The pathogenesis of chronic bronchitis

In chronic bronchitis, the secretory, cleansing and protective functions of the bronchi are violated, the amount of mucus increases (hyperfunction of the secretory glands), its composition and rheological properties change. a transport defect (mucociliary insufficiency) occurs due to degeneration of specialized ciliary epithelial cells. The main mechanism for removing tracheobronchial secretion is coughing. Stagnation of mucus contributes to secondary infection and the development of a chronic infectious and inflammatory process, which is exacerbated by a change in the ratio between the proteolytic activity of bronchial secretion and the level of serum protease inhibitors. In chronic bronchitis, there is both an increase in the amount of ai-antitrypsin in serum and its deficiency along with an increase in the elastase activity of bronchial secretion.

The protective function of the lungs is ensured by the interaction of systemic immunity and local immunity. Changes in local immunity are chaotic: a decrease in the number and functional activity of alveolar macrophages; inhibition of the phagocytic activity of neutrophils and monocytes; deficiency and functional insufficiency of T lymphocytes; the predominance of bacterial antigens in the bronchial contents compared to antibacterial antibodies; a drop in the concentration of immunoglobulin A secretory in bronchial contents and immunoglobulin A in serum; a decrease in the number of plasma cells secreting immunoglobulin A in the mucous membrane of the bronchi in severe forms of chronic bronchitis.
With prolonged chronic bronchitis, the content of the bronchi increases the content of immunoglobulin G, which with a deficiency of secretory immunoglobulin A can have a compensatory character, however, the prolonged predominance of antibodies related to immunoglobulins Q can increase inflammation in the bronchi, activating the complement system. The content of bronchi in chronic bronchitis (without concomitant allergic manifestations) significantly increased the concentration of immunoglobulin E, which indicates its predominantly local synthesis and can be considered as a protective reaction against a background of a decrease in the level of secretory immunoglobulin A, however, a significant imbalance in the levels of immunoglobulin A and immunoglobulin E may cause a relapse of the disease.

Changes in systemic immunity are characterized by cutaneous anergy to antigens that induce delayed hypersensitivity, a decrease in the number and activity of T lymphocytes, phagocytic activity of neutrophils, monocytes and antibody-dependent cellular cytotoxicity, a decrease in killer natural lymphocytes, inhibition of the function of T-suppressors, prolonged circulation of high concentration of immune complexes , the detection of antinuclear antibodies of rheumatoid factor. disimmunoglobulinemic syndrome.

Antibacterial antibodies in the serum are mainly related to immunoglobulin M and immunoglobulin G, in the contents of the bronchi to immunoglobulin A, immunoglobulin E and immunoglobulin G. A high level of antibacterial antibodies related to immunoglobulin E in the contents of the bronchi indicates their possible protective role. It is believed that the significance of allergic reactions in chronic bronchitis is small, however, there is an opinion that allergic reactions of the immediate type are involved in the pathogenesis of B x with transient bronchial obstruction syndrome

Disorders of local and systemic immunities are secondary in nature, depending on the stage of the process and most pronounced with purulent chronic bronchitis. However, this contradicts a significant decrease in many parameters of systemic and local immunities at the stage of remission of chronic bronchitis.

Communication of smoking, toxic chemical. influences, infections and violations of local protection is as follows. The adverse effects of smoking and pollutants lead to defects in local protection, which contributes to secondary infection and the development of the inflammatory process, which is constantly supported by the ongoing invasion of microorganisms. Increasing mucosal damage leads to a progressive violation of the defense mechanisms.

Although a significant role of allergic reactions is not expected in the pathogenesis of chronic bronchitis, consideration of its etiology, pathogenesis, and treatment is important for theoretical and practical allergology, since in one third of patients with bronchial asthma, chronic bronchitis precedes its development, being the basis for the formation of an infectious allergic predastma. An exacerbation of concomitant bronchitis in bronchial infectious-allergic asthma is one of the main causes of its recurrent course, prolonged asthmatic status, and chronic emphysema.

local_offerevent_note November 20, 2019

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