SPECIFIC BINDING OF ULEX-EUROPAEUS AGGLUTININ-I LECTIN TO SARCOLEMMA OF DISTAL MYOPATHY WITH RIMMED VACUOLE FORMATION

Ulex europaeus agglutinin I (UEA I) binding was studied in 83 patients with various neuromuscular disorders. UEA I labelled endomysial capil laries and endothelial cells of perimysial blood vessels in all the ex amined muscles. There was no UEA I binding to muscle fibres except for all (9) cases of distal myopathy with rimmed vacuole formation (DMRV) , 1 of 5 cases of inclusion body myositis and 1 of 36 cases of inflamm atory myopathies. The UEA I binding was completely eliminated by prein cubation of UEA I solution with L-fucose. Using electron microscopy, t he UEA I binding was localized to sarcolemma and intrasarco-plasmic me mbranous organelles other than mitochondria. Myosatellite cells were n ot labelled. These findings revealed the existence of fucosylated prot eins or lipids in a subset of skeletal muscles suffering from DMRV. Bi ochemical identification of the fucosylated substance and further deta iled study on subcellular localization of UEA I binding may yield impo rtant clues to the unknown pathogenesis of DMRV.