Quantitative real-time polymerase chain reaction analysis in herpes simplex virus keratitis with and without epithelial involvement

Purpose To evaluate the quantitative real-time polymerase chain reaction (qRT-PCR) analysis in herpes simplex virus (HSV) keratitis with and without epithelial involvement. Methods This cross-sectional study was performed on 70 patients with different HSV types and an active ocular lesion in Farabi Eye Hospital, Tehran, Iran. From these 70 patients, 171 samples were collected, including seventy tear samples and 33 scraping samples from involved eyes; and 68 samples from uninvolved fellow eyes. Samples were frozen at - 70 degrees C until DNA extraction was performed. Quantity of HSV was measured using qRT-PCR in all three samples. Results The mean age of HSV patients was 52.19 +/- 20.42 years (range, 4-85 years). Forty-one (58.6%) HSV patients had epithelial involvement, and 29 (41.4%) patients did not have epithelial involvement. In PCR-positive cases, the mean number of viruses in affected eyes' tears (8,831,234 +/- 4,051,979) was significantly higher than uninvolved eyes' tears (182,603 +/- 69,141) (P = 0.02). The mean of PCR in HSV patients with and without epithelial involvement was 10,320,269 +/- 5,329,800 and 1,469,419 +/- 1,070,396, respectively (P = 0.04). The qRT-PCR of involved tears in both groups (with and without epithelial involvement) was significantly higher than unaffected eyes' tears (P < 0.0001 and P = 0.01, respectively). In cases with and without epithelial involvement, the cutoff points of viral load in involved eyes' tears were 281,000 and 126,000 copies, respectively. Conclusion The results indicated that qRT-PCR is an excellent method for the detection of herpes simplex keratitis.