Background: Because experimental acute retinal necrosis (ARN) induced by herpes simplex virus in mice develops only if mice fail to acquire virus-specific delayed hypersensitivity (DH), although they produce antiviral antibodies (ie, anterior chamber-associated immune deviation), we sought to determine whether a similar inverse correlation exists for patients with varicella-zoster virus (VZV)-induced ARN.
Design: Patients with acute, VZV-induced ARN and age-matched control subjects were skin tested with VZV and purified protein derivative antigens to evaluate DH. Varicella-zoster virus-induced ARN was diagnosed using polymerase chain reaction and intraocular antibody quotient. Serum samples were collected and analyzed for anti-VZV and anti-herpes simplex virus antibody titers. Acute retinal necrosis activity was assessed clinically, and DH skin tests were repeated 3 months after onset when ocular recovery had taken place.
Results: Whereas controls displayed intense DH when tested with VZV and purified protein derivative antigens, a subset of patients with ARN displayed absent VZV-specific DH (although their purified protein derivative responses were normal). Patients with the most severe ARN had the lowest DH responses to VZV antigens. Serum anti-VZV antibody titers were higher in patients with ARN than in controls, and antiviral titer correlated inversely with the intensity of anti-VZV DH responses. Varicella-zoster virus-specific DH responses were restored in patients who recovered from ARN.
Conclusion: Varicella-zoster virus-ARN develops in a setting where DH reactivity to viral antigens is absent, implying that virus-specific DH might ameliorate the severity of ARN.
Clinical relevance: Linking virus-specific DH to vulnerability to ARN in individuals infected with VZV might reveal an underappreciated pathogenic mechanism.