Threshold for Positivity and Optimal Dipyrone Concentration in Flow Cytometry-Assisted Basophil Activation Test

Abstract

PurposeBasophil activation occurs both in patients with immediate hypersensitivity reactions to anti-inflammatory drugs and in healthy controls in a dose-dependent manner. Our aims were to define the optimal basophil activation test (BAT) concentration and the threshold for BAT positivity for dipyrone.MethodsFrom 45 patients with a positive history of an immediate hypersensitivity reaction to dipyrone, we found 20 patients with dipyrone-induced anaphylaxis demonstrating positive skin tests. All selected patients, as well as 10 healthy controls, were tested in vivo and in vitro. BAT was performed using Flow 2CAST technique with three low dipyrone concentrations: 25 µg/mL (c1), 2.5 µg/mL (c2) and 0.25 µg/mL (c3). The threshold for BAT positivity was established using receiver operating characteristics (ROC) curve analysis.ResultsUsing ROC curve analysis the highest area under curve, 0.79 (0.63-0.95) (P<0.01), was found for c3. When the highest stimulation indexes from the three concentrations for each patient were used, ROC curve analysis revealed an area under curve of 0.81 (0.65-0.96) (P<0.01), sensitivity and specificity were 0.70 and 1 and the optimal threshold value for BAT positivity was 1.71. Thirteen patients had a positive BAT for at least one of the tested dipyrone concentrations. All healthy controls presented negative BAT.ConclusionsBAT might be a useful technique to diagnose dipyrone allergy, provided all three low dipyrone concentrations are used together. With an assay-specific threshold of 1.71, ROC curve analysis yields 70% sensitivity and 100% specificity.

In vitro Diagnosis of Immediate Drug Hypersensitivity: Should We Go with the Flow?

“…However, a minority of IDHRs to NSAIDs appear to be ‘genuine' IgE-mediated reactions, and, in such cases, patients appear to react exclusively to a single NSAID family. So far, 5 publications have reported on BAT in selective hypersensitivity to pyrazolones [31,32,36,43,44], with BAT yielding a sensitivity of 42-70% and a specificity of 86-100%; 1 study showed a significantly lower sensitivity, thereby contradicting the other studies [43]. …”

“…As displayed in tables, the technique has mainly been applied to document allergy to NMBAs (table 1) [8,9,10,11,12,13,14,15,16], antibiotics like β-lactam antibiotics and quinolones (table 2) [17,18,19,20,21,22,23,24,25,26,27,28,29,30], aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs; table 3) [31,32,33,34,35,36,37,38,39,40,41,42,43,44,45], and iodinated radiocontrast media (RCM; table 4) [46,47,48]. In general, the sensitivity of the assay varies between 50 and 60%, whereas specificity easily attains 80%, except for quinolones and NSAIDs (see below).…”

Controversies in drug allergy: In vitro testing

“…Although BATs generally display specificity (>90%), sensitivity rates have been highly variable, depending on the drug involved. Positivity rates ranged from 44% to 63% for BLs, 42,43,[47][48][49][50][51][52] 36% to 92% for NMBAs, 35,36,[53][54][55][56][57][58] 42% to 65% for dipyrone, [59][60][61] 57% to 77% for quinolones, [62][63][64][65] and 46% to 63% for radiocontrast media. 66,67 Regarding platin BATs, a study has provided insight into the risk of breakthrough reactions during desensitization.…”

“…17,19 IDHRs at the resolution phase identifying the relevant drug sIgE by using immunoassay 38% to 85% for BLs [21][22][23][24][25] 44% to 92% for NMBAs [26][27][28][29][30][31][32] 26% to 68% for biological agents 39,40 59% to 75% for platins 41 d sIgE to penicillins can produce falsepositive results in patients with penicillin V allergy 120 and in those with high levels of total serum IgE. 121 BAT 44% to 63% for BLs 42,[47][48][49][50][51][52] 36% to 92% for NMBAs 35,36,[53][54][55][56][57][58] 42% to 65% for dipyrone [59][60][61] 57% to 77% for quinolones [62][63][64][65] 46% to 63% for RCM 66,67 d Use of both markers CD203c and CD63 can improve BAT sensitivity. d Some patients' basophils can be ''nonresponders'' in 10% to 20% of the population.…”

The Value of In Vitro Tests to Diminish Drug Challenges

“…Additional studies have been performed for fluoroquinolones (FQs) [31,40,52,53], pyrazolones [54,55,56] and RCM [57,58] (Table 2). The analyses of these studies, taken together, show an average sensitivity of 59.4%, specificity of 94.6% and PPV and NPV of 93.4% and 66.3%, respectively.…”