Fig. (1) Down-regulation of CD45 on malignant T cells when compared to non-malignant T cells.(A) Non-malignant (MyLa1928) and malignant (MyLa2000) T cells were stained with either a PE conjugated isotype control mAb (left) or an anti-CD45-PE mAb (right) and analysed by flow cytometry. (B) CD45 expression in peripheral blood lymphocytes (PBLs) treated with or without phytohaemagglutinin (PHA) and three malignant T cells derived from early- (PB-1) and late-stage (2A, 2B) CTCL lesions.