Morphologically and enzyme histochemically distinguishable tissue macrophages and stromal cells of human reactive lymph nodes were characterized by the cytoplasmic presence of the subunit A of factor XIII and by the expression of surface antigenic determinants reacting with monoclonal antibodies directed against monocyte/macrophage populations (Mo 1, Leu M3) and HLA‐DR antigens. The distribution of F‐XIIIa positive cells was studied on formaldehyde‐fixed paraffin‐embedded sections with immunoperoxidase techniques. The immunophenotype was established on cryostat sections with double immunofluorescence. α‐Naphthyl acetate esterase (ANAE) reaction was carried out on these cryostat sections to identify tissue macrophages. The antibody against F‐XIIIa detected histiocytes in both intra‐and extra‐sinusoidal locations which were ANAE +, Mo 1 +, Leu M3 + and HLA‐DR–. F‐XIIIa was also present in fibroblast‐like mesenchymal cells with the following phenotypic characteristics: ANAE–, Mo 1 +, Leu M3+ and HLA‐DR+. The anti F‐XIIIa antibody did not stain lymphoid cells, granulocytes, epithelial cells, endothelial cells and mast cells. The immunohistochemical detection of F‐XIIIa works on formaldehyde‐fixed paraffin‐embedded sections. The most promising application seems to be the identification of histiocytes in lymphoid and histiocytic proliferations.
- Factor XIII
- double immunofluorescence
ASJC Scopus subject areas
- Pathology and Forensic Medicine