Erythema multiforme lesions are associated with expression of a herpes simplex virus (HSV) gene and qualitative alterations in the HSV-specific T-cell response.

A common form of erythema multiforme, herpes-associated erythema multiforme (HAEM), occurs following infection with herpes simplex virus (HSV). Here we report that HSV gene expression and the qualitative nature of the virus-specific T-cell responses are related to HAEM lesion development. Skin from HAEM lesions and 1-3 months healed HAEM lesional skin were positive for the viral DNA polymerase gene (Pol) by polymerase chain reaction. However, gene expression as determined by immunohistochemistry with Pol-specific antibody was seen only in HAEM lesions, suggesting that lesion development is associated with Pol gene expression. Similar HSV-specific T-cell lymphoproliferative responses were seen in peripheral blood mononuclear cells (PBMCs) from patients with acute or healed HAEM lesions or HSV lesions and from HSV-seropositive patients with unrelated inflammatory diseases. However, the T-cell receptor variable (V beta) chain repertoire of HSV-stimulated PBMCs obtained from HAEM lesions was altered; the prevalence of some families of variable chain (namely V beta 16 and V beta 19) was reduced, whereas the prevalence of others was increased (namely V beta 2 and V beta 7). V beta 2 cells were found in HAEM lesional skin positive for Pol antigen, suggesting that these cells home to viral antigen-positive skin.