Detection of migration inhibitory factor (MIF) by a monoclonal antibody in the microvasculature of inflamed skin.

Macrophage migration inhibitory factor (MIF) is known as a mediator of cellular immunity with specific effects on the differentiation of mononuclear phagocytes. There is little information on the production of MIF in vivo and its role in the pathophysiology of inflammation. We studied the distribution of MIF in various tissues with a monoclonal antibody against human MIF (1C5/B) using the indirect immunoperoxidase method. Here, we investigate the expression of MIF on endothelial cells of dermal vessels. Our results show that dermal vessels may constitutively express MIF and can be strongly activated to express MIF in acute inflammations such as eczema and psoriasis in contrast to the chronically infiltrated skin from patients with pseudolymphomas and sarcoidosis. In these cases a possibly MIF defective state of vessels and a restriction of positive vessels to distinct anatomical sites of the inflamed skin was detected. The significance of the described association of MIF with vascular endothelium is still a matter of speculation. MIF expression on endothelium may provide an important differentiogenic signal for mononuclear phagocytes on their way to the tissue site.