Differential expression of Ro/SSA 60 kDa and La/SSB, but not Ro/SSA 52 kDa, mRNA and protein in minor salivary glands from patients with primary Sjögren's syndrome.
OBJECTIVE
To analyze the protein and messenger RNA (mRNA) expression of La/SSB, Ro/SSA 60, and Ro/SSA 52 antigens in minor salivary glands (MSG) from patients with primary Sjögren's syndrome (pSS).


METHODS
La/SSB, Ro/SSA 60, and Ro/SSA 52 protein expression was studied by immunohistochemistry in MSG from 26 patients with pSS and 16 controls. mRNA expression was determined by real-time polymerase chain reaction in MSG of 10 patients with pSS and 7 controls.


RESULTS
La/SSB and Ro/SSA 60, but not Ro/SSA 52, mRNA expression was higher in samples from patients with pSS compared to controls (p < 0.05). La/SSB protein had higher expression in the cytoplasm of ductal cells than in the cytoplasm of mucous acinar cells in patients with pSS (p = 0.013) but not in controls. Ro/SSA 60 had higher expression in the cytoplasm of ductal cells than in the cytoplasm of serous acinar cells in patients with pSS (p = 0.006) but not in controls. The Ro/SSA 52 expression pattern was similar in patients and controls. There was no association between circulating autoantibodies to Ro/SSA or La/SSB and the aberrant expression of the cognate autoantigens.


CONCLUSIONS
The increased Ro/SSA 60 and La/SSB mRNA expression in MSG of patients with pSS as well as the differential Ro/SSA 60 and La/SSB protein expression in ductal cells of MSG in patients with pSS suggest that these these 2 autoantigens, but not Ro/SSA 52, are probably involved in triggering and maintaining the tissue-specific autoimmune response in pSS MSG and may contribute to the antigen-driven immune response and local autoantibody production in pSS.
Barcellos
Karin S A
KS
Rheumatology Divisions, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil.
Nonogaki
Suely
S
Enokihara
Milvia M S S
MM
Teixeira
Miriam S
MS
Andrade
Luís E C
LE
D000328:Adult; D000368:Aged; D001324:Autoantigens / Q000235:genetics / Q000378:metabolism*; D016022:Case-Control Studies; D003593:Cytoplasm / Q000378:metabolism / Q000473:pathology; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D020733:RNA, Small Cytoplasmic / Q000235:genetics / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000235:genetics / Q000378:metabolism*; D012470:Salivary Glands, Minor / Q000378:metabolism* / Q000473:pathology; D012859:Sjogren's Syndrome / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D000097585:SS-B Antigen; D000099207:SS-A Antigen
D001324:Autoantigens; D012333:RNA, Messenger; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins; D000097585:SS-B Antigen; D000099207:SS-A Antigen; C116006:RO60 protein, human