Drug hypersensitivities: which room for biological tests?
ABSTRACT Drug allergic reactions frequently represent a serious diagnostic problem. In this paper we summarise the most relevant data published in recent years on the diagnostic reliability of the in vitro techniques in drug allergy diagnosis. The lymphocyte transformation test (LTT) offers a sensitivity of 58% in the diagnosis of late allergic reactions to betalactams and 64.5% in the immediate allergic reactions. The basophil activation test and the antigen-specific sulphidoleukotriene determination have an acceptable diagnostic reliability in muscle relaxant drug-induced reactions and in betalactam allergy. BAT sensitivity in betalactam allergy was 50.7% and its specificity 93.3%, whereas CAP had a sensitivity of 36.7% and a specificity of 83.3%, and CAST, a sensitivity of 47.7% and a specificity of 83.3%. For NSAID hypersensitivity, BAT sensitivity was 63.3% and specificity 93.3%, CAST sensitivity was 38.3% and specificity 76.6%. BAT sensitivity in metamizol allergy was 42.3% and the specificity 100% and CAP was negative in all the 17 cases in which it was performed. The joint use of BAT and CAP (specific IgE) allows diagnosis of 65.2% of the betalactam allergic patients with a specificity of 83.3%. The combined use of CAST and BAT in metamizol allergy detects 76% of the cases and 76.9% when associating the skin tests. In NSAID hypersensitivity, the joint use of BAT and CAST does not increase the diagnostic reliability of BAT alone. BAT is a non-invasive useful technique in the in vitro diagnosis of betalactam and metamizol allergy, and NSAID hypersensitivity.
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ABSTRACT: Prior use of 'lymphocyte transformation test' (LTT) in Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) provided conflicting results, possibly dependent on sampling dates (acute vs. late). Evaluation of LTT in patients with SJS or TEN who reacted to lamotrigine (LTG). In a small subgroup we explored the possible role of regulatory T cells (T-reg). Acute phase samples (9) and post-recovery samples (14) from cases of SJS or TEN to LTG were provided by the RegiSCAR-study group. Controls were persons never exposed to LTG (12), patients exposed without reaction (6), and patients who developed a mild eruption to LTG (6). LTT was performed by measuring (3) H-thymidine incorporation after 3 days of incubation with phytohemmaglutinin, LTG (10 μg/mL) or medium. Stimulation index ≥ 2 was considered positive. In 16 cases LTT was redone after depletion of T-reg by fluorescence activated cell sorting. Positive LTT was observed in 3/6 cases of mild eruptions, 1/9 SJS/TEN-cases tested during the acute phase and 3/14 SJS/TEN-cases tested after recovery. We noted a very mild and nonsignificant trend for an increased response after depletion of T-reg in late samples from SJS or TEN patients. With the largest number of LTT performed in patients with SJS or TEN to a single drug, we confirmed that reactive cells are rarely detected in these reactions. Poor reactivity did not seem related to T-reg. Other in vitro assays than those testing proliferation should be evaluated, before raising the hypothesis that specific cells disappeared by undergoing apoptosis during the reaction.Clinical & Experimental Allergy 10/2011; 42(2):248-54. · 4.79 Impact Factor