KRT10 and rheumatoid arthritis: Taken together with previous evidence of HERV-K antigen-driven autoantibody production (Hervé et al., 2001) and increased HERV-K10 gag expression levels in RA (Ejtehadi et al., 2006), the results obtained by Freimanis et al. (2010) suggest a pathological role for HERV-K10 gag sequences in disease.