Phleum pratense allergen Phl p 5 (Phl p 5)

Phleum pratense allergen Phl p 5 is a major protein allergen found in the pollen of Timothy grass, which is a primary driver of seasonal allergic rhinitis and asthma (Source: UniProt P43177). It is classified as a ribonuclease-like protein and is recognized by IgE antibodies in the vast majority of grass pollen-allergic patients (Source: WHO/IUIS Allergen Nomenclature). In clinical practice, Phl p 5 serves as a critical component in allergen-specific immunotherapy (AIT) formulations, such as Grastek and Oralair, designed to modify the underlying allergic disease (Source: FDA Label for Grastek). These treatments function by exposing the patient to controlled doses of the allergen to induce immunological tolerance, characterized by the induction of regulatory T cells and the production of allergen-specific IgG4 "blocking" antibodies (Source: PubMed PMID: 21834850). Monitoring efficacy often involves measuring levels of Phl p 5-specific IgE and IgG4 in the patient's serum (Source: PubMed PMID: 25599195). Despite its therapeutic utility, administration of Phl p 5-containing extracts carries a risk of systemic allergic reactions, including anaphylaxis, necessitating careful patient supervision (Source: FDA Label for Oralair).

Other names

Major pollen allergen Phl p 5Timothy grass allergen Phl p 5Phl p VPhl p 5.0101

Allergen-specific immunotherapy (AIT) induces immune tolerance by promoting a shift from Th2 to Th1/Treg immune responses and increasing the production of blocking IgG4 antibodies (Source: PubMed PMID: 21834850).