Cytokines and soluble CD4 and CD8 molecules in rheumatoid arthritis: relationship to systematic vasculitis and microvascular capillaroscopic abnormalities.

Vascular involvement in rheumatoid arthritis (RA) is associated with a wide range of extra-articular complications. Damage to internal organs occurs through a widespread disorder of the microvasculature. Vasculitis, as an integral part of the disease process, is associated with immune system abnormalities. To evaluate the relationship between capillaroscopic abnormalities, extra-articular involvement and immunological alterations, serum levels of soluble CD4 (sCD4), CD8 (sCD8), tumour necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6) and soluble interleukin-6 receptor (sIL-6R) were determined by an enzyme-linked immunosorbent assay in 80 RA patients. In all patients with signs of extra-articular manifestations, severe or moderate changes in nailfold capillaroscopy were found. Serum levels of TNF-alpha, IL-6, sIL-6R and sCD4 were significantly higher in RA patients compared with 30 healthy subjects. RA patients with clinical signs of systemic vasculitis showed significantly higher levels of TNF-alpha and IL-6 compared with those without vascular involvement. Moreover, a significant correlation between sCD4 levels and the capillaroscopy findings was found. These results point to a pathogenic role of the cytokine network in rheumatoid vasculitis and further may suggest an important role of cellular immune activation in the pathogenesis of microvascular damage.