Biological Therapy in Treating Patients With Multiple Myeloma That Has Recurred Following Bone Marrow Transplantation

DISEASE CHARACTERISTICS: Histologically confirmed recurrent or persistent multiple myeloma at least 6 months following allogeneic bone marrow transplantation (BMT) from an HLA identical sibling Must meet one of following criteria to be considered persistent, recurrent, or progressive disease: Residual detectable disease 6-12 months after BMT, as determined by the M protein level or bone marrow involvement, without further evidence of clinical or laboratory improvement on 2 consecutive measurements 4 weeks apart Complete response not achieved 12 or more months after BMT and there is no evidence of progressive improvement At least 25% increase of serum paraprotein (greater than 1.0 g/dL) as measured on two occasions or a 50% increase in urinary light chain excretion (greater than 150 mg/day) as measured on 2 occasions A 10% increase in plasma cells in the bone marrow Disease in complete response but with recurrence of M protein and 10% point increase in myeloma cells in the marrow allowed No lytic lesions alone or new soft tissue plasmacytoma as sole evidence of progression PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: More than 4 weeks Hematopoietic: Not specified Hepatic: Bilirubin no greater than 2.0 times upper limit of normal Renal: Not specified Other: No active infection Not pregnant or nursing Fertile patients must use effective contraception PRIOR CONCURRENT THERAPY: Biologic therapy: Must have received prior allogeneic bone marrow transplantation from an HLA A;B;DR genotypically matched sibling donor No concurrent interferon therapy for relapsed disease Chemotherapy: At least 4 weeks since cyclosporine, methotrexate, azathioprine, or other graft versus host disease (GVHD) prophylaxis/treatment without evidence of flare of GVHD At least 4 weeks since prior chemotherapy for relapsed disease Endocrine therapy: Must be receiving a dose no greater than 0.25 mg/kg prednisone for at least 4 weeks prior to registration without flare of GVHD No prior prednisone dose greater than 0.25 mg/kg in the past 4 weeks Must receive concurrent prednisone of a dose no greater than 0.25 mg/kg Concurrent corticosteroids allowed Radiotherapy: Concurrent palliative radiotherapy allowed if evidence of other evaluable disease other than irradiated bony sites Surgery: Not specified