Immunohistochemical analysis of cultured spindle-like cells derived from skin lesions. The cells were removed from the flask using a mild trypsinization cytocentrifuged and immunostained with MoAbs directed against CD68 (A), HLA-DR (B), and ICAM-1 (C) and counterstained with hematoxylin. The staining pattern for CD68 was cytoplasmic and diffuse (A), for HLA-DR, it was mainly granular (B), and for ICAM-1, it was more evident at the cell surface (C). The large majority of the cultured KS cells were HLA-DR positive. Magnifications are (A) ×630, (B) ×700, and (C) ×800.