 - Arm II: Patients receive rituximab IV over 2-4 hours on days 1 and 2 of course 1 and on day 1 of courses 2-6 and pentostatin IV over 30 minutes and cyclophosphamide IV over 30 minutes on day 1. Patients also receive pegfilgrastim SC on day 2. Treatment repeats every 21 days for 6 courses in the absence of disease progression or unacceptable toxicity. 