The most frequently affected joints in children are large and medium joints, knee, ankle, wrist, elbow, hip joints in particular, rarer -small carpal and foot joints. Proliferative-exudative articular alterations quickly lead to the development of lasting deformities and contractures, amiotrophy and hypotrophy [2]. As a rule, JIA takes a progressive course, leads to early incapacitation and reduction in the patients' life quality. Moreover, many authors report that JIA shortens the patients' life span by 10 years at the average, although it may be comparable with population mean values in case of a prolonged controlled treatment [3].Early diagnostics and timely start of adequate immunosuppressive therapy -before the destructive alterations in joints -may change the prognosis, result in a less severe incapacitation degree and bring children back to full life.It should be noticed that immunosuppressive therapy is the basis of pathogenetic approach to treating JIA [4][5][6][7][8].