[Skin memory: the clinical implications].

Activated T lymphocytes give rise to daughter cells that can persist for decades in our body, while retaining their ability to provide a strong immune response. Recent advances have highlighted the fact that a significant portion of these memory cells are found directly in peripheral tissues and lack the capacity to migrate to the blood. We have recently shown that these cells, called Tissue Resident Memory T cells (T(RM)), play a major role in the immune response, regardless of the antigenic challenge. They have a backup of circulating central memory T cells (T(CM)) that bear the exact same T cell receptor. For the clinician, this knowledge is very useful as it allows a better understanding and better choice of therapeutics for several cutaneous diseases, such as contact dermatitis and cutaneous T cell lymphoma (Mycosis Fungoides vs Sezary).