Thrombotic thrombocytopenic purpura: recovery after splenectomy associated with persistence of abnormally large von Willebrand factor multimers.

A patient with thrombotic thrombocytopenic purpura (TTP) responded transiently to four courses of plasma exchange therapy, then subsequently had a sustained completed remission following splenectomy. The von Willebrand factor multimeric pattern during remission following each plasma exchange and during the entire postsplenectomy period showed abnormally large forms that were not present on presentation and with each clinical relapse. These findings support prior observations regarding the presence of abnormal von Willebrand factor multimers in relapsing TTP and suggest that the multimers contribute to platelet aggregation and the thrombotic lesions. The association of sustained remission and persistence of the abnormally large plasma multimers after splenectomy suggests that this response was not coincidental. This supports the concept that a subgroup of patients with TTP may exist in which the pathophysiology of disease is significantly modulated by the spleen and in which splenectomy may induce long-lasting remission.