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D3.183 - Determination of IgE antibodies against recombinant allergens (Phl p 1 and Phl p 5) in a random sample of patients from Madrid with pollinosis before and after one year of subcutaneous immunotherapy

Poster abstract

Background

Recent studies have shown that specific IgE levels against grass pollen molecular components significantly decrease after allergen‑specific immunotherapy (AIT) when measured using multiplex platforms such as ISAC® and/or ALEX®, but not when measured by ImmunoCAP®.The aim of this study was to evaluate changes in specific IgE levels to Phl p 1 and Phl p 5, measured by ALEX®, in patients with pollinosis treated with allergen immunotherapy, before treatment and after one year of therapy.

Method

A retrospective study (January 2019 – January 2024) was conducted in patients with respiratory allergy sensitized to grasses and other pollens (Cupressus, Olea and Platanus), as determined by ALEX®.All patients underwent ALEX® testing prior to initiation of allergen immunotherapy (AIT), with measurements repeated exactly 12 months after starting treatment. Patients with previous immunotherapy were excluded.Annual grass pollen concentrations were measured using a Burkard® 7‑day recording volumetric spore trap

Results

A total of 15 patients were included (8 women, 7 men; mean age: 45 years). Rhinitis was present in 93.3% of patients and asthma in 60%. Patients received Clustoid MAX® allergen immunotherapy to Trisetum–Dactylis and Cupressus and/or Olea and/or Platanus.

A reduction in specific IgE levels was observed for Phl p 1 in 93% of patients (x̅ IgE before immunotherapy: 11.07 kUA/L;x̅ IgE after immunotherapy: 6.89 kUA/L) and for Phl p 5 in 100% of patients (x̅IgE before immunotherapy: 16.86 kUA/L;x̅ IgE after immunotherapy: 10.07 kUA/L).

Annual total grass pollen concentrations(2019–2024)were 1,997;2,579;3,282; 3,271;2,129; and 4,112 grains/m³ of air

Conclusion

  1. After the first year of allergen immunotherapy, specific IgE levels to Phl p 1 and Phl p 5 decreased in the majority of patients.

  2. This decrease does not appear to be related to reduced exposure to grass pollen.

  3. Previous studies suggest that this finding may be associated with the presence of blocking IgG4 antibodies against these allergens.

  4. These data suggest that Phl p 1 and Phl p 5 specific IgE measured by ALEX® could be used as an early biomarker to assess response to allergen immunotherapy.