Since chronic inflammation usually leads to leukocytosis, anemia, thrombocytosis, and elevated ESR, CRP, C3, and C4 [24], laboratory tests including WBC, Hb, PLT, ESR, CRP, C3, and C4 are routinely performed at our clinics to provide another objective parameters for JIA evaluation. This evidence concerns the gene C4A and juvenile idiopathic arthritis.