Background and aims Thrombotic thrombocytopenic purpura (TTP), a form of thrombotic microangiopathies (TMA), is a series of life-threatening disorders. Systemic lupus erythematosus (SLE) is one of most common acquired causes. To identify predictors of prognosis in patients with TTP secondary to SLE, we conducted a single-centre historical study.

Methods Using the electronic medical record system which includes all clinical data of patients who were hospitalised in the department of Rheumatology in Ren Ji Hospital from 2013 January to 2016 June, we identified patients with the query terms “SLE”, “schistocyte”, “TTP”, and “TMA”. Of 2182 SLE patients, a total of 21 consecutive patients with TTP secondary to SLE were enrolled.

Results The 90 day short-term mortality was 33.3%. The kidney involvement (66.7%) was associated with poor prognosis, while the administration of rituximab (n=13) was an independent protective factor according to logistic regression analysis. Although compared to conventional treatment, i.e., plasma exchange, high dose glucocorticoids and intravenous immunoglobulin, the overall survival is significantly higher among patients receiving rituximab add-on (92.2% vs 25%, p=0.0032), 5 out of 7 patients with renal involvement in the rituximab group were eventually hemodialysis dependent.

Conclusions In summary, our data indicated that add-on rituximab in the background of conventional therapy may improve the overall but not the renal survival in SLE-TTP patients.