The present invention relates to amino acid sequences that are directed against/and or that can specifically bind (as defined herein) Interleukin-6 Receptor (IL-6R), as well as to compounds or constructs, and in particular proteins and polypeptides, that comprise or essentially consist of one or more such amino acid sequences. In a specific aspect, the present invention provides amino acid sequences and polypeptides that are capable of binding to two or more different antigenic determinants, epitopes, parts, domains of IL-6R, also referred to as “multiparatopic” (such as e.g. “biparatopic” or “triparatopic”, etc.) amino acid sequences and polypeptides. The invention also relates to nucleic acids encoding such amino acid sequences and polypeptides, methods for preparing such amino acid sequences and polypeptides, host cells expressing or capable of expressing such amino acid sequences or polypeptides, compositions, and in particular to pharmaceutical compositions, that comprise such amino acid sequences, polypeptides, nucleic acids and/or host cells and to uses of such amino acid sequences or polypeptides, nucleic acids, host cells and/or compositions, in particular for prophylactic, therapeutic or diagnostic purposes.
