Immunological profiles of beekeepers and patients allergic to bee venom:
understanding tolerance to bee stings
Abstract
Background. Although exposure to stings has been identified as the main
risk factor for anaphylaxis due to Hymenoptera venom allergy,
professional beekeepers receive hundreds of them yearly without
developing systemic reactions. This study aims to analyse the
immunological profile of people exposed to bee stings. Methods. A
cross-sectional study was conducted. Participants were recruited and
classified into three groups: allergic patients (AP) experiencing
systemic reactions after bee stings, with a positive intradermal test
and specific IgE (sIgE) to Apis mellifera venom (AmV); tolerant
beekeepers (TBK) receiving ≥ 50 stings/year; and healthy non-exposed
controls (HC). Serum levels of sIgE and specific IgG4 (sIgG4) to AmV,
rApi m1, rApi m2, rApi m3, Api m4, rApi m5 and rApi m10, as well as
AmV-induced basophil degranulation, percentage of T-cell subsets, Treg
cells and IL-10 production were measured. Results. APs had high levels
of sIgE to AmV and all allergic components (p<0.001) together
with a high basophil activation rate (p<0.001) compared to
TBKs. Conversely, compared to TBKs, APs showed lower levels of sIgG4
(p<0.001) and IL-10 (p<0.001) as well as a reduced
CTLA-4+ Treg population (p=0.001), together with enhanced Helios+ Treg
(p<0.004), Th1 (p=0.008), Th2 (p=0.004) and Th17 (p=0.007)
populations. Conclusion. Two different profiles were identified: the
allergic profile is well defined by parameters of IgE response, some of
them also present in the tolerant beekeeper profile, which is strongly
marked by Treg activity.