Juvenile idiopathic arthritis: from aetiopathogenesis to therapeutic approaches

Abstract

Juvenile idiopathic arthritis (JIA) is the most common paediatric rheumatological disorder and is classified by subtype according to International League of Associations for Rheumatology criteria. Depending on the number of joints affected, presence of extra-articular manifestations, systemic symptoms, serology and genetic factors, JIA is divided into oligoarticular, polyarticular, systemic, psoriatic, enthesitis-related and undifferentiated arthritis. This review provides an overview of advances in understanding of JIA pathogenesis focusing on aetiology, histopathology, immunological changes associated with disease activity, and best treatment options. Greater understanding of JIA as a collective of complex inflammatory diseases is discussed within the context of therapeutic interventions, including traditional non-biologic and up-to-date biologic disease-modifying anti-rheumatic drugs. Whilst the advent of advanced therapeutics has improved clinical outcomes, a considerable number of patients remain unresponsive to treatment, emphasising the need for further understanding of disease progression and remission to support stratification of patients to treatment pathways.

Keywords: Aetiology of juvenile idiopathic arthritis; Disease-modifying anti-rheumatic drug treatment; Juvenile idiopathic arthritis; Pathogenesis of juvenile idiopathic arthritis.

Fig. 1

Schematic diagram showing the differences between the normal and JIA joint. The pathological process within the JIA synovial joint is characterised by uncontrolled proliferation of synoviocytes resulting in increased number of layers and thickening of the synovial membrane; rapid pathological angiogenesis; formation of pathological synovium, “pannus”, with uncontrolled growth and invasive properties; accumulation of granulocytes, macrophages, plasma cells, lymphocytes and the production of inflammatory mediators, provoking synovitis. Created with BioRender.com