Occurrence of Kawasaki disease and systemic lupus erythematosus in a single patient.

A 5-year-old girl who developed systemic lupus erythematosus 3 1/2 years after having had Kawasaki disease was found to be homozygous at both class I and class II MHC loci. This homozygosity suggests that she may also be homozygous for an MHC or non-MHC linked gene that could allow for the appearance of 2 diseases with similar immunoregulatory abnormalities, as occurs in the MRL/1pr/1pr mouse model. Although this is the first report of the occurrence of a second immunologic disorder in a patient with a history of Kawasaki disease, North American children who developed Kawasaki disease early in life are only now reaching the age when other inflammatory disorders become relatively common. Therefore, this group of children will have to be closely observed for the development of other inflammatory disorders.