APOH and rheumatoid arthritis: Anti-cardiolipin autoantibodies were induced in 3.5% (2 of 57) and 1.8% (1 of 55) of our patients with RA, treated respectively with adalimumab or methotrexate only, whereas only one patient in the adalimumab group became positive for IgG and IgM anti-β2GPI autoantibodies.