IL33 and asthma: Isolated rhinitis and the multimorbidity of rhinitis and asthma represent two distinct diseases with the following differences: (a) Genomic and transcriptomic background (Toll-Like receptors and IL-17 only for rhinitis as a local disease; IL-33 and IL-5 for allergic and non-allergic multimorbidity as a systemic disease), (b) Patterns of sensitization to allergens (mono- or pauci-sensitization vs. polysensitization), (c) Severity of symptoms and (d) Response to treatment.392