Paper Title
The Role of Βeta-2-Microglobulin and Cystatin C As Urinary Biomarkers of Focal Segmental Glomerulosclerosis in The Setting of Paediatric Hiv Infection

Abstract
Background: Africa has the highest rate of Human Immunodeficiency Virus (HIV) infection and HIV associated nephropathy (HIVAN) is currently one of the most frequent paediatric kidney diseases observed in children. The most common form of glomerular damage exhibited by children is focal segmental glomerular sclerosis (FSGS) not otherwise specified according to the Columbia classification. HIVAN in children usually presents as a form of nephrotic syndrome that often leads to end stage kidney disease (ESKD). Due to abnormal kidney functioning, proteins are excreted out into urine. The objective of this study was to determine the urinary concentrations of β-2-Microglobulin (β2M) and cystatin C proteins in children with HIVAN and idiopathic FSGS compared to HIV infected children with no kidney disease and healthy controls (HIV negative with no kidney disease). Methods: The study group comprised of 34 children; 14 with HIVAN and 20 with idiopathic FSGS. The control groups were 20 HIV positive and 20 HIV negative children with no kidney disease. Urine samples collected from these 74 children were stored at -80ºC. Bio-Plex technology was used to analyse urinary protein concentration of cystatin C and β2M. Results: A significant increase in urinary β2M levels was observed in the HIVAN group compared to the HIV negative group (p= 0.0240). High statistical significance was noted in urinary cystatin C excretion in the idiopathic FSGS compared to both HIV negative (p= 0.0041) and HIV positive controls (p= 0.0256). Urinary cystatin C displayed a significant decrease in the HIVAN group compared to idiopathic FSGS (p= 0.0150). However, no significance of cystatin C was noted in the HIVAN group compared to HIV negative (p= 0.9860) and HIV positive control groups (p= 0.4311). Conclusion: Urinary cystatin C levels are significantly elevated in children with HIVAN and idiopathic FSGS. It may be a useful biomarker to detect kidney disease in children. Key Words- biomarkers, children, FSGS, HIV, urinary proteins