Patients under age 60 with an HLA-matched sibling donor, with minimal prior treatment, defined by less than six months prior chemotherapy, and who are in a minimal residual disease state prior to allogeneic BMT, as defined by the achievement of at least a PR, are eligible. HLA matched sibling donors receive a series of three vaccinations during an eight week period prior to bone marrow harvest. Recipients concurrently receive vaccinations pre-BMT, as well as three booster vaccinations at weeks 12, 16, and 24 post-BMT. Id-KLH (0.5 mg) is administered s.c. GM-CSF (250 micrograms/m(2)) is administered s.c. locally with the vaccine on the day of vaccination and for the three consecutive days following vaccination. The objective of this protocol is to induce cellular and humoral immunity in marrow transplant donors and recipients against the unique idiotype expressed by the recipient's myeloma.