A laboratory test based on determination of cytokine profiles: a promising assay to identify exposition to contact allergens and predict the clinical outcome in occupational allergic contact dermatitis.

BACKGROUND: Para-phenylenediamine (PPD) is the main allergen causing adverse reactions to hair dyes and a frequent cause of occupational-related skin sensitization among hairdressers and beauticians. The immunologic mechanism of the disease relies on the production of inflammatory cytokines by allergen-specific T cells, while regulatory T cells are thought to down-modulate the allergic response. This study was aimed at investigating the expression of effector or regulatory cytokines in exposed subjects in order to verify whether different cytokine profiles might predict distinct clinical outcomes. Peripheral blood mononuclear cells (PBMC) from 21 subjects occupationally exposed or not (10) to PPD were kept in short term cultures in the presence of optimized concentrations of NiSO4 × 6H2O or PPD. The production of IFN-γ and IL-10 elicited by antigens were analyzed by the ELISpot assay. RESULTS: The presence of IFN-γ responses toward PPD was significantly correlated with a positive patch test (P = 0.002) and allergic symptoms, while IL10 responses were invariably found in PPD-exposed but clinically asymptomatic subjects with negative patch testing. We found concordance between the different cytokine profiles and patch test results. No false-positive results were found for the different cytokine profiles induced by PPD, resulting in 100% specificity. The sensitivity of the test was 87.5% (95% CI 65.9-100.0) with an overall test accuracy of 93.3%. Although larger prospective-retrospective studies are necessary to validate the predictive potential of the test, the negative and positive predicted values for PPD in this study were NPV = 87.5% and PPV = 100%, respectively. CONCLUSIONS: These data indicate that distinct cytokine profiles are associated with different clinical manifestations. The test, which is based on a simple and rapid profiling of cytokine responses by T lymphocytes against allergens, has proven to be a promising laboratory tool, useful for both the identification of previous contact with allergens and the etiologic diagnosis of contact allergies as well as capable of predicting the clinical outcome (development of an allergic or tolerant response).

Multiple-drug intolerance syndrome: clinical findings and usefulness of challenge tests.

BACKGROUND: Multiple-drug intolerance syndrome (MDIS) is characterized by adverse reactions to several classes of chemically unrelated drugs. OBJECTIVE: To analyze all patients with a history of adverse reactions to at least 3 drugs at the Allergy Unit of Policlinico Gemelli in a 6-year period to better characterize patients with MDIS and to find safe alternative drugs. METHODS: We studied 480 patients (aged >16 years) with a history of adverse reactions to at least 3 unrelated drugs and with negative allergy test results. Patients who had experienced mild adverse reactions that remitted spontaneously underwent challenge tests without any premedication (group A). Patients with a clinical history of moderate reactions received sodium cromolyn, 500 mg, before the challenge (group B). Patients with a clinical history of severe reactions or undergoing parenteral challenges were given an antihistamine 30 minutes before the challenge (group C). RESULTS: In group A, 491 tolerance challenge tests were performed: 414 had negative results and 77 had positive results. In group B, 1,077 tolerance challenge tests were performed: 956 had negative results and 121 had positive results. In group C, 240 tolerance challenge tests were performed: 214 had negative results and 26 had positive results. Comparing the tolerance of alternative drugs in groups A and B, groups A and C, and groups B and C, no significant results were observed (P = .24, .14, and .44, respectively). CONCLUSIONS: Patients with MDIS can tolerate alternative drugs. Premedication with sodium cromolyn or oral H1-antihistamines may be useful in preventing adverse reactions.