Outcomes: (1) Determine whether evidence of serum vitamin B12 deficiency, as measure by either a low vitamin B12 level or elevated methylmalonic acid, will be more common in RA patients with anti-GPC Ab. (2) Determine the prevalence of anti-GPC Ab in a group of patients with RA as compared to a group of patients with AITD and with no known systemic or organ specific autoimmune condition.