Case Report: Temporal dissociation between peripheral B-cell pharmacodynamics and renal remission during sequential rituximab and telitacicept-containing therapy in childhood secondary steroid-resistant nephrotic syndrome
Year: 2026
Type: article
Study design: Case Report
Abstract: Rituximab (RTX) can improve outcomes in children with frequently relapsing or steroid-dependent nephrotic syndrome, although a marked reduction in circulating B cells does not invariably coincide with renal remission. We report a girl who developed frequently relapsing/steroid-dependent nephrotic syndrome after an initial steroid-sensitive course, with kidney biopsy findings supporting minimal change disease. Following a relapse in 2024, persistent nephrotic-range proteinuria despite infection control and 4 weeks of standard-dose prednisone plus tacrolimus led to classification as secondary steroid-resistant nephrotic syndrome. She subsequently received two RTX infusions of 375 mg/m² (340 mg) 49 days apart. The last available pre-RTX peripheral CD19-positive B-cell count was 99.78 cells/μL and was 1.63 cells/μL 13 days after the first infusion; it had risen to 10.43 cells/μL immediately before the second infusion, and then decreased again to 1.29 cells/μL; however, proteinuria persisted. Telitacicept 80 mg once weekly was added to prednisone and tacrolimus on December 11, 2024. Peripheral B-cell reconstitution had begun before complete remission, and urine protein became negative 91 days after telitacicept initiation and 132 days after the second RTX infusion. Telitacicept was discontinued in May 2025 because of financial constraints, but remission was maintained. A transient increase in proteinuria during a respiratory tract infection subsequently resolved without restarting telitacicept. No serious treatment-related reactions were observed. This case illustrates a temporal dissociation between measured peripheral CD19-positive B-cell pharmacodynamics after RTX and complete renal remission. Remission was documented later during telitacicept-containing therapy; however, the prolonged RTX dosing interval, uncertain early RTX exposure, continued prednisone and tacrolimus, and natural disease fluctuations preclude causal attribution to telitacicept and do not establish biological RTX resistance. These observations support prospective evaluation of peripheral and tissue B-cell kinetics, RTX pharmacokinetics, and sequential CD20 and BAFF/APRIL targeting.
Source: Frontiers in Immunology
Institution: Jiangxi Provincial Children's Hospital
Language: English
Subfield: Nephrology
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $3,801
OpenAlex ID: W7223062020