Simplification of intradermal skin testing in Hymenoptera venom allergic children

Skin prick tests are not useful for the qualification for venom immunotherapy in children

Background

The basis for qualification for venom immunotherapy (VIT) is the fulfilment of both the clinical and immunological criteria. Diagnostic tests that confirm the immunological criterion of an IgE-mediated sensitization include skin prick tests (SPT), intradermal tests (IDT), and serum specific IgE (sIgE) for the culprit venom.

Objective

This study aimed to assess the usefulness of SPT as the immunological marker in the diagnosis of insect venom sensitization in children with history of systemic reaction (SR) to insect sting evaluated by means of I-IV-grades Mueller's scale. There are no such studies in children.

Methods

This cross-sectional study sample consisted of 416 children aged 3-18 years (mean age 10.6 ± 3.8), 76% males, all with the history of a systemic reaction (SR) after a Hymenoptera sting (48% of grade III/IV according to Mueller scale), diagnosed between 1999 and 2019 in the tertiary referral centre. The standard diagnostic tests were used. Specificity, sensitivity, and positive and negative predictive values were computed to assess the diagnostic properties of the clinical tests to distinguish between mild and severe SR. To assess the relative value of an individual test in predicting the qualification to VIT we incorporated the Shapley value (SV).

Results

Positive SPT results were found in up to no more than 3% of children; among them less than 1% had only positive SPT and were negative for sIgE and IDT. Approximately 85% of the children had detectable venom sIgE, followed by positive IDT (75%). Almost 70% of children had positive both sIgE and IDT results. In children with grade III/IV reaction, about 80% of children had positive results of both of these tests. sIgE and IDT had sensitivity >0.80, whereas SPT had high specificity (>0.97) in differentiating between mild and severe SR. Relative value of diagnostic tests in predicting qualification to VIT varied between venoms. Bee venom IDT had higher SV (0.052) than sIgE (0.041). In contrast, wasp venom sIgE had higher SV (0.075) than IDT (0.035).

Conclusion

SPTs are not an useful immunological marker of venom sensitization in children, and eliminating SPT does not result in a loss of diagnostic accuracy. Limiting diagnostics to venom sIgE and IDT would shorten the procedure and reduce costs. Future studies are needed to determine if venom sIgE as the first line diagnostic test, with IDT added only if the venom sIgE is undetectable, is an optimal diagnostic process.

Expression of eosinophils, RANTES and IL-25 in the first phase of Hymenoptera venom immunotherapy

Introduction

Venom immunotherapy (VIT) can protect against severe anaphylactic reactions (SR) in 80–100% of subjects allergic to Hymenoptera venom. The mechanisms of induction of immunological tolerance produced by VIT are still little known. It has been shown that VIT modulates Treg activity, Th2 or Th1 cells or both, increases production of IL-10, decreases secretion of IL-13, and causes an IgG4/IgE ratio shift.

Aim

To investigate the blood eosinophil count, CCL5/RANTES and IL-17E/IL-25 concentrations before and after the initial phases of the rush protocol of VIT.

Material and methods

Forty individuals (14 males, 26 females) of mean age 41.03 ±12.43 years were included in the study. The peripheral eosinophils and the concentration of serum interleukin IL-17E/IL-25 and RANTES were determined before and after the initial phase of VIT.

Results

Paired sample t-test revealed that all patients after VIT had significantly higher eosinophil levels compared to the baseline (mean: 0.42 vs. 0.64, p < 0.05). Moreover, in subjects treated with bee venom, RANTES levels proved to rise significantly (51 × 103 vs. 62 × 103, p < 0.05) while IL-17E/IL-25 dropped with near-marginal significance (916 vs. 650, p = 0.069).

Conclusions

Our immunological study on the early phase of venom immunotherapy suggested that eosinophils, cytokines such as CCL5/RANTES and IL-17E/IL-25 contribute to the immunological response.