Characterisation of the cellular infiltrate in the foreign body granuloma of textile meshes with its impact on collagen deposition.

purposeAs part of the foreign body reaction, mesh filaments are surrounded by an infiltrate of inflammatory cells. Though macrophages are considered as being predominant, little is known about the origin of other cells.

methodsOn 55 meshes explanted from humans, we characterised the cells in the inflammatory infiltrate of the granuloma by immunohistochemistry using 10 cellular markers: CD3+ lymphocytes, CD4+ T helper cells, CD8+ cytotoxic T cells, CD20+ B lymphocytes, CD34+ stem cells, CD45R0+ leucocytes, CD68+ macrophages, Mib1 for proliferation, Vimentin for mesenchymal origin, and Desmin for myocytes. Collagen deposits were analysed after staining with Sirius Red.

resultsMore than 80 % of the cells in the infiltrate showed a positive expression of CD68, CD8, CD45R0 and Vimentin. CD4 and Desmin were seen in 30-80 % of the cells, unaffected by material or time. A score summarising the expression of all markers positively correlated significantly with an increased percentage of collagen type III (green) in the mesh wound. The analysis of collagen deposits was only affected to a small degree by size of area for investigation.

conclusionsAt the vicinity of the mesh filaments, the accumulated inflammatory cells represent a mixture of cells of various origins. The high expression of at least four markers requires co-expression of different surface markers and thus confirms the existence of multiple transition forms instead of dominance of just macrophages. This offers new options for interventions to attenuate the inflammatory reaction of mesh implants.