Inability to comply with study and/or follow-up procedures History of HIV (a documented positive lab value within one year of enrollment) Presence of active infection New York Heart Association Classification III or IV heart disease Concomitant malignancies or previous malignancies within the last five years, with the exception of adequately treated basal or squamous cell carcinoma of the skin or carcinoma in situ of the cervix History of psychiatric disorder At the Investigator's discretion, receipt of a live vaccine within 4 weeks prior to randomization At the Investigator's discretion, positive Hepatitis C serology Known history of diabetes mellitus or a Hemoglobin A1c result > 6.0% within 90 days prior to enrollment