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.