A Study to Evaluate the Safety, Tolerability and Pharmacokinetics of Multiple Subcutaneous Injections of ABT-122 in Subjects With Rheumatoid Arthritis

* Diagnosis of Rheumatoid Arthritis (RA) \> 3 months. * On methotrexate (MTX) therapy =\> 3 months and on a stable dose for at least 4 weeks. * Except for MTX, must have discontinued all disease-modifying antirheumatic drugs (DMARDs) for at least 3 months or 5 half-lives, whichever is longer. * Body Mass Index (BMI) is 19 to 38, inclusive. * Other than RA, subjects should be in good general health.

* Evidence of anti-ABT-122 antibody on a serum sample taken at Screening. * History of significant allergic reaction; or history of anaphylactic reaction to any agent; or history of major reaction to any IgG containing product. * History of persistent chronic or active infection(s) requiring hospitalization or treatment with intravenous or oral anti-microbials/antibiotics within the past 30 days. * History or evidence of active tuberculosis (TB) or the subject has evidence of risk factor for latent TB. * Subject has any medical condition or illness other than RA that is not well controlled with treatment.