HIV infection predisposes skin to toxic epidermal necrolysis via depletion of skin-directed CD4⁺ T cells.

BACKGROUND: A greater incidence of adverse cutaneous drug eruptions, including toxic epidermal necrolysis (TEN), occurs among HIV-infected patients.

OBJECTIVE: We sought to determine if immunophenotypical differences exist in the inflammatory infiltrates of TEN lesions from HIV-infected individuals versus noninfected individuals.

METHODS: The inflammatory infiltrates in 12 cases of TEN from HIV-positive patients were characterized and compared with the infiltrates present in 12 cases of TEN from HIV-negative patients.

RESULTS: TEN infiltrates consisted of CD3, CD4, and CD8 immunoreactive T lymphocytes in both the dermis and epidermis. HIV infection was associated with an 8-fold increase in the ratio of CD8(+) to CD4(+) T cells infiltrating the dermis (P = .006) and a decrease in the number of dermal CD4(+) cells (P = .044). There was also a significant decrease in the ratio of CD25(+) to CD4(+) cells in the epidermis of HIV-infected skin (P = .011).

LIMITATIONS: This study is limited by small sample sizes.

CONCLUSION: A decrease in the number of skin-directed CD4(+) cells and an increase in the ratio of CD8(+) to CD4(+) cells exists in TEN lesions among HIV-infected individuals and likely contribute to an increased risk of developing drug reactions because of the loss of skin-protective CD4(+)CD25(+) regulatory T cells.