Prior sensitization

Large granular lymphocytes, not belonging to either the T- or B-cell lineage. Natural killer (NK) cells are considered part of the innate defense system since, in contrast to cytotoxic T-cells, they are able to kill certain tumor cells in vitro without prior sensitization. The basal activity of NIC cells increases dramatically following stimulation with type I IFNs. In addition, NK cells display Fc-receptors for IgG and are important mediators of Antibody-Dependent-Cell-mediated-Cytotoxicity (ADCC). 

NK cells Nonspecific T cells that react directly with target cells (tumor cells) without prior sensitization. 

CNS effects Benzonatate has been associated with adverse CNS effects possibly related to a prior sensitivity to similar agents or interaction with concomitant medication. 

Prior sensitivity to any tricyclic drug. Not recommended for use during the acute recovery phase following myocardial infarction. Concomitant use of monoamine oxidase inhibitors (MAOIs) is generally contraindicated. 

Histamine may be released from mast cells by mechanisms that do not require prior sensitization of the immune system. Drugs, high-molecular-weight proteins, venoms, and other substances that damage or disrupt cell membranes can induce the release of histamine. Any thermal or mechanical stress of sufficient intensity also will result in histamine release. Cytotoxic compounds, may release histamine as the result of disruption of cell membranes. 

C) Be initiated by organic bases such as morphine without prior sensitization... 

Natural killer (NK) cells are mononuclear cells able to lyse tumor cells without prior sensitization to specific antigens [84], When NK cells... 

Direct irritation may thus be dehned as an adverse effect of chemicals directly applied to the skin that does not involve prior sensitization and thus initiation by an immune mechanism. Irritation is usually assessed by a local inflammatory response characterized by erythema (redness) and/or edema (swelling). Other responses may be present that do not elicit inflammation such as an increase in skin thickness. Irritant reactions may be classified as acute, cumulative, traumatic, or pustular. However, two classifications are generally used by toxicologists. Acute irritation is a local response of the skin usually caused by a single agent that induces a reversible inflammatory response. Cumulative irritation occurs after repeated exposures to the same compound and is the most common type of irritant dermatitis. 

Systemic contact dermatitis is a delayed hypersensitivity skin reaction that results from systemic exposure. Exanthematous systemic contact dermatitis from ethylenediamine has been reported with aminophylline. Disodium edetate (ethylenediamine tetra-acetic acid) has caused contact dermatitis after local application (SEDA-23, 242), and ethylenediamine cross-reacted in a patch test in a patient who had had contact dermatitis with hydroxyzine, an ethylenediamine derivative (SEDA-22, 178). Prior sensitization can occur to ethylenediamine in creams and ointments (SED-14, 485). 

A case of temporary thrombocytopenia has been described (11), probably due to prior sensitization by ethylenediamide (a stabilizer in some creams), with which piperazine cross-reacts. 

Many compounds, including a large number of therapeutic agents, stimulate the release of histamine from mast cells directly and without prior sensitization. Responses of this sort are most likely to occur following intravenous injections of certain substances. Tubocurarine, succinyl-choline, morphine, some antibiotics, radiocontrast media, and certain carbohydrate plasma expanders may elicit the response. The phenomenon may account for unexpected anaphylactoid reactions. Vancomycin-induced red-man syndrome involving upper body and facial flushing and hypotension may be mediated through histamine release. 

Anaphylactoid reactions are also caused by release of active compounds from mast cells but do not involve prior sensitization or mediation through IgE. 

A. Aiiergic reactions as a resuit of prior sensitization have been reported. 

NK cells are a subpopulation of lymphoid cells that do not require prior sensitization to recognize and kill various targets including viruses, intracellular bacteria,... 

NK cells are important constituents of the primary natural immune system. NK cell function is modulated by the surface expression of MHC molecules. Unlike T cells, NK cells form a first line of defense and kill target cells without prior sensitization. In addition, stimulatory and inhibitory receptors signal and control NK cell function. Therefore, it is plausible that herpesviruses also address this aspect of natural immunity. The status of this emerging field of research is presented in two reviews. An even more recent addition to the field is the recognition of the importance of chemokines, cytokines and their receptors. As expected from a virus which has co-speciated with the host, herpesviruses use this information and divert it to their advantage. For a virus it makes no difference whether the cell itself responds to virus infection, e.g. by apoptosis or any other type of internal cellular antiviral regulation, or whether the reaction is systemic and involves several specialized cells. It is therefore not surprising that viruses have also found principles to avoid induced cell death. 

Oral medications taken by athletes may also be allergenic, particularly the non-steroidal agents (especially piroxicam) and antibiotics (ciprofloxacin, nalidixic acid, sulfonamides, tetracyclines), which are photosensitizers (Wainwright et al. 1993). Prior sensitization to thiuram rubber accelerators makes athletes susceptible to systemic eczematous dermatitis if Antabuse (disulfiram - a thiuram derivative) is given orally (Pirila 1957 Shelley 1961). 

Unlike the other types of hypersensitivity caused by antibodies, namely types II and ni, only a proportion of the population, the so-called atopies, have a predisposition to developing a type 1 hypersensitivity reaction when exposed to the allergen in question. Atopy may have a genetic component but type 11 and III reactions like, for example, penicillin-induced hemolytic anemia and serum sickness, may occur in all individuals, and this may result without a prior sensitization phase. 

---