Abstract: Objective To investigate the therapeutic effect of low-dose rituximab (RTX) in idiopathic membranous nephropathy (IMN)and its influence factors.Methods Data of 35 patients with idiopathic membranous nephropathy diagnosed by renal biopsy in Beijing Anzhen Hospital Capital Medical University and treated with low-dose RTX January 1, 2019 to July 31, 2021 with follow-up were collected retrospectively to explore the clinical efficacy of low-dose rituximab therapy. Results A total of 35 patients were enrolled in this study, of which 10 cases (28.6%) were treated with RTX as initial treatment. The single dose of RTX in all patients was 0.2-1.0 g, and the cumulative dose was 1.0 (0.6, 1.3) g. The median follow-up time was 6 (4.0, 12.0) months. ① After RTX treatment, the urine protein decreased, and the serum albumin increased. The treatment remission rate was 51.4% and the complete remission rate was 20.0%.According to sex, age, and serum anti-idiopathic membranous nephropathy(PLA2R)-antibody before treatment, patients with non RTX immunosuppressive treatment were randomly matched 1∶1 as the control group. There was no difference in remission rate between two groups after treatment. The range of increase of serum albumin and creatinine in RTX group was lower than that in control group (P<0.05). ② Compared to the previous immunosuppressive treatment group, the level of serum albumin before treatment and dose of RTX achieving B cell <5 μL were lower (all P<0.05)in the initial group, and the proportion of pathological changes of renal ischemia was higher (P < 0.05). There was no significant difference in the remission rate between the two groups. ③ Compared with the non remission group, the serum creatinine level before treatment was lower in the remission group (P < 0.05). Multivariate Cox regression analysis showed that RTX as initial treatment was an independent influencing factor of treatment remission (HR=3.025, 95% CI: 1.024-8.932). Conclusion RTX had satisfactory curative effect on IMN, whether it was used as the initial treatment or as the follow up treatment when the previous treatment effect is poor. The initial use of RTX in IMN is more conducive to disease remission.

Key words: idiopathic membranous nephropathy, rituximab, initial treatment