Decreased CD7 expression in cutaneous infiltrates of HIV-1+ patients. Military Medical Consortium for the Advancement of Retroviral Research (MMCARR).

CD7 is an early T-cell marker that has been used in the diagnosis of stem cell leukemias. Loss of expression of CD7 with a battery of other mature T-cell markers has also been used as one criteria in the diagnosis cutaneous T-cell lymphomas. More recently, CD7-negative T cells have been shown to be a normal population of T cells in the peripheral blood and the skin, and may represent a mature T-cell population with a different pattern of maturation and activation. In addition, in HIV-1 disease expansion of CD7-negative T cells has been found in the peripheral blood. We evaluated the number of CD7-negative T cells in skin infiltrates to determine whether there was an increase of CD7-negative T cells. We studied T-cell markers including CD3, CD4, CD7, CD8, CD20, CD29, and HLA-DR on cutaneous biopsy material from inflammatory dermatoses in 57 patients with HIV-1 disease in Walter Reed stages (WR) 1-6, and in 14 HIV-1-negative patients WR0. The inflammatory infiltrates showed a moderate to marked decrease in CD7 expression on CD3+ T cells in benign inflammatory infiltrates of the majority of HIV-1+ patients. The majority of HIV-1-negative patients showed no decrease in CD7 expression, although 5 of 14 showed a moderate decrease and 1 of 14 showed a marked decrease. Although the nature of CD7- T cells has not been clearly defined, this population of mature T cells appears to have distinct immunologic properties as well as a trophism for skin. Better characterization of these T cells, as well as factors that promote their maturation and activation, may give clues to the high incidence as well as the pathogenesis of skin disease in HIV-1+ patients.