Inclusion Criteria

- INCLUSION CRITERIA: Collection of plasma in recipient:

Patients with Immunoglobulin G (IgG) or Immunoglobulin A (IgA) multiple myeloma.

Patients have siblings.

Human leukocyte antigen (HLA) typing of recipient and donor(s) initiated.

Viral antibody screening initiated.

INCLUSION CRITERIA: Recipient:

Patients with IgG or IgA multiple myeloma.

Patients must have achieved at least a partial remission following initial conventional
chemotherapy regimen or after autologous stem cell transplantation. Patients who have
undergone tandem autologous stem transplants are eligible if they meet all other
eligibility criteria. Patients who have achieved at least a partial remission to initial
(primary) conventional chemotherapy will be encouraged to proceed to autologous
transplantation, but will also be eligible for this protocol.

Patients 18-75 years of age. The upper age limit was chosen as it is felt that the
toxicities would exceed potential benefit in this older population.

Karnofsky performance status greater than or equal to 80%.

Life expectancy greater than 6 months.

Left ventricular ejection fraction has to be greater than 50% by either multi-gated
acquisition scan (MUGA) or 2-D echo.

Carbon monoxide diffusing capacity (DLCO) greater than 50% of the expected value when
corrected for hemoglobin (Hb)(96).

Creatinine less than or equal to 1.5 mg/dl and a creatinine clearance greater than or
equal to 50 ml/min.

Direct bilirubin less than or equal to 2.0 mg/dl serum glutamic oxaloacetic transaminase
(SGOT) less than 4x top normal.

M-protein: the concentration in the harvested plasma must be greater than 70% of the total
Ig of the corresponding isotype.

Patients must be human immunodeficiency virus (HIV)-negative. There is the theoretical
possibility that the degree of immune suppression associated with the treatment may result
in progression of HIV infection. Patients may be Hepatitis B core antigen positive, but
surface antigen negative and without evidence of active infection. Patients must be
Hepatitis C negative.

Not pregnant or lactating. Patients of childbearing potential must use an effective method
of contraception. The effects of the chemotherapy, the subsequent transplant and the
medications used after the transplant are highly likely to be harmful to a fetus. The
effects upon breast milk are also unknown and may potentially be harmful to the infant.

Consenting first degree relative matched at 6/6 or 5/6 HLA antigens, this may include a
mismatch at the D locus.

Ability to give informed consent.

INCLUSION CRITERIA: Donor:

Age 18-75 years. As the potential cerebrovascular and cardiac complications may
potentially increase with age, age 75 has been chosen arbitrarily as the upper age limit.
However, if it is determined after initial accrual of patients in this upper age range
that this procedure is relatively safe, the age range may be extended.

No physical contraindications to stem cell donation (i.e. severe atherosclerosis,
auto-immune disease, cerebrovascular accident, active malignancy (97). Patients with
severe atherosclerosis by history will receive a cardiology consult and be judged eligible
on a case by case basis.

Donors must be HIV-negative, hepatitis B surface antigen (HBsAg-), and Hepatitis C
antibody negative. This is to prevent the possible transmission of these infections to the
recipient.

Not pregnant or lactating. Donors of childbearing potential must use an effective method
of contraception. The effects of cytokine administration on a fetus are unknown and may be
potentially harmful. The effects upon breast milk are also unknown and may potentially be
harmful to the infant.

Normal cluster of differentiation 4 (CD4) and cluster of differentiation 8 (CD8) numbers
as defined by Clinical Center standards.

Ability to give informed consent.