Increased soluble p55 and p75 tumour necrosis factor-α receptors in patients with hepatitis C-associated mixed cryoglobulinaemia

Abstract

Summary To investigate whether tumour necrosis factor α (TNFα) plays a role in the pathogenesis of hepatitis C virus-associated mixed cryoglobulinaemia (HCV-MC), we measured soluble TNFα and its soluble p55 (sTNFR1) and p75 (sTNFR2) receptors in the serum of patients with HCV-MC. TNFα, sTNFR1 and sTNFR2 were measured in the serum of 32 patients with HCV-MC, 18 patients with hepatitis C without MC (HCV) and 18 healthy volunteers, using specific immunoassays. Correlations between clinical and biological parameters and the concentrations of TNFα and sTNFRs were established by studying detailed clinical records of the 32 HCV-MC patients. Although higher, TNFα levels were not significantly different in HCV-MC patients compared with healthy or HCV controls. sTNFR1 and sTNFR2, however, were significantly higher in HCV-MC compared with controls or with HCV patients, and higher concentrations of sTNFR1 and sTNFR2 were observed in patients with severe visceral vasculitis, compared with patients with limited purpura. sTNFR1 concentrations positively correlated with fibrinogen levels but TNFα, sTNFR1 and sTNFR2 did not correlate with other biological parameters such as rheumatoid factor concentrations, CH50 or C4 values. These data suggest a role for TNFα in the pathogenesis of the immune complex-mediated vasculitis associated with HCV-MC.