JC Virus and APOL1 Risk Alleles in Black South Africans With Hypertension-Attributed CKD

High risk APOL1 genotypes and kidney disease among treatment naïve HIV patients at Kano, Nigeria

Introduction

Racial disparities are known in the occurrence of kidney disease with excess risks found among people of African descent. Apolipoprotein L1 (APOL1) gene variants G1 and G2 are associated with kidney disease among HIV infected individuals of African descent in the USA as well as among black population in South Africa. We set out to investigate the prevalence of these high-risk variants and their effects on kidney disease among HIV infected patients in Northern Nigeria with hitherto limited information despite earlier reports of high population frequencies of these alleles from the Southern part of the country.

Methods

DNA samples obtained from the whole blood of 142 participants were genotyped for APOL1 G1 and G2 variants after initial baseline investigations including assessment of kidney function. Participants comprised 50 HIV positive patients with no evidence of kidney disease, 52 HIV negative individuals with no kidney disease and 40 HIV positive patients with chronic kidney disease (CKD) evidenced by persistent proteinuria and/or reduced eGFR, who also had a kidney biopsy. All the HIV positive patients were newly diagnosed and treatment naïve.

Results

The distribution of the APOL1 genotypes among the study participants revealed that 24.6% had a G1 risk allele and 19.0% a G2. The frequency of the High Risk Genotype (HRG) was 12.5% among those with CKD compared to 5.8% in the HIV negative group and zero in the HIV positive no CKD group. Having the HRG was associated with a higher odds for developing HIV Associated Nephropathy (HIVAN) (2 vs 0 risk alleles: OR 10.83, 95% CI 1.38–84.52; P = 0.023; 2 vs 0 or 1 risk alleles: OR 5.5, 95% CI 0.83–36.29; P = 0.07). The HRG was also associated with higher odds for Focal Segmental Glomerulosclerosis (FSGS) (2 vs 0 risk alleles: OR 13.0, 95% CI 2.06–81.91; P = 0.006 and 2 vs 0 or 1 risk alleles: OR 9.0, 95%CI 1.62–50.12; P = 0.01) when compared to the control group.

Conclusion

This study showed a high population frequency of the individual risk alleles of the APOL1 gene with higher frequencies noted among HIV positive patients with kidney disease. There is high association with the presence of kidney disease and especially FSGS and HIVAN among treatment naive HIV patients carrying two copies of the HRG.

Virus-Associated Nephropathies: A Narrative Review

While most viral infections cause mild symptoms and a spontaneous favorable resolution, some can lead to severe or protracted manifestations, specifically in immunocompromised hosts. Kidney injuries related to viral infections may have multiple causes related to the infection severity, drug toxicity or direct or indirect viral-associated nephropathy. We review here the described virus-associated nephropathies in order to guide diagnosis strategies and treatments in cases of acute kidney injury (AKI) occurring concomitantly with a viral infection. The occurrence of virus-associated nephropathy depends on multiple factors: the local epidemiology of the virus, its ability to infect renal cells and the patient's underlying immune response, which varies with the state of immunosuppression. Clear comprehension of pathophysiological mechanisms associated with a summary of described direct and indirect injuries should help physicians to diagnose and treat viral associated nephropathies.

Determining host factors contributing to the reactivation of JC virus in kidney transplant recipients

BACKGROUND AND AIMS

The John Cunningham virus (JCV) is the established etiological agent of the polyomavirus-associated nephropathy among renal transplant recipients. In the present study, we aimed to determine the probable predictive factors leading to JCV replication in renal transplant patients.

MATERIAL AND METHODS

Urine and plasma samples were collected from a total of 120 consecutive renal-transplanted patients without preliminary screening from Jan 2018 to Mar 2019. After DNA extraction, the simultaneous detection and quantification of JCV and BK polyomavirus (BKV) were conducted using a Real-time quantitative PCR method. Moreover, statistical analyses were performed using the statistical software packages, SPSS version 21.

RESULTS

The prevalence of JCV viruria and viremia among renal transplant recipients were 26 (21.67%) and 20 (16.67%), respectively. A significant association was observed between the JCV and two risk factors, diabetes mellitus (P = 0.002) and renal stones (P = 0.015). The prevalence of JCV viremia among recipients who were grafted near time to sampling was significantly higher (P = 0.02). There was a statistically significant coexistence between BK and JC viruses among our patients (P = 0.029). The frequency of JCV viruria in males was reported almost three times more than in females (P = 0.005). The JCV shedding in urine was significantly associated with the tropical steroids like prednisolone acetate, which have been the standard regimen (P = 0.039). Multivariable analysis revealed duration of post-transplantation (OR, 0.89; P = 0.038), diabetes mellitus (OR, 1.85; P = 0.034), and renal stone (OR 1.10; P = 0.04) as independent risk factors associated with JCV viremia post-renal transplantation.

CONCLUSION

It seems that the discovery of potential risk factors, including immunological and non-immunological elements, may offer a possible preventive or therapeutic approach in the JCV disease episodes. The results of this study may also help clarify the probable clinical risk factors involving in progressive multifocal leukoencephalopathy development.

JCV viruria associates with suboptimal recovery of kidney function three years after living kidney donation

ABSTRACT Introduction: Few studies have investigated pre-donation factors that could affect renal recovery after living kidney donation (LKD). We retrospectively investigated the role of John Cunningham virus (JCV) infection and other pre-donation factors on the magnitude of kidney function decline after LKD. Methods: Urine JCV viral loads, glomerular filtration rate, and blood pressure were evaluated in 60 consecutive LK donors before donation. Suboptimal compensatory hypertrophy was defined as an eGFR <60% of the pre-donation eGFR. Results: LKD (40% JCV infected) were followed for 3.2±1.6 years. No association was found between age, gender, and baseline hypertension with 1st, 2nd, 3rd, and 4th years post-donation eGFR <60% of the pre-donation eGFR. Mean eGFR recovery at the 3rd year after donation was lower in JCV infected donors vs non-infected donors (61.8% vs 71.0%, p=0.006). Conclusion: We hypothesized that JCV could shift glomeruli into a hyperfiltration state before nephrectomy, modulating the magnitude of compensatory hypertrophy after donation. Conversely, JCV might curtail the ability of the remaining kidney to promote hyperfiltration. Longer follow up is needed to determine whether JCV viruria ultimately leads to lower eGFR over time or if it is a protective factor for the remaining kidney.

Outcomes of Living Kidney Donor Candidates and Living Kidney Recipient Candidates with JC Polyomavirus and BK Polyomavirus Viruria

Introduction

Recent data have emerged about a protective association between JCV viruria and chronic kidney disease (CKD). Material and Methods. Single-center retrospective cohort study; 230 living kidney donors (LKD) candidates and 59 potential living kidney receptors (LKR) were enrolled. Plasma and urinary JCV and BKV viral loads were measured in all LKD candidates and in nonanuric LKR candidates. Twenty-six living kidney transplant surgeries were performed. LKR were followed in order to evaluate BKV and JCV viremia and urinary viral shedding after KT.

Results

In LKD candidates, JCV viruria was negatively associated with proteinuria of >200 mg/24 hours (JC viruric LKD: 12.5% vs JCV nonviruric LKD: 26.7%, p=0.021, OR:0.393; 95% CI: 0.181–0.854). In a multivariate analysis, LKD candidates with JCV viruria had a lower risk of proteinuria of >200 mg/24 hours (p=0.009, OR: 0.342, 95% CI: 0.153–0.764), in a model adjusted for age, gender, presence of hypertension, and eGFR <80 mL/min. Prevalence of JCV viruria was higher in LKD candidates when compared with LKR candidates (40.0% vs 1.7%, p < 0.001). Among the 26 LKR, 14 (53.8%) KT patients evolved with JCV viruria; 71.4% received a graft from a JCV viruric donor.

Conclusion

Our data corroborate the recent findings of an eventual protective association between JCV viruria and kidney disease, and we extrapolated this concept to a South European population.

Toward a fine-scale population health monitoring system

Understanding population health disparities is an essential component of equitable precision health efforts. Epidemiology research often relies on definitions of race and ethnicity, but these population labels may not adequately capture disease burdens and environmental factors impacting specific sub-populations. Here, we propose a framework for repurposing data from electronic health records (EHRs) in concert with genomic data to explore the demographic ties that can impact disease burdens. Using data from a diverse biobank in New York City, we identified 17 communities sharing recent genetic ancestry. We observed 1,177 health outcomes that were statistically associated with a specific group and demonstrated significant differences in the segregation of genetic variants contributing to Mendelian diseases. We also demonstrated that fine-scale population structure can impact the prediction of complex disease risk within groups. This work reinforces the utility of linking genomic data to EHRs and provides a framework toward fine-scale monitoring of population health.

Diagnostic accuracy of semiquantitative point of care urine albumin to creatinine ratio and urine dipstick analysis in a primary care resource limited setting in South Africa

Background

The prevalence of chronic kidney disease (CKD) is predicted to rise over the next few decades. In resource-limited settings access to central laboratory services is limited. Point-of-care (POC) urine dipstick testing offers the potential to detect markers of kidney damage (albuminuria) as well as markers of other disease processes. We evaluated the diagnostic accuracy of the semi-quantitative albumin-creatinine ratio (ACR) Sysmex UC-1000 POC urine dipstick system as well as the extent of other abnormal dipstick findings in urine.

Methods

700 participants from a rural area in South Africa were screened for albuminuria. A spot urine sample was used to measure POC and central laboratory ACR. We determined the sensitivity, specificity, positive predictive value and negative predictive value of the POC ACR, and recorded dipstick parameters.

Results

The prevalence of albuminuria was 11.6% (95%CI; 9.3–14.2). Those with albuminuria had higher mean diastolic (82 vs 79 mmHg, p = 0.019) and systolic (133 vs 128 mmHg, p = 0.002) blood pressures and a higher proportion of diabetes mellitus (17.6 vs 4.9%, p < 0.001). The sensitivity of the POC ACR system was 0.79, specificity 0.84, positive predictive value 0.39 and negative predictive value 0.97. The sensitivity improved to 0.80, 0.85, 0.85 and 0.89 in those with elevated blood pressure, diabetes mellitus, HIV positive status, and those 65 years and older, respectively. Abnormalities other than albuminuria were detected in 240 (34.3%) of the samples; 88 (12.6%) were positive for haematuria, 113 (16.1%) for leucocytes, 66 (9.4%) for nitrites and 27 (3.9%) for glycosuria.

Conclusion

Our study shows that POC ACR has good negative predictive value and could be used to rule out albuminuria when screening for CKD. Additionally, a high proportion of participants had other urine abnormalities detected with dipsticks which may reflect kidney disease or co-morbid untreated genitourinary pathology such as urinary tract infections or endemic schistosomiasis with important implications for CKD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02290-5.