Background:Lupus nephritis is the most severe and adverse systemic lupus erythematosus (SLE) syndrome. According to modern recommendations, the clinical manifestations of active nephritis should be taken under medical control in 6 months after the start of the disease’s treatment1.Objectives:The aim of this study was to examine the functional status of the kidneys in children with SLE in the course of the disease for more than one year.Methods:The analysis included case histories of 43 patients with SLE, mostly females (41), aged 7 to 18 years (mean age 14.4 years) with disease duration of 4.75 ± 0.58 years of whom 22 were less than three years, 21 - more than three years. All children received corticosteroid therapy, at the time of the examination the average dose was 13.85 ± 1.86 mg per day in terms of prednisolone. The second component of therapy was azathioprine (average dose 97.61 ± 2.11 mg). All children received hydroxychloroquine (5 mg/kg per day).To determine the functional state of the kidneys a clinical analysis of urine, a study of the scope of specific gravity of urine during the day (Zymnytsky test), the content of creatinine and urea in serum to determine the glomerular filtration rate (GFR), the level of microalbuminuria per day were evaluated.Results:Renal involvement in the developed SLE occurred in 73.08% of patients. Among them, therapy during the first 6 months was considered quite effective in 58.06% of patients. It was found that in children with disease duration from one to three years proteinuria was registered in 68.18%, a decrease in GFR in 4.45% and hyperfiltration in 9.09%. In the group of children with duration of SLE more than three years revealed deeper changes in renal function; there was proteinuria in 90.47%, the frequency of GFR decreased was in 19.04%, a decrease of renal concentration function was in 14.28% of cases.Indicators of renal function in children with SLE depending on the duration of the disease (M ± m)IndicatorDuration of the diseasefrom 1 year to 3 years n = 22over 3 yearsn = 21Creatinine, mmol/l0,080 ± 0,0140,090 ± 0,018Мочевина, mmol/l5,66 ± 1,425,63 ± 1,61GFR, ml/min117,05 ± 19,68100,20 ± 18,98 *Microalbuminuria, mg/day24,41 ± 13,1334,73 ± 24,76Density min1,007 ± 0,0051,006 ± 0,005Density max1,024 ± 0,0051,019 ± 0,005 ***р<0,03;**р<0,01 the probability of differences when comparing between groupsConclusion:Long-term follow-up of children with SLE over one year reveals a prolongation of renal dysfunction, which worsens after three years, and is the basis for the development of irreversible renal impairment.References:[1]European evidence-based recommendations for the diagnosis and treatment of childhood-onset lupus nephritis: the SHARE initiative /Noortje Groot, Nienke de Graeff, Stephen D Marks et all. //Ann Rheum Dis. 2017 Dec;76(12):1965-1973.Disclosure of Interests:None declared