Relevance. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) makes it possible to treat severe malignant and non-malignant hematopoietic disorders system. Pulmonary complications (PC) occur in 40–60 % of patients after allo-HSCT. However to date, the effect of HSCT on functional and morphological pulmonary changes in recipients remains insufficiently studied.The objective of current study was to evaluate risk factors affecting long-term survival in children and adolescents after allo-HSCT.Methods and materials. The current study was both retrospective and prospective. The analysis included 362 patients with acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML), aged 5 months to 18 years, who received allo-HSCT at Raisa Gorbacheva Memorial Research Institute for Pediatric Oncology, Hematology and Transplantation in 2000–2018. All the patients underwent chest computed tomography (CT). When detecting CT changes, we performed fibrobronchoscopy (FBS) with microbiological examination of bronchoalveolar lavage (BAL).Results. PC were diagnosed in 124 patients (64 %) who received allo-HSCT in 2014–2018. Decrease of overall survival (OS) is associated with PC development during the first year after allo-HSCT(р<0,001).The development of early PC in remission of the underlying disease significantly affected OS (p=0.001).The probability of PC development is 2.26 times higher in patients older than 9 years (p=0.006). When comparing the intensity of conditioning regimens (MACvsRIC) in remission of the underlying disease, we did not get significant differences in the incidence of PC (p>0.05). Graft source, donor type, HLA-compatibility, recipient gender did not affect the incidence of PC (p>0.05). When using graft-versus-host disease (GVHD) prophylaxis (ptCYvsATG), the 5-year OS in patients without PC was 78.8 % and 62.8 %respectively. The 5-year OS in patients with PC was 51.8 % and 42.4 % respectively (р=0.007). Decrease of OS in patients with PC is associated with chGVHD(58.3 %,) (р=0.03).Conclusion. Pulmonary complications (infectious and non-infectious) in allo-HSCT recipients are more likely to occur in the first year after transplantation. Among bacterial pathogens, the predominance of Gr(-) flora remains. The incidence of pulmonary complications was significantly lower when using ptCY as a prevention of GVHD.
