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During the congress, E-Posters will be accessible to all participants on the congress website 24/7, as well as in the E-poster stations in the congress center.
Preparing your E-Poster
Please review the E-Poster format requirements carefully when preparing your E-Poster. Should your E-Poster not meet the mentioned requirements, it may not be displayed as described above.
E-Poster Submission Deadline
Please prepare and upload your E-Poster no later than March 14, 2026 11.59PM CET. After this date, you will no longer be able to prepare and upload your E-poster and it will not be displayed and accessible on the congress website.
Please follow the instructions below to input your abstract title.
Abstract titles should be brief and reflect the content of the abstract.
Rituximab (RTX) is effective in preventing relapse in children with refractory nephrotic syndrome (NS), however most patients eventually relapse after RTX administration. Therefore, repeated RTX administrations and/or additional immunosuppressive therapies are often required, although a standardized RTX protocol has not yet been established. Adverse events such as late-onset agranulocytosis and hypogammaglobulinemia have also been reported, and the long-term safety of RTX therapy remains uncertain.
This multicenter, retrospective, observational study included pediatric patients with refractory NS who initiated periodic repeated RTX administrations between January and December 2015. RTX was administered four times at 6-month intervals, followed by mizoribine pulse therapy and early discontinuation of calcineurin inhibitors. Thereafter, RTX was re-administered as a single dose at least six months after the initial four infusions, according to the relapse course or disease severity. The efficacy endpoints were the relapse-free survival rate and the proportion of patients maintaining a non–frequently relapsing or steroid-dependent status. The primary safety endpoint was the incidence of adverse events.
Twenty-five patients were analyzed. Nineteen patients (76%) relapsed during the observation period (median follow-up, 7.6 years), and the 50% relapse-free survival time was 893 days. Seven patients (28%) developed frequently relapsing or steroid-dependent NS. No patients developed agranulocytosis, and one patient (4%) experienced a severe infection requiring hospitalization. Hypogammaglobulinemia occurred in 17 patients (68%), among whom five (20%) received prophylactic immunoglobulin replacement therapy; none required continued supplementation at the end of follow-up. A total of 153 RTX administrations were performed in 25 patients, including 34 administrations during episodes of hypogammaglobulinemia. Among the remaining 119 administrations, hypogammaglobulinemia developed after 22 administrations (19%). In multivariate analysis, B-cell depletion (odds ratio [OR]=5.54; 95% confidence interval [CI]=1.43-21.5; P=0.014) and low serum IgG levels (OR=6.09; 95% CI=1.84-20.2; P<0.001) at RTX administration were identified as independent risk factors for hypogammaglobulinemia. In patients aged ≧6 years, in whom hypogammaglobulinemia was defined as a serum IgG level <500 mg/dL, ROC curve analysis demonstrated that serum IgG levels predicted hypogammaglobulinemia with an AUC of 0.816 (95% CI = 0.721–0.91). The optimal cutoff value was 585mg/dL, yielding a sensitivity of 79% and a specificity of 81%.
Periodic repeated RTX administrations achieved favorable long-term outcomes in children with refractory NS, maintaining high relapse-free survival and non–frequently relapsing/steroid-dependent rates. However, hypogammaglobulinemia occurred frequently. Low serum IgG levels and B-cell depletion at the time of RTX administration were identified as independent risk factors for its development.
