Complement consumption in a patient with necrobiotic xanthogranuloma and paraproteinemia

Necrobiotic xanthogranuloma and paraproteinemia have been reported to be associated with acquired deficiency of the early components of the classic pathway of complement. We describe a patient in whom activation of complement was suggested by a high level of C3d, an accelerated catabolism of C1q, and a rapid consumption of C4 after an intravenous infusion of fresh-frozen plasma. This infusion was followed by an episode of pulmonary edema. Patients with complement deficiency or depletion should be monitored closely while receiving plasma, to avoid this potential complication.