Figure 3.

 The dynamics of the synovial inflammatory infiltrate. The dynamic balance of cells in any tissue compartment depends on the balance of cells that enter, exit, proliferate, or die. Homoeostasis is maintained during normal inflammatory responses leading to resolution of the inflammatory infiltrate. In chronic persistent inflammation inappropriate accumulation of leucocytes is caused by stromal production of prosurvival (interferon ß) and proretentive (stromal cell derived factor 1 (SDF-1); CXCL12) factors by fibroblasts and other resident tissue stromal cells.