The role of β-2-microglobulin and cystatin C as urinary biomarkers of focal segmental glomerulosclerosis in the setting of paediatric HIV infection

Background. Africa has the highest rate of HIV infection, and HIV-associated nephropathy (HIVAN) is one of the most frequent kidneydiseases observed in children. HIVAN in children usually presents as a form of nephrotic syndrome, predominantly focal segmentalglomerulosclerosis (FSGS) on histopathology, that often leads to chronic kidney failure.Objective. This study determined the urinary concentrations of β-2-microglobulin (β2M) and cystatin C proteins in children with HIVANand primary FSGS.Methods. The study group comprised 34 children; 14 with HIVAN and 20 with primary FSGS. The control groups were 20 HIV-positiveand 20 HIV-negative children with no kidney disease. Urine samples collected from these 74 children were stored at -80°C. Bio-Plextechnology was used to analyse the urinary protein concentration of cystatin C and β2M.Results. A significant increase in urinary β2M levels was observed in the HIVAN group compared with the HIV-negative group(p=0.0240). No other statistically significant differences in urinary β2M concentrations were noted across the study groups. Urinarycystatin C levels were significantly increased in primary FSGS children compared with both HIV-negative (p=0.0041) and HIV-positivecontrols (p=0.0256). Urinary cystatin C displayed a significant increase in the primary FSGS compared with the HIVAN group (p=0.0150).No significant differences in urinary cystatin C levels were noted in the HIVAN group compared with the HIV-negative and HIV-positivecontrol groups.Conclusion. Urinary cystatin C has promising prognostic value to predict primary FSGS from HIVAN.