Abstract: FR-PO0813
Early B-Cell Return in Patients with Autoimmune Disease Treated with Rituximab
Session Information
- Glomerular Diseases: Practice and New Concepts Shaping Modern Care
October 23, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- Chadha, Ashima, Mass General Brigham Inc, Boston, Massachusetts, United States
- Niles, John L., Mass General Brigham Inc, Boston, Massachusetts, United States
- Aaron, Sydney, Mass General Brigham Inc, Boston, Massachusetts, United States
- Chung, James L., Mass General Brigham Inc, Boston, Massachusetts, United States
- Laliberte, Karen A., Mass General Brigham Inc, Boston, Massachusetts, United States
- Efe, Orhan, Mass General Brigham Inc, Boston, Massachusetts, United States
- Seethapathy, Harish Shanthanu, Mass General Brigham Inc, Boston, Massachusetts, United States
- Al Jurdi, Ayman, Mass General Brigham Inc, Boston, Massachusetts, United States
Background
B-cell depletion with rituximab serves as the backbone of treatment for many antibody-mediated diseases. Successful B-cell depletion often correlates with disease control and lower relapse risk. Inter-patient variability in peripheral B-cell reconstitution kinetics has been observed with various predictive factors posited.
Methods
We conducted a retrospective analysis of all patients treated with rituximab at the MGB Vasculitis and Glomerulonephritis Center. Inclusion criteria required standard rituximab induction followed by a maintenance rituximab dose at a 4-6-month interval. Primary endpoint was peripheral B-cell count at the time of first maintenance rituximab dose, with early B-cell return defined as CD19+ count >5 cells/µL.
Results
Our practice of routinely checking B-cell counts revealed that of 1102 patients meeting inclusion criteria, 18 (1.6%) exhibited early B-cell reconstitution at 4 months. 14 had received concomitant cyclophosphamide for induction. Primary diagnoses included systemic lupus erythematosus (SLE) (n=6), membranous nephropathy (n=5), minimal change disease or FSGS (n=4), and ANCA-associated vasculitis (AAV) (n=3). Diagnosis-specific rates of early B-cell return varied, being highest (10%) in SLE and lowest (0.41%) in AAV (Fisher-Freeman-Halton exact test, p<0.001). Among those with early B-cell return, baseline characteristics varied. No single factor (age, gender, BMI, baseline eGFR, proteinuria, or serum albumin) was uniformly associated with early return. Median pre-treatment B-cell count was 384 cells/µL (IQR 154-513.25). Clinical outcomes varied, with the majority of patients achieving remission due to reactive adjustments to immunosuppressive regimens and rituximab dosing intervals.
Conclusion
Early B-cell reconstitution occurs in a small but clinically meaningful subset of patients receiving rituximab maintenance therapy, with significant variability across autoimmune disease subtypes. Early B-cell return observed at 4-months highlights the potential inadequacy of standard fixed-interval dosing and supports the role of peripheral B-cell monitoring to guide personalized rituximab re-dosing strategies.