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. Author manuscript; available in PMC: 2011 Jul 28.
Published in final edited form as: Front Biosci. 2008 Jan 1;13:2674–2685. doi: 10.2741/2874

Figure 1.

Figure 1

Stromal codes regulating accumulation of leukocytes in the lymph node are aberrantly expressed during lymphoid neogenesis in rheumatoid arthritis. During physiological inflammation and in rheumatoid arthritis, inflammatory chemokines (CCL2-CCL5, CX3CL1 and CXCL1-CXCL11 and inflammatory mediators such as IFN-gamma, TNF-alpha and IL-1 are produced by stromal cells and lead to the recruitment of inflammatory cells (lymphocytes, neutrophils and monocytes). Homeostatic chemokines (CXCL12, CXCL13, CCL19, CCL21) are components of the stromal code that help define stromal niches such as the lymph node and bone marrow, governing leukocyte accumulation, differentiation and survival. Stromal cells express the appropriate chemokine that is recognized by cognate receptors on infiltrating leukocytes. In persistent, pathological inflammation such as occurs in RA, stromal cells begin to aberrantly express components of the physiological stromal code normally associated with lymphoid tissues, leading to lymphoid neogenesis.