Idiopathic autoimmune thrombocytopenia: evidence for redistribution of platelet antibodies into the circulation after immunoadsorption treatment.

Platelet antibodies are detectable in only about 50% of patients with chronic autoimmune thrombocytopenia (AITP). We determined platelet antibodies against GPIa/IIa, GPIb/IX, GPIIb/IIIa, and GPV and reticulated platelets in three female patients with AITP, before and after immunoadsorption treatment. None of the three patients' sera contained platelet antibodies prior to treatment. Thereafter, anti-GPIIb/IIIa, anti-GPIb/IX (n = 3), and anti-GPV (n = 1) were detectable in the patients' sera. These antibody specificities were also found in the eluates from the immunoadsorption columns. Only one patient had elevated levels of reticulated platelets. Immunoadsorption treatment did not induce a sustained increase of platelet counts in any patient. Immunoadsorption treatment in AITP can induce redistribution of antibodies into the circulation. Am. J. Hematol. 73:44–47, 2003. © 2003 Wiley-Liss, Inc.