P25
Accuracy of serial dilution concentrations for intradermal skin testing: a neglectable problem?

Abstract

To understand the mechanisms involved in immunological tolerance to skin-associated proteins, we have developed trangenic (Tg) mice that express a model self antigen, membrane-bound ABSTRACTS 125 FS01.3 Disperse (yes), orange (yes), 3 (no): what do we test in textile dye dermatitis?Para-phenylenediamine (PPD), an arylamine dye, is a strong allergen causing allergic contact dermatitis. Cytokines such as TNF-a and IL-1beta are key mediators in the initiation of this reaction. Both cytokines are predominantly produced by stimulated monocytes and macroghages. We investigated the responses of PPD and Bandrowski's base (BB), an autoxidation product of PPD in human monocytes. We isolated monocytes from healthy volunteers and incubated them with the allergens. TNF-a and IL-1beta mRNA expression and protein levels were estimated after 45 min, 2 h, 4 h and 24 h after allergen contact. IL-1beta and TNF-alpha were measured in cell culture supernatants by ELISA (n ¼ 7) and mRNA expression was determined by real-time RT-PCR. We found that PPD reduced TNF-a protein secretion by 20-69.9% (n ¼ 6). Further, IL-1beta levels were decreased by 44-98%. The same tendency was found studying IL-1beta and TNF-a mRNA steady state levels (n ¼ 3; 1 h incubation). These effects were substance-specific and not found for PPD derivatives nor for the autoxidation product BB. These findings suggest that PPD may specifically modify immune responses by directly infering with the cellular proinflammatory cytokine network.

Immediate Hypersensitivity to Rifampicin in 3 Patients: Diagnostic Procedures and Induction of Clinical Tolerance

“…A non-irritant intradermal cutoff concentration of rifampicin was established in 24 healthy volunteers at a dilution of 1:10,000, which corresponds to approximately 0.006 mg/ml [9]. In 2 patients, patch tests with undiluted rifampicin were done.…”

Practical management of antibiotic allergy in adults

“…Testing a single patient by SPT and graded IDT takes 2 h. Appropriate dilutions of drugs need to be prepared according to published data 22. This is most appropriately carried out by trained pharmacists, rather than by clinical staff making extemporaneous dilutions in the clinic, where errors often occur 23. Pharmacy resources are therefore required to support an effective drug allergy service.…”