The culprit insect but not severity of allergic reactions to bee and wasp venom can be determined by molecular diagnosis

Background. Allergy to bee and wasp venom can lead to life-threatening systemic reactions. The identification of the culprit species is important for allergen-specific immunotherapy. Objectives. To determine a panel of recombinant bee and wasp allergens which is suitable for the identification of bee or wasp as culprit allergen sources and to search for molecular surrogates of clinical severity of sting reactions. Methods. Sera from eighty-seven patients with a detailed documentation of their severity of sting reaction (Mueller grade) and who had been subjected to titrated skin testing with bee and wasp venom were analyzed for bee and wasp-specific IgE levels by ImmunoCAPTM. IgE-reactivity testing was performed using a comprehensive panel of recombinant bee and wasp venom allergens (rApi m 1, 2, 3, 4, 5 and 10rVes v 1 and 5) by ISAC chip technology, ImmunoCAP and ELISA. IgG4 antibodies to rApi m 1 and rVes v 5 were determined by ELISA and IgE/ IgG4 ratios were calculated. Results from skin testing, IgE serology and IgE/IgG4 ratios were compared with severity of sting reactions. Results. The panel of rApi m 1, rApi m 10, rVes v 1 and rVes v 5 allowed identification of the culprit venom in all but two of the 87 patients with good agreement to skin testing. Severities of sting reactions were not associated with results obtained by skin testing, venom-specific IgE levels or molecular diagnosis. Severe sting reactions were observed in patients showing < 1 ISU and < 2kUA/L of IgE to Api m 1 and/or Ves v 5. Conclusion. We identified a minimal panel of recombinant bee and wasp allergens for molecular diagnosis which may permit identification of bee and/or wasp as culprit insect in venom-sensitized subjects. The severity of sting reactions was not associated with parameters obtained by molecular diagnosis

The culprit insect but not severity of allergic reactions to bee and wasp venom can be determined by molecular diagnosis

<div><p>Background</p><p>Allergy to bee and wasp venom can lead to life-threatening systemic reactions. The identification of the culprit species is important for allergen-specific immunotherapy.</p><p>Objectives</p><p>To determine a panel of recombinant bee and wasp allergens which is suitable for the identification of bee or wasp as culprit allergen sources and to search for molecular surrogates of clinical severity of sting reactions.</p><p>Methods</p><p>Sera from eighty-seven patients with a detailed documentation of their severity of sting reaction (Mueller grade) and who had been subjected to titrated skin testing with bee and wasp venom were analyzed for bee and wasp-specific IgE levels by ImmunoCAP^TM. IgE-reactivity testing was performed using a comprehensive panel of recombinant bee and wasp venom allergens (rApi m 1, 2, 3, 4, 5 and 10; rVes v 1 and 5) by ISAC chip technology, ImmunoCAP and ELISA. IgG₄ antibodies to rApi m 1 and rVes v 5 were determined by ELISA and IgE/IgG₄ ratios were calculated. Results from skin testing, IgE serology and IgE/IgG₄ ratios were compared with severity of sting reactions.</p><p>Results</p><p>The panel of rApi m 1, rApi m 10, rVes v 1 and rVes v 5 allowed identification of the culprit venom in all but two of the 87 patients with good agreement to skin testing. Severities of sting reactions were not associated with results obtained by skin testing, venom-specific IgE levels or molecular diagnosis. Severe sting reactions were observed in patients showing < 1 ISU and < 2kU_A/L of IgE to Api m 1 and/or Ves v 5.</p><p>Conclusion</p><p>We identified a minimal panel of recombinant bee and wasp allergens for molecular diagnosis which may permit identification of bee and/or wasp as culprit insect in venom-sensitized subjects. The severity of sting reactions was not associated with parameters obtained by molecular diagnosis.</p></div

Schematic representation of recombinant marker allergens for diagnosis of genuine IgE sensitization to bee (Api m 1, 3, 4 and 10) and wasp (Ves v 1 and 5) and cross-reactive marker allergens (Api m 2 = Ves v 2; Api m 5 = Ves v 3).

<p>Schematic representation of recombinant marker allergens for diagnosis of genuine IgE sensitization to bee (Api m 1, 3, 4 and 10) and wasp (Ves v 1 and 5) and cross-reactive marker allergens (Api m 2 = Ves v 2; Api m 5 = Ves v 3).</p

Association of skin sensitivity and severity of sting reaction.

<p>Large local reaction (0) and Mueller grade (1–4) of sting reactions (y-axes, medians: horizontal lines) to (A) bee and (B), (C) wasp are shown for Slovenian and German patients with identified culprit venom, and were plotted against the lowest concentration (x-axes) causing a positive reaction in skin prick (Slovenian patients) or intradermal testing (German patients).</p

Summary of serology, skin testing and Mueller grading for the Slovenian mono-sensitized population.

<p>Summary of serology, skin testing and Mueller grading for the Slovenian mono-sensitized population.</p

Association of venom extract or allergen-specific IgE levels and severity of sting reactions.

<p>Specific IgE levels (medians: horizontal lines) to (A) bee and (B) wasp venom (kU_A/L), (C) rApi m 1 (kU_A/L), (D) rApi m 1 (ISU), (E) rVes v 5 (kU_A/L), (F) rVes v 5 (ISU) were plotted against the severities of sting reactions (x-axes: Mueller grade) for Slovenian and German patients with identified culprit insect.</p

Summary of serology, skin testing and Mueller grading for the German population.

<p>Summary of serology, skin testing and Mueller grading for the German population.</p

Relation between the number of recognized allergen molecules and severity of sting reactions.

<p>The severity of sting reactions (y-axes) is plotted against the number of recognized bee (A) or wasp allergens (B) in the bee or wasp-sensitized patients. Horizontal lines denote medians.</p

Bee and wasp venom sensitization according to allergen-extract-based serology, skin testing and molecular diagnosis.

<p>Pie charts showing the percentages of patients with bee and wasp venom double sensitization (blue), sensitization to bee (yellow) and wasp (red) according to allergen extract-based serology (left), skin testing (middle) and molecular diagnosis (right; one subject negative: grey) in the German population (n = 67).</p