Immunohistochemistry for SDF-1 in normal, inflamed, and neoplastic CTCL skin biopsies. (A) Normal skin showing epithelial cells of eccrine glands with a strong SDF-1 immunoreactivity associated with membrane and cytoplasm (magnification 20×/0.40 NA). (B) Chronic dermatitis showing endothelial cells of dermal capillary vessels and scant perivascular lymphoid infiltrate with a strong SDF-1 immunoreactivity (magnification 20×/0.40 NA). (C) SS skin lesion showing a strong SDF-1 immunoreactivity associated with neoplastic T lymphocytes of pathognomonic Pautrier microabscess and neoplastic T lymphocytes that infiltrate dermis and epidermis (magnification 20×/0.40 NA). (D) MF skin lesion showing an SDF-1 immunoreactivity associated with neoplastic T lymphocytes that infiltrate dermis and epidermis (magnification × 40/0.65 NA). (E) SS skin lesion showing neoplastic T lymphocytes with an SDF-1 dotlike immunoreactivity (magnification × 60/0.80 NA). (F) SS skin lesion showing SDF-1 positivity associated with neoplastic T lymphocytes infiltrating the dermis, whereas the intravascular neoplastic T lymphocytes appear SDF-1 negative (magnification 20×/0.40 NA).