CD8 Expression in Mycosis Fungoides

Um, Sung Hee; Oh, Chee Won

Abstract

BACKGROUND
Mycosis fungoides (MF) is malignant proliferation of T-helper memory lymphocyte, and only a minority of cases present with other phenotypes such as CD3+, CD4-, CD8+ or CD3+, CD8+. Primary cutaneous CD8+ epidermotropic cytotoxic T-cell lymphoma is known to represent aggressive course. OBJECTIVES: The purpose of this study was to define the CD8 expression in mycosis fungoides and clinical characteristics of CD8+ MFs. In addition, we also studied whether the presence of CD8+ tumor-infiltrating lymphocytes (TIL) had any impact on prognosis of the disease. Patients & METHODS: We retrospectively analyzed 9 patients with MFs by chart review and medical records including age, location, disease duration and patients prognostic features. We also observed CD4 and CD8 expression through the immunohistochemical staining on paraffin-embedded tissue. RESULTS: All the patients, including the present study, showed positive response to CD8 immunohistochemical staining. CD8+ TIL was found in upper dermis (100.0%) of all patients. Two patients had lesion with CD4 TIL more strongly stained than with CD8 TIL, 2 patients with CD8 more than CD4, and the rest showed equally stained lesion. There were no significant differences among the location of CD8 TIL, the density of staining, CD4 TIL/ CD8 TIL and disease prognosis. On long-term follow-up, these results described herein showed that patients with CD8+ cutaneous T-cell lymphomas enjoyed good prognosis. CONCLUSIONS: Our results revealed that all MFs showed positive response to CD8 immunohistochemical staining. Our CD4+ and CD8+ MFs showed clinical features similar to those reported CD4+ and CD8- MFs and enjoyed good prognosis rather than aggressive clinical behavior on long-term clinical follw-up.