Session Type: Poster Session (Monday)
Session Time: 9:00AM-11:00AM
Background/Purpose: ANCA-associated vasculitis (AAV) is characterized by the production of auto-antibodies and can be treated with rituximab, a B cell-depleting agent. Despite this, limited data are available characterizing the B cell dysfunction associated with AAV.
Methods: We performed comprehensive flow-cytometric analyses of major cell markers of B cell function in 20 patients with new diagnosis of AAV with renal involvement and 10 healthy controls (HC). Peripheral blood samples were taken at clinical onset prior to treatment initiation for AAV patients. We measured CD25 hi CD71hi B regulatory cells; subpopulations of memory B cells, including IgD+CD27– naive, IgD+CD27+ unswitched, IgD–CD27+ switched, and IgD–CD27– double negative; and CD38hiCD27hi plasma cells and their expression of CD138.
Results: We found significantly increased percentages of of CD3–CD56–CD19+ B cells in AAV patients compared to HC (Fig. 1A). We did not find a significant difference in CD25 hi CD71hi B regulatory cells between AAV and HC (Fig. 1B). AAV patients had increased frequency of double negative IgD–CD27– memory B cells but no difference in the naïve, switched, or unswitched memory B cell subpopulations (Fig. 1C-F). We found significantly higher levels of CD38hiCD27hi plasma cells in AAV patients, with greater CD138– but no difference in CD138+ expression between groups (Fig. G-I).
Conclusion: Patients with new diagnosis AAV display a unique phenotype of B cell dysfunction that is characterized by an increase in the double negative (DN) memory B cell population, which has been implicated in other autoimmune diseases, and an increase in plasma cells, suggesting persistent antibody production. We did not demonstrate a difference in B regulatory cells, a departure from previously published results that may be explained by our study of early disease activity.
To cite this abstract in AMA style:Chan E, Hartzell S, Anderson L, Cantarelli C, Guglielmo C, Tassiulas I, Andrighetto S, Angeletti A, Manrique Escola J, Cravedi P. New-onset ANCA-associated Vasculitis Is Associated with Significant Phenotypic B Cell Dysfunction [abstract]. Arthritis Rheumatol. 2019; 71 (suppl 10). https://acrabstracts.org/abstract/new-onset-anca-associated-vasculitis-is-associated-with-significant-phenotypic-b-cell-dysfunction/. Accessed March 4, 2021.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/new-onset-anca-associated-vasculitis-is-associated-with-significant-phenotypic-b-cell-dysfunction/