APOL1 Risk Variants Are Strongly Associated with HIV-Associated Nephropathy in Black South Africans.

APOL1 variants are associated with HIV-associated nephropathy and FSGS in African Americans. The prevalence of these variants in African populations with CKD in HIV-1 infection has not been investigated. We determined the role of APOL1 variants in 120 patients with HIV-associated nephropathy and CKD and 108 controls from a South-African black population. Patients with CKD were selected on the basis of histology. Genotypes were successfully determined for APOL1 G1 and G2 variants and 42 single nucleotide polymorphisms, including 18 ancestry informative markers, for 116 patients with CKD (96.7%; 38 patients with HIV-associated nephropathy, 39 patients with HIV-positive CKD, and 39 patients with HIV-negative CKD), and 108 controls (100%). Overall, 79% of patients with HIV-associated nephropathy and 2% of population controls carried two risk alleles. In a recessive model, individuals carrying any combination of two APOL1 risk alleles had 89-fold higher odds (95% confidence interval, 18 to 912; P<0.001) of developing HIV-associated nephropathy compared with HIV-positive controls. Population allele frequencies were 7.3% for G1 and 11.1% for G2. APOL1 risk alleles were not significantly associated with other forms of CKD. These results indicate HIV-positive, antiretroviral therapy-naïve South-African blacks with two APOL1 risk alleles are at very high risk for developing HIV-associated nephropathy. Further studies are required to determine the effect of APOL1 risk variants on kidney diseases in other regions of sub-Saharan Africa.

Clinicopathological correlation of kidney disease in HIV infection pre- and post-ART rollout.

The spectrum of HIV-associated kidney disease has expanded significantly with the introduction of antiretroviral therapy (ART). In the pre-ART era there was prominence of HIV-associated nephropathy (HIVAN). More recently, the spectrum of disease additionally reflects comorbid illness in the ageing HIV population and ART-related nephrotoxicity. We performed a clinicopathological correlation of kidney disease in HIV-positive individuals who underwent kidney biopsy between 1989 and 2014, utilizing the 2018 Kidney Disease Improving Global Outcomes pathologic classification. ART rollout began in 2004 in South Africa. Patients biopsied pre-ART rollout were compared to those biopsied post-ART rollout with respect to demographics, clinical parameters and histology. We assessed kidney survival in a cohort of these patients following biopsy. Six hundred and ninety biopsies were included, 99 (14.3%) were undertaken pre- and 591 (85.7%) post-ART rollout. Most patients were of Black African descent (97.5%). The post-ART rollout patients were older (p = 0.007), had higher eGFR at presentation (p = 0.016) and fewer presented with eGFR of less than 15ml/min/1.73m2 (p = 0.0008). There was a decrease in the prevalence of classic HIVAN (p = 0.00001); and an increase in FSGS (NOS) in the setting of HIV (p = 0.0022) and tubulointerstitial diseases (p = 0.009) post-ART rollout. Kidney function survival over 5 years was poorest in patients with classic HIVAN (p = 0.00005) and best in minimal change nephropathy (p = 0.0013). Kidney biopsy is crucial for the correct diagnosis and management of HIV-related kidney disease. ART rollout has shifted the spectrum of kidney disease away from classic HIVAN but has not eliminated it. Histological diagnosis prognosticates kidney survival.

Profiling Biomarkers in HIV Glomerular Disease - Potential for the Non-Invasive Diagnosis of HIVAN?

BACKGROUND: There is a wide spectrum of kidney pathology in human immunodeficiency virus (HIV) infection, affecting all structures of the kidney. The histology of HIV chronic kidney disease (CKD) is diverse, ranging from HIV-associated nephropathy (HIVAN) to focal glomerulosclerosis (FSGS), HIV-immune complex disease (HIV-ICD), other glomerulopathies and tubulo-interstitial nephritis. Definitive diagnosis is by kidney biopsy, an invasive procedure. However, serum and urinary biomarkers may be useful in predicting the histological diagnosis of HIVAN. PURPOSE: We wished to determine the utility of serum and urinary biomarkers in predicting the histological diagnosis of HIVAN. PATIENTS AND METHODS: We measured neutrophil gelatinase-associated lipocalin (NGAL), cystatin C, transforming growth factor (TGF)-ß isoforms and bone morphogenetic protein (BMP)-7 in the serum and urine in patients with different histological forms of HIV glomerular disease. RESULTS: In HIVAN, we demonstrated increased levels of serum cystatin C and increased levels of serum and urinary NGAL. Urinary TGF-ß1 and TGF-ß2 levels were elevated in HIV-positive patients with CKD but were not significantly different in the different HIV histologies, while urinary BMP-7 levels were elevated in minimal change disease. CONCLUSION: This study confirmed the presence of increased serum and urinary biomarkers of tubular injury in patients with HIVAN, and increased urinary biomarkers of fibrosis in HIV CKD, and may indicate their value as a non-invasive diagnostic tool for the diagnosis of HIVAN.