INCREASED EXPRESSION OF LYSYL OXIDASE IN SKIN WITH SCLERODERMA

Lysyl oxidase initiates cross-linkage of collagen and elastin by catal ysing the formation of a lysine-derived aldehyde. In order to study cr oss-linking in scleroderma, we used monoclonal antibodies to lysyl oxi dase to determine the localization of this enzyme in systemic and loca lized scleroderma, and compared the distributions obtained with that i n normal skin. Using an indirect immunofluorescent antibody method and an avidin-biotinylated enzyme complex method, 11 cases of diffuse typ e of systemic scleroderma and seven cases of localized scleroderma wer e studied. In the oedematous stage of systemic scleroderma, intracellu lar and extracellular lysyl oxidase were remarkably increased in the d ermis, particularly in groups around blood vessels. In the sclerotic s tage of systemic scleroderma, lysyl oxidase was detected intracellular ly in fibroblasts and extracellularly among collagen bundles between t he lower dermis and the subcutaneous fat tissue. In localized sclerode rma, a marked increase in lysyl oxidase was observed in mononuclear ce lls and fibroblasts near blood vessels in the lower dermis and in the subcutaneous fat tissue, in addition to the extracellular deposits bet ween collagen bundles. The increase in lysyl oxidase in localized scle roderma was much more common than in the oedematous stage of systemic scleroderma. These findings indicated that intracellular and extracell ular expression of lysyl oxidase expression was greater in scleroderma tous skin than in normal skin.