The objective of this study was to analyze bone marrow stromal antigen-2 (BST-2) levels in labial glands, total peripheral blood mononuclear cells (PBMCs) and PBMC subpopulations from primary Sjögren's syndrome (pSS) patients and determine the correlation between BST-2 expression and clinical characteristics.
PBMC subsets were positively separated using magnetic microbeads. BST-2 mRNA levels in labial glands, total PBMCs and PBMC subsets of 30 pSS and 30 healthy control (HC) subjects were investigated using real-time polymerase chain reaction (RT-PCR). Distribution of BST-2-positive cells in the labial glands was assessed by immunohistochemistry.
BST-2 was significantly increased in pSS labial glands and was positively correlated with the VAS value for parotid gland swelling and rheumatoid factor and β2-microglobulin serum levels. BST-2 levels were statistically different between pSS patients with positive and negative expression of anti-SSA antibody. Positive focal infiltrating lymphocytes and adjacent ductal epithelial cells were observed in labial glands from pSS patients, while there were a few scattered positive ductal epithelial cells in controls. BST-2 was also up-regulated in CD19+ B cells and the remaining CD4-CD8-CD19- PBMCs.
BST-2 was aberrantly expressed in pSS patients, and expression in labial glands was positively correlated with important clinical characteristics; thus, it may be a potential biomarker of pSS activity.