliation: Department of Pulmonary and Critical Care Medicine, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea.
authors.forename: Yong-Soo
authors.initials: YS
authors.lastname: Kwon
authors.affiliation: Heart Research Center, Chonnam National University Hospital, Gwangju, Republic of Korea.
authors.forename: Hae Jin
authors.initials: HJ
authors.lastname: Kee
authors.affiliation: Department of Surgery, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea.
authors.forename: Jae Kyun
authors.initials: JK
authors.lastname: Ju
authors.affiliation: Department of Surgery, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea.
authors.forename: Jung-Chul
authors.initials: JC
authors.lastname: Kim
authors.affiliation: Department of Infectious Diseases, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea.
authors.forename: Uh Jin
authors.initials: UJ
authors.lastname: Kim
authors.affiliation: Department of Infectious Diseases, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea.
authors.forename: Hee-Chang
authors.initials: HC
authors.lastname: Jang
authors.affiliation: Department of Infectious Diseases, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea.
authors.forename: Sook-In
authors.initials: SI
authors.lastname: Jung
authors.affiliation: Department of Laboratory Medicine, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea.
authors.forename: Seung-Jung
authors.initials: SJ
authors.lastname: Kee
authors.affiliation: Department of Rheumatology, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea.
authors.forename: Yong-Wook
authors.initials: YW
authors.lastname: Park
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D000072336:Mucosal-Associated Invariant T Cells / Q000502:physiology*; D012612:Scrub Typhus / Q000378:metabolism / Q000473:pathology*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D014409:Tumor Necrosis Factor-alpha