The platelet-associated IgG (PAIgG) measured by micro enzyme linked immunosorbent assay and the platelet lifespan (PLS) measured by malondialdehyde method were studied in 8 patients with idiopathic thrombocytopenic purpura (ITP) and 16 patients with various disorders (liver cirrhosis 7, systemic lupus erythematosus 2, etc.). PLS was shortened in 4 of 6 ITP patients, who had elevated PAIgG values, and there was a significant correlation between PAIgG values and PLS. But, none of 10 patients with various disorders, who had also elevated PAIgG values, had shortened PLS, and there was no correlation between PAIgG values and PLS. The binding of IgG to these platelets may exert little influence upon their PLS.
