Herpes simplex virus PCR in 2230 explanted corneal buttons

Prior research has shown that herpetic keratitis can lead to corneal damage requiring transplantation. It was already known that HSV DNA can persist in corneal tissues even after clinical resolution. No prior work had resolved the frequency of HSV DNA in corneal buttons from patients with or without a history of herpetic keratitis. This gap motivated a study to assess HSV prevalence using PCR in explanted corneal tissue. The study aimed to determine whether clinical suspicion of HSK correlates with HSV DNA detection. Researchers also sought to compare cycle threshold values between groups. Understanding these patterns could inform post-transplant management strategies. The absence of data on PCR positivity in HSK-negative corneas remained a key limitation.

This study aimed to investigate HSV DNA prevalence in corneal tissue from patients undergoing penetrating keratoplasty. The researchers focused on comparing corneas with and without a history of herpetic keratitis. They sought to quantify HSV PCR positivity rates in both groups. The specific problem addressed was the lack of data on HSV DNA detection in corneal buttons from HSK-negative patients. The motivation was to determine if clinical suspicion accurately predicts HSV presence. The study also aimed to evaluate cycle threshold values as an indicator of viral load. Researchers intended to assess the risk of undetected HSV in corneal transplants. Their goal was to inform treatment protocols for preventing post-transplant HSK.

The study used a retrospective design involving corneal tissue samples from penetrating keratoplasty procedures. Real-time PCR was employed to detect HSV DNA in explanted corneal buttons. A total of 2230 corneal samples from 1860 patients were analyzed. Clinical data were collected, including patient demographics and diagnoses. The samples were categorized into HSK+ and HSK- groups based on clinical history. Cycle threshold values were calculated for each positive sample. Statistical comparisons were made between the two groups. The study spanned eight years, from March 2010 to September 2018.

HSV PCR was positive in 137 (6.1%) corneal samples across all patients. Among HSK+ corneas, 108 (36.2%) tested positive for HSV DNA. In contrast, only 29 (1.5%) HSK- corneas were HSV PCR-positive. The mean cycle threshold value for all positive samples was 30.57 ± 6.01. HSK+ corneas had a mean Ct of 29.8 ± 5.8, significantly lower than HSK- corneas at 32.6 ± 5.9. The difference in Ct values reached statistical significance (p = 0.008). The overall PCR positivity rate was higher in HSK+ than in HSK- samples (p < 0.0001). These findings suggest a strong association between clinical HSK history and HSV DNA detection.

The authors propose that a clinical history of HSK is strongly linked to HSV PCR positivity in corneal tissue. They suggest that approximately 1 in 2.8 HSK+ patients has detectable HSV DNA. The data indicate that even HSK-negative corneas may harbor HSV DNA in about 1.5% of cases. These findings may imply a need for additional antiviral treatment in some transplant recipients. The lower cycle threshold in HSK+ corneas suggests higher viral load. The study highlights the importance of PCR testing in post-transplant care. The results may inform protocols to prevent newly acquired HSK after surgery. The authors emphasize the value of molecular diagnostics in managing transplant-related risks.