title: [Effect of NK-22 cells in the synovial fluid of patients with rheumatoid arthritis on the proliferation of fibroblast-like synoviocytes and its possible mechanism].
abstract: OBJECTIVE
  To investigate the effect of NK-22 cells isolated from the synovial fluid (SF) of patients with rheumatoid arthritis (RA) on the proliferation of fibroblast-like synoviocytes and explore its possible mechanism.
  
  
  METHODS
  The proportions of NK-22 cells in the peripheral blood (PB) and the SF of 20 RA patients and 20 healthy individuals were determined by flow cytometry. NK-22 cells in the SF sorted by flow cytometry were cultured for two weeks followed by a 4-h stimulation with 20 ng/ml phorbol 12-myristate 13-acetate and 0.5 µ mol/L ionomycin. The culture supernatant of NK-22 cells was then harvested, in which the levels of IL-22 and TNF-α were measured by ELISA. The fibroblast-like synoviocytes were exposed to the culture supernatant for 24, 48, 72, and 96 h, and the changes in the cell proliferation were detected by MTT assay.
  
  
  RESULTS
  RA patients showed a significantly greater proportion of NK-22 cells in both the SF and PB than the normal control subjects (P<0.05). NK-22 cells sorted by flow cytometry reached a purity exceeding 90%, and the levels of IL-22 and TNF-α in the culture supernatant of NK-22 cells cultured for two weeks were 941.16 pg/ml and 368.1 pg/ml, respectively. The culture supernatant of NK-22 cells caused a rapid proliferation of the fibroblast-like synoviocytes at 24, 48, 72, and 96 h after the exposure.
  
  
  CONCLUSIONS
  NK-22 cells in the SF of RA patients can promote the proliferation of fibroblast-like synoviocytes possibly due to the capacity of NK-22 cells to produce IL-22 and TNF-α.
authors.affiliation: Department of Traditional Chinese Medicine and Rheumatology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Ren
authors.forename: Juan
authors.initials: J
authors.lastname: Li
authors.forename: Zhi-Tao
authors.initials: ZT
authors.lastname: Feng
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Lv
mesh_terms: D000328:Adult; D001172:Arthritis, Rheumatoid / Q000473:pathology*; D016022:Case-Control Studies; D049109:Cell Proliferation; D002478:Cells, Cultured; D005260:Female; D005347:Fibroblasts / Q000166:cytology*; D005434:Flow Cytometry; D006801:Humans; D007378:Interleukins / Q000378:metabolism; D007694:Killer Cells, Natural / Q000166:cytology*; D008297:Male; D008875:Middle Aged; D013582:Synovial Fluid / Q000166:cytology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D000097043:Interleukin-22
chemical_list: D007378:Interleukins; D014409:Tumor Necrosis Factor-alpha; D000097043:Interleukin-22