Method of treating rheumatoid arthritis using antibody to IL6R

A method of treating or reducing the risk of rheumatoid arthritis in a human in need thereof, the method comprising administering to said human an antibody or antibody fragment that specifically binds an IL6R protein that comprises a mutation Asp358Ala or Val385Ile in SEQ ID NO:

• 78,
• wherein the antibody or antibody fragment comprises a human gamma-1 heavy chain constant region that comprises an amino acid selected from the group consisting of:
• an Asp at position 204 shown in SEQ ID NO:
• 81 and a Leu at position 206 shown in SEQ ID NO:
• 81;and
• wherein said human comprises
• (i) an IGHG1*01 human heavy chain constant region gene segment,or the human expresses antibodies comprising human gamma-1 heavy chain constant regions comprising said selected amino acid and
• (ii) a nucleotide sequence encoding said IL6R protein comprising said Asp358Ala or Val385Ile in SEQ ID NO:
• 78.