DECREASED CD7 EXPRESSION IN CUTANEOUS INFILTRATES OF HIV-1 PLUS PATIENTS

CD7 is an early T-cell marker that has been used in the diagnosis of s tem 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 diagno sis cutaneous T-cell lymphomas. More recently, CD7-negative T cells ha ve been shown to be a normal population of T cells in the peripheral b lood 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 perip heral blood. We evaluated the number of CD7-negative T cells in skin i nfiltrates 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 derma toses in 57 patients with HIV-1 disease in Waiter 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 cell s in benign inflammatory infiltrates of the majority of HIV-1 + patien ts. 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 sh owed a marked decrease. Although the nature of CD7 - T cells has not b een clearly defined, this population of mature T cells appears to have distinct immunologic properties as well as a trophism for skin. Bette r characterization of these T cells, as well as factors that promote t heir maturation and activation, may give clues to the high incidence a s well as the pathogenesis of skin disease in HIV-1 + patients.