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Kidney Week

Abstract: SA-PO961

B-Cell Lymphocyte Profiling Identifies Steroid-Dependent Forms of Idiopathic Nephrotic Syndrome Since Disease Onset

Session Information

Category: Glomerular Diseases

  • 1402 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Vivarelli, Marina, Ospedale Pediatrico Bambino Gesu, Roma, Lazio, Italy
  • Riganati, Martina, Ospedale Pediatrico Bambino Gesu, Roma, Lazio, Italy
  • Candino, Annalisa, Ospedale Pediatrico Bambino Gesu, Roma, Lazio, Italy
  • Zotta, Federica, Ospedale Pediatrico Bambino Gesu, Roma, Lazio, Italy
  • Emma, Francesco, Ospedale Pediatrico Bambino Gesu, Roma, Lazio, Italy
  • Colucci, Manuela, Ospedale Pediatrico Bambino Gesu, Roma, Lazio, Italy
Background

The clinical evolution of steroid-sensitive forms of idiopathic nephrotic syndrome (SSNS) is highly heterogeneous, ranging from non-relapsing or infrequently relapsing patients (NRNS/IRNS), treated only with standard courses of glucocorticoids (GC), to patients who present frequent relapses (FRNS) and lastly to severe patients showing a steroid-dependent course of disease (SDNS). This last group invariably require second-line steroid-sparing agents. Recently, the therapeutic benefit of anti-CD20 monoclonal antibodies in treating SSNS and the discovery of anti-nephrin antibodies in patients with minimal change disease have pointed to a role of B cells in disease pathogenesis. In particular, we and others have shown that memory B cells predict relapse following and before receiving anti-CD20 (rituximab) infusion in patients with mainly SDNS forms of disease. However, a prospective characterization of B cell subsets from disease onset, before GC and other immunosuppressive treatment, is lacking.

Methods

In this study, we characterized by flow cytometry the profile of circulating B-cell subsets in 19 SSNS children (11 males) at disease onset, before starting GC treatment. All patients were then followed for 12 months in order to define the clinical subtype of their form of SSNS based on the frequency of relapses in relation to GC treatment in the subsequent months.

Results

During follow-up, 6 patients never relapsed (NRNS), 3 were classified as FRNS and 10 as SDNS. Mean (SD) age was higher in NRNS patients (8.5±4.1 years) compared to FRNS patients (4.7±2.3 years, p=0.07) or SDNS patients (4.1±1.8 years, p<0.01). When compared with NRNS patients, FRNS patients showed similar amount of total CD19+ (p=0.66), transitional (p=0.43), mature-naive (p=0.25), and memory (p=0.62) B cells. In contrast, SDNS patients had significantly higher levels of all these B-cell subsets compared to NRNS patients (p<0.05). Moreover, they had similar levels of total CD19+ (p=0.16), transitional (p=0.31) and mature-naive B cells (p=0.77), but a significantly higher amount of memory B cells (p=0.04), when compared to FRNS patients.

Conclusion

Increased levels of circulating memory B cells may allow to discriminate SDNS from FRNS starting from disease onset.

Funding

  • Private Foundation Support