More evidence giant cell arteritis may be triggered by varicella-zoster virus

In this study, the authors found a high prevalence of varicella-zoster virus (VZV) in patients with giant cell arteritis (GCA), suggesting that VZV may trigger giant cell arteritis immunopathology. 

Investigators analyzed VZV infection in 70 temporal artery specimens collected over a 30-year period from patients with clinically suspected GCA. All specimens had temporal arteries that were histopathologically negative for GCA. 

Immunohistochemical analyses detected VZV antigen in 64% of the suspected GCA specimens, compared to just 22% in controls (P<0.001). Of 45 GCA-negative participants whose TAs contained VZV antigen, 1 had histopathological features characteristic of GCA, and 16 showed adventitial inflammation adjacent to viral antigen. 

The authors noted that the prevalence of VZV in specimens from this study was statistically similar to their previous study, with VZV detected in 73% of GCA-positive temporal arteries (P=0.23). In both GCA-negative and positive specimens, viral antigens were most frequently detected in the adventitia, predominantly around the nerve bundles. These findings reinforce earlier findings that VZV may spread transaxonally after the activation from ganglia and initially infects the arterial adventitia. 

The authors speculate that antiviral treatment may provide additional benefit to patients with biopsy negative GCA treated with corticosteroids, although future studies will be needed to determine optimal antiviral dosage and duration.