Modern view on the etiology and immunological aspects of pneumonia

Pneumonia is the most common and deadly nosology among all respiratory diseases associated with microorganisms. Despite advances in antibacterial and antiviral therapy, mortality due to pneumonia is not decreasing. It should be noted that the problem of infectious pathology has always been discussed only in narrow circles of specialists, which led to its underestimation, including during the pandemic of a new coronavirus infection. At present, scientific possibilities have not reached their perfection in the etiological diagnosis of pneumonia. Of no small concern is the lack of sections on immunology in the training program for general practitioners and pulmonologists and, as a result, the lack of knowledge by most medical specialists of the basics of the immune response in various infectious diseases, in particular, the differences in the immune response of a macroorganism in viral and bacterial infections, the stages of the immune response, differences between innate and adaptive immune responses, possibilities of immunocorrective therapy. Being followers  of the scientific school of pulmonology of academician N.S. Molchanov,  in this review, we evaluated the features of etiological factors and immune characteristics of the body on the course and out-comes of pneumonia, taking into account modern scientific knowledge. The current definition of pneumonia is formulated, the issues of the etiology of pneumonia from the perspective of the lung microbiome, the features of the immune response of the macroorganism in viral and bacterial pneumonia, the inconsistency of immune protection and the impact of comorbidity on this are covered in detail. Understanding the processes that lead to the disruption of the respiratory microbiome, the multiplication of pathobionts, the attachment of multiresistant microorganisms and the reactivity of the macroorganism will contribute to the development of new therapeutic approaches in the treatment of pneumonia.

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