RT Journal Article
SR Electronic
T1 Serum antibodies against intact human collagen IX are elevated at onset of rheumatoid arthritis but are not related to development of erosions.
JF The Journal of Rheumatology
JO J Rheumatol
FD The Journal of Rheumatology
SP 745
OP 751
VO 35
IS 5
A1 Juha Jäälinoja
A1 Martti Nissilä
A1 Markku J Kauppi
A1 Markku Hakala
A1 Kari Laiho
A1 Riitta Karttunen
A1 Sohvi Hörkkö
A1 Leena Ala-Kokko
YR 2008
UL http://www.jrheum.org/content/35/5/745.abstract
AB OBJECTIVE: To measure the presence of autoantibodies binding to intact human recombinant collagen IX and assess their usefulness as a diagnostic marker and an indicator of disease activity in rheumatoid arthritis (RA). METHODS: Recombinant human full-length collagen IX (rCIX) was produced in a baculovirus expression system and purified for use in ELISA developed to detect antibodies to native and denatured collagen IX. Fifty-three patients with recent-onset rheumatoid factor-seropositive RA were analyzed for the presence of rCIX antibodies of the IgG type at the time of initial diagnosis and after 3, 6, 12, and 24 months of followup. The RA sera were accompanied by 30 controls. Associations were determined between patients' antibody titers, development of erosions in the hands and feet, and various clinical and laboratory markers. RESULTS: Serum antibody levels among patients with RA at time of diagnosis were 1.78 times higher against native rCIX (p < 0.001) and 1.71 times higher against denatured rCIX (p < 0.001) than in the controls, and they remained high during the followup. No correlation was seen between antibody levels and clinical and laboratory findings. CONCLUSION: Our data show that patients with recent-onset RA have significantly elevated levels of autoantibodies to human rCIX. These autoantibodies were observed already at the early stages of the disease, which may reflect their diagnostic potential in RA.