MODULATION OF IDIOTYPIC AND ANTIIDIOTYPIC IMMUNOGLOBULIN-G RESPONSES IN AN ALLOIMMUNE THROMBOCYTOPENIC PATIENT ASSOCIATED WITH EXTRACORPOREAL PROTEIN-A IMMUNOADSORPTION

In the present case study, a patient with Non-Hodgkins Lymphoma underw ent combination chemotherapy resulting in severe pancytopenia requirin g transfusion support with blood products. The patient became refracto ry to random donor platelet transfusions and subsequently received fiv e immunoadsorption treatments. The patient's clinical response to immu noadsorption therapy was assessed by monitoring platelet transfusion r ecovery and survival. In addition, changes in antibody responses were assessed. Early during the course of immunoadsorption therapy, antipla telet immunoglobulin G (IgG) alloantibody was detected. There was a de cline in antiplatelet IgG alloantibody levels by the last immunoadsorp tion treatment associated with increases in platelet corrected count i ncrements after completion of immunoadsorption therapy. In addition, e levated levels of antiidiotypic IgG antibody detected early during the course of therapy were significantly reduced by the last immunoadsorp tion treatment. This case study suggests that specific alloimmune idio typic IgG antibody and corresponding antiidiotypic IgG antibody respon ses may be modulated in association with extracorporeal immunoadsorpti on employing protein A/silica columns.