German cockroach allergen (Blattella germanica allergen) (Bla g)

German cockroach allergens are a diverse group of proteins produced by the Blattella germanica species, found primarily in their saliva, feces, and decaying body parts [1, 5]. These proteins, such as Bla g 1 and Bla g 2, are potent environmental antigens that trigger IgE-mediated hypersensitivity reactions in susceptible individuals [4, 11]. Exposure is a major risk factor for the development of chronic respiratory conditions, most notably allergic asthma and rhinitis, especially in densely populated urban areas [1, 13]. Structurally, these allergens belong to various families, including inactive aspartic proteases, lipocalins, and glutathione S-transferases, many of which are highly stable and persist in indoor environments for long periods [2, 4]. In clinical practice, these allergens serve as the basis for diagnostic skin prick tests and are the active components in allergen-specific immunotherapy (AIT) [8, 14]. AIT aims to induce immunological tolerance by modulating T-cell responses and increasing the production of protective IgG4 antibodies [14]. While environmental control and symptomatic medications like antihistamines are standard, targeted immunotherapy remains the only disease-modifying treatment for cockroach-induced allergies [8].

Other names

Blattella germanica allergenCockroach allergenBla g 1Bla g 2Bla g 4Bla g 5Bla g 6Bla g 7Bla g 9Bla g 11

Allergen-specific immunotherapy (AIT) induces immune tolerance by shifting the immune response from a Th2-mediated allergic profile to a Treg/Th1-mediated profile, increasing the production of blocking IgG4 antibodies and reducing IgE-mediated mast cell degranulation.