 ARM A: Patients receive rituximab IV over 2-6 hours once weekly in weeks 1-4 and ipilimumab IV over 90 minutes once weekly in weeks 1, 4, 7, and 10. Patients then receive ipilimumab IV over 90 minutes and rituximab IV over 2-6 hours once every 12 weeks for up to 1 year in the absence of disease progression or unacceptable toxicity. 