CHANGES IN ANTI-CARD10LIPIN ANTIBODY TITER IN SERA OF I TP PATIENTS AFTER TREATMENT WITH INTRAVENOUS IMMUNOGLOBULIN
PLATELET GYCOPROTEINS IIb-IIIa
Antibodies to cardiolipin have previously been demonstrated in the sera of patients with idiopathic thrombocytopenia purpura (ITP). We questioned whether the levels of anti-cardiolipin in the sera of patients with ITP would be altered after treatment with intravenous immunoglobulin (IVGG). Using flexible polyvinyl chloride microtiter plates coated with bovine cardiolipin, we measured IgG and IgM anti-cardio1ipin levels by ELISA before and at multiple intervals during and after IVGG treatment
... 17 patients who had ITP. We found that within 7-10 days of treatment, 16 of 17 patients had further increases of IgG anti-cardiolipin antibody. This is probably due to the infusion of IVGG concentrates, which we found contained substantial amounts of IgG anti-cardio1ipin. Increases in platelet counts had significant correlation with increased IgG anti-cardio1ipin (p>0.01), presumably also due to the infusion of IVGG. Surprisingly, 16 of 17 patients had a marked increase in serum levels of IgM anti-cardiolipin 7-10 days post IVGG treatment. Since IVGG does not contain IgM anti-cardiolipin and our assay is specific for this isotype, this antibody represents de novo synthesis. We previously reported and have also confirmed here, that 16 of these 17 patients had increased serum IgM levels after IVGG treatment. The increase in serum IgM anti-cardio1ipin antibody may explain part of the increased total serum IgM observed. IVGG has been believed to be potentially suppressive of various immunologic activities; our data shows that immunologic stimulation also occurs. The biologic effect of increased serum IgG and IgM anti-cardiol ipin after IVGG treatment in ITP, particularly since cardiolipin may be a constituent of platelet membranes, is still uncertain.