We studied anti-neutrophil cytoplasmic antibodies (ANCA) and anti-endothelial cell antibodies (AECA) in 58 children with acute Kawasaki disease (KD) before i.v. gamma globulin treatment, 35 children with infection and fever > 38.5 degrees C, and 48 healthy afebrile children. ANCA were studied by indirect immunofluorescence (IIF) on ethanol-fixed neutrophils and by ELISA with crude neutrophil extract as antigen. AECA were studied using ELISA on resting and activated endothelial cells. ANCA IIF was weakly positive, cytoplasmic, diffuse and homogeneous in all three groups. ANCA IIF, ANCA ELISA and AECA ELISA were no higher in KD than in febrile children. There was no difference between KD with and KD without coronary artery aneurysms. AECA differences between the KD and afebrile group were not significant after correction for total IgM. In contrast with our previous findings, we conclude that ANCA and AECA are not raised in KD compared with febrile controls. It therefore seems unlikely that they are important in the pathogenesis of vasculitis in KD.