Wasp venom allergy screening with recombinant allergen testing. Diagnostic performance of rPol d 5 and rVes v 5 for differentiating sensitization to Vespula and Polistes subspecies

Background. The appropriate therapeutic management of patients with wasp-induced allergic reactions necessitates an accurate allergologic workup, entailing differentiation between sensitization against Vespula or Polistes venoms. Materials and methods. We studied 52 consecutive adult subjects diagnosed with hypersensitivity to wasp venoms. Cap inhibition was performed using UniCAP Specific IgE. The concentration of serum IgE against two recombinant constituents of Antigen 5 (rVes v 5 and rPol d 5) was also measured using Immuno CAP 250. The ratio between values of specific IgE against recombinant allergens was calculated and a percentage difference > 50% was considered significant for specific immunization against one of the two venoms. Results. The diagnostic agreement between recombinant allergens testing and CAP inhibition was 54% (kappa statistics, 0.34; 95% CI, 0.18–0.50) in the whole study population. In the 24 patients with recombinant allergens ratio > 50% and non dubious results of CAP inhibition assay the diagnostic agreement was perfect (100%; kappa of agreement, 1.00; 95% CI; 1.00–1.00). Discussion. The results of this study show that the assessment of specific IgE against rVes v 5 and rPol d 5 may be regarded as a low-cost screening, providing valuable diagnostic information for differentiating the sensitization against Vespula or Polistes venoms. In patients with suggestive clinical history and ratio > 50% between specific IgE against rVes v 5 and specific IgE against and rPol d 5, the CAP inhibition assay may be safely withheld, thus allowing to achieve an early diagnosis at lower cost.