Demonstration of lymphatics in human synovial tissue.

Using a cocktail of monoclonal antibodies PAL-E and DE-U-10 (anti-desmin), combined in double labelling techniques with the lectin Ulex europaeus agglutinin I (UEAI), vessels consistent with lymphatics were demonstrated in normal human synovial tissue. These vessels were negative for the monoclonal cocktail and positive for UEAI, were thin-walled and were located close to deep arterioles and venules as expected. Elastin was not found to assist identification of lymphatics in synovium. In rheumatoid arthritic synovium no vessels staining in the manner of normal lymphatics were found. This may indicate absence or change of phenotype of this type of endothelium in disease.