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Journal of Biomedicine and Biotechnology
Volume 2010 (2010), Article ID 826434, 7 pages
http://dx.doi.org/10.1155/2010/826434
Research Article

Promoter Variant of PIK3C3 Is Associated with Autoimmunity against Ro and Sm Epitopes in African-American Lupus Patients

1Section of Rheumatology and Gwen Knapp Center for Lupus and Immunology Research, University of Chicago, 5841 S. Maryland Ave. MC 0930, Chicago, IL 60637, USA
2Section of Rheumatology, Rush University Medical Center, Chicago, IL 60612, USA
3Section of Genetic Medicine, University of Chicago, Chicago, IL 60637, USA

Received 15 January 2010; Revised 7 May 2010; Accepted 24 May 2010

Academic Editor: Brian Poole

Copyright © 2010 Silvia N. Kariuki et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The PIK3C3 locus was implicated in case-case genome-wide association study of systemic lupus erythematosus (SLE) which we had performed to detect genes associated with autoantibodies and serum interferon-alpha (IFN- ). Herein, we examine a PIK3C3 promoter variant (rs3813065/-442 C/T) in an independent multiancestral cohort of 478 SLE cases and 522 controls. rs3813065 C was strongly associated with the simultaneous presence of both anti-Ro and anti-Sm antibodies in African-American patients [ (1.34–3.73), ]. This autoantibody profile was associated with higher serum IFN- ( ). In the HapMap Yoruba population, rs3813065 was associated with differential expression of ERAP2 ( ), which encodes an enzyme involved in MHC class I peptide processing. Thus, rs3813065 C is associated with a particular autoantibody profile and altered expression of an MHC peptide processing enzyme, suggesting that this variant modulates serologic autoimmunity in African-American SLE patients.