von Willebrand factor antigen—a possible biomarker of disease activity in childhood central nervous system vasculitis?

OBJECTIVE: The main objective was to develop a trajectory for von Willebrand factor (vWF) antigen in childhood primary CNS vasculitis (cPACNS) after treatment and compare this with disease activity and other inflammatory markers. METHODS: A single-centre cohort study of consecutive children diagnosed with cPACNS was performed. Demographic, clinical, laboratory, imaging and histological data were collected at diagnosis and during standardized clinic visits. Outcome measures included disease activity measured by physician global assessment and serial measures of vWF antigen. Analysis included descriptive statistics and parametric methods. RESULTS: The study cohort consisted of 39 children diagnosed with cPACNS: 25 with angiography-negative cPACNS and 14 with angiography-positive disease. Twenty-one patients were female, median age at diagnosis was 9.8 years, and median follow-up was 18 months. All patients presented with neurological deficits. Disease activity and neurological outcome improved significantly during follow-up. vWF antigen levels were increased at diagnosis in 65% of children with cPACNS and were decreased significantly after treatment. In contrast, levels of CRP and ESR fluctuated over time. Higher vWF antigen levels at diagnosis were associated with lower measures of disease activity at 12 months. CONCLUSION: In our study, all children with cPACNS improved over time. Changes in CRP and ESR, other laboratory tests, and MRI did not consistently reflect altered disease activity. However, vWF antigen may help clinicians to identify changes in disease activity during follow-up and predict treatment response. Controlled studies are necessary to evaluate the sensitivity and specificity of vWF antigen as a biomarker of disease activity.