Background. Long-term consequences of polychemotherapy (PCT) for acute lymphoblastic leukemia (ALL), adversely affecting the kidneys, require study in pediatric practice.
Objective. Evaluation of the markers of kidney damage in children with acute lymphoblastic leukemia after completion of polychemotherapy.
Methods. A cross-sectional study of kidney damage markers in the serum (creatinine and cystatin C) and urine (neutrophil gelatinase-associated lipocalin (NGAL), β2-microglobulin, kidney injury molecule-1 (KIM-1), and interleukin 18 (IL-18)) was conducted in 38 children aged 3–18 years with ALL in the period from 2 weeks to 6.5 years after the end of chemotherapy. The control group included 50 children of the corresponding age and sex, II health group. The data are presented as median and interquartiles (Me [25; 75]), comparison of groups – according to the Mann-Whitney criterion.
Results. A higher serum cystatin C level was found in children with ALL, regardless of the renal filtration function in all studied periods after the end of chemotherapy (p < 0.001). In the first two years after the end of chemotherapy, children with ALL had an increased urine KIM-1 level compared to the control group (p =0.009). In children with ALL after chemotherapy, who have a decrease in eGFR <90 ml/min/1.73 m2 based on the CKiD U25 formula for serum cystatin C using an age-dependent coefficient, an increased urine KIM-1 level (p=0.005) and its normalized value – urine KIM-1/ creatinine ratio (p=0.016) were observed.
Conclusion. An increase in the serum cystatin C levels for 6.5 years after chemotherapy and urine KIM-1 levels in the first two years after the end of therapy may indicate persistent changes in the glomeruli and tubules of the kidneys and serve as predictors of the development of CKD in children.

Keywords: acute lymphoblastic leukemia, markers of kidney damage, children, chronic kidney disease