CD8-POSITIVE TUMOR-INFILTRATING LYMPHOCYTES INFLUENCE THE LONG-TERM SURVIVAL OF PATIENTS WITH MYCOSIS-FUNGOIDES

Background: Nonneoplastic mononuclear cells commonly infiltrate lesions of mycosis fungoides. Objective: We sought to determine the immunophenotypic characteristics of these cells and to determine whether the presence of CD8(+) tumor-infiltrating lymphocytes has an impact on prognosis. Methods: Skin biopsy specimens from 78 patients were stained with immunopleroxidase techniques to determine their phenotypic characteristics. The proportion of CD8(+) tumor-infiltrating lymphocytes was quantified and compared with stage of disease and survival rate. Results: Patients with more limited T-stage disease tended to have a higher proportion of CD8(+) cells in their skin biopsy specimens, compared with patients with more advanced T-stage disease. Within each T-stage patients with a larger proportion of CD8(+) cells had a better survival rate than those with fewer CD8(+) cells (p < 0.05 for T1 and T3). A multivariate analysis confirmed the importance of T stage (p = 0.0006), overall stage (p = 0.0112), and CD8 positivity (p = 0.0335) in this cohort of patients. Conclusion: CD8(+) tumor-infiltrating lymphocytes in mycosis fungoides correlate with improved survival rate and may exert an antitumor effect rather than being mere bystander cells.