A total of 288 children with chronic inflammatory diseases of the lung (HIDL), including cystic fibrosis (CF), were examined comprehensively. Significant activation of neutrophilic elastase (NE) in the chronic pulmonary heart (CPH) and an increase in the activity of cathepsin G (according to the activation of anti-cathepsin-G) in CPH patients was established. An increase in the level of matrilysin - matrix metalloproteinase-7 (MMP-7) as the condition worsened was also found in patients with chronic leukemia; A significant increase in the content of MMP-7 is typical not so much for CPH patients, but for СF patients, in particular, during the formation of CPH in them. In СF patients, even without worsening the condition in the form of pulmonary arterial hypertension (PAH), the developing pulmonary heart (DPH) and CPH, the levels of MMP-7 were increased more significantly than in congenital lung malformations cases. In patients with pulmonary arterial hypertension (PAH) grade 1, the levels of IL-4 and IL-6 were 11.1 and 4.4 times higher than in controls, respectively. In PAH grade 2 children, the concentrations of IL-4 and IL-6 were 11.5 and 4.8 times higher than in controls. The dynamics of the content of endothelin-1 in the blood of patients was also characterized by an increase in its concentrations in HIDL patients by 4.5, 2.4 and 4.7 times, respectively, compared with the control. The content of nitric oxide in the blood of PAH patients was significantly lower than in the control and directly depended on the severity of PAH.