Abstract
Purpose: :
Acute retinal necrosis and progressive outer retinal necrosis are due to herpes simplex virus (HSV) infection of the retina. Herpes simplex encephalitis may also occur in some patients with acute retinal necrosis. Toll like receptors (TLR) are thought to play an important role in the natural immunity of humans. TLR3 deficiency has been described as a possible mechanism for herpes simplex encephalitis. Given the possible common mechanism of infection in patients with encephalitis and acute retinal necrosis, we sought to analyze our patients with known acute retinal necrosis for mutations in genes in the TLR pathway.
Methods: :
11 patients with acute retinal necrosis were identified. 8 patients were PCR positive for herpes infection. 3 of the 11 patients also had a history of herpes associated encephalitis. Genetic analysis was performed of several genes including STAT1, NEMO, TRL3 and UNC93B.
Results: :
None of our patients had the previously described TLR3 or UNC93B mutations associated with HSV encephalitis. A few novel mutations were found. Several polymorphisms in both TRL3 and UNC93B were also identified at greater frequency in our patients than seen in the general population.
Conclusions: :
TRL3 mutations implicated in the pathogenesis of HSV encephalitis were not identified in our cohort of patients with acute retinal necrosis and combined acute retinal necrosis and HSV encephalitis. Several novel mutations and possible risk polymorphisms were identified, though their role in TLR deficiency is not known at this time. TLR deficiency may play a role in the pathogenesis of HSV associated retinal necrosis.
Keywords: retinitis • genetics • herpes simplex virus