Effects of birch pollen-specific immunotherapy on apple allergy in birch pollen-hypersensitive patients

Clin Exp Allergy. 1998 Nov;28(11):1368-73. doi: 10.1046/j.1365-2222.1998.00399.x.

Abstract

Background: Most patients with birch pollen allergy report oral allergy symptoms after eating fresh apples and other vegetable foods. Major birch pollen and apple allergens, Bet v 1 and Mal d 1, are highly homologous; as a consequence, pollen-specific immunotherapy (SIT) might be expected to improve apple hypersensitivity.

Objective: To evaluate the clinical and immunological effects of birch pollen SIT on oral allergy syndrome (OAS) induced by apples.

Methods: A prospective study carried out in 49 birch pollen-sensitive patients with apple-induced OAS who received injection immunotherapy for 12, 24, or 36 months. Twenty-six patients not submitted to SIT and followed up for 12-48 months were used as controls. Both SPT and open oral challenges with fresh golden delicious apple were performed, as well as specific IgE measurements, before and after SIT.

Results: Forty-one patients (84%) vs no control (0%) reported a significant reduction (50-95%) or a total disappearance (100%) of OAS symptoms after SIT (P < 0. 001). Similar responses were observed in patients treated for 12, 24, or 36 months. SIT also induced a marked reduction in skin reactivity against fresh apple in 43 patients (88%). The effect of SIT was inversely related with baseline skin reactivity: 50% and 8% patients with a weakly or strongly positive baseline apple skin prick tests (SPT), respectively, did not report changes in OAS severity after SIT (P < 0.01). In contrast, baseline birch pollen-specific or apple-specific IgE antibodies levels did not influence SIT effectiveness on OAS. SIT induced a marked decrease in birch pollen-specific IgE levels (P < 0.001), whereas apple-specific IgE showed an unexpected variability (reduction in 21%, no change in 43%, increase in 38%). No control subject reported a reduction in OAS severity or showed a decrease in skin reactivity at follow-up (P < 0.001).

Conclusions: SIT with birch pollen extracts effectively reduces clinical apple sensitivity and skin reactivity in most cases after only 1 year of treatment; these effects are not paralleled by a similar reduction in apple-specific IgE. These findings suggest a decrease in activability of effector cells as the mechanism underlying clinical benefit.

Publication types

  • Clinical Trial
  • Controlled Clinical Trial

MeSH terms

  • Adult
  • Desensitization, Immunologic*
  • Female
  • Food Hypersensitivity / etiology
  • Food Hypersensitivity / therapy*
  • Fruit / adverse effects*
  • Fruit / immunology
  • Humans
  • Hypersensitivity / etiology*
  • Immunoglobulin E / immunology
  • Male
  • Pollen / adverse effects
  • Pollen / immunology*
  • Skin Tests

Substances

  • Immunoglobulin E