Renal pathology and HIV infection in Thailand

Patterns of biopsy-proven renal disease in people living with HIV: 10 years experience in Sydney, Australia

Background

Acute and chronic kidney diseases are important comorbidities in People Living With HIV (PLWH). Biopsy is often pursued in this cohort with ongoing renal impairment without a clear aetiology, in order to establish the diagnosis and to guide management. Despite the importance of renal disease in PLWH, there is a paucity of biopsy data—especially in the Australian setting. Consequently, who and when to biopsy is mainly based on clinical experience. The aims of this study were to describe biopsy-proven renal disease in PLWH at our institution and to assess for correlation between any demographic or laboratory characteristics with histological diagnosis.

Methods

A retrospective review of all PLWH who underwent renal biopsy between January 2010 and December 2020 at Royal Prince Alfred Hospital, Sydney, Australia was performed. All PLWH over 18 years, who were not transplant recipients were included. Demographic, laboratory and biopsy data was extracted from the electronic medical records. Basic descriptive statistics were performed, and correlation was assessed using chi square and Kendall’s coefficient of rank test.

Results

19 renal biopsies were included in the study. The majority of PLWH were Australian born (53%), male (84%) and had a mean age of 48 years (SD 13). Comorbid hypertension and diabetes were present in 74% and 21% of people respectively. The mean serum creatinine was 132 µmol/L (SD 55) and the mean estimated glomerular filtration rate (eGFR) was 61 ml/min/1.73m² (SD 24). The most common histological diagnosis was tubulointerstial nephritis in 5 people (24%). Hypertensive glomerulosclerosis and IgA nephropathy were present in 4 (19%) and 3 (14%) people respectively. There were no cases of HIV-associated nephropathy. There was no significant correlation between any cohort characteristics and diagnoses.

Conclusions

This study represents the first description of biopsy-proven kidney disease in the HIV-infected population of Australia. Our results support the use of renal biopsy in PLWH with ongoing renal impairment for accurate diagnosis and to guide further management. Although a small sample size, our study is larger than other published international biopsy studies.

Microalbuminuria and Urinary Neutrophil Gelatinase-associated Lipocalin (uNGAL) in human immunodeficiency virus infected children

Introduction:

Renal dysfunction and progression to end stage renal disease is well known in human immunodeficiency virus (HIV) infection. We studied the role of microalbuminuria and urinary NGAL levels in children with HIV infection for the prediction of renal dysfunction.

Design and Methods:

A cross-sectional study was carried out and 60 HIV infected children, aged (18 months to 15 years) were screened for microalbuminuria by nephelometry and for uNGAL by ELISA. Thirty healthy children were screened for uNGAL for normative data in Indian children.

Results:

The prevalence of microalbuminuria in studied population was 3.3%. The mean uNGAL and uNGAL/creatinine in study population was higher than controls (26.94 ± 93.12 ng/ml vs. 88.94 ± 345.20 mcg/g, and 15.53 ± 37.52 ng/ml vs. 30.12 ± 78.66 ng/ml; P = 0.003, P = 0.002). Children with lower CD4 counts had significant higher mean Albumin Creatinine Ratio (ACR) and mean uNGAL; P = 0.03, P = 0.01.

Conclusions:

uNGAL and urine microalbumin are useful biomarkers of early tubular and glomerular injury in children with HIV infection.

Histopathological Pattern of Kidney Diseases Among HIV-Infected Treatment-Naïve Patients in Kano, Nigeria

Introduction

Kidney biopsy in patients with HIV-associated kidney diseases allows for histopathologic diagnosis and institution of appropriate treatment as well as proper prognostication. There is a paucity of data on the histopathological pattern of HIV-associated kidney diseases in most sub-Saharan African countries. This study was aimed at evaluating the histopathologic patterns of kidney diseases seen among HIV-infected treatment-naive patients in our center as this will allow for proper diagnosis and institution of appropriate treatment.

Methods

In this cross-sectional study, consecutive patients who satisfied inclusion criteria and consented to participate were recruited. Percutaneous kidney biopsies were carried out as day procedures under real-time ultrasound guidance using an automatic spring-loaded biopsy gun as per our unit protocols. Baseline investigations including urea, creatinine, electrolytes, CD4 count, complete blood count, and glomerular filtration rate (eGFR) calculations, urinalysis and urine protein creatinine ratios were done on all the participants.

Results

Fifty-five patients who satisfied the inclusion criteria were studied. The mean age of the study population was 38.34± 9.26 years, with 32% females. Mean serum creatinine was 249.6±164.6 μmol/L, and mean CD4 count was 238 ±210 cells/mL. The commonest histological type was FSGS seen in 20 patients (37.7%), followed by HIVAN seen in 17 (32.1%) patients; chronic interstitial nephritis in 7 patients (13.2%) and 6 (11%) had no significant pathological finding. Compared to non-HIVAN, HIVAN patients tended to have higher systolic BP (p= 0.05); higher serum creatinine levels (p= 0.05); lower eGFR (0.03) and higher urine protein to creatinine ratio [uPCR; p= 0.02].

Conclusion

Kidney involvement is still a form of presentation among HIV-infected treatment-naïve patients and though a wide range of glomerular and tubulointerstitial lesions may be seen, FSGS and HIVAN are still the most common. We recommend assessment of kidney function, including urinalysis, as part of the routine evaluation of newly diagnosed HIV patients and biopsy where indicated to prognosticate and institute appropriate early treatment.

Membranous nephropathy in patients with HIV: a report of 11 cases

Background

Membranous nephropathy (MN) has been recognized to occur in patients with human immunodeficiency virus (HIV) infection since the beginning of the HIV epidemic. The prevalence of phospholipase A2 receptor (PLA2R)-associated MN in this group has not been well studied.

Methods

We conducted a retrospective review of electronic pathology databases at three institutions to identify patients with MN and known HIV at the time of renal biopsy. Patients with comorbidities and coinfections known to be independently associated with MN were excluded.

Results

We identified 11 HIV-positive patients with biopsy-confirmed MN meeting inclusion and exclusion criteria. Patient ages ranged from 39 to 66 years old, and 10 of 11 patients (91%) were male. The majority of patients presented with nephrotic-range proteinuria, were on anti-retroviral therapy at the time of biopsy and had low or undetectable HIV viral loads. Biopsies from 5 of 10 (50%) patients demonstrated capillary wall staining for PLA2R. Measurement of serum anti-PLA2R antibodies was performed in three patients, one of whom had positive anti-PLA2R antibody titers. Follow-up data was available on 10 of 11 patients (median length of follow-up: 44 months; range: 4–145 months). All patients were maintained on anti-retroviral therapy (ARV) and 5 patients (52%) received concomitant immunosuppressive regimens. Three patients developed end-stage renal disease (ESRD) during the follow-up period.

Conclusions

MN in the setting of HIV is often identified in the setting of an undetectable viral loads, and similar to other chronic viral infection-associated MNs, ~ 50% of cases demonstrate tissue reactivity with PLA2R antigen, which may be seen without corresponding anti-PLA2R serum antibodies.

Histological spectrum of renal disease in HIV/AIDS patients with significant proteinuria: An Indian perspective

Background:

Chronic kidney disease (CKD) has become epidemic in HIV/AIDS patients across Western and Eastern countries. HIV-associated nephropathy (HIVAN) has been consistently reported in studies from North America, Europe and African countries. However, studies from Asian countries are very sparse and differ strikingly in histological spectrum of renal disease, particularly in presence of HIVAN.

Objectives:

The study was carried out to in a teaching hospital from India to delineate the histological spectrum of renal disease and detect presence HIVAN in those with significant proteinuria (≥1gm/day).

Patients and Methods:

Urine analysis was done in 510 consecutive hospitalised HIV/AIDS patients after screening 640 such patients with age >18years. Patients with dipstick proteinuria ≥1+ were subjected to 24-hour urinary protein estimation. Renal biopsy was done in 10 patients with proteinuria ≥1gm/day.

Results:

Dipstick proteinuria ≥1+ was present in 29% patients. In patients undergoing kidney biopsy, the most frequent glomerular lesion was mesangial proliferative glomerulonephritis (30%) followed by HIVAN (20%). Tubulo-interstitial lesions were seen in 60% of biopsies. Pooled analysis of all the available kidney biopsy series from India revealed prevalence of HIVAN to be 16.5%.

Conclusion:

Contrary to the popular belief, HIVAN appears to be a common entity in this part of world too. High degree of clinical suspicion is required as diagnosis of HIVAN caries higher morbidity and mortality. Moreover, an early diagnosis and timely management can improve prognosis in such patients.

The renal pathological findings in Japanese HIV-infected individuals with CKD: a clinical case series from a single center

BACKGROUND

Chronic kidney diseases (CKD) have emerged as a significant cause of morbidity and mortality in patients infected with human immunodeficiency virus (HIV). However, the detailed study of renal pathological findings currently remains unclear in these Japanese patients.

METHODS

A retrospective cohort study was undertaken to investigate renal pathological findings between January 1996 and July 2016. Our study included 20 Japanese HIV-infected patients with CKD; 10 cases had undergone renal biopsies, and 10 cases had undergone autopsies, respectively. Moreover, in the 10 biopsied patients, their clinical courses as well as renal outcomes after renal biopsy were also reviewed.

RESULTS

All of the patients had received combination antiretroviral therapy (cART). The 10 biopsy cases (mean age, 54 ± 14 years and duration of cART, 8 ± 5 years) included three cases of diabetic nephropathy (DMN), two of IgA nephropathy, two of cART-induced tubulointerstitial nephritis (TIN), one of minimal change disease, one case of only finding intrarenal arterioles, and one case without abnormal findings. Among those patients, their clinical courses were preferable except for in the DMN cases. In the autopsy cases (mean age, 52 ± 10 years and duration of cART, 5 ± 5 years), no distinct mesangial or membranous abnormalities were detected. Mild to moderate tubulointerstitial atrophies were observed in six cases. Intrarenal arteriosclerosis was identified in nine cases, and the proportion of global glomerulosclerosis seen was 8.4 ± 12.5%/100 glomeruli.

CONCLUSION

DMN and cART-induced TIN was noted in the biopsy cases. In the autopsy cases, renal arteriosclerosis, global glomerulosclerosis, and tubulointerstitial atrophy were remarkable. Early diagnosis of kidney diseases should be crucial to introduce optimal management, including controlling rigorous comorbidities and appropriate use of cART, to prevent further progression of CKD.

Chronic kidney disease incidence and survival of Thai HIV-infected patients

OBJECTIVES

As data on chronic kidney disease (CKD) incidence among Asian HIV patients has been limited, the present study aimed to estimate the CKD incidence in HIV-infected patients who received standard antiretroviral therapy in Thailand and to compare baseline demographics and clinical characteristics of the patients who developed CKD with those who do not.

DESIGN

A multicenter, observational prospective cohort of HIV patients with normal kidney functions who received standard antiretroviral therapy.

METHODS

CKD was diagnosed based on the KDIGO 2012 criteria, using Chronic Kidney Disease Epidemiology Collaboration based estimated glomerular filtration rate with and without urine protein. The cumulative probability of CKD incidence was analyzed using Kaplan-Meier estimation.

RESULTS

Of 5552 patients, 96 patients with pre-existing CKD and 26 patients with incomplete data were excluded, and 5430 patients were analyzed. Their mean age was 39.87 years, 41.52% were women, and 49.45% were homosexual. They were followed up for 49.41 months on average, with 229 incident cases (4.22%) being identified during 22 035 person-years at risk. Overall CKD incidence rate was 10.39 per 1000 person-years. Average time to CKD was 26.4 months (95% confidence interval: 24.44-28.83). The adjusted relative hazard significantly increased by 8.6% and 10.3% for each additional year of patient age and each additional log10 copies/ml of HIV viral load, respectively. Patients with diabetes mellitus and hypercholesterolemia had significantly higher adjusted relative hazard (3.37 and 1.41; P < 0.001 and P = 0.014), respectively.

CONCLUSION

CKD incidence among the Thai HIV-infected patients was lower than in white and non-Southeast Asian populations. Diabetes, hypercholesterolemia, age, and HIV viral load were the significant risk factors.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01328275.

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.

Pathogenesis of Focal Segmental Glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) is characterized by focal and segmental obliteration of glomerular capillary tufts with increased matrix. FSGS is classified as collapsing, tip, cellular, perihilar and not otherwise specified variants according to the location and character of the sclerotic lesion. Primary or idiopathic FSGS is considered to be related to podocyte injury, and the pathogenesis of podocyte injury has been actively investigated. Several circulating factors affecting podocyte permeability barrier have been proposed, but not proven to cause FSGS. FSGS may also be caused by genetic alterations. These genes are mainly those regulating slit diaphragm structure, actin cytoskeleton of podocytes, and foot process structure. The mode of inheritance and age of onset are different according to the gene involved. Recently, the role of parietal epithelial cells (PECs) has been highlighted. Podocytes and PECs have common mesenchymal progenitors, therefore, PECs could be a source of podocyte repopulation after podocyte injury. Activated PECs migrate along adhesion to the glomerular tuft and may also contribute to the progression of sclerosis. Markers of activated PECs, including CD44, could be used to distinguish FSGS from minimal change disease. The pathogenesis of FSGS is very complex; however, understanding basic mechanisms of podocyte injury is important not only for basic research, but also for daily diagnostic pathology practice.

CKD and Infectious Diseases in Asia Pacific: Challenges and Opportunities

The exact number of patients with chronic kidney disease (CKD) in Asia Pacific is uncertain. In numeric terms, the region is home to the largest population of patients with untreated chronic kidney failure. The climatic, geographic, social, cultural, economic, and environmental diversity within this region is higher than in any other part of the world. Large parts of the region face a climate-related burden of infectious diseases. Infections contribute to the development and progression of CKD and complicate the course of patients with pre-existing CKD (especially those on dialysis therapy or who are immunosuppressed), increase the cost of CKD care, and contribute to mortality and morbidity. Kidney involvement is a feature of several infectious diseases prevalent in Asia Pacific. Examples include malaria, leptospirosis, scrub typhus, tuberculosis, hepatitis B and C virus, dengue hemorrhagic fever, and Hantaan virus infections. The contribution of infection-associated acute kidney injury to the overall burden of CKD has not been evaluated systematically. Research is needed to quantify the impact of infections on kidney health by undertaking prospective studies. Nephrologists need to work with infectious disease research groups and government infection surveillance and control programs.

HIV-associated immune complex kidney disease

The introduction in the late 20(th) century of combination antiretroviral therapy (cART) to treat patients infected with HIV has changed the natural history of the disease from an acute illness that rapidly culminates in death, to a chronic condition that can be managed with medications. Over the past decade the epidemiology of kidney disease in US patients infected with HIV has changed, perhaps because of the increased availability and use of cART. Patients with HIV infection exhibit unique immunologic characteristics, including immunodeficiency and dysregulation of immunoglobulin synthetic responses and T-cell function, which can result in glomerular immune complex deposition and subsequent kidney injury. This Review examines the differential diagnoses of HIV-associated immune complex kidney diseases (HIVICD), and discusses the clinical manifestations and mechanisms underlying their development. We address the issues associated with treatment, clinical outcomes, and research needs to enhance our ability to diagnose and optimally treat patients with HIVICD.

HIV-associated nephropathies: epidemiology, pathology, mechanisms and treatment

HIV is a highly adaptive, rapidly evolving virus, which is associated with renal diseases including collapsing glomerulopathy-the classic histomorphological form of HIV-associated nephropathy. Other nephropathies related to viral factors include HIV-immune-complex kidney disease and thrombotic microangiopathy. The distribution of HIV-associated kidney diseases has changed over time and continues to vary across geographic regions worldwide. The reasons for this diversity are complex and include a critical role of APOL1 variants and possibly other genetic factors, disparities in access to effective antiviral therapies, and likely other factors that we do not yet fully understand. The mechanisms responsible for HIVAN, including HIV infection of podocytes and tubular epithelial cells, the molecules responsible for HIV entry, and diverse mechanisms of cell injury, have been the focus of much study. Although combined antiretroviral therapy is effective at preventing and reversing HIVAN, focal segmental glomerulosclerosis, arterionephrosclerosis and diabetic nephropathy are increasingly common in individuals who have received such therapy for many years. These diseases are associated with metabolic syndrome, obesity and premature ageing. Future directions for HIV-related kidney disease will involve regular screening for drug nephrotoxicity and incipient renal disease, as well as further research into the mechanisms by which chronic inflammation can lead to glomerular disease.

[HIV-associated nephropathy with amoebic enteritis: a case report and literature review]

We herein describe a case of HIV-associated nephropathy (HIVAN) in a 64-year-old HIV antibody-positive man presenting with proteinuria. Laboratory examinations showed positive proteinuria, a high β2-microglobulin level and decreased creatinine clearance. He underwent a percutaneous renal biopsy, and a pathologic evaluation revealed a collapsing form of focal sclerosing glomerulosclerosis. Histologically, HIVAN is a collapsing form of focal sclerosing glomerulosclerosis (FSGS), which can be distinguished from idiopathic FSGS by the presence of microcystic tubular dilatation and interstitial inflammation. The patient was diagnosed with HIV-associated nephropathy and was started on ART. The HIV-associated nephropathy did not progress to acute renal failure, and long-term survival has been observed for over 12 years.

Recurrent HIV-associated immune complex glomerulonephritis with lupus-like features after kidney transplantation

A spectrum of kidney diseases besides classic human immunodeficiency virus (HIV)-associated nephropathy (HIVAN) exists in HIV-infected patients. Immune complex-mediated glomerulonephritis has emerged as a significant contributor to the burden of kidney disease in this population, particularly in patients of non-African descent. Lupus-like nephritis, a form of immune complex glomerulonephritis with histologic features identical to lupus nephritis in the absence of clinical or serologic markers of lupus, is well recognized as a cause of end-stage renal disease in HIV-infected patients. None of the HIV-associated kidney lesions, whether classic HIVAN or non-HIVAN, has been reported to recur in kidney transplants. We report here for the first time clinical and histologic recurrence of HIV-associated lupus-like nephritis after successful kidney transplantation, causing proteinuria, hematuria, and impaired kidney transplant function.

Collapsing glomerulopathy in an HIV-positive patient in a low-incidence belt

Human immunodeficiency virus (HIV) involves glomerular, tubulointerstitial, and vascular compartments of the kidney. The most common glomerular lesion is HIV-associated focal segmental glomerulosclerosis (FSGS) and related mesangiopathies collectively termed HIV-associated nephropathy (HIVAN). A variety of immune-complex mediated glomerular diseases such as membranoproliferative glomerulonephritis (MPGN), IgA nephropathy, and lupus-like glomerulonephritis also occur. HIVAN is restricted to patients presenting with proteinuria and progressive reduction of renal function and with distinctive but not pathognomonic pathology (FSGS often coexisting with glomerular collapse and tubular microcystic dilatations). The worldwide incidence of collapsing glomerulopathy (CG) in HIV-positive patients is high in Americans. But in India and other Asian countries, other forms of kidney diseases are more commonly seen. We report the first case of CG in the state of Jammu and Kashmir which also happens to be a very low incidence belt for HIV.

Characteristics of patients with HIV and biopsy-proven acute interstitial nephritis

BACKGROUND AND OBJECTIVES

The objective of this study was to describe the characteristics of patients with HIV infection and biopsy-proven acute interstitial nephritis (AIN).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Pathology reports were reviewed for patients who had HIV infection and underwent renal biopsy at Johns Hopkins Hospital from January 1, 1995, through January 1, 2008. Patients who received a diagnosis of AIN without evidence of HIV-associated nephropathy were identified, and their clinical course was reviewed up to 18 months after biopsy.

RESULTS

Of 262 biopsies, 29 (11%) patients who had AIN without evidence of HIV-associated nephropathy were identified. The mean age at the time of biopsy was 47.5 years (range 28 to 71 years), 17 (59%) were men, and 23 (79%) were black. The majority (62%) of patients were on antiretroviral therapy, 59% were current or former intravenous drug users, and 62% had hepatitis C co-infection. Drugs were identified as the cause of AIN in the majority (72%) of cases. Nonsteroidal anti-inflammatory drugs were most commonly implicated, followed by sulfamethoxazole/trimethoprim. Antiretroviral therapy was identified as the cause in only three cases. None of the patients presented with the classic triad of fever, rash, and pyuria, and only seven (24%) patients presented with <1 g/d proteinuria.

CONCLUSIONS

In our series, AIN was prevalent (11%) and was often drug induced. AIN should not be excluded from the differential diagnosis on the basis of absence of the classic clinical triad of fever, rash, and pyuria.

Is there a genetic basis for health disparities in human immunodeficiency virus disease?

The highest global prevalence rates for human immunodeficiency virus and acquired immune deficiency syndrome have been recorded in southern Africa; in the United States, individuals of African descent are disproportionately affected by human immunodeficiency virus infection. Human immunodeficiency virus-infected individuals with African ancestry are also estimated to have a 17-fold or greater risk for developing human immunodeficiency virus-associated nephropathy in comparison with their counterparts of non-African descent. Several recent studies have implicated genetic alleles that are more frequent in populations of African descent and increase the risk of human immunodeficiency virus infection and the risk of human immunodeficiency virus-associated neuropathy (HIVAN). The supposition that persons of African descent are more susceptible to human immunodeficiency virus infection because of an underlying genetic predisposition is not supported by available evidence. However, strong, replicated data show that the increased risk for human immunodeficiency virus-associated nephropathy, as well as other major forms of kidney disease in individuals of African descent, is due in part to MYH9 (myosin, heavy chain 9, non-muscle) renal disease susceptibility alleles that are very frequent throughout sub-Saharan Africa but are infrequent or absent in non-Africans. Selection, drift, and demographic events shape the allelic architecture of the human genome: it is expected that these events will be reflected in geographic-specific differentiation in allele frequencies for a small subset of alleles that may be associated with either increased or reduced risk for complex and infectious diseases.

CKD in HIV-infected patients other than HIV-associated nephropathy

A spectrum of kidney diseases in HIV-infected patients has been reported both before and after the introduction of highly active antiretroviral therapy (HAART). Kidney syndromes affecting HIV-infected patients include CKD as well as proteinuria, nephrotic syndrome, and acute nephritic syndrome. Thrombotic microangiopathy should be considered in patients with kidney disease and typical clinical characteristics. As the HIV-infected population ages, there is increased concern regarding the incidence of vascular and metabolic disease, leading to an increased burden of CKD. Although HIV-associated nephropathy is still the major cause of nephrotic syndrome in HIV-infected patients, immune complex glomerulonephritis (ICGN) still comprises a substantial proportion of the disease burden, especially in people of European origin. Genetic investigations into the underpinnings of the various histologic expressions of HIV-associated kidney disease hold great promise. The single most important diagnostic test to differentiate various forms of kidney disease in HIV-infected patients is a kidney biopsy. The results of treating kidney disease in HIV-infected patients remain unclear, and properly designed randomized controlled trials of the treatment of ICGN with HAART and other approaches are desperately needed.

Ignoring the obvious missing piece of chronic kidney disease in HIV: cigarette smoking

The impact of tobacco use on the development of chronic kidney disease (CKD) in people living with HIV (PLWH) has been overlooked, despite remarkably higher rates of smoking in these individuals. The authors examined the association between smoking and the risk of CKD in a case-controlled study that included 75 PLWH with CKD and 461 PLWH consecutively admitted to the hospital for other causes. Significant differences in gender, race/ethnicity, hypertension, hepatitis B, CD4 cell counts, and smoking between cases and controls were reported, suggesting that these variables may be risk factors for CKD. In logistic regression analyses, smoking (OR=1.97, p=.003), hypertension (OR=2), and African ancestry, particularly for Black Caribbeans (OR=2.6), were independent factors associated with CKD. Moreover, the results pointed to a dose-response relationship between packs smoked per day and CKD. Smoking was reported to contribute a significant risk for CKD in these subjects.

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.

HIV-1 infection and the kidney: an evolving challenge in HIV medicine

With the advent of highly active antiretroviral therapy (HAART), the incidence of opportunistic infections has declined substantially, and cardiovascular, liver, and renal diseases have emerged as major causes of morbidity and mortality in individuals with human immunodeficiency virus (HIV). Acute renal failure is common in HIV-infected patients and is associated with acute infection and medication-related nephrotoxicity. HIV-associated nephropathy is the most common cause of chronic kidney disease in HIV-positive African American populations and may respond to HAART. Other important HIV-associated renal diseases include HIV immune complex kidney diseases and thrombotic microangiopathy. The increasing importance of non-HIV-associated diseases, such as diabetes mellitus, hypertension, and vascular disease, to the burden of chronic kidney disease has been recognized, focusing attention on prevention and control of these diseases in HIV-positive individuals. HIV-positive individuals who experience progression to end-stage renal disease and who have undetectable HIV-1 viral loads while receiving HAART should be evaluated for renal transplant. Emerging evidence suggests that HIV-positive individuals may have graft and patient survival comparable to HIV-negative individuals. Several studies suggest that HIV-1 can potentially infect renal cells, and HIV transgenic mice have clarified the roles of a number of HIV proteins in the pathogenesis of HIV-associated renal disease. Host factors may modify disease expression at the level of cytokine networks and the renal microvasculature and contribute to the pathogenic effects of HIV-1 infection on the kidney.

A cross-sectional study of HIV-seropositive patients with varying degrees of proteinuria in South Africa

Human immunodeficiency virus (HIV)-associated nephropathy (HIVAN) is the most common finding on renal biopsy in HIV-infected black patients and is also the commonest cause of end-stage renal disease in these patients. Early detection of HIVAN may be beneficial in evaluating early treatment. This study examined the pattern of renal diseases in HIV-infected South Africans and also attempted to diagnose HIVAN at an early stage. In this single-center cross-sectional study, 615 HIV-infected patients were screened for proteinuria. Thirty patients with varying degrees of proteinuria underwent renal biopsy. Patients with diabetes mellitus, uncontrolled hypertension, known causes of chronic kidney disease, and serum creatinine above 250 mumol/l were excluded. Patients in this study were not on antiretroviral therapy. HIVAN was found in 25 (83%) patients. Six of them (24%) had microalbuminuria. Altogether, seven patients with persistent microalbuminuria were biopsied and six (86%) showed HIVAN. Other biopsy findings included membranoproliferative nephropathy in two (7%) and interstitial nephritis in three (10%). Four patients with HIVAN had associated membranous nephropathy. HIVAN is the commonest biopsy finding among our study patients with HIV infection who present with varying degrees of proteinuria. Microalbuminuria is a manifestation of HIVAN in our study patients. Therefore, microalbuminuria may be an early marker of HIVAN, and screening for its presence may be beneficial. Renal biopsy may be considered in seropositive patients who present with persistent microalbuminuria, especially with low CD4 counts irrespective of good renal function. This will allow diagnosis and treatment of HIVAN at an early stage and may prevent further disease progression.

Absence of HIV-associated nephropathy in Ethiopians

BACKGROUND

Population-based epidemiological surveys in several countries have shown approximately 10- to 15-fold increased susceptibility to human immunodeficiency virus (HIV)-associated nephropathy (HIVAN) for populations of recent African ancestry. Accordingly, we sought to determine whether a similar or different pattern of susceptibility was evident among Ethiopians followed up in an HIV clinic in Israel.

METHODS

One hundred seventy-six consecutive patients (126 Ethiopians, 50 non-Ethiopian Israelis) followed up at the HIV clinic of Rambam Medical Center in northern Israel were examined for the presence of proteinuria and/or decreased glomerular filtration rate. HIV viral load, CD4 count, and treatment modality also were determined.

RESULTS

Overall, 73% of patients were treated with highly active antiretroviral therapy, and there was no difference between Ethiopians and non-Ethiopian Israelis in this regard. Mean CD4 count in Ethiopians was 288 +/- 140/microL, significantly less than the corresponding CD4 count of 398 +/- 190/microL for non-Ethiopian Israelis. Mean viral loads were greater in Ethiopians compared with non-Ethiopian Israelis. None of 176 HIV-infected patients fulfilled clinical criteria for HIVAN as delineated in this study.

CONCLUSION

HIV-infected individuals of Ethiopian descent have a level of susceptibility to HIVAN similar to that of non-Ethiopian Israelis, which is strikingly less than that reported for other populations for recent African ancestry. This does not appear to be attributable to differences in HIV infection control or viral subtype and most likely represents population-based differences in host genetic factors. This finding emphasizes the importance of avoiding generalizations with respect to phylogeographic ancestry in disease-susceptibility studies.

Human Immunodeficiency Virus-associated Nephropathy

Human immunodeficiency virus-associated nephropathy (HIVAN) is characterized by high-grade proteinuria and rapid progression to end-stage renal disease (ESRD). Despite the large numbers of HIV-infected cases in Asian countries, data on HIVAN in this area are limited. We report a 54-year-old Taiwanese man with HIVAN who presented with cytomegalovirus retinitis, renal insufficiency (serum creatinine, 3.8 mg/dL) and nephrotic range proteinuria with a daily protein loss of 10.8 g. Despite highly active antiretroviral therapy (HAART) for 31 months, renal failure developed requiring maintenance hemodialysis. Renal biopsy showed collapsing focal segmental glomerular sclerosis, podocyte proliferation and tubulointerstitial nephritis with mononuclear cell infiltration. These features were compatible with HIVAN. Although hemodialysis was instituted, he died 2 months later due to nosocomial pneumonia complicated with multiple organ failure. In summary, this case of HIVAN in a Taiwanese patient shows that the condition may progress to ESRD despite successful viral suppression with HAART.

HIV-associated immune complex glomerulonephritis with "lupus-like" features: a clinicopathologic study of 14 cases

BACKGROUND

While the most common glomerular lesion associated with human immunodeficiency virus (HIV) infection is collapsing focal segmental glomerulosclerosis (FSGS) [HIV-associated nephropathy (HIVAN)], immune complex-mediated forms of glomerulonephritis have been increasingly reported. One form of glomerulonephritis that has been described in the HIV-infected population is immune complex glomerulonephritis with "lupus-like" features, characterized by histologic, immunohistologic, and ultrastructural features resembling lupus nephritis, but occurring in patients without evidence of systemic lupus erythematosus (SLE). Data regarding clinical outcomes in patients with this form of glomerulonephritis are very limited.

METHODS

We reviewed pathology reports for all native renal biopsy specimens from HIV-positive patients processed at our center from January 1999 through December 2003. Of 77 total specimens, 14 met the following criteria for lupus-like glomerulonephritis: (1) immunofluorescence microscopy showed granular glomerular staining for IgG, IgA, IgM, C3 and C1q, with > or=1+ (0 to 4+ scale) staining for C1q; and (2) the patient's serum was negative for antinuclear antibodies (ANA), or weakly positive (titer < or =1:80) for ANA and negative for antidouble-stranded DNA.

RESULTS

Clinically, ten of the 14 patients with lupus-like glomerulonephritis presented with nephrotic syndrome, all had microscopic hematuria, and nine had serum creatinine >3.0 mg/dL. All but one were African American. Histologically, seven biopsies showed diffuse proliferative glomerulonephritis, six focal proliferative glomerulonephritis, and one membranous nephropathy. All but two biopsies showed moderate or severe chronic change, and three showed concurrent HIVAN. Ten of the 14 patients developed end-stage renal disease (ESRD) within 1 year of the biopsy. Nine of these ten patients presented with proteinuria >5.0 g/24 hours and nephrotic syndrome, while three of four patients who did not develop ESRD had proteinuria < or =3.0 g/24 hours.

CONCLUSION

Lupus-like glomerulonephritis, defined by immunohistologic features and absence of serologic evidence of SLE, is not an uncommon form of glomerular disease in HIV-infected patients undergoing a renal biopsy. Renal outcomes in these patients were poor, although this may be due largely to most patients presenting with advanced disease.

Mapping a locus for susceptibility to HIV-1-associated nephropathy to mouse chromosome 3

HIV-1-associated nephropathy (HIVAN) is a major complication of HIV-1 infection with distinct pathologic features. Introduction of the HIV-1 genome into mice results in a renal disease with all of the histologic and clinical hallmarks of HIVAN on the FVB/N genetic background (TgFVB). We assessed the influence of genetic background on the development or progression of HIVAN by making F1 hybrids of TgFVB with five other inbred strains (CBA, DBA/2, CAST/Ei, C3H/He, BALB/c) and determining phenotypes relevant to renal failure among transgenic offspring (histology, blood urea nitrogen, proteinuria, serum albumin, and serum cholesterol). We found striking variation in phenotypes among F1s, ranging from severe renal disease to no renal disease whatsoever (P<0.001 for ANOVA across all groups). To map genes responsible for this variation, we produced a backcross of TgFVB/CAST F1 x TgFVB. By genome-wide analysis of linkage in 185 heterozygous transgenic backcross mice, we identified a locus on chromosome 3A1-3, HIVAN1, that showed highly significant linkage to renal disease [logarithm of odds (lod) score 4.9 at D3Mit203, accounting for 15% of the variance in renal disease]. Other loci on chromosomes 11, 14, and 16 were suggestive of linkage to renal disease, and a locus on chromosome 9 influenced serum cholesterol but not nephropathy. Interestingly, HIVAN1 is syntenic to human chromosome 3q25-27, an interval showing suggestive evidence of linkage to various nephropathies. These findings demonstrate a strong genetic influence on HIVAN and demonstrate a major renal disease susceptibility locus on mouse chromosome 3A1-3.

The HIV-associated renal diseases: current insight into pathogenesis and treatment

Since the description of a new renal syndrome in patients with the acquired immunodeficiency syndrome (AIDS) in the middle 1980s, much has been learned regarding the association of human immunodeficiency virus (HIV) infection and renal disease. The HIV-associated renal diseases represent a spectrum of clinical and histopathologic conditions. In this review, epidemiologic and clinical aspects of HIV-associated renal diseases are presented. Particular attention is placed on the pathologic and pathophysiologic mechanisms involved in HIV-associated focal glomerulosclerosis, immune complex-mediated disease, and thrombotic microangiopathies. Pharmaceutical treatment options, including the use of glucocorticoids, angiotensin-converting enzyme (ACE) inhibitors, and highly active antiretroviral therapy, are discussed. The therapeutic option of renal transplantation is presented, with insight into new clinical and basic research supporting a possible role of immunosuppressive therapy in this already immunocompromised patient population.

HIV-associated nephropathy in African Americans

Human immunodeficiency virus-1 (HIV-1) infection is associated with several glomerular syndromes, the most prevalent of which is HIV-associated focal segmental glomerulosclerosis (FSGS). At present, HIV-associated FSGS may account for up to 30% of patients in the United States entering end-stage renal disease (ESRD) as a consequence of FSGS. The mechanisms responsible for HIV-associated FSGS are not well defined, but evidence has been presented in favor of direct infection of renal parenchymal cells and toxicity of HIV-1 accessory proteins. HIV-associated FSGS has a striking predilection for patients of African descent. This likely has a genetic basis, although the gene or genes responsible have not yet been identified. One approach is to examine candidate genes for polymorphisms that are associated with disease. Another approach uses a genome-wide scan, relying upon linkage disequilibrium between DNA markers and the disease gene, to identify the causal gene or genes. African Americans are an admixed population, with genetic contributions from African, European, and Native American populations. In admixed populations, linkage disequilibrium between disease genes and marker genes can be exploited to identify disease genes, using an approach termed mapping by admixture linkage disequilibrium (MALD).

Glomerular disease in the tropics

Glomerular disease in the tropics differs considerably from that in temperate climates and between the developed and the developing world. The prevalence and pattern of glomerular disease in the tropics in turn varies widely in different geographic regions and is influenced by environmental, nutritional, and socioeconomic factors. Among the infective agents that have been identified as contributing to an increased prevalence of glomerular disease in the tropics are Plasmodium malaria, Schistsomiasis mansoni, Mycobacterium leprosy, and hepatitis B virus (HBV). A decline in the prevalence can only be expected with the eradication of infections. Accurate knowledge of the prevalence, histologic features, and causes is essential to achieve prevention and management of glomerular diseases in the tropics.

Renal Dysfunction in HIV-1-infected Patients

Improved therapy directed against opportunistic infection and HIV-1 itself has resulted in greatly enhanced patient survival in the past decade among patients infected with HIV-1. Since patients are living longer, HIV-1 infection is associated with a rising burden of kidney disease. Approximately 14% of black patients and 6% of white patients dying with HIV-1 infection in 1999 in the United States had renal disease. Overall, 10% of patients dying with HIV-1 infection had renal failure. The most common glomerular diseases are focal segmental glomerulosclerosis and immune complex glomerulonephritis. Appropriate therapy for focal segmental glomerulosclerosis includes effective antiretroviral therapy and angiotensin antagonist medication. Drug toxicity is also common, often manifesting as electrolyte abnormalities, acute renal failure, interstitial nephritis, or nephrolithiasis. In particular, indinavir is associated with crystalluria, nephrolithiasis, interstitial nephritis, and lower urinary tract inflammation. Appropriate screening for renal disease and appropriate intervention will likely reduce the morbidity and mortality associated with progressive renal disease.

HIV associated nephropathy: a treatable condition

OBJECTIVES

To describe current knowledge on the aetiology, pathology, diagnosis, and treatment of HIV associated nephropathy.

METHODS

A Medline search was performed using the key words "HIV," "nephropathy," "renal," and "kidney." A further search was performed for each of the currently licensed antiretroviral agents linked to key words "renal" or "kidney" and also using the MeSH heading "pharmacokinetics."

RESULTS

HIV associated nephropathy is a common complication of HIV in black African and Afro-Caribbean patients and presents with progressive renal failure and heavy proteinuria. As other causes of renal failure are likely to fall in incidence among patients successfully treated with highly active antiretroviral therapy (HAART), HIV associated nephropathy will become increasingly prominent as a cause of renal impairment in HIV infected patients. Recent evidence suggests that HIV associated nephropathy will respond to HAART with a dramatic improvement in renal function.

CONCLUSION

HIV associated nephropathy is a treatable condition. This condition should be actively sought in HIV infected patients if they are to receive the benefits of therapy.

Infection of mesangial cells with HIV and SIV: identification of GPR1 as a coreceptor

BACKGROUND

Mesangial cells are an important component of the glomerulus. Dysfunction of mesangial cells is thought to be involved in the development of human immunodeficiency virus type 1 (HIV-1)-associated nephropathy (HIVAN). HIVAN is a structural renal failure frequently observed in patients with acquired immune deficiency syndrome. However, the susceptibility of mesangial cells to HIV-1 is disputable. More than ten G protein-coupled receptors, including chemokine receptors, have been shown to act as HIV-1 coreceptors that determine the susceptibilities of cells to HIV-1 strains with specific cell tropisms.

METHODS

We examined the susceptibility of mesangial cells to various HIV-1, HIV type 2 (HIV-2) and simian immunodeficiency virus (SIV) strains. Expression of CD4 and HIV/SIV coreceptors was examined by Western blotting and polymerase chain reaction.

RESULTS

Mesangial cells were found to be susceptible to HIV-1 variant and mutants that infect brain-derived cells, but highly resistant to T-tropic (X4), M-tropic (R5) or dual-tropic (X4R5) HIV-1 strains. In addition, mesangial cells were also susceptible to HIV-2 and SIV strains that infect the brain-derived cells. Among HIV/SIV coreceptors we tested, the expression of GPR1 mRNA was detected in mesangial cells. Expression of CD4 mRNA and protein was also detected in them. Mesangial cells and GPR1-transduced CD4-positive cells showed similar susceptibilities to the HIV-1 variant and mutants and HIV-2 and SIV strains.

CONCLUSIONS

CD4 and GPR1 mRNAs were detected in mesangial cells. Mesangial cells were susceptible to HIV/SIV strains that use GPR1 as a coreceptor. Our findings suggest that an orphan G protein-coupled receptor, GPR1, is a coreceptor expressed in mesangial cells. It remains to be investigated whether the interaction of mesangial cells with specific HIV-1 strains through GPR1 plays a role in the development of HIVAN.