Autoantibody production in Kawasaki syndrome.

Although a variety of autoantibodies are produced in patients with Kawasaki syndrome (KS), their specificities in many instances are controversial and their role in disease pathogenesis is undetermined. Autoantibody production was studied in 14 patients with Kawasaki syndrome (KS). Antibodies to myeloperoxidase (MPO), the dominant antigen responsible for perinuclear antineutrophil cytoplasmic antibody (pANCA) reactivity, were detected by ELISA in 73% of acute phase and 89% of convalescent phase KS specimens, in contrast to 4% of normal adult control subjects (p < 0.002 and p < 0.001, respectively). MPO and cytoplasmic antineutrophil antibody (cANCA) levels measured by ELISA were significantly elevated above levels for adult normal control subjects (p < 0.005 and p < 0.01, respectively), but not above recently ill childhood controls. Among patients who developed a positive ANCA, antibody titers tended to rise in serial specimens despite clinical improvement. Antibodies to myocardial muscle, cardiac perimysial connective tissue, nuclear antigens (ANA), and smooth muscle were also detected in some KS patients, but titers did not differ significantly from control patients. Autoantibody results were not predictive of patients with echocardiographic abnormalities.