Metabolomics: An Emerging Approach to Understand the Pathogenesis of Reactive Arthritis

Reactive arthritis (ReA) is characterized by immune-mediated sterile synovitis brought on by an infection that enters the body through the gastrointestinal or urogenital tracts from a distance. The diseases known as seronegative spondyloarthropathy (SSA) include undifferentiated arthritis (uSpA) and reactive arthritis (ReA). Cytokines are crucial in orchestrating an effective immune response to eliminate bacterial infections, such as those seen in ReA (Reactive Arthritis) conditions. The balance between Th1 and Th2 cytokines is particularly important in determining the outcome of infections associated with ReA. TNF-α and IFN-γ are key antibacterial Th1 cytokines that promote cell-mediated immunity, essential for effective cellular responses against intracellular bacteria. In contrast, Th2 cytokines like IL-4, IL-5, IL-9, and IL-13 are more involved in generating humoral immunity and allergic responses. The mechanisms underlying the differentiation of T helper lymphocytes, which lead to a skewed cytokine secretion profile, remain unclear. Several factors, including the local inflammatory environment, IL-12 levels during T cell priming, variations among antigen-presenting cells (APCs), and antigen dose, have been suggested as potential contributors. This review will explore the critical role of metabolomics in cytokine production and its profound impact on the pathogenesis of reactive arthritis.