title: Experience with protein A-immunoadsorption in treatment-resistant adult immune thrombocytopenic purpura.
abstract: Extracorporeal immunoadsorption of plasma to remove IgG and circulating immune complexes (CIC) was evaluated as a therapy for adults with treatment-resistant immune thrombocytopenic purpura (ITP). Seventy-two patients with initial platelet counts less than 50,000/microL who had failed at least two other therapies were studied. They received an average of six treatments of 0.25 to 2.0 L plasma per procedure over a 2- to 3-week period using columns of staphylococcal protein A-silica (PROSORBA immunoadsorption treatment columns; IMRE Corp, Seattle, WA). The treatments caused an acute increase in the platelet count to greater than 100,000/microL in 18 patients and to 50,000 to 100,000/microL in 15 patients. The median time to response was 2 weeks. Responses were transient (less than 1 month duration) in seven of those patients (10%), but no additional relapses were reported over a follow-up period of up to 26 months (mean of 8 months). Clinical responses were associated with significant decreases in specific serum platelet autoantibodies (including anti-glycoprotein IIb/IIIa), platelet-associated Ig, and CIC. Thirty percent of treatments were associated with transient mild to moderate side effects usually presenting as a hypersensitivity-type reaction. Continued administration of failed therapies for ITP, which always included low-dose corticosteroids (less than or equal to 30 mg/d), had no demonstrable influence on the effectiveness of immunoadsorption treatment but did depress the incidence and severity of side effects. The degree of effectiveness of protein A immunoadsorption therapy in patients with treatment-resistant ITP is promising and further controlled studies in this patient population are warranted.
authors.affiliation: North Idaho Cancer Center, Coeur d'Alene.
authors.forename: H W
authors.initials: HW
authors.lastname: Snyder
authors.forename: S K
authors.initials: SK
authors.lastname: Cochran
authors.forename: J P
authors.initials: JP
authors.lastname: Balint
authors.forename: J H
authors.initials: JH
authors.lastname: Bertram
authors.forename: A
authors.initials: A
authors.lastname: Mittelman
authors.forename: T H
authors.initials: TH
authors.lastname: Guthrie
authors.forename: F R
authors.initials: FR
authors.lastname: Jones
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000936:Antigen-Antibody Complex / Q000302:isolation & purification*; D003365:Costs and Cost Analysis; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000302:isolation & purification*; D007164:Immunosorbents / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000276:immunology / Q000628:therapy*; D013205:Staphylococcal Protein A / Q000378:metabolism*
chemical_list: D000936:Antigen-Antibody Complex; D007074:Immunoglobulin G; D007164:Immunosorbents; D013205:Staphylococcal Protein A