Relapse Prediction Model for Immune-Mediated Thrombotic Thrombocytopenic Purpura.

Immune mediated thrombotic thrombocytopenic purpura (iTTP) is defined by thrombocytopenia and microangiopathic hemolytic anemia caused by severely deficient ADAMTS13 activity (<10%). After resolution of their initial episode, patients remain at risk for relapse. Relapse is most common during the first year, but can occur at any point in their lives. In asymptomatic patients, severely deficient ADAMTS13 activity in remission has been shown to be a risk factor for relapses and can guide consideration of preemptive therapy with Rituximab. However, severely deficient ADAMTS13 activity alone does not uniformly lead to relapse, and patients with non-deficient ADAMTS13 activity in remission may still relapse in the following months. The aim of this study was to develop a multivariable model to identify patients at high risk of relapse, using other biomarkers known to have a role in the pathophysiology of iTTP.