Since 2017, a systemic therapy with brentuximab vedotin (BV)4, 5 has been approved for CD30‐positive cutaneous T cell lymphomas as second‐line therapy and shows high efficacy with acceptable tolerability in mycosis fungoides (MF), Sézary syndrome and CD30‐positive lymphoproliferations.6, 7. This evidence concerns the gene TNFRSF8 and Sezary syndrome.