The present invention relates to a high mobility group box 1 (HMGB1) polypeptide, wherein in said HMGB1 polypeptide at least one, preferably two, more preferably three, most preferably all four tyrosine residues at positions corresponding to amino acid positions Y109, Y144, Y155 and/or Y162 of human HMGB1 have been exchanged to an amino acid residue independently selected from glutamic acid, glutamine, aspartic acid, asparagine, homoglutamic acid (2-aminohexanedioic acid), and homoglutamine (2,6-diamino-6-oxohexanoic acid). The present invention further relates to a polynucleotide encoding a polypeptide according to the present invention, to a vector comprising said polynucleotide, and to a host cell comprising said polypeptide, said polynucleotide and/or said vector. Also, the present invention relates to methods, kits, and uses related thereto.