Arthritis & Rheumatism, Volume 60,
October 2009 Abstract Supplement
The 2009 ACR/ARHP Annual Scientific Meeting
Philadelphia October 16-21, 2009.
TNF-Induced Expansion of CD23/CD21hi B Cells in Draining Lymph Nodes Are Associated with the Onset of Inflammatory-Erosive Arthritis in Proximal Joints and Are Targets of Anti-CD20 Therapy
Li1, J., Kuzin1, I., Moshkani1, S., Ritchlin2, Christopher, Anolik1, Jennifer H., Sanz1, I., Looney1, R. J.
B cell depletion therapy (BCDT) with anti-CD20 is an effective treatment for some RA patients. However, the role of B cells in arthritis and the primary target of BCDT are unknown. Previously we utilized the TNF-Tg mouse model of RA and longitudinal contrast enhanced (CE) MRI to evaluate their arthritis, which initiates in distal joints of the ankle and progresses proximally with age. We also noticed that the popliteal lymph nodes (PLN) become enlarged following ankle synovitis, but prior to knee arthritis. Flow cytometry (FC) revealed that PLN enlargement was due to a 4 to 7-fold increase in B cell numbers, accounting for the expansion in cellularity. We proposed that these B cells in inflamed nodes (B-in) could be the primary target of anti-CD20 BCDT. To test the hypothesis we performed a formal phenotypic characterization of B-in and their response to anti-CD20 therapy.
Multicolor FC with probes for B220, IgM, IgD, CD1d, CD5, CD19, CD21, CD23, CD24, CD25a, CD69, CD80, CD86, CD93 (AA4.1), CD138 and GL7, was performed on cells from spleen, PLN, mesenteric (M)LN and axillary (A)LN from young (<2-months), adult (36 months) and old (>8 months) TNF-Tg and wt mice (N= 4 to 13), which were untreated or received anti-CD20 (10mg/kg/i.v. every 2 weeks for 6 weeks). Luminex was performed on B-in and follicular B cells from TNF-Tg PLN, as well as pooled LN follicular B cells and peritoneal B cells from WT mice. 105 cells/well were cultured with CpG, PMA, and ionomycyn for 48 hrs, and the supernatants were assayed for the cytokines IL1b, IL2, IL4, IL6, IL10, IL12p70, IFNg, RANTES, and muTNF.
TNF-Tg PLN had significantly (p<0.001) more IgMhi, IgD+, CD21hi, CD23+, CD1d+, CD24hi, CD93 lo B-in, which increase from 10% to >30% of PLN B cells and localize to the medullary/paracortical areas in mice with overt knee arthritis. No other differences in wt vs. TNF-Tg were detected. PLN of young TNF-Tg with ankle synovitis showed an expansion of B-in before CE-MRI detected changes in PLN or the knee. No increases in B-in were detected in spleen (wt: 12%; TNF-tg: 1115%), MLN (wt: 10%; TNF-tg: 814%) or ALN of TNF-Tg mice <8 months of age (wt: 9%; TNF-Tg: 411%), while B-in were significantly increased in ALN of old arthritic TNF-Tg with forelimb arthritis (wt: 9%; TNF-tg: 24%; p<0.01). Anti-CD20 treatment resulted in a >90% decrease in PLN B-in. Luminex, confirmed by qPCR, revealed an increase in secretion of IL6, but not other cytokines, by stimulated PLN B cells from arthritic mice.
A unique B cell population B-in - accumulates in efferent LN that drain inflamed joints in TNF-Tg mice, and is efficiently depleted by BCDT. B-in surface phenotype, but not cytokine profiles, resembles that of B-regs in the spleen of mice with remission-phase collagen-induced arthritis. Based on the cytokine data, a model for B-in derived IL-6 in arthritic progression is proposed.
To cite this abstract, please use the following information:
Li, J., Kuzin, I., Moshkani, S., Ritchlin, Christopher, Anolik, Jennifer H., Sanz, I., et al; TNF-Induced Expansion of CD23/CD21hi B Cells in Draining Lymph Nodes Are Associated with the Onset of Inflammatory-Erosive Arthritis in Proximal Joints and Are Targets of Anti-CD20 Therapy [abstract]. Arthritis Rheum 2009;60 Suppl 10 :687