Protein A columns for the treatment of patients with idiopathic thrombocytopenic purpura and other indications.

ECI using protein A columns has been designed to selectively remove circulating CICs and IgG from the plasma of patients in whom these substances are associated with their disease. The use of protein A columns appears to be a reasonable alternative to plasmapheresis in many autoimmune disorders for which plasma exchange is indicated. Although preliminary evidence suggests efficacy of plasma exchange, there is a paucity of data indicating that ECI would indeed provide comparable efficacious results. Although the role of ECI using protein A columns for the treatment of ITP continues to be poorly defined, its use in urgent and life-threatening situations in both ITP and HUS appears reasonable. The results of any treatment for chronic refractory ITP continue to be unsatisfactory. However, favorable responses have been achieved using protein A columns, suggesting the need for further investigation. The role of ECI in the treatment of other disorders, including AIDS, TTP, and the treatment of malignancies, where clinical effects are transient, continues to be investigational. The true clinical response rates and duration of responses to ECI using protein A in treating any disorder requires definition in studies involving a larger number of patients with longer followup. The demonstration of the ultimate clinical value of this therapy will require clinical trials comparing its efficacy to other therapies. Although more serious reactions have been reported, toxicities associated with the use of protein A columns are generally transient and mild.