Nonimmunologic mechanisms

Improve the function of the digestive system defense barrier via immunological and nonimmunological mechanisms... 

Upon systemic distribution, many drugs evoke skin reactions that are caused on an immunological basis. Moreover, cutaneous injury can also arise from nonimmunological mechanisms. Cutaneous side effects vary in severity from harmless to lethal. Cutaneous reactions are a common form of drug adverse reaction. Nearly half of them are attributed to antibiotics or sulfonamides, and one-third to nonsteroidal anti-inflammatory agents, with many other pharmaceuticals joining the list... 

The gastrointestinal (Gl) tract defends the host from toxins and antigens by both immunologic and nonimmunologic mechanisms, collectively referred to as the gut barrier function. Whenever possible, enteral nutrition (EN) is preferred over parenteral nutrition (PN) because it is as effective, may reduce metabolic and infectious complications, and is less expensive. 

Botana et al. [143] analyzed possible nonimmunological mechanisms involved in the release of anaphylactic mediators like histamine using rat mast cells. They were able to show that there was some release upon incubation of... 

CHAN-YEUNG, M. (1982) Immunologic and nonimmunologic mechanisms in asthma due to western red cedar (Thuja plicataj. Journal of Allergy and Clinical Immunology, 70, 32-37. 

Frontier between immunologic and nonimmunologic mechanisms difficult to trace... 

Acute rejection usually occurs within the first year after transplantation and is characterized by an intense cellular immune response within the graft. Acute rejection can usually be treated effectively with anti-inflammatory and anti-T-cell therapies. However, recurrent episodes of acute rejection may result in graft destruction or may lead to the development of chronic rejection. Chronic rejection usually occurs years after transplantation and is manifested by progressive loss of graft function, arteriosclerosis, and fibrosis. Whereas the pathogenesis of chronic rejection is not clear, both immunological and nonimmunological mechanisms seem to be involved (7). Based on the available data, chemokines are most likely to play a role in acute and chronic rejection as indicated schematically in Fig. 1. 

The number of known cytokines, as well as the diversity of biological functions, have led to a very complex and often confusing picture of the immunologic and nonimmunologic processes involved. The role of cytokiaes in local or systemic homeostatic mechanisms related to physiological functions may be utilized therapeutically for treatment of cancer and a variety of other diseases (2). Pharmaceutical research and development efforts surrounding lL-1 are typical examples of the cytokine inhibition approach to chronic inflammation research (2). 

Objective irritation is defined as nonimmunologically mediated, localized inflammation of the skin, usually resulting from contact with a substance that chemically damages the skin.2,9 The exact mechanism is unknown, and it is likely that both endogenous and exogenous factors are involved. In vivo predictive testing in animals (e.g., modified Draize test, repeated application patch tests,... 

Three mechanisms are implicated in CUS immunologic (ICU), nonimmunologic (NICU), or uncertain mechanism.20 ICU is a type I hypersensitivity reaction that is IgE mediated and is associated with atopy. NICU is the more common variety of CUS. NICU due to cosmetics is most commonly caused by fragrances (e.g., cinnamic aldehyde) and preservatives (e.g., benzoic acid and sorbic acid).2 Parabens have been documented by passive transfer to cause ICU.21... 

A wide spectrum of adverse reactions may occur after ingestion of food. Adverse food reactions can be divided on the basis of immunologic and nonimmunologic pathogenetic mechanisms (Johansson et al., 2001 Sicherer, 2002). 

Mechanisms of drug-induced kidney disease include immune-mediated toxicities (e.g., glomerulonephritis and allergic interstitial nephritis) and nonimmunologic-mediated toxicities which effect specialized characteristics of normal renal physiology. 

The mechanisms underlying immediate-contact reactions are divided into two main types immunologic and nonimmunologic. However, there are substances that cause immediate contact reactions whose mechanisms (immunologic or not) remain unknown [9, 10, 14]. 

Nonimmunologic contact urticaria (NICU) occurs in individuals not sensitized to the contactant, i.e., almost any normal subject. The mechanism of action is the result of a direct release of vasoactive substances, which causes a localized response [20]. Prostaglandins are mediators in the reaction to at least benzoic and sorbic acids and to methyl nicotinate, and systemic or topical inhibitors of prostaglandin synthesis inhibit the reaction to these substances [21-23]. Ultraviolet radiation (UVB and UVA) has also been shown to inhibit NICU reactions to some substances [24]. The NICU reaction is often redness without edema rather than a real wheal-and-flare reaction. The appearance of clinical signs depends mainly on the duration of exposure, the concentration of the contactant and other factors, such as rubbing or scratching. The reaction usually remains localized and systemic reactions are probably... 

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