Lack of evidence for epstein‐barr virus infection in myasthenia gravis thymus

Abstract

A role for Epstein-Barr virus (EBV) in myasthenia gravis pathogenesis has been suggested recently. Using in situ hybridization for the detection of the EBV-encoded RNAs and EBNA1-specific immunohistochemistry, we found no latently infected cells in a series of thymus specimens from patients with myasthenia gravis showing lymphofollicular thymitis. In addition, using immunohistochemistry and an antibody specific for the viral immediate early protein BZLF1, no evidence of lytic EBV infection was seen in these cases. Our results therefore do not support a direct role of thymic EBV infection in the pathogenesis of myasthenia gravis.

Implication of double‐stranded RNA signaling in the etiology of autoimmune myasthenia gravis

“…In addition, this research group observed poliovirus‐infected macrophages and the presence of Epstein–Barr virus (EBV)‐infected B cells in MG thymus . Nevertheless, the observation of EBV‐positive cells in MG thymus was not confirmed by 2 other independent investigations . A recent study, showing higher levels of antibodies against the type 1 nuclear antigen of EBV in the serum of MG patients compared to healthy controls, reopened the debate .…”

High anti‐EBNA‐1 IgG levels are associated with early‐onset myasthenia gravis

“…Of note, another recent report was unable to support a direct role of thymic EBV infection in the pathogenesis of myasthenia gravis. [18]. Unfortunately, because thymectomy in our series was performed mainly in cases with thymoma, the number of cases with hyperplastic thymus was low to examine correlations with EBNA‐1 titers.…”

Lack of Epstein-Barr virus infection in Chinese myasthenia gravis patients

“…Our study goal was to evaluate whether EBV infection was present in a cohort of 30 Chinese patients with MG and to determine the frequency of any such incidence. Using standardized evaluation techniques for EBV infection , we did not find any evidence of EBV infection in these MG cases.…”

“…However, two independent studies did not find evidence of EBV infection in thymic specimens of patients with MG . Of note, all the aforementioned studies were conducted in Caucasian subjects . Our study goal was to evaluate whether EBV infection was present in a cohort of 30 Chinese patients with MG and to determine the frequency of any such incidence.…”