The pathogenesis of nephrotic syndrome is unclear. However, the efficacy of rituximab, a B
cell–depleting antibody, in nephrotic syndrome suggests a pathogenic role of B cells. In this
retrospective study, we determined by flow cytometry levels of B and T cell subpopulations
before and after rituximab infusion in 28 pediatric patients with frequently relapsing or
steroid–dependent nephrotic syndrome. At baseline, patients had lower median
percentages of transitional and mature B cells than age–matched healthy controls (P< …