Skin-associated lymphoid tissues

The interaction of a chemical (hapten) with epidermal proteins (carrier) can result in a hapten-carrier complex capable of activating skin-associated lymphoid tissue (sensitisation) and dissemination of antigen-specific T l)unphocytes (induction). Subsequent encoimter with the same or cross-reactive chemicals can result in the elicitation of a characteristic inflammatory skin reaction. The clinical condition is referred to as allergic contact dermatitis and is characterised by erythema, oedema, vesiculation and pruritus. Allergic contact sensitisation is, therefore, classed as a cell-mediated immunological response to chemicals that contact and penetrate the skin. 

SALT—skin-associated lymphoid tissue SAXS—small-angle x-ray scattering SCF—stem cell factor SCS—spent culture supernatant... 

Evidences for Skin-Associated Lymphoid Tissues [SALT]... 

The hypothesis of skin-associated lymphoid tissues [SALT] was built with the evidences obtained by several research centers which investigated contact sensitivity, delayed-type hypersensitivity, tumor subcutaneous transplantation, and skin transplantation [4-8] as it follows. 

Toews GB, BeigstresserPR, StreUein JW. Langerhans cells sentinels of skin associated lymphoid tissue. J Invest Dermatol. 1980 75 78-82. 

B2. Bailey, E. M., Ferry, J. A., Harris, N. L., Mihm, M. C., Jr., Jacobson, J. O., and Duncan, L. M., Marginal zone lymphoma (low-grade B-cell lymphoma of mucosa-associated lymphoid tissue type) of skin and subcutaneous tissue A study of 15 patients. Am. J. Surg. Pathol. 20,1011-1023 (1996). 

The organs of the body which comprise the immune system and/or contribute to immune function include the bone marrow, spleen, thymus, lymph nodes, a network of lymphoid tissue along secretory surfaces (i.e., the so-called mucosa-associated lymphoid tissue, MALT), and the skin. Lymphoid organs can be classified in two ways. The first classification is based on the role that organs play in the development of the immune system and/or its ability to elicit a response. 

Within the body there may exist at any one time only a handful of naive B lymphocytes capable of recognizing the same epitope. The meeting of an antigen and a naive B lymphocyte capable of recognizing an epitope within the antigen occurs through the delivery of antigen to lymphoid tissues of the spleen, lymph nodes and local lymphoid tissue within mucosal surfaces (mucosal associated lymphoid tissue, MALT) and skin (SALT). This lym-... 

Mora JR, Cheng G, Picarella D et al. 2005. Reciprocal and dynamic control of CD8 T cell homing by dendritic cells from skin- and gut-associated lymphoid tissues. J. Exp. Med. 201 303-316. 

In analogy with the mucosa-associated lymphoid tissue [MALT], SALT would work as a specific sentinel for invading pathogens. In this context, skin would play not only a barrier role but also be a component of the lymphatic system. Therefore,... 

Yu, H.-S. et al., Alterations of skin-associated tissue lymphoid tissue in the carcinogenesis of arsenical skin cancer, Proc. Natl. Sci. Counc. Repub. China B, 16, 17, 1992. 

---