This study will consist of a screening phase, followed by an in-house phase whereby otelixizumab will be administered to cohorts in a staggered fashion. Six cumulative doses will be evaluated covering a 10-fold dose range in seven cohorts. The starting regimen will be three doses (1.5 mg cumulative dose), increasing to 15 doses (15 mg cumulative dose). Cohorts 1a and 1b have been included as optional lower doses. Serial blood samples will be obtained for clinical laboratory testing, determination of pharmacodynamic markers, serum otelixizumab PK parameters, and immunogenicity. Safety and pharmacodynamic data from the previous dose(s) will be evaluated prior to dose escalation or modification to ensure safety and to achieve target systemic peripheral blood pharmacology. Adverse events, laboratory values, vital signs and ECG's will be monitored closely during this study. All subjects in the study will undergo long-term follow-up out to 48 months to monitor and ensure patient safety.