Studies on fibronectin in the skin. III. Indirect immunofluorescence studies in lichen planus.

Fibronectin is a glycoprotein which is responsible for a varity of functions in the human organism, such as mediation of contact between cells and between cells and fibres, opsonic qualities, interaction in the stabilization of fibrin, etc. Fibronectin is an important constituent of the ground substance having a special affinity to collagen. In indirect immunofluorescence studies its presence has been abundantly demonstrated in normal human skin, in collagen-rich structures such as the basement membranes, the papillary and reticular dermis, and in the vascular and neural structures, demonstrable by its characteristic staining patterns. Fibronectin is not found in the epidermis. In lichen planus, the distribution in unaffected skin is identical with that in normal skin, whereas in affected skin, changes in the pattern of fibronectin are found. The basement membrane zone becomes broader and hazy, later undergoing disintegration and destruction, concomitant with swelling and homogenization of the reticular distribution of fibronectin in the papillary dermis. Globular structures containing fibronectin are found in the basement membrane area, together with an intensified immunofluorescence in the vascular system. Fibronectin has certain adhesional properties and changes in the distribution of this glycoprotein may result in loss of tissue stability. The pathophysiological significance of the changes of fibronectin in lichen planus is, however, difficult to evaluate at present.