To evaluate the clinical value of determining circulating IgA-alpha 1-antitrypsin (IgA-AT) complex in rheumatoid arthritis.
The IgA-AT complex was assayed by a prototype ELISA kit using a specific monoclonal antibody against the complex.
The median level of serum IgA-AT complex in rheumatoid patients (2.26 AU ml-1) was significantly higher than in osteoarthritis patients (1.37 AU ml-1, P < 0.05) and healthy volunteers (1.03 AU ml-1, P < 0.001). The concentration of IgA-AT complex in rheumatoid arthritis patients at baseline was correlated with the number of painful joints (P < 0.05), number of swollen joints (P < 0.01), erythrocyte sedimentation rate (P < 0.05), and modified Lansbury index (P < 0.01). The median serum level of IgA-AT complex in rheumatoid patients at baseline was higher than that at three months (P < 0.01), six months (P < 0.01), and 12 months (P < 0.01) after the start of treatment. The difference and ratio of IgA-AT complex levels before and after treatment were significantly associated with radiographic progression.
The findings validate the usefulness of determining IgA-AT complex using ELISA in the management of rheumatoid arthritis.