IL-4 receptor α blockade prevents sensitization and alters acute and long-lasting effects of allergen-specific immunotherapy of murine allergic asthma.

BACKGROUND: Allergen-specific immunotherapy (AIT) is the only causal treatment for allergy. However, success rates vary depending on the type of allergy and disease background of the patient. Hence, strategies targeting an increased therapeutic efficacy are urgently needed. Here, the effects of blockade of IL-4 and IL-13 signaling on different phases of AIT were addressed. METHODS: The impact of the recombinantly produced IL-4 and IL-13 antagonist IL-4 mutein (IL-4M) on allergic sensitization and AIT outcome in experimental allergic asthma were analyzed in a murine model. The effects of IL-4M administration were assessed prior/during sensitization, immediately after AIT under allergen challenge, and two weeks post-treatment. RESULTS: Intervention with IL-4M prior/during sensitization led to strong induction of IgG1, IgG2a, IgG2b, and IgG3, decrease of specific and total IgE, as well as of IL-5 in serum. Similar effects on the serum immunoglobulin levels were observed immediately after IL4M-supplemented AIT during allergen challenge. Additionally, IL4M markedly suppressed type-2 cytokine secretion of splenocytes beyond the effect of AIT alone. These effects were equaled to those of AIT alone two weeks post-treatment. Intriguingly, here, IL-4M induced a sustained decrease of Th2-biased Tregs (ST2+ FOXP3+ GATA3intermediate ). CONCLUSIONS: IL-4 and IL-13 blockade during experimental AIT demonstrates beneficial effects on immunological key parameters such as immunoglobulin and cytokine secretion immediately after AIT. Although two weeks later these effects were dropped to those of AIT alone, the number of potentially disease-triggering Th2-biased Tregs was further significantly decreased by IL-4M treatment. Hence, IL-4/IL13-targeting therapies prime the immune memory in therapy success-favoring manner.

Application of recombinant antigen 5 allergens from seven allergy-relevant Hymenoptera species in diagnostics.

BACKGROUND: Hymenoptera stings can cause severe anaphylaxis in untreated venom-allergic patients. A correct diagnosis regarding the relevant species for immunotherapy is often hampered by clinically irrelevant cross-reactivity. In vespid venom allergy, cross-reactivity between venoms of different species can be a diagnostic challenge. To address immunological IgE cross-reactivity on molecular level, seven recombinant antigens 5 of the most important Vespoidea groups were assessed by different diagnostic setups. METHODS: The antigens 5 of yellow jackets, hornets, European and American paper wasps, fire ants, white-faced hornets, and Polybia wasps were recombinantly produced in insect cells, immunologically and structurally characterized, and their sIgE reactivity assessed by ImmunoCAP, ELISA, cross-inhibition, and basophil activation test (BAT) in patients with yellow jacket or Polistes venom allergy of two European geographical areas. RESULTS: All recombinant allergens were correctly folded and structural models and patient reactivity profiles suggested the presence of conserved and unique B-cell epitopes. All antigens 5 showed extensive cross-reactivity in sIgE analyses, inhibition assays, and BAT. This cross-reactivity was more pronounced in ImmunoCAP measurements with venom extracts than in sIgE analyses with recombinant antigens 5. Dose-response curves with the allergens in BAT allowed a differentiated individual dissection of relevant sensitization. CONCLUSIONS: Due to extensive cross-reactivity in various diagnostic settings, antigens 5 are inappropriate markers for differential sIgE diagnostics in vespid venom allergy. However, the newly available antigens 5 from further vespid species and the combination of recombinant allergen-based sIgE measurements with BAT represents a practicable way to diagnose clinically relevant sensitization in vespid venom allergy.