Plasma exchange and immune complex diseases: the predictability of immune complexes removal to clinical response.

58 patients were treated by discontinuous flow plasma exchange because of an immune complex (IC) disease. 41 patients who had a high level of circulating IC prior to plasmapheresis showed both clinical and immunochemical evidence of improvement with plasma exchange. Only 2 patients with a high level of IC did not improve after therapy: these patients suffered from multiple sclerosis and idiopathic thrombocytopenic purpura, respectively. Prior to PE therapy the level of circulating IC in 15 patients was within the normal range, when measured according to Manca et al. In this group none of the patients worsened after therapy, whereas 8 patients showed an objective improvement. The positive correlation between IC removal and clinical results suggests that patients with a high level of circulating IC are most likely to benefit from apheretic treatment.