Monitoring herpesviruses DNA in three cases of acute retinal necrosis by real-time PCR

Background: It is not clear whether quantitative analysis of viral DNA in ocular specimens is correlated with disease activities of acute retinal necrosis (ARN). Objectives: To monitor viral load in ocular specimens collected from patients with ARN by real-time polymerase chain reaction (PCR). Study design: Ocular samples (aqueous humor and vitreous) were serially collected from three patients with ARN. Viral load in those samples was evaluated by real-time PCR. Result and conclusion: In case 1, large amounts of varicella zoster virus (VZV) DNA (4.8×10⁶ to 5.5×10⁶ copies/ml) were detected in aqueous humor during the first 2 weeks after admission. The viral load in vitreous was higher than that in aqueous humor at the time of vitrectomy. As ophthamoscopic findings and visual acuity improved through acyclovir (ACV) treatment, the viral load in aqueous humor decreased dramatically. In case 2, the patient was treated with intravenous ACV at first, but clinical features did not improve. The herpes simplex virus (HSV)-2 viral load in aqueous humor remained stable (2.3×10³ to 2.8×10³ copies/ml) during the first 3 weeks after admission. The amount of HSV-2 DNA in vitreous was again higher than that in aqueous humor. Although neither clinical features nor viral load had changed by ACV, intra-ocular ganciclovir (GCV) injection improved clinical features, and decreased viral load to undetectable levels. In case 3, the patient developed ARN within 1 month after the onset of varicella and demonstrated only mild clinical symptoms. She was treated with ACV administration alone and recovered quickly. In contrast to case 1, the copy number of VZV DNA at the time of admission was low (9×10² copies/ml), and decreased quickly in response to the treatment. Correlation between viral load in ocular specimens and clinical course of the disease was demonstrated in these patients.