Ultrastructural differences of interdigitating cells in human lymph nodes.

Eleven axillary lymph nodes from patients with different cutaneous disorders (systemic scleroderma, atopic eczema, psoriasis, hairy cell erythroderma, dermatopathic lymphadenitis) were examined by electron microscopy. In systemic scleroderma interdigitating cells (IDC's) showed typical ultrastructural features as well as intimate contacts with neighboring lymphocytes. In atopic eczema IDC's were characterized by widespread invaginations of the cell membrane, and an increase in tubulo-vesicular structures and microfilaments. Similar observations have been made in dermatopathic lymphadenitis. In psoriasis and hairy cell erythroderma. IDC's showed only a few interdigitations and invaginations of the cell surface. It is supposed that these structural changes in IDC's reflect the different immunological conditions of the diverse cutaneous disorders.