Systemic autoimmune disorders associated with thrombotic microangiopathy: A cross-sectional analysis from the French National TMA registry: Systemic autoimmune disease-associated TMA

Context The management of systemic auto-immune diseases (SAID) -associated thrombotic microangiopathies (TMA) [SAID-TMA] remains debated. Objectives To provide a demographic, clinical and therapeutic picture of SAID-TMA. Methods A cross-sectional analysis was conducted on adult patients presenting with SAID and TMA from the French National TMA Registry over a 20-year period. Clinical features were extracted and compared to those from a historical cohort of atypical haemolytic and uremic syndrome (aHUS) patients. Results Forty-one patients with SAID-TMA were compared to 78 patients with aHUS from a historical cohort. Connective tissue diseases (CTD) were systemic lupus erythematosus (n=18), primary Sjogren's syndrome (n=7), systemic sclerosis (n=11), mixed CTD (n=2) and 2 cases of vasculitides, including 7 overlapping forms and 8 cases of primary antiphospholipid syndromes (APLS). Patients with SAID-TMA generally had pre-existing chronic kidney failure (OR= 3.17, 95%CI: 1.204 to 7.923; p= 0.016) compared to aHUS patients, though creatinine levels were significantly lower (216 [IQR, 108-334] µmol/L vs. 368 [IQR, 170-722] µmol/L; p= 0.002). Patients were less likely to recover if renal replacement therapy was needed at onset (OR= 0.07; 0.02 to 0.34; p 0.05). Conclusion The management of SAID-TMA implies an early initiation of immunosuppressive drugs for flares of the associated SAID, whereas TPE seem ineffective. Key messages • Systemic auto-immune diseases (SAID) in thrombotic microangiopathies (TMA) [SAID-TMA] include mainly systemic lupus erythematosus, systemic sclerosis and primary Sjogren's syndrome. • SAID-TMA improves with the treatment of the underlying SAID • Therapeutic plasma exchange does not seem to have an early effect on TMA features at Day-7 nor Day-15