Polymorphism in the 5 ' regulatory region of the B-lymphocyte activating factor gene is associated with the Ro/La autoantibody response and serum BAFF levels in primary Sjogren's syndrome
Date
2008
Authors
Nossent, J.
Lester, S.
Zahra, D.
Mackay, C.
Rischmueller, M.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Journal article
Citation
Rheumatology, 2008; 47(9):1311-1316
Statement of Responsibility
J. C. Nossent, S. Lester, D. Zahra, C. R. Mackay and M. Rischmueller
Conference Name
Abstract
Objective. To investigate the association between haplotypes in the 5' regulatory region of the B-lymphocyte activating factor (BAFF) gene, disease susceptibility and serum BAFF (s-BAFF) levels in Caucasian primary SS (pSS) patients. Methods. Case–control study in an established pSS cohort with PCR–RFLP genotyping for four SNPs (-2841 TC, -2704 TC, -2701 TA, -871 CT), which tag a haplotype block in the 5' regulatory region of the BAFF gene and s-BAFF determination by ELISA. Results. s-BAFF levels were elevated in Ro/La-positive pSS patients (n = 85, 1770 pg/ml) compared with both Ro/La-negative pSS patients (n = 27, 1193 pg/ml) and controls (n = 59, 1171 pg/ml), P < 0.001. s-BAFF increased with diversification of the anti-Ro/La antibody response, but was not correlated with age, RF or immunoglobulin G levels. There were four common BAFF haplotypes. While the CTAT haplotype was associated with Ro/La-positive pSS [odds ratio (OR) 2.6; 95% CI 1.7, 4.1; P = 0.00004], the TTTT haplotype was associated with elevated s-BAFF in autoantibody-positive pSS (n = 85; 88% females; P = 0.008). The shared -871 T allele had no independent contribution to disease susceptibility or s-BAFF. Conclusions. Disease susceptibility for Ro/La-positive pSS is increased with the CTAT haplotype, but not associated with high s-BAFF levels. Elevated s-BAFF levels in pSS are associated with the TTTT haplotype and may be a secondary phenomenon in Ro/La-positive pSS. While both haplotypes carry the -871 T allele, this allele is not independently associated with disease susceptibility.