Treatment of thrombotic microangiopathy associated with systemic lupus erythematosus with low-dose rituximab as an induction agent and belimumab as a maintenance agent.

Introduction: Thrombotic microangiopathy (TMA) is a serious complication that can occur in patients with systemic lupus erythematosus (SLE), and TMA adversely affects prognosis and increases mortality. The treatment of TMA often requires immunosuppressive agents, high-dose corticosteroids and plasma exchange (PEX). Both rituximab (RTX) and belimumab (BEL) target B cells. The combination of RTX and BEL has recently been used for refractory and severe organ involvement in systemic lupus erythematosus. However, the clinical outcome of patients with TMA and SLE treated with sequential therapy between RTX and BEL remains elusive.

Case Reports: We reported 2 patients who were diagnosed with SLE with TMA and were administered a combination treatment of high-dose corticosteroids, immunoglobulin, and PEX at the initial stage. No improvements in microangiopathic anaemia, thrombocytopenia, or renal failure were observed. Low-dose RTX was administered in both patients, and both patients responded well. BEL was utilized to rapidly reduce the reliance on these agents and prevent the relapse of SLE at the maintenance stage. Ultimately, 2 patients fully recovered with an SLE Disease Activity Index score of 0, and prednisolone was stopped without relapse.

Conclusion: Sequential treatment with low-dose RTX and BEL could be an encouraging approach for the treatment of TMA in patients with SLE and rapid glucocorticoid reduction.