Thrombotic thrombocytopenic purpura and relapses: why do case series differ? The Italian Cooperative Group for TTP

We examined the retrospective case series of the Italian Cooperative Group to determine the incidence of relapses in TTP patients. Of 60 patients who have crossed the 10-year threshold from the first episode, only 9 (15%) relapsed during that period, a figure far lower than that reported recently. Such difference is hardly explainable on the basis of our current knowledge of the biological behaviour of TTP. Furthermore, we unsuccessfully analyzed the treatment performed in each of our relapsed patients, in search of some element that could retrospectively predict the subsequent relapse.