Th1/Th2-like immunity and resistance to herpes simplex labialis

Area of Science:

• Immunology
• Virology
• Dermatology

Background:

• Recurrent herpes simplex labialis (cold sores) is common.
• Immune mechanisms underlying resistance to cold sores are not fully understood.

Purpose of the Study:

• To investigate the immunologic mechanisms associated with resistance to recurrent herpes simplex labialis.
• To compare immune responses between individuals with frequent cold sore episodes, seropositive individuals without cold sores, and seronegative individuals.

Main Methods:

• Assayed serum antibody titers and peripheral blood mononuclear cell (PBMC) cytokine production (IFN-gamma, IL-2).
• Exposed patients with a history of frequent episodes to ultraviolet radiation (UVR) to induce experimental lesions.
• Compared immune assay results between groups and correlated them with lesion development and severity.

Main Results:

• Patients with frequent cold sores (H+S+) showed higher HSV antibody titers and trends toward lower levels of HSV-specific IFN-gamma and IL-2 compared to controls (H-S+).
• In contrast, H+S+ patients who developed UVR-induced lesions had lower antibody titers and trends toward higher IFN-gamma and IL-2 levels.
• UVR-induced lesion size and duration positively correlated with IFN-gamma and IL-2 levels.

Conclusions:

• A Th1-like cytokine response (IFN-gamma and IL-2) may be associated with resistance to naturally occurring herpes labialis episodes.
• The development and severity of experimental UVR-induced herpes labialis appear to be regulated differently, potentially involving an immunopathologic mechanism.