Studies of anti‐f(ab')₂ antibodies and possible immunologic control mechanisms in systemic lupus erythematosus

Studies of anti-DNA and anti-F(ab')2 antibodies were performed by enzyme-linked immunosorbent assay in 51 patients with systemic lupus erythematosus (SLE). Patients with severe, uncontrolled disease showed high levels of anti-DNA and low levels of anti-F(ab')2 antibodies. Patients with quiescent SLE usually showed high levels of anti-F(ab')2 and low levels of anti-DNA antibodies. Isolated anti-F(ab')2 antibodies from autologous SLE remission serum or from the sera of unaffected siblings of SLE patients showed maximum inhibition in test systems using affinity-purified SLE anti-DNA antibodies reacting with single-stranded DNA.