This is an experimental, interventional study, following on from a clinical trial comparing the efficacy and safety of oral immunotherapy with low and high doses of sesame protein, in which patient desensitisation was achieved (High and Low Dose Oral Sesame Immunotherapy - Comparison of Efficacy and Safety, NCT05158413).

The aim of this study is to assess a sustained unresponsiveness (SU) to sesame protein after at least 8 months of previously assigned high- or low-dose sesame OIT, followed by 4-week-allergen avoidance, and verified by an open oral food challenge (OOFC).

Oral immunotherapy is considered the most effective treatment for food allergy. There are two main goals of food immunotherapy: achievement of desensitisation and sustained unresponsiveness.

Desensitisation involves achieving temporary tolerance of the allergenic food by the patient only during regular intake of the allergen. The most desirable effect of immunotherapy is to achieve sustained unresponsiveness, i.e. to maintain the absence of adverse symptoms to a given allergen after specific immunotherapy has been discontinued for a defined period of time.

The study is a continuation of a clinical trial NCT05158413 which was designed to compare the efficacy and safety of oral immunotherapy (OIT) with low or high doses of sesame protein (300 or 1200 mg, respectively) in children with a confirmed diagnosis of sesame allergy. The participants of current study will be recruited from patients who have accomplished their per-protocol participation in previous trial.

Patients will receive the same maintenance dose of sesame allergen, which was used in previous trial (300 or 1200 mg, respectively), for 32 weeks (+/-2 weeks). Then, OIT will be discontinued for 4 weeks with strict sesame avoidance. Subsequently, an open oral food challenge (OOFC) will be performed to assess the achievement of sustained unresponsiveness.

Inclusion Criteria:

• patients who have accomplished their per-protocol participation in trial NCT05158413.
• signed Informed Consent by parent/legal guardian and patient aged>16 years old
• patient's/caregiver's cooperation with researcher

Exclusion Criteria:

• severe asthma

• uncontrolled mild/moderate asthma: forced expiratory volume at one second (FEV1)<80% (under 5 percentile), FEV1/forced vital capacity (FEV)<75% (under 5 percentile), hospitalization due to asthma exacerbation within last 12 months

• current oral/sublingual/subcutaneous immunotherapy with another allergen

• eosinophilic esophagitis

• allergic reaction of 4th or higher grade according to the World Allergy Organisation Systemic Allergic Reaction Grading System during immunotherapy

• a history of severe recurrent anaphylaxis episodes

• chronic diseases requiring continous treatment, including heart disease, epilepsy, metabolic disease, diabetes

• medication:

  • oral, daily steroid therapy exceeding 1 month within the last 12 months
  • at least two courses of oral steroid therapy (at least 7 days) within the last 12 months
  • oral steroid therapy longer than 7 days within the last 3 months
  • biological treatment
  • the need to constantly take antihistamines
  • therapy with b-blockers, angiotensin converting enzyme (ACE) inhibitors, calcium channel inhibitors

• pregnancy

• no consent to participate in the study

• lack of patient cooperation