Antibody affinity to retinal S-antigen in patients with retinal vasculitis.

Using a modified enzyme-linked immunosorbent antibody method that included dissociation of antigen antibody complexes with sodium thiocyanate, we examined the functional affinity of antibody to retinal S-antigen in 48 patients with retinal vasculitis and 46 age-matched healthy control subjects. Antibody affinity was markedly lower in patients with retinal vasculitis than in healthy subjects. Low-affinity antibody was more prevalent in acute retinal vasculitis and in patients with normal levels of circulating immune complexes. We found distinct differences between the antiretinal antibodies found in patients with retinal vasculitis and those in control subjects. The association of low-affinity antibody with normal levels of circulating immune complexes may suggest defective regulation of antiretinal autoimmunity and have important pathogenic implications.