Insights into rheumatoid arthritis derived from the Sa immune system

The Sa system is a recently described immune system that has a specificity and positive predictive value of nearly 100% for rheumatoid arthritis (RA) in Asia, Europe and the Americas. Its sensitivity of 30-40% suggests that it identifies a subset of RA patients. Anti-Sa antibodies are present from d...

Full description

Saved in:
Bibliographic Details
Published in:Arthritis research 2000, Vol.2 (6), p.429-432
Main Authors: Ménard, H A, Lapointe, E, Rochdi, M D, Zhou, Z J
Format: Article
Language:English
Subjects:
Antigens - immunology
Arthritis, Rheumatoid - immunology
Haptens - immunology
Humans
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The Sa system is a recently described immune system that has a specificity and positive predictive value of nearly 100% for rheumatoid arthritis (RA) in Asia, Europe and the Americas. Its sensitivity of 30-40% suggests that it identifies a subset of RA patients. Anti-Sa antibodies are present from disease onset and are predictive of disease severity. The immune reactants are plentiful in the target tissue: antigen is present in the synovium, IgG antibody in the fluid. Immunologically, Sa is a hapten-carrier antigen in which vimentin is the carrier and citrulline is the hapten. The citrullination of vimentin is closely related to apoptosis, and citrullinated vimentin is extremely sensitive to digestion by the ubiquitous calpains. Nevertheless, Sa is found in only a few cell lines. Calpastatin, the natural specific inhibitor of calpains, is also a RA-associated, albeit non-specific, autoimmune system. Is it possible that calpain-related apoptotic pathways could be prominent in cells containing Sa? The task is to reconcile the specificity of Sa/citrullinated proteins in a multifactorial and polygenic disease such as RA.
ISSN:1465-9905
1465-9913
DOI:10.1186/ar122