DIFFERENTIAL CHANGES OF CORTICOTROPIN-RELEASING HORMONE (CRH) CONCENTRATIONS IN PLASMA AND SYNOVIAL-FLUIDS OF PATIENTS WITH RHEUMATOID-ARTHRITIS (RA)

Corticotropin releasing hormone (CRH) and ACTH concentrations in plasm a and CRH and IL-6 concentrations in synovial fluid in patients with r heumatoid arthritis (RA) were examined to clarify the relationship bet ween cytokines and the hypothalamic-pituitary-adrenal axis (HPA axis). Concentrations of serum amyloid A protein (SAA), one of the acute pha se proteins, were also measured as an indicator of inflammation. CRH a nd IL-G concentrations in synovial fluid were higher in RA patients th an in control patients (osteoarthritis, GA). Plasma ACTH and CRH level s were significantly lower in RA patients than in OA patients. This su ggests that CRH secretion in synovial fluid is regulated differently f rom plasma CRH secretion, as CRH levels in synovial fluid and plasma s howed opposite changes in RA patients. SAA levels were positively corr elated with the levels of CRH or IL-6 in synovial fluid, whereas there was no correlation between CRH and IL-6 levels. The results suggest t hat CRH and IL-6 play important independent roles in producing SAA in synovial fluid.