1. A method for treating low grade or follicular non-Hodgkin’s lymphoma (NHL) comprising administering to a patient a therapeutically effective amount of rituximab during a chemotherapeutic regimen, wherein the chemotherapeutic regimen consists of cyclophosphamide, vincristine, and prednisone (CVP therapy), wherein the method comprises administering 375 mg/m.sup.2 of rituximab, and wherein the method provides a beneficial synergistic effect in the patient.

2. A method for treating low grade or follicular non-Hodgkin’s lymphoma (NHL) comprising administering to a patient 375 mg/m.sup.2 of C2B8 during a chemotherapeutic regimen consisting of cyclophosphamide, vincristine, and prednisone (CVP therapy).

3. A method for treating low grade or follicular non-Hodgkin’s lymphoma (NHL) comprising administering to a patient 375 mg/m.sup.2 of a chimeric anti-CD20 antibody during a chemotherapeutic regimen consisting of cyclophosphamide, vincristine, and prednisone (CVP therapy), wherein the chimeric anti-CD20 antibody is produced from nucleic acid encoding a light chain variable region comprising the amino acid sequence in SEQ ID NO: 1 and a heavy chain variable region comprising the amino acid sequence in SEQ ID NO: 2, and comprises human gamma 1 heavy-chain and kappa light-chain constant region sequences.

4. A method for treating low grade or follicular non-Hodgkin’s lymphoma (NHL) comprising administering to a patient a therapeutically effective amount of rituximab during a chemotherapeutic regimen, wherein the chemotherapeutic regimen consists of cyclophosphamide, vincristine, and prednisone (CVP therapy), wherein the method comprises administering 375 mg/m.sup.2 of rituximab once every 3 weeks for 8 doses, and wherein the method provides a beneficial synergistic effect in the patient.

5. A method for treating low grade or follicular non-Hodgkin’s lymphoma (NHL) comprising administering to a patient 375 mg/m.sup.2 of C2B8 once every 3 weeks for 8 doses during a chemotherapeutic regimen consisting of cyclophosphamide, vincristine, and prednisone (CVP therapy).

6. A method for treating low grade or follicular non-Hodgkin’s lymphoma (NHL) comprising administering to a patient 375 mg/m.sup.2 of a chimeric anti-CD20 antibody once every 3 weeks for 8 doses during a chemotherapeutic regimen consisting of cyclophosphamide, vincristine, and prednisone (CVP therapy), wherein the chimeric anti-CD20 antibody is produced from nucleic acid encoding a light chain variable region comprising the amino acid sequence in SEQ ID NO: 1 and a heavy chain variable region comprising the amino acid sequence in SEQ ID NO: 2, and comprises human gamma 1 heavy-chain and kappa light-chain constant region sequences.