Birmingham vasculitis activity score, disease extent index and complement factor C3c reflect disease activity best in hepatitis C virus-associated cryoglobulinemic vasculitis.

Objective: Clinical measures of vasculitis activity (Birmingham vasculitis activity score = BVAS) and disease extent (Disease Extent Index = DEI), serological and immunological parameters were evaluated for the monitoring of hepatitis C virus (HCV)-associated cryoglobulinemic vasculitis (CV), treated with either cyclophosphamide or interferon-alpha 2b depending on disease severity.
Methods: Serial serum samples of 15 patients with HCV-associated CV were analyzed, and BVAS, DEI, serological and immunological parameters were recorded at diagnosis and during therapy. Eight patients were treated with interferon-alpha 2b and 7 patients with cyclophosphamide.
Results: A complete or partial response of the CV was seen in both treatment groups. BVAS, complement factor C3c, cryoglobulinemia, and rheumatoid factor significantly decreased in both treatment groups during 6 months (p < 0.05). DEI decrease was significant in the cyclophosphamide group (p < 0.05), and there was a trend in the interferon-alpha 2b group (p = 0.06). BVAS and DEI were significantly positively correlated, and both parameters were significantly negatively correlated with C3c levels in both treatment groups (interferon-alpha 2b/cyclophosphamide: r = -0.89, p = 0.001 versus r = -0.87, p < 0.001, respectively) whereas other parameters were not, e.g. ESR and CRP.
Conclusions: Patients with different degrees of disease severity, treated with either cyclophosphamide or interferon-alpha 2b depending on their disease activity, achieved remission of their CV. BVAS, DEI and C3c were especially useful in the follow-up of HCV-associated CV. C3c correlated with BVAS and DEI during therapy and provided additional information about vasculitis activity that was not reflected by other serological or immunological parameters, e.g. ESR or CRP.