Human herpesviruses in the cornea

Area of Science:

• Ophthalmology
• Virology
• Molecular Biology

Background:

• Herpes simplex keratitis (HSK) is a significant cause of corneal disease.
• Accurate detection of herpes simplex virus type 1 (HSV-1) in corneal tissue is crucial for diagnosis and management.
• The presence and incidence of other viral pathogens in corneal disease require further investigation.

Purpose of the Study:

• To evaluate the sensitivity and specificity of culture, immunohistochemistry (IHC), polymerase chain reaction (PCR), and in situ hybridization (ISH) for detecting HSV-1 in corneas.
• To compare the incidence of HSV-1 with varicella zoster virus (VZV), cytomegalovirus (CMV), and Epstein-Barr virus (EBV) in corneal tissue.
• To assess the correlation between diagnostic methods and clinical history of HSK.

Main Methods:

• Corneal tissues from 110 patients (52 with HSK history, 58 without) were analyzed.
• Techniques employed included IHC, PCR, ISH, and viral culture.
• Detection of viral DNA and antigens was performed for HSV-1, VZV, CMV, and EBV.

Main Results:

• HSV-1 DNA and antigen were detected in 82% and 74% of HSK corneas, respectively.
• PCR and IHC showed high sensitivity (82% and 74%) and specificity (78% and 85%) for HSV-1 detection.
• VZV DNA/antigen was significantly more frequent in HSK corneas (p<0.001); no EBV or CMV was detected.

Conclusions:

• PCR and IHC are highly sensitive methods for detecting HSV-1 in corneal tissue.
• Combining PCR and IHC enhances diagnostic specificity for HSK to 97%.
• HSV-1 clearance from the cornea may be slow, and co-infection with VZV is possible.