The present invention relates to a nucleic acid molecule encoding a single chain triplebody capable of specifically binding to CD33, CD16 and CD123, wherein said nucleic acid molecule comprises: (a) a nucleic acid molecule encoding a protein represented by SEQ ID NO:1； (b) a nucleic acid molecule represented by SEQ ID NO:2； (c) the nucleic acid molecule of (b), wherein each thymine is replaced by uracil； (d) a nucleic acid molecule encoding a protein having at least 98% sequence identity to the protein of (a)； or (e) a nucleic acid molecule that is degenerate with respect to the nucleic acid molecule of (b) or (c). The present invention further relates to a vector comprising the nucleic acid molecule of the invention, a host cell transformed or transfected with the nucleic acid molecule or the vector of the invention, as well as to a method for the production of a single chain triplebody capable of specifically binding to CD33, CD16 and CD123. Furthermore, the present invention also relates to a single chain triplebody capable of specifically binding to CD33, CD16 and CD123 encoded by the nucleic acid molecule of the invention, as well as to a composition comprising the nucleic acid molecule, the vector, the host cell and/or the single chain triplebody of the invention. Also encompassed by the present invention are the nucleic acid molecule, the vector, the single chain triplebody and/or the composition of the invention for use in the treatment of acute myeloid leukaemia and/or myelodysplastic syndrome, as well as a method of treating acute myeloid leukaemia and/or myelodysplastic syndrome.La présente invention concerne une molécule d'acide nucléique codant pour un triplecorps à chaîne unique capable de se lier spécifiquement à CD33, CD16 et CD123, ladite molécule d'acide nucléique comprenant : (a) une molécule d'acide nucléique codant pour une protéine représentée par SEQ ID NO : 1 ； (b) une molécule d'acide nucléique représentée par SEQ ID NO : 2 ； (c) une molécul
