Abstract: Ｏｂｊｅｃｔｉｖｅ：To investigate clinical efficacy and safety of lowdose rituximab (RTX) regimens for the treatment of refractory and relapsing lupus nephritis (LN).
Ｍｅｔｈｏｄｏｌｏｇｙ：Patients with refractory or relapsing LN received lowdose RTX regimens (RTX 375 mg／m2×1 at month 0 and 6, or RTX 375 mg／m2×1 followed by RTX 100 mg every 3 months) combined with another immunosuppressive (IS) agent and followed at least 24 months were analyzed retrospectively. B cell depletion(BCD) was defined as CD19+cells <5／μL and B cell reconstruction was defined as CD19+cells≥5／μL.
Ｒｅｓｕｌｔｓ：Twentythree patients including 18 refractory and 5 relapsing LN were enrolled in this study. 17 patients received single dose followed by ultralow dose RTX every 3 months and the rest 6 patients received two single dose RTX. Combined IS agent included calcineurin inhibitors in 18 cases and mycophenolate mofetil in 5 cases. B cell depletion rate at 1st, 3rd, 6th, 12th month was 870%, 652%, 43,5% and 652% respectively. A total of 20 patients (87％) achieved renal remission accumulatively, including 9 (391％) complete remission. After a median followup time of 30 (25,38) months, 7 patients (35％) experienced renal relapse. The median time to renal relapse was 18(6,21) months. All patients experienced B cell reconstruction when LN relapse and B (CD19+) cells count was 19(6,21)/μL. In the univariate Cox regression analysis, female, completement 4, BCD duration more than 55 months within 12 months was associated with lower risk of LN relapse, while B cell reconstitution at 12th month increased risk of LN relapse (HR=222, 95％CI 26~200, P=0005).
Ｃｏｎｃｌｕｓｉｏｎ：Low dose RTX regimens is effective and safe for refractory／relapsing LN. Long duration of BCD was important for the prevention of relapse.