Proliferation of normal blood CLA-positive T cells incubated in matrices colonized with skin cells from CTCL lesions or normal skin. CFSE-labeled CLA-positive T cells were isolated from peripheral blood and incubated for 1 week in matrices colonized with skin cells from either CTCL or normal skin. T cells were analyzed by flow cytometry. CD3⁺ CLA⁺ CFSE⁺ lymphocytes divided up to 3 times in CTCL skin matrices (open histograms, bold line); this cellular division of T cells could be blocked significantly by addition of antibodies to IL-7 (open histograms, broken line). Normal skin matrices did not support cell proliferation (filled histograms).