Introduction to the immune system, concept of innate immunity and adaptive immunity, immune system of the intestinal mucosa, types of immune reaction, toxic reactions; allergic reaction to food; Food intolerance; Food allergens; Pollen and Dermatophagoides aeroallergens, concept of anaphylaxis; concept of primary and secondary sensitization Oral Allergic Syndrome (OAS); Systemic Nickel Allergy Syndrome (SNAS); Atopic Contact Dermatitis (ACD); concepts of cross-reactivity; Allergometric tests; Recombinant Molecular Allergens; Complement Resolved Diagnosis (CRD); Allergen immunotherapy (AIT), Nickel, PFAS, food additives. Concept of Autoimmunity; Food-induced / aggravated autoimmune diseases.