Prognostic implications of quantitative polymerase chain reaction in the severity of necrotizing herpetic retinitis

Abstract

Purpose : The purpose of this study is to analyze the role of RT-PCR testing in prognosis and management of necrotizing herpetic retinitis.

Methods : Retrospective chart review of patients seen in the uveitis and retina clinics at University of Illinois at Chicago with necrotizing herpetic retinitis 2008 -2015. Demographic data, including age, immune status, and treatments were recorded. Dilated fundoscopic examination records were reviewed to determine retina involvement. Results of RT- PCR from intraocular samples were recorded.

Results : 19 eyes of 16 patients were diagnosed with necrotizing herpetic retinitis and had aqueous or vitreous samples. Mean age at disease onset was 47 years (17-69). 9 were female. 6 patients were immunocompromised with 4 HIV positive.
13 eyes had detectable viral DNA. In 6 eyes with varicella zoster virus (VZV), the average number of viral copies was 5.6 x 10⁷ copies/ml. In the remaining 7 eyes (4 herpes simplex virus type 1 (HSV1), 1 with herpes simplex virus type 2 (HSV2), and 2 with cytomegalovirus (CMV)), the average number of viral copies was 1.3 x 10⁷ copies/ml (p=0.05).
Sixteen eyes underwent an average of 3.53 intravitreal injections with either foscarnet, ganciclovir or both. Eyes with VZV received an average of 5.17 injections, with an average of 9.83 clock hours of retina involved. In comparison, those with HSV1/2 or CMV received an average of 2.29 injections (p=0.17) with an average of 6.14 clock hours of retina involved (p=0.10).
The 8 eyes with less than the average number of viral copies (3.3 x10⁷ copies/ml) had an average of 2.63 injections and 7 clock hours of retina involved. In comparison, the 5 eyes with greater than the average 3.3 x10⁷ copies/ml had an average of 5.2 injections (p=0.31) and 9.2 clock hours of retina involved (p=0.35).

Conclusions : In this small series of necrotizing herpetic retinitis, patients with VZV had a higher viral load compared to those with CMV and HSV. VZV was also associated with more severe disease both in clock hours of retina involved and number of intravitreal injection treatments, although this did not reach statistical significance. Viral RT-PCR from ocular samples suggest that viral species among those assayed and number of viral copies have prognostic implications that should be explored in a larger series.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.