T-cell malignancies are a broad, heterogenous group of diseases and include T-cell lymphomas and T-cell leukemias. T-cell lymphomas are a heterogeneous group of malignancies involving T lymphocytes and generally characterized by a poor prognosis.
Among them, cutaneous T-cell lymphomas involve primarily the skin. Mycosis fungoides and Sézary syndrome are the most frequent cutaneous T-cell lymphomas. The inventors showed
that both circulating malignant and non-malignant T cells express CD51 in patients with Sézary syndrome. CD51 therefore appears as a useful diagnostic, prognostic and follow-up marker, and as a potential therapeutic target in T-cell lymphomas.