D2.173 - Subcutaneous allergen-specific immunotherapies for inhalation allergens induce higher levels of therapy specific IgG4 antibodies than sublingual therapies: a retrospective data analysis
Background
Allergen-specific immunotherapy (AIT) is the only causal treatment for inhalation- and hymenoptera venom allergies. The primary mechanisms involve the difficult-to-measure induction of allergen-specific regulatory T-cells, as well as the induction of blocking IgG4 antibodies. Currently, there are two common forms of administration: subcutaneous (SCIT) and sublingual (SLIT). This study investigated whether there are differences in the induction of IgG4 antibodies against the major allergens of birch pollen (Bet v1) and grass pollen (Phl p1/5) between SCIT and SLIT preparations from the same manufacturer, and whether there are differences in IgG4 increase between the major allergens of wasp venom, Ves v1 and Ves v5. (1)
Method
In the Floridsdorfer allergy center, over 48,000 patients with history of allergic rhinoconjunctivitis and/or asthma or allergic shock (Grades 1-4), treated with SCIT or SLIT for birch or grass pollen or wasp venom between 2009 and 2024, were screened. Based on medical reports and laboratory findings, a retrospective database was created. The inclusion criterion was the availability of specific IgG4 values against Bet v1, Phl p1/5, Ves v1 or Ves v5 at both the start of AIT and at least one value during AIT.
Results
190 individuals (including 93 females (49%)) met the inclusion criteria. 69 (36.3%) were treated with birch pollen-AIT; 58 (84.1%) with SCIT, 11 (15.9%) with SLIT. 95 patients (50%) were treated with grass pollen-AIT, 68 (71.5%) receiving SCIT, 27 (28.5%) SLIT. 25 patients (13.2%) were treated with wasp venom-AIT. The increase in IgG4 levels against Bet v1 in the SCIT group 1-2 years after therapy start was on average 4.01 ± 3.52 mg/dl, compared to 1.12 ± 0.85 mg/dl in the SLIT group (p=0.007). The increase in IgG4 levels against Phl p1/5 was 15.54 ± 10.01 mg/dl in the SCIT group and 0.54 ± 0.97 mg/dl in the SLIT group (p<0.001). The increase in IgG4 levels against Ves v1 was 6.73 ± 7.56 mg/dl, compared to 8.04 ± 6.15 mg/dl in the Ves v5 group (p=0.77).
Conclusion
One year after start, SCIT induced significantly higher increase of IgG4 levels in both birch and grass pollen allergy patients compared to SLIT preparations from the same manufacturer. There was no difference in increase of IgG4 level changes between Ves v1 and Ves v5.
1. Burks AW et al. Update on allergy immunotherapy: PRACTALL consensus report. J Allergy Clin Immunol. 2013;131(5):1288-96.e3.
