Abstract: FR-OR51
The Predictive and Prognostic Value of Antigen-Specific Memory B Cell Levels in PLA2R-Associated Primary Membranous Nephropathy
Session Information
- Glomerular Diseases: From Bench to Bedside
November 04, 2022 | Location: W414, Orange County Convention Center‚ West Building
Abstract Time: 04:30 PM - 04:39 PM
Category: Glomerular Diseases
- 1302 Glomerular Diseases: Immunology and Inflammation
Authors
- Zhu, Quansheng, ImmunoWork, Monrovia, California, United States
- Waldman, Meryl A., National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, United States
- Zhu, Richard, ImmunoWork, Monrovia, California, United States
- Tang, Hong, ImmunoWork, Monrovia, California, United States
Background
B lymphocytes play a critical role in developing autoimmunity in patients through antigen-presentation, cytokine release, and antibody production. Antigen stimulation of the cognate memory B cells triggers their rapid differentiation into plasma cells, producing massive amounts of pathogenic antibodies in a short period. In idiopathic nephrotic syndrome, rheumatoid arthritis, systemic lupus erythematosus, and IgG4-related disease, an early recovery of memory B cells in patients post-Rituximab therapy is the only reliable parameter that strongly predicts disease relapse. The phospholipase A2 receptor (PLA2R) is the dominant autoantigen in primary membranous nephropathy (PMN), associated with ~80% of clinical cases. Considering that memory B cells are a heterogenous pool of antigen-experienced B cells, we developed a sensitive and reliable method to detect and quantify the PLA2R antigen-specific memory B cells (PLA2R-MB) in patients diagnosed with PLA2R-associated PMN.
Methods
The PLA2R antigen was expressed in the HEK 293 cells and affinity purified. The purified antigens were then conjugated to a fluorochrome. Peripheral blood mononuclear cells (PBMCs) from biopsy-proven PMN patients and healthy volunteers were isolated using the BD Vacutainer® CPT™ mononuclear cell preparation tubes, stained with the PLA2R fluorescent probe, anti-CD19, and anti-CD27 monoclonal antibodies, and subsequently analyzed by the flow cytometry.
Results
The PBMCs isolated from healthy volunteers or patients with non-PLA2R-associated PMN had little PLA2R fluorescent probe staining in the memory B cell repertoire, less than 2%, whereas the PBMCs isolated from patients with PLA2R-associated PMN had up to 70% of positive staining that correlated to the disease status. Importantly, patients with early signs of relapse, while possessing undetectable anti-PLA2R antibodies, showed at least a one-fold increase in the PLA2R-MB level. Moreover, patients with partial remission showed a sustained high level of PLA2R-MBs, which fluctuated with the immunosuppressive therapy.
Conclusion
Our data indicate that the PLA2R antigen-specific memory B cell levels in patients have a substantial value in serving as a new biomarker to assess the patient response to immunosuppressive therapies for treatment adjustment and predict the pre-clinical signs of PMN relapse.
Funding
- NIDDK Support –