Authors: Nuwayri-Salti N, Knio K
The skin is the largest organ of the body. It is the one entirely exposed to the environment. It has an outer avascular stratified, squamous epithelial layer with its appendages the epidermis, and a deep vascular connective tissue layer the dermis. The dermal blood capillaries exhude fluid and leucocytes into the surrounding tissues in The exuded cells, and fluids are collected by blind ended lymphatic vessels starting in tissues and draining into major veins
and the Cysterna Chyli. Lymphatic venules exist in all organs, except a few debatable sanctuaries. These vessels differ from blood capillaries and venules, by having discontinuous, scanty basal lamina, contoured by irregularly spaced, muscle fiber. The latter, suck in the extracellular fluid, by spontaneously contracting, in a fashion similar to cardiac muscle cells. The endothelial lining cells are separated by fenestrations always patent. Once the vessels are distended the fenestrations become covered by the endothelial cell extensions. To obtain pure leucocytes, it is enough to scrape superficially the epidermis, removing part of the keratinized dry layer, to open an epidermal window (EW). The superficial injury, induces an inflammatory reaction with both leucocyte components, the acute and chronic phases. Both types of responding cells (the granulocytes and the a-granulocytes) are collected on
sterile slides or cover slips, for easy handling and use in many types of studies. These cells are studied for form, content, function, and can even be expanded in cultures. The EW has been and still is a very useful tool to identify the defect in patients complaining of poor immunity. In addition, it is used to evaluate the epidemiology of several diseases such as some infections, autoimmune disorders and even neoplasm. In this manuscript we are describing
our experience with EW for more than 30 years, in patients suspected to be immune-deficient.