The article presents a clinical case of systemic juvenile idiopathic arthritis that began after a spinal injury in a 9-year-old child. The authors noted the importance of dysregulation of the innate immune system in the pathogenesis of systemic juvenile idiopathic arthritis that entitled this variant of the disease to be regarded as autoinflammatory, and not “classical” autoimmune diseases. The article emphasized the leading role played by interleukin 6 in the development of extra-articular manifestations of the disease (fever and thrombocytosis, stimulation of hepatic production of acute-phase proteins of inflammation, anaemia, inhibition of the production of adrenocorticotropic hormone and cortisol, production of growth hormone and procalcitonin, development of amyloidosis), highlighting the need for inhibition of interleukin 6 activity in patients receiving therapy for systemic juvenile rheumatoid arthritis. It stressed the importance of early initiation of therapy from the standpoint of modern understanding of the pathogenesis of this disease: the use of new biological agents, which action is directed at interleukins 1 and 6. This approach is associated with inefficiency of such drugs as corticosteroids, methotrexate, tumour necrosis factor inhibitors. Of no less importance is the fact that the use of these biological agents can significantly reduce the effect of corticosteroids. The course of the presented disease caused some difficulties in its diagnosis and selection of therapy. This is largely due to the fact that the pathology of the sacroiliac joint is extremely difficult to diagnose clinically. Inflammatory immune response associated with trauma may be accompanied by cytokine release, free radical accumulation and apoptosis, pointing to the need to exclude juvenile spondyloarthritis and other juvenile arthritis with a view to administer adequate therapy. In this case, an attempt to treat sacroiliitis as an inflammatory disease was unsuccessful. The focus on persisting fever, arthralgia, anemia, lymphadenopathy, high values of acute phase parameters in the patient, who received courses of antibiotic therapy, allowed the doctors of the surgical department to refer the patient to a specialized pediatric rheumatology department. Resistance to glucocorticoids and a tumour necrosis factor inhibitor (etanercept) was also noted. The successful result of the use of tocilizumab (interleukin 6 receptor blocker) includes: relief of visceral manifestations, normalization of laboratory activity indicators of the disease that persisted for 1.5 years.
