Pathophysiology of viral vasculitis.

Viral infections can cause vasculitides via mechanisms that remain incomple tely understood but may involve circulating immune complexes or endothelial cell infection. Many viruses are capable of infecting the endothelial cell s and modifying their phenotype, thus facilitating thrombosis and inflammat ory cell recruitment. Although the main animal models of vasculitis are vir us-induced viruses are responsible for only a minority of cases of vasculit is in humans. However, a role of undetected viruses in vasculitides current ly classified as primary cannot be completely ruled out.