<prompt> Rh factor isIgM antibodyMucppolysaccharideIgG antibodyFatty acid  <response>: A i.e. IgM antibody - Rheumatoid Rh factor in rheumatoid ahritis is an autoantibody of IgM class directed against Fc fragment of IgGQ. - Antibodies immunoglobins are glycoproteins. And Rh factors is an autoantibody of any immunoglobin class directed against Fc fragment of IgG immunoglobin Davidson. 