Do epidermal Langerhans cells, migrating from skin lesions, induce the paracortical hyperplasia of dermatopathic lymphadenopathy?

In the present study, immunohistochemical and immunoelectron microscopic techniques were used to differentiate Langerhans cells (LC) from interdigitating cells (IDC) in the lymph nodes (LN) of dermatopathic lymphadenopathy. The majority of the dendritic cells that existed in the LN of dermatopathic lymphadenopathy were positive for OKT-6 (CD 1a) antibody. It was concluded that these dendritic cells were not IDC, but LC. Electron microscopically, LC in these LN contained a few Birbeck granules (BG). In order to prove the fact that these dendritic cells were LC, the existence of BG was investigated ultrastructurally by examining aerial sections, and immunoelectron microscopically for CD 1a positive cells. Most of the LC In the lymph nodes we examined were negative for the anti-proliferating nuclear antigen (PCNA) antibody. This finding may mean that LC In the LN are fully developed cells and do not divide In the LN. Langerhans cells may migrate from the skin lesions to the paracortical areas in the LN, which then may become enlarged.