One of the most intriguing questions in the study of
human autoimmune diseases is what determines the
phenotype and organ specifi city of a disease. In juvenile
idiopathic arthritis, for example, the occurrence of
uveitis is related to explicit risk factors, such as age at
disease onset, sex, the presence of ANA auto-antibodies,
and the subtype of juvenile idiopathic arthritis.28–30
Despite these associations, the immune pathogenesis
underlying the link between arthritis and uveitis is
unknown. However, studies done in the past 5 years
have provided information about the immune
pathogenesis of juvenile idiopathic arthritis, confi rming,
among other things, that the systemic form is a diff erent
disease from other types of juvenile idiopathic arthritis,
with a distinct immune pathogenesis, and should be
treated as would an acquired autoinfl ammatory disease.