Immune-mediated thrombotic thrombocytopenic purpura with systemic lupus erythematosus: clinical features and outcome.

Abstract

Objective: The association of immune-mediated thrombotic thrombocytopenic purpura (iTTP) and SLE was previously described, but patients with iTTP with coexistent SLE remain poorly characterised.

Methods: We compared the clinical presentation and the outcome of patients with iTTP with coexistent SLE (SLE-iTTP) to an age-sex matched cohort of patients with idiopathic iTTP without SLE.

Results: During the study period, 1409 patients with iTTP were recruited in our registry. Of these, 79 (6%) had a prior or concurrent diagnosis of SLE at the time of iTTP diagnosis, and 437 (31%) had detectable ANAs without other clinical features of SLE. When compared with idiopathic iTTP, patients with SLE-iTTP had more severe renal involvement, and cardiac involvement was more prevalent, whereas central nervous system involvement was less common. Patients with SLE-iTTP received more immunosuppressive agents. There was no difference in response categories during the acute phase. During follow-up, SLE-iTTP had superior ADAMTS13 relapse-free survival than idiopathic iTTP. Among patients with ANAs without other clinical features of SLE, 33 (8%) were diagnosed with SLE 27 months (IQR: 7-65 months) following iTTP diagnosis; 32 additional patients (7%) developed another systemic autoimmune disease. No patient from the idiopathic iTTP group developed clinical SLE during follow-up.

Conclusion: Patients with iTTP are prone to develop autoimmune features, and patients with SLE-iTTP have distinct clinical features and outcome. Relapse-free survival seems better in patients with SLE-iTTP, underscoring the need for tailored management strategies in this population, including a specific follow-up to assess early features suggestive of SLE.

Trial registration number: NCT00426686.