title: [Association of HLA-DR4, PAD4, and STAT4 expression in the peripheral blood with disease activity in patients with rheumatoid arthritis].
abstract: OBJECTIVE
  To explore the association of the expressions of human leukocyte antigen (HLA)-DR4, peptidyl arginine deiminase type4(PAD4), and signal transducer and activator of transcription 4 (STAT4) in the peripheral blood with the disease activity in patients with rheumatoid arthritis (RA).
  
  
  METHODS
  Twenty-four RA patients in active stage (DAS28 score>or=2.6) and 14 RA patients in remission stage (DAS28 score<2.6) were enrolled in this study, with 12 healthy volunteers as the control. The QuantiGene Plex method was used to measure the expression level of HLA-DR4, PAD4, and STAT4 mRNA, and the relationship between the expressions of these genes and the DAS28 score, levels of anti-cyclic citrullinated peptide antibody (anti-CCP antibody) and rheumatoid factor (RF) was analyzed.
  
  
  RESULTS
  The expressions of HLA-DR4, PAD4, and STAT4 were significantly higher in RA patients than in the healthy controls (P<0.05). The level of HLA-DR4 mRNA in the two RA groups showed no significant difference, but was significantly higher than that in the healthy controls. HLA-DR4 expression was not found to correlated to DAS28 score, anti-CCP antibody level or RF in the RA patients. The expressions of PAD4 and STAT4 were significantly different between the two RA groups (P<0.05). In the RA patients, PAD4 mRNA expression was positively correlated to DAS28 and anti-CCP antibody level (P<0.05), and STAT4 expression showed positive correlations to DAS28 and RF levels (P<0.05).
  
  
  CONCLUSIONS
  HLA-DR4, PAD4 and STAT4 are overexpressed in RA patients and may be involved in the pathogenesis of RA. The expressions of PAD4 and STAT4, but not HLA-DR4, are closely related to the disease activity of RA. Detection of peripheral blood PAD4 and STAT4 expressions can be helpful for evaluating the disease activity of RA.
authors.affiliation: Department of Traditional Chinese Rheumatology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China. zhuozhuotu@163.com
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Lü
authors.forename: Juan
authors.initials: J
authors.lastname: Li
authors.forename: Zhi-Tao
authors.initials: ZT
authors.lastname: Feng
authors.forename: Jie
authors.initials: J
authors.lastname: Ren
mesh_terms: D000328:Adult; D001172:Arthritis, Rheumatoid / Q000097:blood*; D005260:Female; D015804:HLA-DR4 Antigen / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D006867:Hydrolases / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D000080002:Protein-Arginine Deiminase Type 4; D000076342:Protein-Arginine Deiminases; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D050797:STAT4 Transcription Factor / Q000097:blood / Q000235:genetics / Q000378:metabolism*
chemical_list: D015804:HLA-DR4 Antigen; D012333:RNA, Messenger; D050797:STAT4 Transcription Factor; C494090:STAT4 protein, human; D006867:Hydrolases; C000629235:PADI4 protein, human; D000080002:Protein-Arginine Deiminase Type 4; D000076342:Protein-Arginine Deiminases