Hypersensitivities delayed reactions

Diethylenetriaminepentaacetic acid DFMO al-Difluoromethyl ornithine DFP Diisopropyl fluorophosphate DFX Desferrioxamine DGLA Dihomo-y-linolenic acid DH Delayed hypersensitivity DHA Docosahexaenoic acid DHBA Dihydroxybenzoic acid DHR Delayed hypersensitivity reaction... 

Allergic contact dermatitis is a delayed hypersensitivity reaction.30 Upon initial exposure, a substance penetrates the skin, binds to a protein and develops into sensitizing antigens. Subsequent exposures to that substance will then elicit an allergic reaction.25,29,30 Symptoms of allergic contact dermatitis are similar to those of the irritant type, but may take several hours to several days to develop following re-exposure.25,26... 

Monitor the patient for the development of potential complications of treatment such as delayed hypersensitivity reactions, antibiotic-induced diarrhea, pseudomembraneous colitis, or fungal superinfections (manifested as oral thrush). 

It has been postulated that Chlamydia may produce a heat shock protein that causes tissue damage through a delayed hypersensitivity reaction. C. trachomatis may also possess DNA evidence of toxin-like genes that code for high-molecular-weight proteins with structures similar to Clostridium difficile cytotoxins, enabling inhibition of immune activation. This may explain the observation of a chronic C. trachomatis infection in subclinical PID. 

Y. Kaminer, A. Apter, S. Tyano, E. Livni, and H. Wysenbeek, Delayed hypersensitivity reaction to orally administered methylparaben, Clin. Pharm., 1, 469 (1982). 

These are called delayed hypersensitivity reactions since they normally occur 6-24 hours after exposure. A cell-mediated allergy involves the interaction of food allergens with sensitised lymphocytes, which usually occurs in the gastrointestinal tract. The sensitised lymphocytes produce lymphokines and the generation of cytotoxic T lymphocytes. These latter cells destroy other intestinal cells, including the epithelial cells that are critical for absorption. 

Second, there are specific endpoint assays for which an adverse outcome clearly dictates the action to be taken. These endpoints include either immediate or delayed hypersensitivity reactions, because once the individual is sensitized a dose-response relationship may not apply. 

To initiate a T-cell immune response, antigen presenting cells have to display antigenic peptides com-plexed with the major histocompatibility complex (MHC) on their cell surface. The T-cell receptor of CDS cells is specific for the peptide-MHC class I complex while the CD4 cell receptor binds the peptide-MHC class II complex. This binding of the peptide-MHC II complex stimulates CD4 cell proliferation and subsequent lymphokine release. This CD4 cell response can initiate a delayed hypersensitivity reaction. However CD4 activation and the production of various lymphokines is also needed for the generation of cytotoxic T-cells and for the differentiation of plasma cells from B-lymphocytes and the antibody response by these plasma cells. For their role in also the humoral immune response CD4 cells are called T-helper cells. 

A delayed hypersensitivity reaction, characterized by a skin rash, due to dexamethasone has been reported (171). These kinds of reactions to systemic glucocorticoids are rarely reported. 

Mechanisms of Cell-Mediated Delayed Hypersensitivity Reactions (Th1)... 

Antioxidants make up a large group of food additives, as they can prevent spoilage of easily oxidizable substances (containing much fat or oil). Typical examples of antioxidants used as food additives are the synthetic antioxidants butylated hydroxyanisole (BH A) and butylated hydroxytoluene (BHT), widely used in packaged foods (Directive 2006/52/EC). It has been discovered that these antioxidants can cause adverse reaction in the upper and lower respiratory tract (not well documented), utricarial reactions (very common), and delayed hypersensitivity reactions (well documented) (Weber 2008a). 

Kaminer Y, Apter A, Tyano S, Livni E, Wijsenbeek H. Use of the microphage migration inhibition factor test to determine the cause of delayed hypersensitivity reaction to haloperidol syrup. Am J Psychiatry 1982 139(ll) 1503-4. 

Hypersensitivity reactions are rare, but a few have been reported after inhalation. Delayed hypersensitivity reactions, particularly affecting vascular tissue, have been recorded with chronic systemic administration. Tumor-inducing effects are difficult to attribute to cannabis alone. Animal studies have shown neoplastic pulmonary lesions superimposed on chronic inflammation, but such pathology may be primarily associated with the tar produced by burning marijuana. The most serious potential adverse effects of cannabis use come from the inhalation of the same carcinogenic hydrocarbons that are present in tobacco, and some data suggest that heavy cannabis users are at risk of chronic respiratory diseases and lung cancer. 

Immunologic Complications of infusion, drug-induced lupus erythematosus, delayed hypersensitivity reaction... 

A phlyctenule is a focal nodule composed of leukocytes, generally the result of a delayed hypersensitivity reaction to microbes or their toxins. For this antigenic response to occur, the patient must have a history of previous exposure and sensitization to the causative organism... 

Allergic disease also affects the lids and ocular adnexa. Contact dermatitis is an example of a delayed hypersensitivity reaction that affects the ocular adnexa. In contact dermatitis, exposure to antigen results in the infiltration of T cells and macrophages into the dermis within approximately 3 hours. Over a 48- to 72-hour period the peak response occurs, withT cells and macrophages spreading to the epidermis in an attempt to eliminate the antigen. Clinically, eczema or dermatitis develops. Even with the antigen removed, dermatitis may continue for up to 3 weeks. 

A dose-escalation study in 35 patients with psoriasis confirmed that constitutional symptoms in response to denileukin diftitox were dose-related and less frequent at lower doses (below 5 micrograms/kg/day) (17). There was only one case of mild vascular leak syndrome. Skin reactions compatible with delayed hypersensitivity reactions were noted in three patients, including one case of exfoliative dermatitis. 

Various mechanisms were postulated to explain these persistent lesions, such as a non-allergic direct toxic effect of aluminium and a delayed hypersensitivity reaction to aluminium. 

Yung MW, Rajendra T. Delayed hypersensitivity reaction to topical aminoglycosides in patients undergoing middle ear surgery. Clin Otolaryngol Allied Sci 2002 27(5) 365-8. 

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