Regardless of the differences in the underlying pathogenesis of the various types of JIA, the immunopathology involves a predominant abnormality of the adaptive immune system with a consistent overproduction of pro-inflammatory cytokines, many of which, such as TNF-α, IL-1, and IL-6, have been shown to be increased also in the presence of adipose expansion. This evidence concerns the gene TNF and juvenile idiopathic arthritis.