Primary immunodeficiencies (PIDs) are a group of congenital diseases of the immune system, which numbers more than 230 nosological entities associated with lost, decreased, or wrong function of its one or several components. Due to the common misconception that these are extremely rare diseases that occur only in children and lead to their death at an early age, PIDs are frequently ruled out by physicians of related specialties from the range of differential diagnosis. The most common forms of PIDs, such as humoral immunity defects, common variable immune deficiency, X-linked agammaglobulinemia, selective IgA deficiency, etc., are milder than other forms of PID, enabling patients to attain their adult age, and may even manifest in adulthood. Bronchopulmonary involvements are the most common manifestations of the disease in patients with a defect in humoral immunity. Thus, a therapist and a pulmonologist are mostly the first doctors who begin to treat these patients and play a key role in their fate, since only timely diagnosis and initiation of adequate therapy can preserve not only the patient's life, but also its quality, avoiding irreversible complications. Chest computed tomography changes play a large role in diagnosis. These are not specific for PID; however, there are a number of characteristic signs that permit this diagnosis to be presumed.

Common variable immunodeficiency (CVID) is the most prevalent clinically important form of primary immunodeficiencies (PID). CVID is characterized by a wide variability of complications which can affect almost all organs and systems. Infectious complications are more typical, but non-infectious complications, in particular granulomatous lymphocytic interstitial lung disease (GLILD), have more strong influence on the course, prognosis and severity of the disease and the patient’s quality of life. GLILD is a challenge not only from a diagnostic point of view (manifestations are often misdiagnosed and treated as sarcoidosis, tuberculosis, lymphoproliferative disease), but also in terms of treatment strategy selection. Rituximab - is one of the most promising methods of GLILD therapy, which showed its efficiency in limited clinical observations. A clinical case of successful treatment of GLILD associated with CVID, using rituximab on the background of a regular replacement immunotherapy with immunoglobulin for intravenous administration (IVIG) is described in this article.

Airway inflammation plays a key role in asthma and chronic rhinosinusitis with nasal polyps (CRSwNP). The inflammatory process can vary in intensity thus affecting the clinical picture of the disease and, most importantly, the effectiveness of therapy. Today, there is still a high rate of growth in the incidence of asthma and CRSwNP and dissatisfaction with the effectiveness of existing therapy for severe forms of asthma, especially when asthma is associated with CRSwNP, so the main task is to find new approaches to diagnosis and therapy. The development of biologics is a promising step forward in achieving control of severe and poorly controlled asthma and recurrent CRSwNP that target individual and specific components of inflammation. One of the latest monoclonal antibodies is Dupilumab that has shown significant success in the treatment of asthma and CRSwNP. Dupilumab is a fully human monoclonal antibody directed against the subunit of the Il-4 interleukin receptor (IL-4ra), common to both IL-4 and IL-4/IL-13 receptor complexes. This contributes to the suppression of type 2 cytokine signaling (IL-4 and IL-13), since the IL-4/IL-13/STAT6 signaling pathway plays a crucial role in type 2- inflammation. Currently, Dupilumab is approved for the treatment of severe asthma and CRSwNP, so this article summarizes the main information about Dupilumab and its effectiveness in these diseases, as well as presents the results of clinical observation.