High Dose Rituximab for Initial Treatment of Indolent B-Cell Lymphomas

* All participants will receive increased-dose rituximab through a vein in the arm once a week for 4 weeks (on Days 1, 8, 15, and 22 of the initial 28-day study cycle). This first cycle of study treatment is called the Induction Phase. If the participant responds well to the Induction Phase, they then may continue to the Maintenance Therapy Phase, where they will receive a lower dose of rituximab once every three months for up to 2 years. * During the Induction Phase, the following procedures will take place before the participant receives each dose of rituximab: medical review, physical exam, performance status, and ECG. Blood tests will be drawn about 30-60 minutes after the first dose of rituximab on Day 1. Samples will be drawn immediately before each dose and again 30-60 minutes after each dose on Days 1, 8, 15 and 22. * During the Maintenance Therapy Phase, the following procedures will take place before the participant receives each dose of rituximab: medical review, physical exam, performance status, ECG, blood tests and response assessments by CT scan.