TCR BV CDR3 spectratyping profiles are strongly restricted in CTCL patients. (A) CDR3 spectratypes of CD3⁺ T cells from a representative healthy donor showing highly diverse profiles, reflecting a heterogeneous TCR repertoire. (B) A patient with stage III CTCL with a numerically expanded malignant clone (BV 20), demonstrating multiple monoclonal and oligoclonal profiles. (C-D) Similarly contracted profiles as well as some apparent deletions (BV 4, BV 21) are also found in patients with stage III CTCL without a numerically expanded clone (C) and even in some patients with stage IA CTCL (D). The y-axis represents relative fluorescence intensity (RFI), and the x-axis is CDR3 size (nucleotides).