CD23+/CD21hi B-cell translocation and ipsilateral lymph node collapse is associated with asymmetric arthritic flare in TNF-Tg mice

Abstract

IntroductionRheumatoid arthritis (RA) is a chronic autoimmune disease with episodic flares in affected joints. However, how arthritic flare occurs only in select joints during a systemic autoimmune disease remains an enigma. To better understand these observations, we developed longitudinal imaging outcomes of synovitis and lymphatic flow in mouse models of RA, and identified that asymmetric knee flare is associated with ipsilateral popliteal lymph node (PLN) collapse and the translocation of CD23+/CD21hi B-cells (B-in) into the paracortical sinus space of the node. In order to understand the relationship between this B-in translocation and lymph drainage from flaring joints, we tested the hypothesis that asymmetric tumor necrosis factor (TNF)-induced knee arthritis is associated with ipsilateral PLN and iliac lymph node (ILN) collapse, B-in translocation, and decreased afferent lymphatic flow.MethodsTNF transgenic (Tg) mice with asymmetric knee arthritis were identified by contrast-enhanced (CE) magnetic resonance imaging (MRI), and PLN were phenotyped as "expanding" or "collapsed" using LNcap threshold = 30 (Arbitrary Unit (AU)). Inflammatory-erosive arthritis was confirmed by histology. Afferent lymphatic flow to PLN and ILN was quantified by near infrared imaging of injected indocyanine green (NIR-ICG). The B-in population in PLN and ILN was assessed by immunohistochemistry (IHC) and flow cytometry. Linear regression analyses of ipsilateral knee synovial volume and afferent lymphatic flow to PLN and ILN were performed.ResultsAfferent lymph flow to collapsed nodes was significantly lower (P < 0.05) than flow to expanding nodes by NIR-ICG imaging, and this occurred ipsilaterally. While both collapsed and expanding PLN and ILN had a significant increase (P < 0.05) of B-in compared to wild type (WT) and pre-arthritic TNF-Tg nodes, B-in of expanding lymph nodes (LN) resided in follicular areas while B-in of collapsed LN were present within LYVE-1+ lymphatic vessels. A significant correlation (P < 0.002) was noted in afferent lymphatic flow between ipsilateral PLN and ILN during knee synovitis.ConclusionsAsymmetric knee arthritis in TNF-Tg mice occurs simultaneously with ipsilateral PLN and ILN collapse. This is likely due to translocation of the expanded B-in population to the lumen of the lymphatic vessels, resulting in a dramatic decrease in afferent lymphatic flow. PLN collapse phenotype can serve as a new biomarker of knee flare.

The role of the lymphatic system in inflammatory-erosive arthritis

“…Thus, the PLN cannot be a direct measure of lymphatic egress from the knee. To resolve this we tested the hypothesis that LN collapse during asymmetric knee flare in TNF-Tg mice occurs in series along the ipsilateral axis [35]. Consistently, we found that B cells were located within the LYVE-1 + lymphatic sinuses in both collapsed ILN and PLN ipsilateral to flaring knees, and NIR-ICG imaging demonstrated that a decrease in lymphatic transport to the PLN was accompanied with a decrease in transport from the knee to the ILN.…”

Brief Report: Treatment of Tumor Necrosis Factor–Transgenic Mice With Anti–Tumor Necrosis Factor Restores Lymphatic Contractions, Repairs Lymphatic Vessels, and May Increase Monocyte/Macrophage Egress

“…This collapse, which occurs at variable time intervals in ~80% of TNF-Tg mice, is associated with B-in translocation from the follicles to LYVE-1 + lymphatic vessels of the paracortical sinuses, a reduction in volume and increase in PLN fluid pressure (6, 8, 16). Thereafter, lymphatic drainage declines significantly due to loss of intrisic lymphatic contractions and passive flow (8, 10, 13, 17). It was also demonstrated that B-cell depletion therapy (BCDT) with anti-CD20 antibodies ameliorated knee flare afferent to collapsed PLN by “clearing” the LN sinuses, and restoring passive lymphatic flow in the absence of lymphatic contractions (8).…”

TNF signals are dispensable for the generation of CD23+ CD21/35-high CD1d-high B cells in inflamed lymph nodes

“…Consistent with this model, we have previously shown that progressive joint inflammation in the TNF transgenic (TNF-tg) mouse model of inflammatory-erosive arthritis is accompanied by an increase in draining lymph node’s size, cellularity and drainage capacity, and that disease flares (as detected by increased synovial volume) and bone erosion at the knees are preceded by a rapid decrease in drainage capacity and substantial structural remodeling of the affected nodes [2–5]. These changes are specifically associated with unique alterations in the resident B cell population within the reactive nodes, resulting in the local differentiation of a follicular B cell-derived subset with a unique CD23+, CD21/35-high, CD1d-high, IgM-high, IgD-high phenotype and increased ability to capture and process antigen immune complexes ( B cell in i nflamed n odes, or Bin cells) [4–6].…”

“…These changes are specifically associated with unique alterations in the resident B cell population within the reactive nodes, resulting in the local differentiation of a follicular B cell-derived subset with a unique CD23+, CD21/35-high, CD1d-high, IgM-high, IgD-high phenotype and increased ability to capture and process antigen immune complexes ( B cell in i nflamed n odes, or Bin cells) [4–6]. Most significantly from a pathogenic standpoint, Bin cells localize to, and substantially occupy paracortical sinusoids in collapsed TNF-tg lymph nodes, likely contributing to the decreased lymphatic drainage function of the nodes [2–5, 7, 8]. Consistent with this hypothesis, in vivo depletion of B cells in TNF-tg mice using anti-CD20 antibodies restores lymphatic drainage and ameliorates disease progression [4, 8].…”