Impaired Cognitive Function in Immune-TTP Is Better Predicted By Serum Thrombomodulin Than ADAMTS13 Activity: Results of a Longitudinal Multicenter Pilot Study

Background: High rates of mood disorders and cognitive dysfunction in immune-mediated thrombotic thrombocytopenic purpura (iTTP) survivors have been observed. However, there are no long-term prospective studies to precisely define the proportion of affected patients, rate of progression, and underlying mechanisms. We hypothesized that a large-scale multicenter study is essential to determine the natural history of these complications. Thus, we conducted a multicenter pilot study of iTTP patients in remission to assess feasibility, study design, and explore novel biomarkers. Given ADAMTS13 deficiency during remission is a risk factor for stroke, we also hypothesized that low ADAMTS13 activity predisposes patients to cognitive impairment. Methods: We aimed to enroll 50 participants from 3 USTMA Consortium sites, prospectively including adult iTTP patients (age ≥ 18 years) in clinical remission (ADAMTS13 remission was not required) for at least 90 days. Diagnosis of iTTP relied on ADAMTS13 activity