Transfusion-induced serum sickness.

Background: Transfusion-induced serum sickness reactions are rarely reported in the literature. The Type III hypersensitivity reaction to heterologous proteins involves deposition of complement and immune complexes in small vessel walls resulting in a leukocytoclastic vasculitis. A case of a multiply transfused patient with several episodes of serum sickness reactions is presented.

Case Report: A 61-year-old man with myelodysplastic syndrome type refractory anemia presented with fever, rash, and polyarthralgia 5 days after transfusion of red blood cells (RBCs). By transfusing plasma-free "washed" RBCs, similar serum sickness reactions were avoided.

Results: Laboratory investigation showed an increase of serum creatinine, hematuria, and proteinuria. Levels of circulating immune complexes immunoglobulin G and immunoglobulin M were increased. Hypocomplementemia could not be demonstrated. Histopathologic examination of the skin showed leukocytoclastic vasculitis, compatible with serum sickness.

Conclusion: The importance of early recognition of transfusion-induced serum sickness reactions is emphasized, because this can reduce unnecessary morbidity from this unusual complication of transfusion. To prevent this type of transfusion reaction, patients who experienced serum sickness-like reactions after transfusion should only receive plasma-free washed RBCs.