The Role of Varicella Zoster Virus in Giant Cell Arteritis

Giant cell arteritis (GCA), the most common systemic vasculitis in the elderly, is characterized by excruciating unilateral headache/head pain. The temporal artery (TA) is often nodular and tender. Many patients with GCA have jaw claudication and a history of polymyalgia rheumatica. Erythrocyte sedimentation rates and C-reactive protein are elevated. Diagnosis is confirmed by TA biopsy which reveals vessel wall damage and inflammation, with multinucleated giant cells and/or epithelioid macrophages in skip areas. The pathologies of GCA and that of intracerebral varicella zoster virus (VZV) vasculopathy are identical and characterized by granulomatous arteritis, suggesting that GCA represents an extracranial variant of VZV vasculopathy predominantly affecting the TA. Virological analysis of TAs from patients with GCA or from patients with clinically suspected GCA whose TA biopsies were pathologically negative revealed the presence of VZV in most TA biopsies, particularly in skip areas that correlate with adjacent GCA pathology or adventitial inflammation. The presence of VZV in GCA-positive and GCA-negative TAs implicates the virus in triggering the immunopathology of GCA and indicates the need for treatment with antiviral drugs in addition to corticosteroids in both groups of patients. Whether oral antiviral agents and steroids are as effective as intravenous acyclovir and steroids remains to be determined, as does the dosage and duration of treatment.