Separation of rCor a 1.04, rCor a 2 and rCor a 11 by SDS/PAGE (a selection of 10 out of 65 patients; NC, negative control). All sera shown were positive to rCor a 1.04, whereas patient 4 and 8 were also positive to rCor a 2. Four patients showed positive IgE reactivity to rCor a 11 (sera 1, 3, 5 and 10). Sera 3, 6, 8 and 10 were used in histamine-release assays. IgE binding to rCor a 8 was assayed in a separate experiment under non-reducing conditions and was negative for all patients (results not shown).