IgG subclasses in the serum and circulating immune complexes in patients with Kawasaki disease

IgG subclass levels in sera of 17 patients with Kawasaki disease were determined and a significant increase of IgG 1 (P less than 0.001) and IgG 3 (P less than 0.001) was found in the patients compared with 22 age-matched healthy children, while IgG 2 and IgG 4 were normal or slightly decreased. IgG immune complexes were measured by SPA-ELISA combined with PEG precipitations, and 8 out of 17 patients (47.1%) were found to have CIC values above the normal control range (geometric mean +2 SD). IgG subclass composition in CIC was analysed. The subclasses in CIC were predominantly in IgG 1 and IgG 3. Because the antibody responses to different antigens have IgG subclass restriction. These results suggest that the change of serum and CIC IgG subclasses in Kawasaki disease may be related to the pathogenesis of the disease.