Involvement of CD5+CD19+Cell in steroid‐dependent nephrotic syndrome treated with B‐cell targeting therapy

We showed in this study the longitudinal changes of the B‐cell counts in patients with steroid‐dependent nephrotic syndrome (SDNS) treated with cyclophosphamide (CPM) and mycophenolate mofetil (MMF). In our case with SDNS, this combined therapy not only decreased B‐cell counts but also increased CD5+CD19+ (CD5+B)/ CD5‐CD19+ (CD5‐B) cell ratio. Recurrence was not observed when an elevated CD5+B/CD5‐B cell ratio was maintained even after the B cells increased. Therefore, this ratio might be more important than the whole B‐cell counts. The changes of this ratio could be a good predictor of the clinical course of the patients treated with B‐cell targeting therapy.