At the Investigator s discretion, receipt of a live vaccine within 4 weeks prior to randomization. Efficacy and/or safety of immunization during periods of B-cell depletion have not been adequately studied. It is recommended that a patient s vaccination record and possible requirements be reviewed. Per the investigator s discretion, the patient may have any required vaccination/booster administered at least 4 weeks prior to the initiation of study treatment. Review of the patient s immunization status for the following vaccinations is recommended: tetanus; diphtheria; influenza; pneumococcal polysaccharide; Varicella; measles, mumps and rubella (MMR); and hepatitis B. Patients who are considered to be at high risk for hepatitis B virus (HBV) infection and for whom the investigator has determined that immunization is indicated should complete the entire HBV vaccine series at least 4 weeks prior to participation in the study.