Adhesion of inflammatory infiltrating cells to fibroblasts in erythema nodosum-like lesions of Behcet's disease.

In this study biopsy specimens of erythema nodosum-like lesions from 18 patients with Behcet's disease were examined with the electron microscope to elucidate the close relationship between lymphocytes and/or macrophages and fibroblasts in the perivascular regions of the corium accompanied by marked edematous changes. Adhesion of lymphocytes and/or macrophages to fibroblasts were observed in 11 of the 18 patients in whom biopsy specimens were collected one to four days after the onset of the skin lesions. The lymphocytes adhering to fibroblasts contained a number of polyribosomes and few organelles in the cytoplasm. The fibroblasts with these lymphocytes showed remarkable development of rough endoplasmic reticulum and any other cytoplasmic organelles, indicating activated cellular function as collagen synthesis. In the triads of lymphocyte-fibroblast-macrophage as well as adhesion of macrophages to fibroblasts, morphological profiles of the fibroblasts suggested strongly suppression of collagen synthesis. Our findings indicate that fibroblasts are regulated directly by adhesion of lymphocytes and/or macrophages in fibrous repair of the erythema nodosumlike lesions of Behcet's disease.