Absence of HIV-associated nephropathy in Ethiopians

Infectious diseases among Ethiopian immigrants in Israel: a descriptive literature review

The mass immigration of Ethiopian Jews to Israel began in the 1980s. For most of these immigrants this was a time of sharp transition from a village life with very basic living conditions, in most cases without a regular supply of water, electricity, or healthcare services, to a modern Western urban society. The aim of this review was to search the medical literature on the characteristics of infectious diseases that are typical in Ethiopian immigrants (EI), using relevant keywords. There has been success in coping with diseases among EI, that are rare although recognized in Israel, in terms of screening and early identification. TB was common in Ethiopia over all the years of immigration to Israel. In contrast, HIV appeared in EI from 1999 when they had long stayovers in transition camps in Gondar and Addis Ababa where there was a high risk of infection with sexually transmitted diseases. There were often delays in diagnosing 'exotic' diseases that are endemic in Africa, but not well known in Israel, such as Onchocerciasis, Schistosomiasis, Strongyloidiasis, and Bartonella endocarditis, which cause severe morbidity and mortality among EI. We describe the effect on general morbidity in Israel, and how the healthcare services coped with these diseases, including obstacles, and failures and successes. In light of the ongoing immigration of African refugees to the United States and Europe, the Israeli experience can be of value to healthcare policy makers in developing strategies for the effective management by medical staff treating these immigrants.

Renal function in a cohort of HIV-infected patients initiating antiretroviral therapy in an outpatient setting in Ethiopia

Aim

To evaluate the prevalence and associated factors of abnormal renal function among Ethiopian HIV-infected patients at baseline prior to initiation of antiretroviral therapy (ART) and during follow-up.

Methods

We conducted a retrospective observational cohort study of HIV infected patients who initiated ART at the outpatient ART clinic of Mehal Meda Hospital of North Shewa, Ethiopia from January 2012 to August 2018. Demographic and clinical data were abstracted from the medical records of patients. Renal function was assessed by estimated glomerular filtration rate (eGFR) calculated using the Modification of Diet in Renal Disease (MDRD) equation. Univariate and multivariate analysis were conducted to determine the factors associated with abnormal renal function at baseline and during follow-up.

Results

Among 353 patients, 70 (19.8%) had baseline eGFR <60 ml/min/1.73m² and 102 (28.9%) had eGFR = 60–89.9 ml/min/1.73m². Factors associated with baseline renal impairment (eGFR <60 ml/min/1.73m²) included female sex (AOR = 3.52, CI 1.75–7.09), CD4 count < 200 cells/mm³ (AOR = 2.75, CI 1.40–5.42), BMI < 25 Kg/m² (AOR = 3.04, CI 1.15–8.92), low hemoglobin (AOR = 2.19, CI 1.16–4.09) and high total cholesterol (AOR = 3.15, CI 1.68–5.92). After a median of 3.0 years of ART, the mean eGFR declined from 112.9 ± 81.2 ml/min/1.73m² at baseline to 93.9 ± 60.6 ml/min/1.73m² (P < 0.001). The prevalence of renal impairment increased from 19.8% at baseline to 22.1% during follow-up. Of 181 patients with baseline normal renal function, 49.7% experienced some degree of renal impairment. Older age (AOR = 3.85, 95% CI 2.03–7.31), female sex (AOR = 4.18, 95% CI 2.08–8.40), low baseline CD4 (AOR = 2.41, 95% CI 1.24–4.69), low current CD4 count (AOR = 2.32, 95% CI 1.15–4.68), high BMI (AOR = 2.91, 95% CI 1.49–5.71), and low hemoglobin (AOR = 3.38, 95% CI 2.00–7.46) were the factors associated with renal impairment during follow-up.

Conclusion

Impaired renal function was common in HIV-infected patients initiating ART in an outpatient setting in Ethiopia, and there appears to be a high prevalence of renal impairment after a median ART follow-up of 3 years. There is a need for assessment of renal function at baseline before ART initiation and regular monitoring of renal function for patients with HIV during follow-up.

Adolescent BMI and early-onset type 2 diabetes among Ethiopian immigrants and their descendants: a nationwide study

BACKGROUND

We assessed in a nationwide cohort the association between adolescent BMI and early-onset (< 40 years) type 2 diabetes among Israelis of Ethiopian origin.

METHODS

Normoglycemic adolescents (range 16-20 years old), including 93,806 native Israelis (≥ 3rd generation in Israel) and 27,684 Israelis of Ethiopian origin, were medically assessed for military service between 1996 and 2011. Weight and height were measured. Data were linked to the Israeli National Diabetes Registry. Incident type 2 diabetes by December 31, 2016 was the outcome. Cox regression models stratified by sex and BMI categories were applied.

RESULTS

226 (0.29%) men and 79 (0.18%) women developed diabetes during 992,980 and 530,814 person-years follow-up, respectively, at a mean age of 30.4 and 27.4 years, respectively. Among native Israeli men with normal and high (overweight and obese) BMI, diabetes incidence was 9.5 and 62.0 (per 105 person-years), respectively. The respective incidences were 46.9 and 112.3 among men of Ethiopian origin. After adjustment for sociodemographic confounders, the hazard ratios for type 2 diabetes among Ethiopian men with normal and high BMI were 3.4 (2.3-5.1) and 15.8 (8.3-30.3) respectively, compared to third-generation Israelis with normal BMI. When this analysis was limited to Israeli-born Ethiopian men, the hazard ratios were 4.4 (1.7-11.4) and 29.1 (12.9-70.6), respectively. Results persisted when immigrants of other white Caucasian origin were the reference; and among women with normal, but not high, BMI.

CONCLUSIONS

Ethiopian origin is a risk factor for early-onset type 2 diabetes among young men at any BMI, and may require selective interventions.

Renal function in Ethiopian HIV-positive adults on antiretroviral treatment with and without tenofovir

Background

Limited data are available on the effect of antiretroviral treatment (ART) or Tenofovir disoproxil fumarate (TDF) on renal function in Ethiopians. We aimed to assess factors associated with renal function changes during the first year of ART with special focus on TDF.

Methods

HIV positive persons who were ≥ 18 years of age and eligible for ART initiation were recruited. Creatinine measurement to estimate glomerular filtration rate (eGFR) and spot urine analyses were performed at baseline and after 3, 6 and 12 months of ART. Univariate and multivariate linear regression and univariate logistic regression were used to determine factors associated with eGFR as continuous and categorical variable respectively. A linear mixed model was used to assess 12 month eGFR difference in TDF and non-TDF based regimen.

Result

Of 340 ART-naïve HIV patients with baseline renal function tests, 82.3% (279/339) were initiated on a TDF based ART regimen. All patients were on non-nucleoside reverse transcriptase inhibitors (NNRTI) based ART regimen. The median (IQR) change in eGFR with 12 months of ART was 0.8 (− 11.1; 10.0) ml/min/1.73m². About 41 and 26.9% of HIV patients had a drop of greater than 3 and 10 mL/min/1.73 m² in eGFR at 12 month, respectively. However, none of the HIV patients declined to < 60 ml/min/1.73m² within 12 months. Moreover, none of the HIV patients had persistent proteinuria or glycosuria. Older HIV patients especially age > 45 years and those with unsuppressed viral load at 6 month of ART had a significantly lower eGFR at 12 months of ART initiation. However, there was no difference in 12 month eGFR between HIV patients initiated on TDF based regimen and non-TDF based regimen.

Conclusion

Renal function remained stable with no difference between HIV patients treated with TDF or non-TDF NNRTI based ART regimen over 12 months. However, older HIV patients and those with unsuppressed viral load deserve special focus on renal monitoring. Data on long-term safety of TDF (> 1 year) is still warranted in this population.

Impact of Immigration on Body Mass Index and Blood Pressure Among Adolescent Males and Females: A Nationwide Study

Immigration from one cultural milieu to another has been associated with a greater risk for incident cardio-metabolic morbidity among adults. In this nationwide, population-based, cross-sectional study of data recorded from 1992 to 2016, we assessed the association between body mass index and blood pressure levels among adolescent immigrants, aged 16 to 19 years, of Ethiopian origin, and their secular trend of overweight and obesity. Adolescents of Ethiopian origin were classified as Israeli-born (n=16 153) or immigrants (N=23 487), with stratification by age at immigration. Adolescents whose fathers were at least 3 generations in Israel (n=277 789) served as a comparative group. Hypertensive-range blood pressure values adjusted for age, sex, and height served as outcome. Among adolescents of Ethiopian origin, overweight and obesity (body mass index ≥85th percentile), increased by 2.5 and 4-fold in males and females, respectively, during the study period, compared with a 1.5-fold increase among native Israeli-born males and females. The odds for hypertensive-range measurements increased with the length of residence in Israel: 7.3%, 10.6%, and 14.4% among males who immigrated at ages 12 to 19, 6 to 11.9, and 0 to 5.9 years, respectively; and 11.5%, 16.7%, and 19.3%, respectively, among females. Israeli-born Ethiopians had a significantly higher risk for hypertensive-range measurements at any body mass index level compared with native Israeli-born examinees, after adjusting for sociodemographic factors and health status. In conclusion, among Ethiopian Israeli adolescents, abnormal blood pressure correlates directly with the time-lapse since immigration. Immigrant populations require targeted surveillance and appropriate intervention.

Serum creatinine and estimated glomerular filtration rates in HIV positive and negative adults in Ethiopia

BACKGROUND

Glomerular filtration rate estimating equations using serum creatinine are not validated in most African settings. We compared serum creatinine and estimated glomerular filtration rate (eGFR) in HIV positive and negative adults and assessed the performance of eGFR equations ((Cockcroft and Gault (CG), Modification of Diet in Renal Disease (MDRD), and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI)) compared to 24-hour creatinine clearance in HIV positive adults.

METHODS

Data were collected on demographic, anthropometric, body composition, clinical parameters and serum creatinine in HIV positive and negative adults. 24-hour urine was collected from some of the HIV positive adults who volunteered. Bias was calculated as mean difference between 24-hr creatinine clearance and eGFR (eGFR- 24 hour creatinine clearance) and the accuracy of each eGFR equation was calculated as the percentage of estimates within 30% of creatinine clearance.

RESULTS

A total of 340 HIV positive and 100 HIV negative adults were included in this study. Creatinine clearance was determined for 46 of HIV positive adults. Serum creatinine increased with increasing age, weight, height, body surface area, fat free mass and grip strength in both HIV positive and negative adults (P<0.05). No difference was observed in eGFR between HIV positive and HIV negative adults. For all eGFR equations, the correlation between eGFR and 24-hr creatinine clearance was 0.45-0.53 and the accuracy within 30% of 24-hr creatinine clearance was 24-46%. Removing ethnic coefficient reduced the bias and improved accuracy of the CKD-EPI and the MDRD estimates.

CONCLUSION

Ethiopian HIV positive adults in the present study had good kidney function at the initiation of antiretroviral treatment. However, all eGFR equations overestimated 24-hr creatinine clearance in the study population. Creatinine based eGFR equations that accounts for low muscle mass and body surface area are needed.

Prevalence and correlates of chronic kidney disease (CKD) among ART-naive HIV patients in the Niger-Delta region of Nigeria

Widespread use of antiretroviral therapy (ART) in human immunodeficiency virus (HIV) patients has led to improved longevity with the attendant increase in noncommunicable disease prevalence including chronic kidney disease (CKD). This study documents the prevalence of CKD in a large HIV population in Southern Nigeria.This is a single center, 15-year analysis in ART-naïve patients. CKD was defined as the occurrence of estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m on 2 consecutive occasions 3 to 12 months apart using the chronic kidney disease epidemiology collaboration (CKD-EPI) equation. The Cochran-Armitage and Cuzick tests were employed to assess for trend across the years for CKD prevalence and CD4 count, respectively. Multivariable logistic regression models were used to identify independent associations with CKD.In all, 1317 patients (62.2% females) with mean age of 34.5 years and median CD4 count of 194 cells/μL were included. CKD prevalence was 13.4% (95%CI 11.6%-15.4%) using the CKD-EPI equation (without the race factor). Multivariable analysis identified increasing age and CD4 count <200 cells/μL as being independently associated with CKD occurrence.This study reports a high prevalence of CKD in ART-naïve HIV-infected patients. Measures to improve diagnosis of kidney disease and ensure early initiation of treatment should be integrated in HIV treatment programmes in this setting.

HIV-Associated Nephropathy in Africa: Pathology, Clinical Presentation and Strategy for Prevention

The human immunodeficiency virus (HIV) infection can lead to progressive decline in renal function known as HIV-associated nephropathy (HIVAN). Importantly, individuals of African ancestry are more at risk of developing HIVAN than their European descent counterparts. An in-depth search on Google Scholar, Medline and PubMed was conducted using the terms "HIVAN" and "pathology and clinical presentation", in addition to "prevalence and risk factors for HIVAN", with special emphasis on African countries for any articles published between 1990 and 2017. HIVAN is characterized by progressive acute renal failure, proteinuria and enlarged kidneys. A renal biopsy is necessary to establish definitive diagnosis. Risk factors are male gender, low CD4 counts, high viral load and long use of combined antiretroviral medication (cART). There is a wide geographical variation in the prevalence of HIVAN as it ranges from 4.7% to 38% worldwide and little published literature is available about its prevalence in African nations. Microalbuminuria is a common finding in African populations and is significantly associated with severity of HIV disease progression and CD4 count less than 350 cells/µL. Other clinical presentations in African populations include acute kidney injury (AKI), nephrotic syndrome and chronic kidney disease. The main HIV-associated renal pathological lesions were focal segmental glomerulosclerosis, mainly the collapsing form, acute interstitial nephritis (AIN), and immune complex-mediated glomerulonephritis (ICGN). HIV infection-induced transcriptional program in renal tubular epithelial cells as well as genetic factors is incriminated in the pathogenesis of HIVAN. This narrative review discusses the prevalence, presentation, pathogenesis and the management of HIVAN in Africa. In low resource setting countries in Africa, dealing with HIV complications like HIVAN may add more of a burden on the health system (particularly renal units) than HIV medication itself. Therefore, the obvious recommendation is early use of cART in order to decrease risk factors that lead to HIVAN.

Kidney Disease in Human Immunodeficiency Virus-seropositive Patients: Absence of Human Immunodeficiency Virus-associated Nephropathy was a Characteristic Feature

Human immunodeficiency virus (HIV) infection can cause a broad spectrum of renal diseases. However, there is paucity of Indian data on the patterns of renal lesions in HIV-seropositive patients. The aim of the present study was to delineate the spectrum of renal lesions in HIV/acquired immunodeficiency syndrome patients. In this prospective study, all HIV-positive patients of both genders aged >18 years were screened for renal disease. Patients with proteinuria of more than 1 g/24 h were subjected to renal biopsy. A total of 293 HIV-positive patients were screened; of these, 136 (46.4%) patients found to have renal involvement. Dipstick-positive proteinuria of 1+ or more was observed in 112 (38.2%) patients, and 16 (14.2%) patients had proteinuria of more than 1 g/24 h. Renal biopsy in 14 cases revealed glomerulonephritis (GN) in 12 (85.7%) (isolated GN in 4 [28.5%] and GN mixed with chronic TIN in 8 [57.1%]) patients. These include mesangioproliferative GN in 5 (35.7%), membranoproliferative GN in 2 (14.2%), focal segmental glomerulosclerosis in 2 (14.2%), diffuse proliferative GN in 2 (14.2%), and diabetic nephropathy in 1 (7.1%) patients. Chronic interstitial nephritis was noted in 10 (71.42%) (superimposed on GN in 8 [57.1%], isolated in 2 [14.2%]) patients. Granulomatous interstitial nephritis was seen in 3 (24.1%) cases. GN and chronic interstitial nephritis were noted in 85.7% and 71.42% of patients, respectively, mostly superimposed on each other. Mesangioproliferative GN was the most common glomerular lesion, but classical HIV-associated nephropathy was not observed.

Absence of HIV-Associated Nephropathy Among Antiretroviral Naive Adults With Persistent Albuminuria in Western Kenya

Introduction

HIV-associated nephropathy (HIVAN) has been strongly linked to African ancestry. However, studies have demonstrated wide variability in the prevalence of HIVAN in different sub-Saharan African populations. Accurate assessment of the disease burden is important because antiretroviral therapy (ART) is increasingly available and may prevent progression to end-stage renal disease.

Methods

We prospectively screened ART-naïve, afebrile, nonhypertensive, and nondiabetic adults attending a large HIV care program in Western Kenya for the presence of albuminuria (dipstick albumin ≥ trace or urine albumin to creatinine ratio [UACR] ≥ 30 mg/g). Those with albuminuria confirmed on 2 occasions, subject to consent, underwent kidney biopsy.

Results

Among 523 subjects screened, 85 (16.3%) had albuminuria on the initial screen, and persistent albuminuria was confirmed in 32 of the 53 (60%) who returned for confirmatory testing. A total of 27 subjects with persistent albuminuria underwent biopsy. The median age was 34 years (interquartile range [IQR] 30−42 years), and 63% were female. The median CD4 count was 369 cells/μl (IQR 89−492 cells/μl). Renal function was normal in 92%. Median UACR was 257.5 mg/g (IQR 93.5−543 mg/g), and 92% had UACR < 1 g/g. No subject had histologic features consistent with HIVAN; 41% had acute interstitial nephritis (AIN); 33% had nonspecific findings, and 2 patients had arteriosclerosis. Focal segmental glomerulosclerosis, acute postinfectious glomerulonephritis, chronic interstitial nephritis, pyelitis, and papillary sickling were seen in 1 patient each.

Discussion

Among ART-naïve adults with persistent albuminuria at a referral center in Western Kenya, we observed no cases of HIVAN. AIN was the most common cause of persistent proteinuria in this setting.

HIV associated lupus like nephropathy

Background

Human immunodeficiency virus type 1 (HIV-1)-seropositive patients are at a high risk for the development of a variety of acute and chronic renal diseases. Most patients with HIVAN are of African descent, presenting late in the course of their HIV-1 infection. The only reliable test to establish or rule out the presence of HIVAN (HIV associated nephropathy) is renal biopsy. The most common lesion associated with HIV is a focal segmental glomeruloscelerosis, but several times, other biopsy findings may also be seen. Our patient had lupus nephritis like pathology picture. The therapeutic agents with the most promise are angiotensin-converting enzyme inhibitors and antiretroviral medications. Role of steroids are less well-defined although they have been used with success many times.

Case Details

Our patient was a young male who presented with a pulmonary renal syndrome like picture and wasting. On evaluation, he was found to be HIV-1 positive, and renal biopsy showed lupus nephritis like pathological picture. The patient was treated with HAART (Highly active anti retroviral therapy) , steroids and ACE inhibitors and showed an excellent response.

Conclusion

The case highlights the fact that immune mediated glomerulonephritis, although rare, can be the presenting feature of HIV infection and can be controlled, if not cured, with proper treatment.

African origins and chronic kidney disease susceptibility in the human immunodeficiency virus era

Chronic kidney disease (CKD) is a major public health problem worldwide with the estimated incidence growing by approximately 6% annually. There are striking ethnic differences in the prevalence of CKD such that, in the United States, African Americans have the highest prevalence of CKD, four times the incidence of end stage renal disease when compared to Americans of European ancestry suggestive of genetic predisposition. Diabetes mellitus, hypertension and human immunodeficiency virus (HIV) infection are the major causes of CKD. HIV-associated nephropathy (HIVAN) is an irreversible form of CKD with considerable morbidity and mortality and is present predominantly in people of African ancestry. The APOL1 G1 and G2 alleles were more strongly associated with the risk for CKD than the previously examined MYH9 E1 risk haplotype in individuals of African ancestry. A strong association was reported in HIVAN, suggesting that 50% of African Americans with two APOL1 risk alleles, if untreated, would develop HIVAN. However these two variants are not enough to cause disease. The prevailing belief is that modifying factors or second hits (including genetic hits) underlie the pathogenesis of kidney disease. This work reviews the history of genetic susceptibility of CKD and outlines current theories regarding the role for APOL1 in CKD in the HIV era.

APOL1 nephropathy: from gene to mechanisms of kidney injury

The contribution of African ancestry to the risk of focal segmental glomerulosclerosis and chronic kidney disease has been partially explained by the recently described chromosome 22q variants in the gene apolipoprotein L1 (APOL1). The APOL1 variants appear at a high allele frequency in populations of West African ancestry as a result of apparent adaptive selection of the heterozygous state. Heterozygosity protects from infection with Trypanosoma brucei rhodesiense. This review will describe the role of the approaches in population genetics for the description of APOL1-associated nephropathies and draw inferences as to the biologic mechanisms from genetic epidemiology findings to date. Modifier loci can influence APOL1 risk for the development of kidney disease. 'Second hits', both viral and non-viral, may explain the discrepancy between the remarkably high odds ratios and the low lifetime risks of kidney disease in two allele carriers of APOL1 risk variants. Therapeutic strategies for APOL1-associated nephropathies will require the prevention and treatment of these 'second hits' and the development of drugs to protect the APOL1 downstream renal injury pathways.

APOL1 kidney risk alleles: population genetics and disease associations

APOL1 kidney disease is a unique case in the field of the genetics of common disease: 2 variants (termed G1 and G2) with high population frequency have been repeatedly associated with nondiabetic CKDs, with very strong effect size (odds ratios 3-29) in populations of sub-Saharan African descent. This review provides an update on the spectrum of APOL1 kidney disease and on the worldwide distribution of these kidney risk variants. We also summarize the proper way to run a recessive analysis on joint and independent effects of APOL1 G1 and G2 kidney risk variants.

APOL1 and nephropathy progression in populations of African ancestry

Marked familial aggregation of chronic kidney disease suggests that inherited factors play a major role in nephropathy susceptibility. Molecular genetics analyses have identified a number of genes reproducibly associated with a broad range of renal phenotypes. Most associations show polygenic inheritance patterns with limited effect size. In contrast, genetic association between the apolipoprotein L1 (APOL1) gene and several severe nondiabetic forms of kidney disease in African Americans approach Mendelian inheritance patterns and account for a large proportion of glomerulosclerosis in populations of African ancestry. Emerging data support an important role for APOL1 in the progression of diverse etiologies of kidney disease, in concert with requisite environmental (gene*environment) and inherited (gene*gene) interactions. This article reviews the current status of APOL1-associated nephropathy and discusses research questions under active investigation in the search for a cure for these severe and often progressive kidney diseases.

MYH9 and APOL1 gene polymorphisms and the risk of CKD in patients with lupus nephritis from an admixture population

MYH9 polymorphisms have been described to be associated with the risk of CKD in non-diabetic nephropathy, HIV nephropathy and FSGS. Predominating in black descendants, MHY9 genetic variants could partially explain the excess risk of CKD associated with African ancestry. However, recent data suggests that APOL1 gene co-segregate with MYH9, and could be the gene truly associated with CKD risk. In this study, we evaluated the role of MYH9 and APOL1 gene polymorphisms in the risk of CKD in Brazilian patients with lupus nephritis (LN). A retrospective analysis of 196 LN patients was done. MYH9 rs4821480, rs2032487, rs4821481 and rs3752462, APOL 1rs73885319, rs16996616, rs60910145, rs71785313, and APOL3 rs11089781 gene polymorphisms were determined. Genetic ancestry was ascertained both by autossomal ancestry and mitochondrial haplogroup. Primary outcome was defined as doubling of serum creatinine (DC) or end stage renal disease (ESRD). Sixty-two patients presented the PO. In our population, MYH9 and APOL1 were not in LD. None APOL polymorphism was associated with the PO, whereas rs3752462 MYH9 polymorphism showed a positive association (HR3.72, 95%CI 1.47–9.38, p = 0.005). When we analyzed the MYH9 E1 haplotype, the GCCT carriers (1 or 2 alelles present in 29.7% in the PO group vs. 18.5% in controls) showed a significant association to the risk of PO, even after adjustments for baseline estimated creatinine clearance and autossomal ancestry (HR 2.0, 95%CI 1.2–3.4, p = 0.01). Our results show that in our population MYH9, but not APOL1, gene polymorphisms confer an increased risk of CKD in LN patients, independently of race.

High population frequencies of APOL1 risk variants are associated with increased prevalence of non-diabetic chronic kidney disease in the Igbo people from south-eastern Nigeria

BACKGROUND

Continental Africa is facing an epidemic of chronic kidney disease (CKD). APOL1 risk variants have been shown to be strongly associated with an increased risk for non-diabetic kidney disease including HIV nephropathy, primary non-monogenic focal and segmental glomerulosclerosis, and hypertension-attributed nephropathy among African ancestry populations in the USA. The world's highest frequencies of APOL1 risk alleles have been reported in West African nations, overlapping regions with a high incidence of CKD and hypertension. One such region is south-eastern Nigeria, and therefore we sought to quantify the association of APOL1 risk alleles with CKD in this region.

METHODS

APOL1 risk variants were genotyped in a case-control sample set consisting of non-diabetic, CKD patients (n = 44) and control individuals (n = 43) from Enugu and Abakaliki, Nigeria.

RESULTS

We found a high frequency of two APOL1 risk alleles in the general population of Igbo people of south-eastern Nigeria (23.3%). The two APOL1 risk allele frequency in the CKD patient group was 66%. Logistic regression analysis under a recessive inheritance model showed a strong and significant association of APOL1 two-risk alleles with CKD, yielding an odds ratio of 6.4 (unadjusted p = 1.2E-4); following correction for age, gender, HIV and BMI, the odds ratio was 4.8 (adjusted p = 5.1E-03).

CONCLUSION

APOL1 risk variants are common in the Igbo population of south-eastern Nigeria, and are also highly associated with non-diabetic CKD in this area. APOL1 may explain the increased prevalence of CKD in this region.

APOL1 risk variants predict histopathology and progression to ESRD in HIV-related kidney disease

With earlier institution of antiretroviral therapy, kidney diseases other than HIV-associated nephropathy (HIVAN) predominate in HIV-infected persons. Outcomes for these diseases are typically worse among those infected with HIV, but the reasons for this are not clear. Here, we examined the role of APOL1 risk variants in predicting renal histopathology and progression to ESRD in 98 HIV-infected African Americans with non-HIVAN kidney disease on biopsy. We used survival analysis to determine time to ESRD associated with APOL1 genotype. Among the 29 patients with two APOL1 risk alleles, the majority (76%) had FSGS and 10% had hypertensive nephrosclerosis. In contrast, among the 54 patients with one APOL1 risk allele, 47% had immune-complex GN as the predominant lesion and only 23% had FSGS. Among the 25 patients with no APOL1 risk allele, 40% had immune-complex GN and 12% had FSGS. In 310 person-years of observation, 29 patients progressed to ESRD. In adjusted analyses, individuals with two APOL1 risk alleles had a nearly three-fold higher risk for ESRD compared with those with one or zero risk alleles (P=0.03). In summary, these data demonstrate an association between APOL1 variants and renal outcomes in non-HIVAN kidney disease, suggesting a possible use for APOL1 genotyping to help guide the care of HIV-infected patients.

Absence of APOL1 risk variants protects against HIV-associated nephropathy in the Ethiopian population

BACKGROUND

Susceptibility to end-stage kidney disease (ESKD) among HIV-infected Americans of African ancestral heritage has been attributed to APOL1 genetic variation. We determined the frequency of the APOL1 G1 and G2 risk variants together with the prevalence of HIV-associated nephropathy (HIVAN) among individuals of Ethiopian ancestry to determine whether the kidney disease genetic risk is PanAfrican or restricted to West Africa, and can explain the previously reported low risk of HIVAN among Ethiopians.

METHODS

We studied a cohort of 338 HIV-infected individuals of Ethiopian ancestry treated in one Israeli and one Ethiopian center. We sought clinical evidence for HIVAN (serum creatinine >1.4 mg/dl or proteinuria >30 mg/dl in a spot urine sample). Genetic analyses included the genotyping of the APOL1 G1 and G2 variants, and a panel of 33 genomic ancestry-informative markers. Statistical analysis compared clinical and genetic indices for HIV-infected individuals of Ethiopian ancestry and overall Ethiopians to those reported for HIV-infected African-Americans, overall African-Americans, West Africans and non-Africans.

FINDINGS

Three (0.8%) of 338 HIV-infected patients of Ethiopian ancestry showed clinical criteria compatible with renal impairment. Two of these 3 patients also have severe poorly controlled diabetes mellitus. The third nondiabetic patient underwent renal biopsy which ruled out HIVAN. This absence of clinically apparent HIVAN was significantly different from that reported for African-Americans. The APOL1 G1 and G2 risk variants were found, respectively, in 0 and 2 (heterozygote state) of the 338 HIV-infected individuals. Global ancestry and the frequencies of the APOL1 G1 and G2 variants are not statistically different from their frequencies in the general Ethiopian population, but are significantly and dramatically lower than those observed among HIV-infected African-Americans, African-Americans and West Africans.

INTERPRETATION

The coinciding absence of HIVAN and the APOL1 risk variants among HIV-infected individuals of Ethiopian ancestry support a Western rather than Pan-African ancestry risk for ESKD, and can readily explain the lack of HIVAN among individuals of Ethiopian ancestry.

Renal disease in an urban HIV population in the era prior and following the introduction of highly active antiretroviral therapy

Renal disease related to human immunodeficiency virus (HIV) has been a past and present burden on the HIV positive community, both in the United States and worldwide. Previously, focus has been on the impact of HIV-associated nephropathy (HIVAN) on the black population. This paper presents a large renal biopsy series of 108 HIV patients from an urban setting with early renal dysfunction. The purpose of the paper is to highlight clinical characteristics and epidemiological changes in HIV-related renal disease between 2 distinct time periods: pre- and postintroduction of highly active antiretroviral therapy. Our data show a persistence of HIVAN in the black HIV US population and, in addition, an increase in other renal diseases in that population. These findings are discussed in regard to current and future HIV renal disease management.

Genetics of kidney failure and the evolving story of APOL1

Chronic kidney disease (CKD) results from a wide array of processes that impair the kidney's ability to perform its major functions. As many as 20 million Americans suffer from CKD and nearly a half million from end-stage renal disease, but there are also examples of centenarians with adequate renal function. Family-based and genome-wide studies suggest that genetic differences substantially influence an individual's lifetime risk for kidney disease. One emerging theme is that evolution of genes related to host defense against pathogens may limit kidney longevity. The identification of these genetic factors will be critical for expanding our understanding of renal development and function as well as for the design of novel therapeutics for kidney disease.

Prevalence of chronic kidney disease among people living with HIV/AIDS in Burundi: a cross-sectional study

BACKGROUND

Since little is known about chronic kidney disease (CKD) among people living with HIV/AIDS (PLWHA) in Sub-Saharan Africa, the prevalence and nature of CKD were assessed in Burundi through a multicenter cross-sectional study.

METHODS

Patients underwent assessments at baseline and 3 months later. Glomerular Filtration Rate (GFR) was estimated using abbreviated 4-variable Modification of Diet in Renal Diseases (MDRD) and Cockroft-Gault estimation methods. Patients were classified at month 3 into various CKD stages using the National Kidney Foundation (NKF) definition, which combines GFR and urinary abnormalities. Risk factors for presence of proteinuria (PRO) and aseptic leukocyturia (LEU) were further analyzed using multiple logistic regression.

RESULTS

Median age of the patients in the study (N = 300) was 40 years, 70.3% were female and 71.7% were on highly active antiretroviral therapy. Using the MDRD method, CKD prevalence in patients was 45.7%, 30.2% of whom being classified as stage 1 according to the NKF classification, 13.5% as stage 2 and 2% as stage 3. No patient was classified as stage 4 or 5. Among CKD patients with urinary abnormality, PRO accounted for 6.1% and LEU for 18.4%. Significant associations were found between LEU and non-steroidal anti-inflammatory drug (NSAID) use, previous history of tuberculosis, low body mass index and female gender and between PRO and high viral load.

CONCLUSION

Our study, using a very sensitive definition for CKD evaluation, suggests a potentially high prevalence of CKD among PLWHA in Burundi. Patients should be regularly monitored and preventative measures implemented, such as monitoring NSAID use and adjustment of drug dosages according to body weight. Urine dipsticks could be used as a screening tool to detect patients at risk of renal impairment.

The population genetics of chronic kidney disease: insights from the MYH9-APOL1 locus

Many rare kidney disorders exhibit a monogenic, Mendelian pattern of inheritance. Population-based genetic studies have identified many genetic variants associated with an increased risk of developing common kidney diseases. Strongly associated variants have potential clinical uses as predictive markers and may advance our understanding of disease pathogenesis. These principles are elegantly illustrated by a region within chromosome 22q12 that has a strong association with common forms of kidney disease. Researchers had identified DNA sequence variants in this locus that were highly associated with an increased prevalence of common chronic kidney diseases in people of African ancestry. Initial research concentrated on MYH9 as the most likely candidate gene; however, population-based whole-genome analysis enabled two independent research teams to discover more strongly associated mutations in the neighboring APOL1 gene. The powerful evolutionary selection pressure of an infectious pathogen in West Africa favored the spread of APOL1 variants that protect against a lethal form of African sleeping sickness but are highly associated with an increased risk of kidney disease. We describe the data sources, process of discovery, and reasons for initial misidentification of the candidate gene, as well as the lessons that can be learned for future population genetics research.

Missense mutations in the APOL1 gene are highly associated with end stage kidney disease risk previously attributed to the MYH9 gene

MYH9 has been proposed as a major genetic risk locus for a spectrum of nondiabetic end stage kidney disease (ESKD). We use recently released sequences from the 1000 Genomes Project to identify two western African-specific missense mutations (S342G and I384M) in the neighboring APOL1 gene, and demonstrate that these are more strongly associated with ESKD than previously reported MYH9 variants. The APOL1 gene product, apolipoprotein L-1, has been studied for its roles in trypanosomal lysis, autophagic cell death, lipid metabolism, as well as vascular and other biological activities. We also show that the distribution of these newly identified APOL1 risk variants in African populations is consistent with the pattern of African ancestry ESKD risk previously attributed to MYH9.

Mapping by admixture linkage disequilibrium (MALD) localized an interval on chromosome 22, in a region that includes the MYH9 gene, which was shown to contain African ancestry risk variants associated with certain forms of ESKD (Kao et al. 2008; Kopp et al. 2008). MYH9 encodes nonmuscle myosin heavy chain IIa, a major cytoskeletal nanomotor protein expressed in many cell types, including podocyte cells of the renal glomerulus. Moreover, 39 different coding region mutations in MYH9 have been identified in patients with a group of rare syndromes, collectively termed the Giant Platelet Syndromes, with clear autosomal dominant inheritance, and various clinical manifestations, sometimes also including glomerular pathology and chronic kidney disease (Kopp 2010; Sekine et al. 2010). Accordingly, MYH9 was further explored in these studies as the leading candidate gene responsible for the MALD signal. Dense mapping of MYH9 identified individual single nucleotide polymorphisms (SNPs) and sets of such SNPs grouped as haplotypes that were found to be highly associated with a large and important group of ESKD risk phenotypes, which as a consequence were designated as MYH9-associated nephropathies (Bostrom and Freedman 2010). These included HIV-associated nephropathy (HIVAN), primary nonmonogenic forms of focal segmental glomerulosclerosis, and hypertension affiliated chronic kidney disease not attributed to other etiologies (Bostrom and Freedman 2010). The MYH9 SNP and haplotype associations observed with these forms of ESKD yielded the largest odds ratios (OR) reported to date for the association of common variants with common disease risk (Winkler et al. 2010). Two specific MYH9 variants (rs5750250 of S-haplotype and rs11912763 of F-haplotype) were designated as most strongly predictive on the basis of Receiver Operating Characteristic analysis (Nelson et al. 2010). These MYH9 association studies were then also extended to earlier stage and related kidney disease phenotypes and to population groups with varying degrees of recent African ancestry admixture (Behar et al. 2010; Freedman et al. 2009a, b; Nelson et al. 2010), and led to the expectation of finding a functional African ancestry causative variant within MYH9. However, despite intensive efforts including re-sequencing of the MYH9 gene no suggested functional mutation has been identified (Nelson et al. 2010; Winkler et al. 2010). This led us to re-examine the interval surrounding MYH9 and to the detection of novel missense mutations with predicted functional effects in the neighboring APOL1 gene, which are significantly more associated with ESKD than all previously reported SNPs in MYH9.

Worldwide distribution of the MYH9 kidney disease susceptibility alleles and haplotypes: evidence of historical selection in Africa

MYH9 was recently identified as renal susceptibility gene (OR 3-8, p < 10(-8)) for major forms of kidney disease disproportionately affecting individuals of African descent. The risk haplotype (E-1) occurs at much higher frequencies in African Americans (> or = 60%) than in European Americans (< 4%), revealing a genetic basis for a major health disparity. The population distributions of MYH9 risk alleles and the E-1 risk haplotype and the demographic and selective forces acting on the MYH9 region are not well explored. We reconstructed MYH9 haplotypes from 4 tagging single nucleotide polymorphisms (SNPs) spanning introns 12-23 using available data from HapMap Phase II, and by genotyping 938 DNAs from the Human Genome Diversity Panel (HGDP). The E-1 risk haplotype followed a cline, being most frequent within sub-Saharan African populations (range 50-80%), less frequent in populations from the Middle East (9-27%) and Europe (0-9%), and rare or absent in Asia, the Americas, and Oceania. The fixation indexes (F(ST)) for pairwise comparisons between the risk haplotypes for continental populations were calculated for MYH9 haplotypes; F(ST) ranged from 0.27-0.40 for Africa compared to other continental populations, possibly due to selection. Uniquely in Africa, the Yoruba population showed high frequency extended haplotype length around the core risk allele (C) compared to the alternative allele (T) at the same locus (rs4821481, iHs = 2.67), as well as high population differentiation (F(ST(CEU vs. YRI)) = 0.51) in HapMap Phase II data, also observable only in the Yoruba population from HGDP (F(ST) = 0.49), pointing to an instance of recent selection in the genomic region. The population-specific divergence in MYH9 risk allele frequencies among the world's populations may prove important in risk assessment and public health policies to mitigate the burden of kidney disease in vulnerable populations.

African ancestry allelic variation at the MYH9 gene contributes to increased susceptibility to non-diabetic end-stage kidney disease in Hispanic Americans

Recent studies identified MYH9 as a major susceptibility gene for common forms of non-diabetic end-stage kidney disease (ESKD). A set of African ancestry DNA sequence variants comprising the E-1 haplotype, was significantly associated with ESKD. In order to determine whether African ancestry variants are also associated with disease susceptibility in admixed populations with differing genomic backgrounds, we genotyped a total of 1425 African and Hispanic American subjects comprising dialysis patients with diabetic and non-diabetic ESKD and controls, using 42 single nucleotide polymorphisms (SNPs) within the MYH9 gene and 40 genome-wide and 38 chromosome 22 ancestry informative markers. Following ancestry correction, logistic regression demonstrated that three of the E-1 SNPs are also associated with non-diabetic ESKD in the new sample sets of both African and Hispanic Americans, with a stronger association in Hispanic Americans. We also identified MYH9 SNPs that are even more powerfully associated with the disease phenotype than the E-1 SNPs. These newly associated SNPs, could be divided into those comprising a haplotype termed S-1 whose association was significant under a recessive or additive inheritance mode (rs5750248, OR 4.21, P < 0.01, Hispanic Americans, recessive), and those comprising a haplotype termed F-1 whose association was significant under a dominant or additive inheritance mode (rs11912763, OR 4.59, P < 0.01, Hispanic Americans, dominant). These findings strengthen the contention that a sequence variant of MYH9, common in populations with varying degrees of African ancestry admixture, and in strong linkage disequilibrium with the associated SNPs and haplotypes reported herein, strongly predisposes to non-diabetic ESKD.

High prevalence of undiagnosed chronic kidney disease among at-risk population in Kinshasa, the Democratic Republic of Congo

Background

There is limited knowledge of Chronic Kidney Disease (CKD) among high risk populations, especially in the developing countries. We report our study of testing for CKD in at-risk subjects.

Methods

In a cross-sectional study, 527 people from primary and secondary health care areas in the city of Kinshasa were studied from a random sample of at-risk out-patients with hypertension, diabetes, obesity, or HIV+. We measured blood pressure (BP), blood glucose level, proteinuria, body mass index, and estimated glomerular filtration rate (eGFR by MDRD equation) using calibrated creatinine levels based on one random measurement. The associations between health characteristics, indicators of kidney damage (proteinuria) and kidney function (<60 ml/min/1.73 m²) were also examined.

Results

The prevalence of CKD in this study was 36%, but only 12% were aware of their condition. 4% of patients had stage 1 CKD, 6% stage 2, 18% stage 3, 2% stage 4, and 6% had stage 5. 24 hour quantitative proteinuria (>300 mg/day) was found in 19%. In those with the at-risk conditions, the % of CKD was: 44% in patients with hypertension, 39% in those with diabetes; 16% in the obese and 12% in those who were HIV+. 82% of those with a history of diabetes had elevated serum glucose levels at screening (≥ 126 mg/dl). Only 6% of individuals with hypertension having CKD had reduced BP to lower than 130/80 mmHg. In multivariate analysis, diabetes, proteinuria and hypertension were the strongest determinants of CKD 3+.

Conclusion

It appears that one out of three people in this at-risk population has undiagnosed CKD and poorly controlled CKD risk factors. This growing problem poses clear challenges to this developing country. Therefore, CKD should be addressed through the development of multidisciplinary teams and improved communication between traditional health care givers and nephrology services. Attention to CKD risk factors must become a priority.

Immune complex renal disease and human immunodeficiency virus infection

Immune complex glomerulonephritis is a common diagnosis in renal biopsy series of human immunodeficiency virus (HIV)-infected patients. There are a variety of glomerulonephritides associated with HIV infection, including IgA nephropathy, membranoproliferative glomerulonephritis, membranous nephropathy, lupus-like glomerulonephritis, immunotactoid glomerulopathy, and fibrillary glomerulonephritis. In addition, HIV-related proteins may be implicated in circulating immune complexes directly related to a response to the infection. In some cases, the relationship of the HIV infection to the glomerulonephritis is unclear. HIV infection is associated with the development of polyclonal hypergammaglobulinemia, which can promote the development of circulating immune complexes. It is not clear if HIV-associated glomerulonephritis is caused by the passive trapping of these circulating immune complexes or the in situ deposition of antibodies binding to HIV viral antigens. Some renal lesions that are seen in the setting of HIV infection more likely may be related to the presence of a co-infection such as hepatitis C virus infection. The optimal therapy for immune complex glomerulonephritis in the setting of HIV infection is unknown. Because of the underlying immunosuppressed state of many HIV-infected patients, caution with traditional cytotoxic therapies is advised. The role of antiretroviral therapy in modifying the course of these renal lesions is unclear.

Genetic susceptibility, HIV infection, and the kidney

In recent years, the sequencing of mammalian and microbial genomes has provided the opportunity to study how genetic variation in the host and pathogen influence the course of infectious disease. In the case of HIV-1 infection, such studies have led to identification of key viral proteins that determine pathogenicity, immune evasion, or drug resistance. In addition, candidate gene association studies have uncovered a large number of host genetic variants that influence the outcome of infection and some organ-specific complications. HIV-associated nephropathy (HIVAN) is a pathologically distinct complication of HIV infection. Interindividual variability in incidence, skewed ethnic distribution, and familial aggregation of HIVAN with other forms of ESRD have suggested genetic susceptibility as a major contributing factor. This article reviews the host genetic factors that influence the course of HIV-1 infection and discusses murine models that have increased the understanding of HIVAN pathogenesis and demonstrated the role of genetic background on determination of disease.