title: Expression of proteasome immunosubunit in labial glands of patients with primary Sjogren's syndrome.
abstract: OBJECTIVE
  To investigate the expression of proteasome immunosubunit low molecular weight polypeptide (LMP)2 and LMP7 in labial glands of patients with primary Sjogren's syndrome patients, and thus explore their role in the diagnosis, differential diagnosis and pathogenesis of primary Sjogren's syndrome (pSS).
  
  
  METHODS
  Labial specimens were collected from 40 patients with pSS, 15 patients with connective tissue diseases other than pSS, and 9 healthy controls. The expressions of LMP2 and LMP7 in labial specimens were determined using immunohistochemical approaches and analyzed using semi-quantitative methods. The positive rate of acinar was calculated. After the square arcsine transformation of data, the differences of the positive rate in acinar between LMP2 and LMP7 were compared among three groups. Spearman's rank correlation coefficient was used for analyzing the correlation of clinical manifestations with LMP2 and LMP7 expressions.
  
  
  RESULTS
  The expressions of LMP2 and LMP7 within the acinar and ductal epithelial cells were confirmed. Although the LMP2 expression in labial specimens was not significantly different among three groups(P=0.369), the expression of LMP7 was significantly higher in pSS patients compared with patients with connective tissue disease and healthy controls (P<0.01). Only in pSS group, LMP7 was found to be with higher positive rate in acinar than LMP2 (P<0.01). No significant correlation was found between LMP2/LMP7 and clinical manifestations (P>0.05).
  
  
  CONCLUSIONS
  In patients with pSS, the expression of LMP7 (but not LMP2) is up-regulated in labial gland, indicating these two proteins have different genetic regulation mechanisms.
authors.affiliation: Department of Stomatology,PUMC Hospital, CAMS and PUMC, Beijing 100730, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhen
authors.forename: Luo
authors.initials: L
authors.lastname: Yu-feng
authors.forename: Cao
authors.initials: C
authors.lastname: Jin-ling
authors.forename: Guo
authors.initials: G
authors.lastname: Chun-lan
authors.forename: Wang
authors.initials: W
authors.lastname: Hong-lin
authors.forename: Xiao
authors.initials: X
authors.lastname: Jing-lian
authors.forename: Zhang
authors.initials: Z
authors.lastname: Jie
authors.forename: Zhang
authors.initials: Z
authors.lastname: Ding
mesh_terms: D000328:Adult; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D012470:Salivary Glands, Minor / Q000378:metabolism; D012859:Sjogren's Syndrome / Q000175:diagnosis / Q000378:metabolism*
chemical_list: C071313:LMP-2 protein; D003546:Cysteine Endopeptidases; C077436:LMP7 protein; D046988:Proteasome Endopeptidase Complex