Scientific Study

BACKGROUND: Allergy can be diagnosed using basophil tests. Several methods measuring basophil activation are available. This study aimed at comparing basophil activation test (BAT), histamine release assay (HR) and passive sensitization histamine release assay (passive HR) in the diagnosis of peanut allergy. METHODS: BAT, HR, and passive HR were performed on eleven peanut allergic and fourteen non-allergic subjects. Blood was incubated with peanut extract or anti-IgE and tests performed as follows: BAT - CD63-upregulation assessed by flow cytometry; HR - released histamine quantified by a glass fiber-based fluorometric method; Passive HR - IgE-stripped donor basophils were incubated with participants' serum and histamine release quantified as HR. RESULTS: CDsens, a measure of basophil allergen sensitivity, was significantly higher for BAT (80.1 ± 17.4) compared to HR (23.4 ± 10.31) and passive HR (11.1 ± 2.0). BAT, HR, and passive HR had a clinical sensitivity of 100%, 100%, and 82%, and specificity of 100%, 100%, and 100%, respectively when excluding inconclusive results. BAT identified 11 of 11 allergic patients, HR 10 and passive HR 9. Likewise, BAT recognized 12 of 14 non-allergic subjects, HR 10 and passive HR 13. However, the tests' diagnostic performances were not statistically different. Interestingly, non-releasers in HR but not in BAT had lower basophil count compared to releasers (249 vs. 630 counts/min). CONCLUSION: BAT displayed a significant higher CDsens compared to HR and passive HR. The basophil tests' diagnostic performances were not significantly different. Still, BAT could diagnose subjects with low basophil number in contrast to HR.