Autoreactivity in patients with Behçet's disease.

Behçet's disease (BD) has features consistent with an immunopathogenic mechanism. We tested 23 patients with BD and 139 normal controls for autoantibodies to nuclear, cardiolipin and smooth muscle antigens using indirect immunofluorescence, immunodiffusion, Western blots and an enzyme immunosorbent assay. Serum immunoglobulin G, M and A levels were measured by standard radial immunodiffusion techniques. The prevalence of the following autoantibodies was raised in patients with BD compared with the control group: ANA on rodent (P < 0.05) and human (P < 0.01) substrates and smooth muscle antibody (P < 0.001). Anticardiolipin antibody was detected in one patient (GPL 23.1 U). Antibodies to the ribonucleoproteins Ro, La, Sm and RNP were not found. Levels of serum immunoglobulins G, M and A were elevated in BD compared with the controls and this was significant for immunoglobulin M (P < 0.05) and A (P < 0.001). These findings support the concept of a polyclonal B cell activation in BD.