HCMV infection and IFITM3 rs12252 are associated with Rasmussen's encephalitis disease progression

Rasmussen's encephalitis (RE) is a rare and severe progressive epileptic syndrome with unknown etiology. Infection by viruses such as human cytomegalovirus (HCMV) has been hypothesized to be a potential trigger for RE. Interferon-induced transmembrane protein-3 (IFITM3) single-nucleotide polymorphism (SNP) rs12252 is associated with the severity of viral infection disease. This study aimed to address the possibility that HCMV infection and IFITM3 rs12252 might be associated with RE disease progression.

The expression of HCMV and IFITM3 was detected with immunohistochemical staining, in situ hybridization and immunofluorescence double staining. The genotype of IFITM3 rs12252 was detected using the Sanger sequencing method. A genetic association analysis was carried out for this SNP and HCMV antigen expression. The relationship between this SNP and the clinical characteristics of these patients was further analyzed. In in vitro study, HCMV replication in SH-SY5Y cells with overexpressed IFITM3 variant was detected by immunofluorescence and real-time RT-PCR.

Elevated expression of HCMV and IFITM3 was observed in the brain tissue of RE patients. Moreover, the IFITM3 polymorphism rs12252-C was found to associate with HCMV high detection and rapid disease progression in RE patients with the IFITM3 rs12252-CC genotype. In vitro study showed the overexpressed IFITM3 variant was associated with HCMV high infection level.

These results suggest that the IFITM3 rs12252-C is associated with the disease progression of RE patients via facilitating persistent HCMV infection in brain tissue and provides new insight into understanding the pathogenesis of RE.