Interrelationship between ultraviolet light and recurrent herpes simplex infections in man

Area of Science:

• Immunology
• Dermatology
• Photobiology

Background:

• UVB radiation (UVB) exposure can impair the skin's ability to develop contact hypersensitivity (CH).
• A UVB-susceptible (UVB-S) trait, characterized by reduced CH induction after UVB exposure, is more frequent in individuals with skin cancer.
• Recurrent herpes labialis is often linked to sun exposure, suggesting a potential role for UVB sensitivity.

Purpose of the Study:

• To investigate the association between the UVB-S trait and recurrent herpes labialis.
• To determine if UVB sensitivity is a risk factor for sun-induced herpes simplex virus-1 reactivation.

Main Methods:

• 31 volunteers with recurrent herpes labialis underwent epicutaneous dinitrochlorobenzene (DNCB) application after UVB exposure to assess CH.
• Participants were evaluated for UVB-S or UVB-resistant (UVB-R) phenotypes.
• A subset of participants received facial UVB exposure to monitor for herpes labialis recurrence.

Main Results:

• 65% of individuals with recurrent herpes labialis exhibited the UVB-S trait, a higher frequency than in the general population.
• A history of sun-induced herpes labialis did not predict UVB phenotype.
• UVB-S individuals were more likely to develop recurrent herpes labialis after facial UVB exposure compared to UVB-R individuals.

Conclusions:

• The UVB-S trait is more prevalent in individuals suffering from recurrent herpes labialis.
• UVB sensitivity may increase the risk of herpes simplex virus-1 reactivation following sun exposure.
• This suggests a potential link between impaired immune response to UVB and recurrent viral infections.