User:Cassiepark/Allergy to Cats

Allergies to cats are one of the most common allergies among individuals, resulting in 99.7 and 99.9% of households in the United States that are affected by responsible allergens. Among the eight known cat allergens, the most prominent allergen is secretoglobin Fel d 1, and it is produced in the anal glands, salivary glands, and, mainly, in sebaceous glands of cats. Allergic symptoms associated with cats include coughing, wheezing, chest tightening, itching, nasal congestion, rash, watering eyes, sneezing, chapped lips, and similar symptoms. In worst case scenarios, allergies to cats can develop into more life-threatening conditions such as rhinitis and mild to severe forms of asthma. Despite these symptoms, there are many types of solutions to mitigate the allergic effects of cats, including medications, vaccines, and home remedies. Hypoallergenic cats are another solution for individuals who want to pets without the allergic consequences. Furthermore, prospective pet owners can reduce allergic reactions by selecting cats of a specific gender or color, which are associated with a lower production of allergens.

Cat Allergens
Eight cat allergens have been recognized by the World Health Organization/International Union of Immunological Societies (WHO/IUIS) Allergen Nomenclature Sub‐Committee. Fel d 1 is the most prominent cat allergen, accounting for 96% of human cat allergies. The remaining cat allergens are Fel d 2-8, with Fel d 4 occurring the most in humans among the other seven allergens. All cats produce Fel d 1 including hypoallergenic cats. The main way these allergens are spread is through a cat’s saliva or dander, which gets stuck on clothing.

Fel d 1
Fel d 1 is the most dominant cat allergen. It is part of the secretoglobulin family, which are proteins found only in mammals. Fel d 1 is primarily secreted through the sebaceous glands and can be found on the skin and fur of a cat. It is less commonly secreted through the salivary gland, lacrimal glands, skin and anal glands.

Fel d 4 and Fel d 7
Fel d 4 and Fel d 7 are cat lipocalins. Fel d 4 and Fel d 7 are one of the most common cat allergens after Fel d 1. Fel d 4 is primarily found in cats' saliva and is associated with atopic dermatitis in children with cat allergies.

Body’s Response to the Allergen
As the allergen enters through the nose or mouth, antigen cells analyze the allergen and present antigenic peptides to helper T cells. The helper T cells acquire a type 2 phenotype (Th2) and produce IgE due the presence of specific cytokines. If Th2 is expressed too much, the symptoms of cat allergies appear. Inhaled cat allergens will activate mast cells, causing coughing, increased mucous production, and airway constriction.

Allergy shots
In its early stages, AIT utilized cat dander extract, which consists of microscopic dry skin flakes of cats, but later resorted to Fel d 1 due to issues of standardization. One way researchers use Fel 1 d in immunotherapy is through the alteration of its chemical structure. Disulfide bonds between Fel d 1 chains were broken to reduce the binding between the allergen and immunoglobulin E (IgE), inhibiting an allergic response. (combine Synthetic epitope vaccine into this section) A second method utilizes synthetic epitope vaccines, an in-development vaccine to provide a long-term vaccine for allergies. This method selects Fel d 1 peptides containing T-cell epitopes to produce a vaccine called Allervax CAT®. These peptides induce allergic symptoms in less than 1 % of individuals allergic to cats, and, by using this vaccine, the body’s response to Fel d 1 epitopes is diminished.

Cat bathing
After bathing, the levels of Fel d 1 on cat skin and fur return within two days of bathing. In addition, amounts of Fel d 1 in the surrounding air return after a 24 hour period of bathing the cat.