The purpose of this study was to assess the ability of active immunotherapy to induce tumor regressions in relapsed low-grade lymphoma. B-cell malignancies express a unique antigen, the immunoglobulin idiotype (Id), on their surface. Each B-cell harbors a unique genetic sequence used in the production of immunoglobulin idiotype. B-cell lymphomas arise from the clonal expansion of a single B-cell and all tumor cells express that unique Id protein. No normal B-cells possess that Id on their cell surface. Hence, Id protein should serve as an ideal target for individualized active immune therapy of NHL. Many of the antigens expressed by tumors (including Id) are only weak immunogens. To augment the immune response against Id, the Id protein must be chemically coupled to a strongly immunogenic protein. Keyhole limpet hemocyanin (KLH) is a commonly used protein carrier capable of augmenting the body's immune reaction against Id protein. While initial studies reported a predominately humoral (antibody) response, cellular immunity (T-cells) also plays a critical role in anti-tumor immunity. GM-CSF is a hematopoietic growth factor that stimulates T-cell proliferation.