Kidney Week

Abstract: FR-PO0635

Rituximab Reduces Specific Antibody Titres in Childhood-Onset Idiopathic Nephrotic Syndrome

Session Information

• Glomerular Diseases: Clinical, Outcomes, and Therapeutics Research - ANCA/FSGS
  October 23, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics

Authors

• Lu, Liangjian, Khoo Teck Puat-National University Children’s Medical Institute, National University Health System, Singapore, Singapore

Liangjian Lu, MA, MBChB

• Chan, Chang-Yien, National University of Singapore Yong Loo Lin School of Medicine, Singapore, Singapore

Chang-Yien Chan, PhD

• Quek, Li Ling, Khoo Teck Puat-National University Children’s Medical Institute, National University Health System, Singapore, Singapore

Li Ling Quek, MBBS

• Teo, Sharon, Khoo Teck Puat-National University Children’s Medical Institute, National University Health System, Singapore, Singapore

Sharon Teo, MBBS

• Than, Mya, National University of Singapore Yong Loo Lin School of Medicine, Singapore, Singapore

Mya Than, MBBS, MPH

• Lau, Yew Weng Perry, National University of Singapore Yong Loo Lin School of Medicine, Singapore, Singapore

Yew Weng Perry Lau, MBBS

• Ng, Kar Hui, National University of Singapore Yong Loo Lin School of Medicine, Singapore, Singapore

Kar Hui Ng, MBBS

• Yap, Hui Kim, National University of Singapore Yong Loo Lin School of Medicine, Singapore, Singapore

Hui Kim Yap, MD, FASN

Background

Rituximab is widely used in children with idiopathic nephrotic syndrome (INS), and is associated with increased infections. While Rituximab causes hypogammaglobulinemia, previous studies of short follow-up duration reported that specific antibody titres remained unchanged, presumably due to the inability of Rituximab to deplete plasma cells. Thus, the mechanism by which Rituximab increases infection risk remains unclear. We aimed to determine changes in antibody titres against vaccine antigens following Rituximab.

Methods

Patients with childhood-onset INS receiving Rituximab were recruited. Paired blood samples were obtained prior to Rituximab (pre-), and within one year after (post-), for each course. Antibody titres against Measles, Diphtheria, Hepatitis B surface antigen (HbSAg), Pneumococcus and Varicella zoster were measured using ELISA. Linear mixed models were used to model the effect of time, repeat Rituximab courses and timing of sample collection (i.e. pre- or post-Rituximab) on antibody titres.

Results

52 patients (14.6±0.93 years old, 77% male) received 1.9±0.16 courses of Rituximab over follow-up of 2.2±0.29 years. Antibody titres for measles (p<0.001) and HbSAg (p=0.01) decreased with time, while pneumococcal titres decreased following successive courses of Rituximab (p=0.005) (Table 1). Intriguingly, Diphtheria, Measles and HbSAg antibody titres were higher in samples obtained after Rituximab rather than before (Table 1). This was likely due to fewer patients being in nephrotic relapse (0% vs 10%, p=0.02), as well as reduced steroid (20% vs 54%, p<0.001) and calcineurin inhibitor use (38% vs 75%, p<0.001), following Rituximab.

Conclusion

Antibody titres to measles, HbSAg and pneumococcus decreased longitudinally in INS patients receiving Rituximab. In particular, pneumococcal titres declined following multiple courses of Rituximab. Surveillance of specific antibody titres following Rituximab, ideally when in remission on minimal immunosuppression, should be considered in INS patients, with booster vaccine doses as needed.

Table 1: Effect of time, Rituximab courses, and time from Rituximab on antibody titres

Funding

• Government Support – Non-U.S.