Analysis of Prophylactic Parameters and the Relative Cut-off Values for Predicting Stromal Herpes Simplex Keratitis Recurrence

Background: To assess the potential values of clinical characters, tear HSV-sIgA and tear HSV-DNA for prediction of stromal HSK recurrence.Methods: Tears and serum IgG/IgM/IgA from 187 stromal HSK patients were collected. All the 187 tear samples serum samples were tested by ELISA for sIgA/ IgG/IgM/IgA. 146 tear samples were also tested by PCR for tear HSV-DNA. Subsequent follow-up time for monitoring recurrence was performed on all the 187 patients for 2 to 55 months.Results: The positive rate of tear HSV-sIgA was 36.90% (69/187), while for tear HSV-DNA, the positive rate was 10.96% (16/146). Totally 29 of the 187 participants experienced recurrence (15.51%). Previous episodes, tear HSV-sIgA–positive and tear HSV-DNA-positive patients had significantly shorter relapse-free survival (P<0.01, P<0.01 and P=0.0123 respectively). Patients combined univariate and multivariate analysis together, only tear HSV-sIgA was the factor for predicting the risk of herpes keratitis recurrence (HR=2.768, 95% CI =1.148-6.674, p= 0.023). By using Youden index, the concentration of tear HSV-sIgA >= 22.34 U/ul indicated a higher risks for relapse (sensitivity=79.31%, specificity=63.92%, Youden index=0.43).Conclusions: Though episode, tear HSV-sIgA and tear HSV-DNA all have high correlation with recurrent herpes keratitis, only tear HSV-sIgA is considered to be the most appropriated candidate for predicting the risk of recrudescent HSK. As tear HSV-sIgA >=22.34 U/ul, the risks for recurrence will be much higher. It is might be an appropriate cut-off value for predicting recurrence.