We measured antibody levels against human type I, II, III and IV collagens in Japanese patients with ankylosing spondylitis (AS) by enzyme linked immunosorbent assay (ELISA).
Significant elevations of antibodies against type II (IgG and IgA classes) and type IV (IgA class) collagens were observed in AS patients, whilst there was no significant elevation of any antibody class against type I or III collagen when compared to controls.
These findings indicate that AS patients have immune responses to type II and IV collagens, which may be responsible for sustaining the characteristic local inflammations in AS.