It has been proposed that circulating HSCs play a role in graft survival after liver transplantation. The aim was to analyze the relationship between the number of HSCs before and after LDLT and liver function, immune biomarkers, and clinical outcomes in pediatric patients. We studied 15 pairs of adult healthy liver donors and pediatric recipients with ESLD. The CD34/CD45+ cell number was measured in the blood via flow cytometry, and plasma levels of immune biomarkers - via ELISA. CD34/CD45+ cell number in the recipients decreased within the first week after LDLT. The cell number before LDLT was negatively correlated with the plasma levels of CRP and the development of graft dysfunction in the early post-transplant period. After LDLT, the CD34/CD45+ cell number was positively correlated with the pretransplant plasma level of sCD40L, a T-cell activation marker. In adult liver donors, the cell number did not change within the first week after liver resection and was lower than in pediatric recipients. The results suggest that in pediatric recipients, the HSC number may be associated with graft function and could be regarded as a potential predictor of the clinical outcome after LDLT.

The transforming growth factor 1 (TGF1), whose level may depend on the polymorphism of the TGFB1 gene, is involved in the formation of myocardial fibrosis. Myocardial fibrosis in a cardiac allograft may lead to a hearts structural and functional remodeling and subsequent dysfunction. The frequency of occurrence of alleles and genotypes of the TGFB1 gene polymorphic regions rs1800469, rs1800470, and rs1800471 in heart transplant recipients and their association with graft myocardial fibrosis were analyzed. Carriers of the CC genotype (p = 0.023, OR = 0.12, 95% CI: 0.0171.0), and more often the G allele of rs1800471 (p = 0.023, OR = 7.76, 95% CI: 1.060.20), were found among heart transplant recipients less frequently than among healthy individuals. In patients with ischemic heart disease (IHD), the GG genotype was less common (p = 0.035, OR = 2.68, 95% CI: 1.0616.793), while the A allele of rs1800469 was found more frequently (p = 0.035, OR = 0.37 95% CI: 0.1480.942) than in patients with dilated cardiomyopathy (DCM). In heart transplant recipients with the AA genotype of rs1800470, myocardial fibrosis, verified by endomyocardial biopsy, was detected more often than in carriers of the G allele (OR = 10.4, 95% CI: 1.15294.538, p = 0.013). The revealed differences suggest a relationship between TGFB1 gene polymorphism and graft myocardial fibrosis. Studies on a larger group of patients would make it possible to characterize the influence of genetic factors on the formation of myocardial fibrosis in heart transplant recipients.