Immunohistology of the skin rash associated with acute HIV infection.

An immunohistological study of the rash associated with acute HIV infection in a homosexual man was undertaken. The salient feature was an infiltrate of mononuclear cells predominantly of the CD4+ phenotype around the superficial dermal vessels. HIV p24 antigen was detected in occasional cells, possibly Langerhans' cells, of the infiltrate. Their presentation of HIV antigen to local CD4+ cells may lead to a delayed type hypersensitivity reaction.