Delayed hypersensitivity skin test

The most common in vivo assay of lymphocyte function is the delayed hypersensitivity skin test. This test specifically evaluates the presence... 

The accepted indications for delayed hypersensitivity skin testing include evaluation of immune disorders or chronic diseases that cause cellular immune dysfunction (e.g., uremia, cancer, AIDS, etc), exposure to infectious pathogens (e.g., Mycobacterium tuberculosis), evaluation of nutritional status (because malnutrition can result in cell-mediated immune deficiency), and in some cases, assessment of immune senescence. 

The first patient treated with a thymic factor was a 4-year-old girl with thymic hypoplasia and abnormal immunoglobulin synthesis (Wara et al, 1975 Wara, 1983). She was treated with TF5 at a dose of 20 mg/kg/week for a total of 33 months. After 1 month of thymosin therapy, she had conversion of delayed hypersensitivity skin tests as well as an increase in absolute lymphocyte count. In addition, T cell percentages increased from 10 to 60% and serum immunoglobulin levels increased from 220 to 1220 mg/dl. However, no effects were seen on T cell functions in lymphoproliferative responses to T cell mitogens or in MLR. The patient s clinical condition improved with a decrease in the number and severity of infections and diarrhea. She has continued off therapy and appears healthy at age 13. This initial success prompted the many subsequent therapeutic attempts with a variety of thymic preparations. 

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). 

Tuberculin skin testing is an important part of the care of all HIV-1-infected patients or persons at risk for HIV-1 infection. Tuberculin skin testing should be done using the Mantoux method. A tuberculin reaction of >5 mm of induration is classified as positive in persons known to have or suspected of having HIV-1 infection. Unfortunately, as the CD4 lymphocyte count declines with progression of HIV-1 disease, many patients no longer react to delayed-type hypersensitivity testing. More than 60% of persons with CD4 lymphocyte counts of <200 cells/pl may have skin test reactions of <5 mm. Thus, it is impossible to detect the presence of tuberculous infection in many HIV-l-infected individuals. 

Observations regarding the cellular immune response in PTSD are also consistent with enhanced GR responsiveness in the periphery. In one study, beclomethasone-induced vasoconstriction was increased in women PTSD subjects compared to healthy, non-trauma-exposed comparison subjects (Coupland et al. 2003). Similarly, an enhanced delayed-type hypersensitivity of skin test responses was observed in women who survived childhood sexual abuse vs those who did not (Altemus et al. 2003). Because immune responses, like endocrine ones, can be multiply regulated, these studies provide only indirect evidence of GR responsiveness. However, when considered in the context of the observation that PTSD patients showed increased expression of the re-... 

The authors of the last report commented that generalized delayed type hypersensitivity to systemic administration of a glucocorticoid is rare. Despite the potent immunosuppressive effect of glucocorticoids on immunocompetent cells, the clinical features, the skin biopsy specimen, and the positive delayed skin test reactions strongly suggested an immunological mechanism T cells were clearly involved and the high concentrations of interleukins 5, 6, and 10 were consistent with a T helper type 2 reaction. The raised concentrations of interleukin-5 were probably responsible for the blood and tissue eosinophilia. 

Levamisole was first synthesized for the treatment of parasitic infections. Later studies suggested that it increases the magnitude of delayed hypersensitivity or T cell-mediated immunity in humans. In immunodeficiency associated with Hodgkin s disease, levamisole has been noted to increase the number of T cells in vitro and to enhance skin test reactivity. Levamisole has also been widely tested in rheumatoid arthritis and found to have some efficacy. However, it has induced severe agranulocytosis (mainly in HLA-B27-positive patients), which required discontinuation of its use. The drug may also potentiate the action of fluorouracil (5-FU) in adjuvant therapy of colorectal cancer, and this combination has been approved for clinical use in the treatment of Dukes class C colorectal cancer after surgery. Its use in these cases reduces recurrences, and the mechanism... 

The authors interpreted these reactions as being allergic. A patch test was very positive to the commercial formulation. Clonidine is a weak sensitizer, but occlusion and prolonged skin contact during transdermal application can cause delayed hypersensitivity. 

A fixed drug eruption due to erythromycin has been observed (53). In another case skin tests with erythromycin were positive for the immediate and or delayed types of hypersensitivity (54). 

This report documents a rare chnical reaction to ioxaglate, with a combination of a maculopapular rash, fever, hepatic and muscle involvement, eosinophiha, and a very high serum IgE concentration. The intradermal tests confirmed a delayed hypersensitivity reaction to ioxaglate. Histological examination of a skin biopsy identified the predominantly T lymphocyte nature of the infiltrate. A contributing role of the beta-blocker atenolol to the seriousness of the clinical syndrome must also be considered. 

This reaction shared the features of a delayed hypersensitivity reaction (exanthematous rash, positive patch test) and of a late phase reaction (CD4+ lymphocjdic infiltrate together with eosinophils). The authors emphasized the importance of skin testing in the diagnosis of delayed skin reactions to contrast media. 

Delayed skin reactions after contrast media have the featnres of true delayed hypersensitivity reactions, including positive skin tests (SEDA-24, 523). A generalized macnlar rash 24 hours after injection of ioversol with positive skin tests has been reported (208). 

Measles Infection. In a historical cohort study in Guinea-Bissau, measles infection was associated with a large reduction in the risk of skin test positivity to house dust mites, compared with children who had been vaccinated against measles and not acquired the infection [ 102(111C)]. The mechanism of this effect is difficult to fit into the hygiene hypothesis because measles causes sequential Thl and Th2 cytokine responses. Measles vaccination leads to an enhanced Th2-like effect, with suppression of delayed-type hypersensitivity reactions [159(NC)]. 

Although supplementation with to-3 fatty acids did not significantly alter the humoral immune response to keyhole limpet hemocyanin (KLH) in geriatric beagles (Wander et al., 1997), it significantly suppressed the cell-mediated immune response based on results of a delayed-type hypersensitivity (DTH) skin test. After consumption of the 1.4 1 diet, stimulated mononuclear cells produced 52% less PGE2 than those from dogs fed the 31 1 diet. 

One of the most helpful tests to evaluate risk of penicillin allergy is the skin test. Skin testing can demonstrate the presence of penicillin-specific IgE and predict a relatively high risk of immediate hypersensitivity reactions. Skin testing does not predict the risk of delayed or most dermatologic reactions. 

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