Asthma patients’ immune systems respond differently with allergies

Researchers from the University of Chihuahua in Mexico report that immune systems of patients with asthma responded differently to a common laboratory challenge, depending on whether their white blood cells had been obtained during a time when they were suffering from common season allergic rhinitis or when they were free of such allergic symptoms.

The study was presented by Dr. Irene Leal-Berumen on Saturday, April 2, at The American Association of Immunologists scientific sessions during Experimental Biology 2005 in San Diego. She says the findings are an important first step to personalizing treatments for allergy and asthma, both worldwide diseases that interfere with life quality and generate high economic burden.

Asthma is a chronic obstructive inflammatory lung disease with symptoms including wheezing, coughing, chest tightness, and shortness of breath. Asthma attacks can be triggered by viral upper respiratory infections, exercise, extreme temperature condition, and chemical irritants – and also by the same allergens that cause seasonal allergies to pollen or mold spore or perennial allergies to dust mites, cockroaches, feathers, animal fur and other allergens. In fact, the vast majority of patients with asthma also experience one or both of these forms of allergy, with the same symptoms of frequent sneezing, itchy eyes, runny nose and nasal stuffiness.

In people with and without asthma, the body’s response to allergens is based in the leukocytes, or white blood cells, that rush to defend the body against foreign agents. The leukocytes produce cytokines that mediate and regulate immunity and inflammation to an immune stimulus. Because people with asthma and allergy share this common etiological pathway, they show different expressions of their disease with a wide variety of therapeutic responses. That’s why Dr. Leal-Berumen’s laboratory became interested in studying the different response of these cytokines in asthma patients when they were and were not experiencing allergies.

The study involved 10 patients with clinical diagnosis for allergic rhinitis, who also have or had had asthma. Peripheral blood leucocytes were obtained both during rhinitis symptoms and during a period when the patients were not experiencing rhinitis symptoms, then cultured with a type of prostaglandin, a substance that causes inflammation. In nine of the ten asthma patients, leucocytes produced a greater amount of the cytokine IL-5 when isolated during the no symptoms season, whereas five of the nine showed a greater production of IL-13, another cytokine, during the symptoms season. These results indicate that leucocytes from the same patient present different susceptibility to IL-5 and IL-13 production depending on the presence or absence of allergic rhinitis symptoms.

Dr. Leal-Berumen says the group now plans to study cell response to more specific allergens similar to what was done with the prostaglandin challenge. They believe these studies will contribute to a better understanding of asthma, allergy and other inflammatory disease and guide the pharmacogenetic development of new therapies.

Dr. Leal-Berumen’s coauthors are Drs. Elsa Sanchez, Maria Cepeda, Aleli Valenzuela, and Maria de la Luz Arevalo. The study received funding from the University of Chihuahua and from its own researchers.