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Leukocytoclastic vasculitis following staphylococcal protein A column immunoadsorption therapy. Two cases and a review of the literature.

BACKGROUND
Protein A immunoadsorption is a novel therapy for the treatment of diseases mediated by pathogenic autoantibodies. This procedure consists of circulating patients' plasma through a column containing staphylococcal protein A, which binds to the Fc portion of IgG, enabling removal of IgG. Presently, protein A immunoadsorption is used in the treatment of idiopathic thrombocytopenic purpura, but may be more widely used as an immunomodulator in human immunodeficiency virus infection and metastatic carcinoma.


OBSERVATIONS
We present two histologically documented cases of leukocytoclastic vasculitis in the setting of protein A immunoadsorption. This potentially severe adverse effect is probably more common than the literature reflects and should be recognized by physicians who are treating patients with protein A column pheresis.


CONCLUSIONS
The pathogenesis of protein A therapy-associated leukocytoclastic vasculitis remains unclear. Further study of vasculitis in the setting of protein A column pheresis may lead to modifications of this therapy, resulting in fewer adverse effects. Protein A-associated leukocytoclastic vasculitis may serve as a useful model of the relation of immune complexes and vasculitis.