CD 31

Accurate (JC70A, CLB-HEC75), Becton Dickinson (L133.1), Biogenex (9G11), Coulter (56E), Dako (JC/70A), Monosan (CLB-58, VM64), Novocastra (HC1.6), Pharmingen (2ET, M290, WM59), Research Diagnostics and Sanbio (VM64).

Antibodies to CD 31 are generally immunoreactive in fixed, paraffin-embedded tissue sections as well as fresh cell preparations and cryostat sections. HIER enhances immunoreactivity and, if employed, enzyme predigestion is not necessary.

CD 31 is a 130 kD glycoprotein, also designated platelet endothelial cell adhesion molecule-1 (PECAM-1), that is normally expressed on endothelial cells and circulating and tissue-phase hematopoietic cells, including platelets, monocytes/macrophages, granulocytes and B cells. This antigen is also expressed by sinusoidal endothelial cells in the liver, lymph node and spleen (Parums et al, 1990). The same endothelial cells display variable staining withUlex europeaus agglutinin-I (UEA-1) and for von Willebrand factor (factor VIII - related protein), indicating that the sinusoidal endothelium differs from other vascular endothelium. CD 31 does not label connective tissue, basement membrane, squamous epithelium or adnexal structures of the skin (Suthipintawong et al, 1995). The exact function of CD 31 has not been fully elucidated but it appears to mediate platelet adhesion to endothelial cells and may promote vascular adhesion of leukocytes (Stokinger et al, 1990; Albelda et al, 1991).

The main application of CD 31 is as a marker of both benign and malignant endothelial cells (Leong et al, 1997). It is an apparently more sensitive marker than CD 34, von Willebrand factor or UEA-1 as a marker of malignant vascular endothelium (DeYoung et al, 1993) (Appendices 1.22 and 1.23). Despite the earlier suggestion that CD 31 is specific for vascular endothelium (Parums et al, 1990) with no expression by lymphangiomas, we clearly showed that there was distinct staining for CD 31 in all 19 cases of lymphangioma studied, albeit of lesser intensity than that observed in vascular endothelium (Suthipintawong et al, 1995). Indeed, the endothelium of blood and lymphatic vessels share many common antigens such as CD 34, von Willebrand factor and UEA-1 and none provides absolute distinction between the two types of vessels. In the light of these findings, claims that Kaposi's sarcoma shows vascular endothelial differentiation or derivation (Scully et al, 1988; Hoerl & Goldblum, 1997) will need to be reassessed.

Some form of HIER should be used with anti-CD 31 to produce optimal immunoreactivity in fixed tissue sections (we employ microwave-stimulated HIER). The antigen is localized to the cell membrane with some weaker staining of the cytoplasm.

•Albelda SM, Muller WA, Buck CA, Newman PJ 1991. Molecular and cellular properties of PECAM-1 (endoCAM/CD31): a novel vascular cell-cell adhesion molecule. Journal of Cell Biology 114: 1059-1061.

•DeYoung BR, Wick MR, Fitzgibbon JF et al 1993 CD 31: an immunospecific marker for endothelial differentiation in differentiation in human neoplasms. Applied Immunohistochemistry 1: 97-100.

•Hoerl HD, Goldblum JR 1997. Immunoreactivity patterns of CD 31 and CD 68 in 28 cases of Kaposi's sarcoma. Evidence supporting endothelial differentiation in the spindle cell component. Applied Immunohistochemistry 5: 173-178.

•Leong AS-Y, Wick MR, Swanson PE 1997. Immunohistology and electron microscopy of anaplastic and pleomorphic tumors. Cambridge: Cambridge University Press, pp 79-81 and 160-161.

•Parums DV, Cordell JL, Micklem K et al 1990. JC70: a new monoclonal antibody that detects vascular endothelium associated antigen on routinely processed tissue sections. Journal of Clinical Pathology 43: 572-577.

•Scully PA, Steinmann HK, Kennedy C et al 1988. AIDS-related Kaposi's sarcoma displays differential expression of endothelial cell surface antigens. American Journal of Pathology 130: 244-251.

•Stokinger H, Gadd SJ, Eher R et al 1990. Molecular characterization and functional analysis of the leukocyte surface protein CD31. Journal of Immunology 145: 3889-3897.

•Suthipintawong C, Leong AS-Y, Vinyuvat S 1995. A comparative study of immunomarkers for lymphangiomas and hemangiomas. Applied Immunohistochemistry 3: 239-244.

Manual of diagnostic antibodies for immunohistology / Anthony S.-Y. Leong, Kumarasen Cooper, F. Joel W.-M. Leong.