Interleukin 8 and monocyte chemoattractant protein-1 in patients with juvenile rheumatoid arthritis. Relation to onset types, disease activity, and synovial fluid leukocytes

Objective. To measure serum and synovial fluid (SF) levels of interleukin 8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) in patients with juv enile rheumatoid arthritis (JRA) and to compare them with adult rheumatoid factor-positive rheumatoid arthritis (RA), Methods. IL-8 and MCP-I were measured by immunoassay (1) in sera obtained f rom 55 children with JRA and from 16 adults with RA, and (2) in SF obtained from 30 children with JRA and II adults with RA. Results, Patients with active systemic JRA had serum levels of IL-8 and MCP -I higher than in controls (p < 0.01) and in patients with active polyartic ular or pauciarticular JRA (p < 0.05), In patients with RA serum MCP-1 leve ls were higher than in patients with the 3 JRA onset types, while no differ ence was found for IL-8 levels. Patients with systemic JRA and with current systemic features had serum levels of IL-8 and MCP-1 higher (p = 0.03 and p = 0.04, respectively) than patients in which systemic features had subsid ed, No significant differences in SF IL-8 or MCP-I levels were found among the 3 JRA onset types or adults with RA. In patients with JRA SF leukocyte counts were correlated with SF IL-8 levels (p = 0.002), but not with MCP-1 levels. Moreover, SF levels of both IL-8 and MCP-1 were correlated with tho se of IL-1 beta (p < 0.001) and IL-6 (p<0.01), but not with those of TNF-al pha, Conclusion. Elevated serum levels of IL-8 and MCP-1 in patients with system ic JRA with current systemic features at sampling suggest systemic producti on of the 2 chemokines during systemic phases of the disease. Similar SF le vels of IL-8 and MCP-1 among the 3 JRA onset-types and RA suggest comparabl e local production of the 2 chemokines.