Bronchial asthma . Eosinophils are most actively involved in the inflammatory reaction that develops in the respiratory tract of patients with AD. Histologically, in the lungs of AD patients along the bronchioles near the sites of epithelial damage, deposits of ICBMs, ESR, as well as a large number of degranulated eosinophils are found. In addition, an increased number of eosinophils is observed in the peripheral blood of patients with AD. Some authors have observed a correlation between the number of eosinophils and the degree of dysfunction of external respiration, as well as the concentration of ESR and bronchial hyperreactivity. A large number of eosinophils and their products have been identified in the sputum of patients with AD, including aspirin-dependent.
In the sputum of patients with AD there is an increased amount of ESR and ICBMs, with the latter being considered by some authors to be specific for AD. Also, an increased number of eosinophils is determined in the BAA of patients with AD, and it is much higher with the atopic form of the disease than with the non-atopic and even more with aspirin BA. It should be noted that eosinophil defects probably play one of the key roles in AD development and are already detected at the stage of pre-illness (pre-asthma). Thus, in studies conducted at the Department of Hospital Therapy of St. Petersburg State Medical University named after IP Pavlov, it was found that in healthy blood relatives with signs of bronchial hyperreactivity, significantly higher than in healthy individuals with a negative acetylcholine test revealed an increased absorption and receptor activity of eosinophils.
Bronchogenic tumors . The association of eosinophilia and malignant neoplasms was first described in 1893. Since then, numerous works have confirmed this observation, including the example of lung carcinoma. However, the degree of eosinophilia in the blood and in the tumor tissue is different. More importantly, there is a positive correlation between eosinophilia in the tumor tissue and the degree of survival. Significant tissue infiltration with eosinophils was observed in 59% of patients with primary lung cancer. Subsequent studies showed that eosinophil tumor infiltration is associated with a positive prognosis, while the absence of eosinophils was observed in the malignant course of the disease.
In these patients, as well as in AD, bronchiectasis, and allergic pneumonitis , an increased level of serum ECP was determined, which is a more preferable indicator of eosinophil involvement than counting the number of eosinophils. Although the significance of eosinophils in the development of bronchial cancer is still unclear, it is possible to consider eosinophils as part of the antitumor defense. This assumption has already received partial confirmation. So, cancer patients who responded to radiation therapy with peripheral blood eosinophilia lived twice as long as patients who did not induce an eosinophilic response. In an experiment in mice, the antitumor role of IL-4 and 1L-2, the mechanism of action of which is associated with the involvement of eosinophils, was also shown.