Comparison of phenotype expression by mononuclear phagocytes within subcutaneous gouty tophi and rheumatoid nodules

Abstract

The mononuclear phagocyte infiltrate which occupies the gout tophus has been compared with that of the subcutaneous rheumatoid nodule. In the gout tophus, macrophage migration appears to be at a relatively low level and effectively terminates once these cells have been recruited into the corona. In the nodule the evidence suggests that both macrophage and granulocyte populations continuously migrate towards, and are progressively incorporated into, the necrotic centres. These observations indicate that chemotactic activity in rheumatoid nodules is at a higher level than in gout tophi, or that the rheumatoid mononuclear phagocyte is more responsive to such stimuli.

The pathogenesis of bone erosions in gouty arthritis

“…These include a central zone that consists of a MSU crystal deposit surrounded by a cellular zone, the corona zone. Large numbers of macrophages, mast cells and plasma cells were detected within the corona zone of the tophus 20. The cells of the corona zone form a well-defined compact zone which is demarcated from both the central MSU crystal deposit and the surrounding fibrovascular zone.…”

“…Gouty tophi are characterised by foreign body granulomas consisting of mono- and multinucleated macrophages surrounding deposits of MSU microcrystals 19. Several zones have been identified within the tophus 20. These include a central zone that consists of a MSU crystal deposit surrounded by a cellular zone, the corona zone.…”

The Gouty Tophus: a Review

“…Three main zones have been identified within the tophus; the central crystalline core of MSU crystals, the surrounding highly cellular corona zone and the outer fibrovascular zone [1] (Fig. 1).…”

Gout treatment: should we aim for rapid crystal dissolution?

“…At the same time the production of transforming growth factor β—with a role in resolution of inflammation, but also in tissue remodelling, angiogenesis and fibrosis in granulomatous diseases18—rises, probably contributing to the spontaneous resolution of the attacks that occurs naturally. In the inflammatory infiltrate that surrounds tophi, both IL1β and transforming growth factor β are being expressed,19 suggesting a chronic inflammatory tissue response against crystals 20. Interestingly, both ultrasound21 and contrast-enhanced MRI studies22 show raised vascularity in, and surrounding, tophi.…”