Abstract: one of the first symptoms allowing to suspect an immune deficiency is pneumonia. The most common in HIV-infected patients is pneumocyst pneumonia.

The aim of the investigation was to study the clinical course of pneumocyst pneumonia in HIV-infected patients.

Materials and methods: the analysis of literature data and retrospective analysis of 143 case histories of deceased patients admitted to the hospital of GO BUZ “Novgorod regional infectious diseases hospital” for the period from 2004 to 2016. The study included patients with different stages of the disease, with previously known HIV status for the first time revealed patients. Socio-demographic, clinical (AIDS-indicator and related diseases), as well as immunological characteristics were taken into account.

Conclusion: verification of the diagnosis of pneumocyst pneumonia is based on the identification of a characteristic clinical picture (leading syndrome — progressive respiratory failure); determining the immunodeficiency status of the patient; high rates of ESR and total LDH activity, arterial hypoxemia (decrease in Rao2); isolation of the causative agent from the biological material of the respiratory tract; radiological and bilateral interstitial infiltrative changes in the lungs.

To prevent the development of pneumocystic pneumonia, it is necessary to increase the number of HIV tests in vulnerable groups (to reduce the frequency of late-onset patients), increase the number of patients who are on dispensary supervision, timely prevent pneumonia of HIV-infected patients (with a decrease in SD4-lymphocytes <200 with Biseptol), as well as timely prescribe and use art as prevention. Keywords: HIV infection, Pneumocystis penumonia, opportunistic infections, clinical features, diagnosis, CD4-lymphocytes