<prompt> Rh factor is a:AntibodyMucopolysaccharideLipoproteinGlycoprotein  <response>: A Rheumatoid factor is an antibody auto-antibody of any immunoglobulin class directed against a specific region of the Fc fragment of human IgG. Ref: Harrisons Principles of Internal Medicine, 17th Edition, Page 2155; Davidsons Principles and Practice of Medicine, 20th Edition, Page 1074 