Abstract
Purpose::
HSV-1 is a cause of acute retinal necrosis (ARN), which may be due to virus reactivation. The purpose of this study was to investigate the prevalence of HSV-1 in human ganglia and to determine whether there is a correlation between an HSV-1 positive ganglion in one location and other positive ganglia on the same or opposite side of the body.
Methods::
Ganglia of nerves that supply the eye were carefully dissected from formalin-fixed cadavers, being careful to avoid cross-contamination between samples. After slightly basic tris/glycine/EDTA overnight washings to reverse formalin cross-linking, DNA was extracted from the trigeminal ganglion (TG), superior cervical ganglion (SCG), ciliary ganglion (CG), and pterygopalatine ganglion (PTG). The presence of HSV-1 DNA was determined using nested PCR for a short unique sequence of the HSV-1 RL2 gene (sensitivity = 40 copies). Statistical comparison of viral presence between ganglia within the same cadaver, both ipsi- and contralaterally, was performed using Chi-square analysis.
Results::
Statistical comparison of the eight ganglia in each cadaver (four on each side) revealed no significant correlation between detection of HSV-1 genomic sequences in one ganglion to the presence of HSV-1 in other ganglia. Ipsilateral comparison between ganglia in different locations, as well as comparison between the same ganglion on different sides of the head, also revealed no statistically significant relationship; so for example, the presence of a positive TG did not predict whether other ganglia on the same side and/or the contralateral side would also be virus-positive.
Conclusions::
Since there was no statistically significant relationship between HSV-1 positive ganglia, consideration of latency in ocularly-related ganglia must be done separately for each ganglion. These results suggest that reactivation of virus any of these ganglia followed by spread of virus to the retina could result in ARN.
Keywords: herpes simplex virus • retina • clinical (human) or epidemiologic studies: prevalence/incidence