COMPARATIVE CYTOKINE GENE-EXPRESSION IN SYNOVIAL TISSUE OF EARLY RHEUMATOID-ARTHRITIS AND SERONEGATIVE SPONDYLOARTHROPATHIES

Interleukin 1-beta (1L-1 beta), IL-2, IL-4, IL-5, IL-6, IL-8, tumour n ecrosis factor-alpha (TNF-alpha), transforming growth factor-beta (TGF -beta) and granulocyte-macrophage colony-stimulating factor (GM-CSF) g ene expression was determined in knee synovium of 16 patients with rhe umatoid arthritis (RA) and 16 patients with seronegative spondyloarthr opathies (SSP), by using polymerase chain reaction (PCR) amplification . The pattern of cytokines observed in RA synovium is of the macrophag e-fibroblast type, with the highest expression of IL-1 beta and TGF-be ta. GM-CSF and IL-2 bands were visualized in a minority of patients. N either IL-4 nor IL-5 could be detected. No significant differences wer e observed in the cytokine profile between patients with early (<12 mo nths) and more advanced disease. No differences were observed accordin g to gender, age, rheumatoid factor status and the duration of knee sy novitis. The pattern of cytokines in the synovium of SSP patients is s imilar to that observed in RA patients and does not change in relation to disease duration. IL-2 was the only T-cell cytokine observed. Thes e data provide evidence that the macrophage-fibroblast cells have an i mportant role in early and more advanced rheumatoid synovitis, and sho w that this is also true for SSP peripheral synovitis.