HIV-associated nephropathy: Epidemiology, pathogenesis, and treatment

Belatacept-based immunosuppressive regimen in HIV-positive kidney transplant recipients

Background

Kidney allograft survival in human immunodeficiency virus (HIV)-positive patients is lower than that in the general population. Belatacept increases long-term patient and allograft survival rates when compared with calcineurin inhibitors (CNIs). Its use in HIV-positive recipients remains poorly documented.

Methods

We retrospectively report a French cohort of HIV-positive kidney allograft recipients who were switched from CNI to belatacept, between June 2012 and December 2018. Patient and allograft survival rates, HIV immunovirological and clinical outcomes, acute rejection, opportunistic infections (OIs) and HLA donor-specific antibodies (DSAs) were analysed at 3 and 12 months, and at the end of follow-up (last clinical visit attended after transplantation). Results were compared with HIV-positive recipients group treated with CNI.

Results

Twelve patients were switched to belatacept 10 (2–25) months after transplantation. One year after belatacept therapy, patient and allograft survival rates scored 92% for both, two (17%) HIV virological rebounds occurred due to antiretroviral therapy non-compliance, and CD4⁺ and CD8⁺ T-cell counts remained stable over time. Serious adverse events included two (17%) acute steroid-resistant T-cell-mediated rejections and three (25%) OIs. Kidney allograft function significantly increased over the 12 post-switch months (P = 0.009), and DSAs remained stable at 12 months after treatment. The control group showed similar results in terms of patient and kidney allograft survival rates, DSA characteristics and proteinuria

Conclusions

Switch from CNI to belatacept can be considered safe and may increase long-term kidney allograft survival in HIV-positive kidney allograft recipients. These results need to be confirmed in a larger cohort.

HIV Prevalence and Morbidity in Older Inpatients in a High HIV Prevalence Setting

Understanding of the burden of HIV infection and comorbid conditions in older adults is limited, especially in low- and middle-income countries. Antiretroviral therapy (ART) has increased longevity of HIV-positive individuals, making age-related comorbidities more likely. This study aimed to compare the demographic and disease profiles, including chronic comorbid conditions of inpatients, at least 50 years of age, by HIV status, admitted to a regional hospital in South Africa. Adults, 50 years of age and older, admitted to internal medicine wards from November 2015 to February 2016 were approached to participate. Sociodemographic data, laboratory results, anthropometric data, discharge diagnoses, and HIV status were collected and compared by HIV serostatus. Overall, 151 participants were enrolled. Their median age was 61 years (IQR: 56-68 years); 89 (58.9%) were women. Overall, 47 (31.1%) were HIV positive, of whom 10 (6.6%) were first diagnosed during the admission. HIV-positive inpatients were younger than HIV-negative patients. The leading discharge diagnoses of all participants were acute gastroenteritis (11.5%) and community-acquired pneumonia (11.5%). Hypertension and type 2 diabetes mellitus (T2DM) were the leading comorbidities in both HIV-negative and HIV-positive participants. Prevalence of hypertension was 75.0% in seronegative, 59.5% in those with a prior diagnosis of HIV, and 40.0% in newly diagnosed; similarly, prevalence of T2DM was 22.1% in HIV-negative and 24.3% in known HIV-positive participants. Similar proportions died during admission; 11.3% of HIV-negative and 12.7% of HIV-positive admitted inpatients died. Almost one third of patients admitted were HIV positive. In HIV-positive older admitted to hospital, the leading cause for hospitalization was coinfections. In the ART era, irrespective of HIV status, older patients have similar age-related chronic illnesses and similar mortality rates, despite younger age at admission.

Prevalence and Pattern of Human Immunodeficiency Virus-Associated Nephropathy among Human Immunodeficiency Virus-Positive Children at the University of Maiduguri Teaching Hospital, Nigeria

The kidney is an important target organ in human immunodeficiency virus (HIV) infection, and a variety of renal disorders could occur throughout the course of the disease. HIV- associated nephropathy (HIVAN) is the most common form of kidney disease resulting directly from HIV infection. The true prevalence of HIVAN among infected African children is unknown largely due to lack of surveillance and reporting. We thus aimed to determine the prevalence of HIVAN and associated factors among HIV-infected children at the University of Maiduguri Teaching Hospital. This was a cross-sectional study carried out at the Pediatric Infectious Clinic. Children aged ≤15 years were recruited through systematic random sampling. Relevant sociodemographic and clinical information were obtained. Spot urine sample was analyzed using a multistix (Combi-Screen 10SL Analyticon Biotechnologies AG, Germany), and proteinuria of ≥2+ was considered significant. The CD4+ count and CD4+% (for those <5 years) were obtained using a PARTEC™ CD4+ easy count kit. The obtained data were entered and analyzed using Statistical Package for the Social Sciences version 16.0. A total of 250 children were recruited. Eighty-five (34%) of them had HIVAN. Sex, social class, and mode of transmission were not significantly associated with HIVAN (P >0.05). However, age, medication status (highly active antiretroviral therapy [HAART]), duration on HAART, and disease severity (both clinical and immunological) all had a significant association to HIVAN (p = 0.005, 0.004, 0.008, and <0.001, respectively). These factors also showed a positive but weak correlation to HIVAN; while age had the least correlation coefficient (0.157), immunological class had the highest r = 0.458. However, these relationships were all significant (P <0.5). HIVAN is highly prevalent among children living with HIV in Maiduguri. Routine screening through urina-lysis and early commencement of HAART is recommended.

A cross-sectional study on renal involvement among HIV-infected patients attending a tertiary care hospital in Kolkata

Background and objectives

The HIV-associated renal diseases represent a spectrum. Indian data on this is sparse. This study was undertaken to find out the prevalence and clinicopathological spectrum of renal involvement in HIV among antiretroviral therapy (ART) naïve patients (Group 1) and among those on ART (Group 2).

Methods

Systematic random sampling was undertaken to select 109 patients each from virology outpatient department (VOPD) and ART centre of a tertiary care hospital. They were screened and further investigated if renal involvement was found.

Results

Renal involvement was present in 25/109 (22.94%) and 15/109 (13.76%) patients of Groups 1 and 2, respectively. Among patients of Groups 1 and 2, 9/24 (37.5%) and 2/13 (15.4%), respectively, had clinically significant proteinuria, but none in the nephrotic range. Statistically significant relationships of renal involvement were observed with CD4 count <100/μl and with low BMI. Of the patients of Group 2, 20% of those on a tenofovir-based regimen had renal involvement with tubular changes, while only 4.6% of those on other regimens had renal involvement. This difference was statistically significant (p<0.05; OR=5.25).

Conclusion

Renal involvement was less common among those on ART. Low CD4 count and body mass index (BMI) were associated with renal dysfunction. Patients on a tenofovir-based regimen had more renal involvement compared with not on a tenofovir-based regimen.

Low incidence of acute rejection within 6 months of kidney transplantation in HIV-infected recipients treated with raltegravir: the Agence Nationale de Recherche sur le Sida et les Hépatites Virales (ANRS) 153 TREVE trial

OBJECTIVES

High rates of clinical acute rejection after kidney transplantation have been reported in people living with HIV (PLHIV), probably as a consequence of drug interactions. We therefore investigated the incidence of acute rejection within 6 months of transplantation in HIV-infected recipients treated with a protease-inhibitor-free raltegravir-based regimen.

METHODS

The Agence Nationale de Recherche sur le Sida et les Hépatites Virales (ANRS) 153 TREVE (NCT01453192) study was a prospective multicentre single-arm trial in adult PLHIV awaiting kidney transplantation, with viral load < 50 HIV-1 RNA copies/mL, CD4 T-cell count > 200 cells/μL, and HIV-1 strains sensitive to raltegravir, aiming to demonstrate 6-month clinical acute rejection rates < 30%. Time to transplantation was compared with that for uninfected subjects matched for age, sex and registration date.

RESULTS

In total, 61 participants were enrolled in the study, and 26 underwent kidney transplantation. Two participants experienced clinical acute rejection, corresponding to an estimated clinical acute rejection rate of 8% [95% confidence interval (CI) 2-24%] at 6 and 12 months post-transplantation. HIV infection remained under control in all but one participant, who temporarily stopped antiretroviral treatment. Median time to transplantation was longer in PLHIV than in controls (4.3 versus 2.8 years, respectively; P = 0.002) and was not influenced by blood group.

CONCLUSIONS

Acute rejection rates were low after kidney transplantation in PLHIV treated with a raltegravir-based regimen. However, PLHIV have poorer access to transplantation than HIV-uninfected individuals after registration on the waiting list.

A National Study of Outcomes among HIV-Infected Kidney Transplant Recipients

Kidney transplantation is a viable treatment for select patients with HIV and ESRD, but data are lacking regarding long-term outcomes and comparisons with appropriately matched HIV-negative patients. We analyzed data from the Scientific Registry of Transplant Recipients (SRTR; 2002-2011): 510 adult kidney transplant recipients with HIV (median follow-up, 3.8 years) matched 1:10 to HIV-negative controls. Compared with HIV-negative controls, HIV-infected recipients had significantly lower 5-year (75.3% versus 69.2%) and 10-year (54.4% versus 49.8%) post-transplant graft survival (GS) (hazard ratio [HR], 1.37; 95% confidence interval [95% CI], 1.15 to 1.64; P<0.001) that persisted when censoring for death (HR, 1.43; 95% CI, 1.12 to 1.84; P=0.005). However, compared with HIV-negative/hepatitis C virus (HCV)-negative controls, HIV monoinfected recipients had similar 5-year and 10-year GS, whereas HIV/HCV coinfected recipients had worse GS (5-year: 64.0% versus 52.0%, P=0.02; 10-year: 36.2% versus 27.0%, P=0.004 [HR, 1.38; 95% CI, 1.08 to 1.77; P=0.01]). Patient survival (PS) among HIV-infected recipients was 83.5% at 5 years and 51.6% at 10 years and was significantly lower than PS among HIV-negative controls (HR, 1.34; 95% CI, 1.08 to 1.68; P<0.01). However, PS was similar for HIV monoinfected recipients and HIV-negative/HCV-negative controls at both times. HIV/HCV coinfected recipients had worse PS compared with HIV-negative/HCV-infected controls (5-year: 67.0% versus 78.6%, P=0.007; 10-year: 29.3% versus 56.23%, P=0.002 [HR, 1.57; 95% CI, 1.11 to 2.22; P=0.01]). In conclusion, HIV-negative and HIV monoinfected kidney transplant recipients had similar GS and PS, whereas HIV/HCV coinfected recipients had worse outcomes. Although encouraging, these results suggest caution in transplanting coinfected patients.

Differentiating HIV-associated nephropathy from antiretroviral drug-induced nephropathy: a clinical challenge

With the introduction of potent combination antiretroviral therapy (cART) into clinical practice, HIV-infected patients have garnered much benefit. However, kidney disease continues to be a potential complication in this group. Whereas HIV-associated nephropathy (HIVAN) was the major renal complication prior to cART, co-morbid diseases and adverse renal effects of various drugs, in particular cART, now complicate the landscape. Clinicians now must differentiate HIVAN from cART nephrotoxicity. While sometimes this is easy and relatively straightforward, often the clinician faces a difficult challenge distinguishing these two etiologies of kidney disease. This review will discuss HIVAN and cART-related kidney disease and review the clinical and laboratory data that may be useful in differentiating these processes. Often, however, kidney biopsy may be required to differentiate HIVAN from cART nephrotoxicity as well as other kidney lesions associated with concurrent co-morbidities, both infectious and non-infectious.

Clinical remission of IgA nephropathy in an HIV-positive patient after combined treatment with tonsillectomy and steroid pulse therapy

Various renal diseases other than human immunodeficiency virus (HIV)-associated nephropathy, including IgA nephropathy (IgAN), have been recently reported to cause chronic kidney disease and end-stage renal disease in HIV-infected patients. The case of a 37-year-old HIV-infected male diagnosed as having IgAN with proteinuria and microscopic hematuria that was successfully treated with tonsillectomy and steroid pulse therapy in combination, resulting in disappearance of urinary abnormalities (clinical remission), is reported, the first such case in the literature. A renal biopsy revealed mesangial proliferation associated with mesangial deposition of IgA and C3, consistent with IgAN. Antiretroviral therapy and angiotensin receptor blocker therapy did not improve his proteinuria. Therefore, he underwent tonsillectomy and steroid pulse therapy, and clinical remission was successfully achieved with no opportunistic infections. Clinical remission has continued for more than 3 years even after discontinuation of steroid therapy. It appears that combined treatment with tonsillectomy and steroid pulse therapy can be a good choice in managing HIV-infected patients with IgAN as long as secondary infection is strictly and continuously monitored.

The spectrum of HIV-related nephropathy in children

BACKGROUND

Despite the burden of human immunodeficiency virus (HIV) disease in Southern Africa, there have been few reports of HIV-related nephropathy in children. This study outlines the spectrum of HIV-1-related kidney diseases of children in KwaZulu-Natal, South Africa.

METHODS

A review of the clinical presentation, laboratory and histopathological findings of children diagnosed with HIV-related nephropathy.

RESULTS

Forty-nine out of 71 children (1-16 years old) with HIV-1 related nephropathy underwent kidney biopsy. The most common histopathological finding was focal segmental glomerulosclerosis (FSGS), which was present in 32 (65.3%) children; 13 (26.5%) having collapsing glomerulopathy and 19 (38.8%) classic FSGS. The majority of patients showed haematological (86.4%) and electrolyte abnormalities (69.4%). Renal impairment was present in 41% of patients on initial presentation. However, end-stage kidney disease was present in only 4% of these patients. All patients were treated with highly active anti-retroviral therapy (HAART), the majority (79.6%) showed decreased proteinuria with 38.8% having complete remission.

CONCLUSIONS

This study, one of the largest series of children reported from Africa, demonstrates that nephrotic syndrome due to HIV-associated nephropathy (HIVAN) is the commonest presentation of HIV-related nephropathy in childhood. Highly active anti-retroviral therapy in combination with angiotensin-converting enzyme antagonists is highly effective in decreasing proteinuria and preserving renal function.

HIV-associated kidney disease in the context of an aging population

Acute renal failure and chronic kidney disease are more common in HIV-infected patients compared with the general population. Several studies have shown age to be a risk factor for HIV-associated kidney disease. The improved life expectancy of HIV-infected patients as a result of widespread use of antiretroviral therapy has resulted in progressive aging of HIV cohorts in the developed world, and an increased burden of cardiovascular and kidney disease. Consequently, HIV care increasingly needs to incorporate strategies to detect and manage these non-infectious co-morbidities.

Membranous nephropathy in an HIV-positive patient complicated with hepatitis B virus infection

In ordinary settings, human immunodeficiency virus (HIV)-associated nephropathy should be considered when HIV infection is associated with heavy proteinuria. On the other hand, hepatitis B virus (HBV) may also play a role in the development of glomerular injury among patients with HIV infection, since HIV and HBV infections commonly occur together due to shared modes of transmission. We present here a case of nephrotic syndrome in an HIV-positive patient complicated with HBV infection. A renal biopsy revealed sparse granular deposits of immunoglobulin G in the subepithelial region, consistent with membranous nephropathy (MN) stage I. Moreover, immunostaining exhibited weak anti-hepatitis B core activity within glomeruli. These results led us to consider that HBV-associated MN might play a role in the development of nephrotic syndrome. Although anti-viral treatment for patients with HBV-associated MN has been suggested to be clinically effective, the use of two anti-HIV agents (tenofovir and emtricitabine), both of which have anti-HBV activities, was not effective for the patient's nephrotic syndrome, despite obtaining a decrease in the serum HBV-DNA levels. A lack of prospective data suggests that many decisions on the treatment of glomerulopathies with HIV infections are potentially empirical. Obviously, further studies and accumulated clinical experience are required to better determine the pathogenesis and management of HBV-associated MN among patients with HIV infections.

Complete remission of non-HIV collapsing glomerulopathy with deflazacort and lisinopril in an adult patient

Collapsing glomerulopathy is a form of focal segmental glomerulosclerosis that is usually associated with HIV-1 infection, and is characterized by its poor prognosis and almost inevitable progression to end-stage renal disease. Its pathological features include collapsed glomeruli, podocyte hypertrophy and hyperplasia, and pseudocrescents. This case report shows the evolution of a 58-year-old patient with non-HIV idiopathic collapsing glomerulopathy who presented with severe nephrotic syndrome and renal insufficiency and was treated with lisinopril and deflazacort, a synthetic corticosteroid that has shown fewer cosmetic effects and glucose and bone metabolism complications than prednisone. The patient responded with full recovery of renal function and normal range of protein excreted in urine after less than two years of treatment. The patient has not suffered a recurrence of his nephrotic syndrome after three years of steroid withdrawal. There is no proven therapy for collapsing glomerulopathy, and this case highlights an alternative for treating this disease with few secondary effects.

[Diagnosis, treatment and prevention of renal diseases in HIV infected patients. Recommendations of the Spanish AIDS Study Group/National AIDS Plan]

The incidence of opportunistic infections and tumours in HIV-infected patients has sharply declined in the HAART era. At the same time there has been a growing increase of other diseases not directly linked to immunodeficiency. Renal diseases are an increasing cause of morbidity and mortality among HIV-infected patients. In the general population, chronic renal failure has considerable multiorgan repercussions that have particular implications in patients with HIV infection. The detection of occult or subclinical chronic kidney disease is crucial since effective measures for delaying progression exist. Furthermore, the deterioration in glomerular filtration should prompt clinicians to adjust doses of some antiretroviral agents and other drugs used for treating associated comorbidities. Suppression of viral replication, strict control of blood pressure, dyslipidemia and diabetes mellitus, and avoidance of nephrotoxic drugs in certain patients are fundamental components of programs aimed to prevent renal damage and delaying progression of chronic kidney disease in patients with HIV. Renal transplantation and dialysis have also special implications in HIV-infected patients. In this article, we summarise the updated clinical practice guidelines for the evaluation, management and prevention of renal diseases in HIV-infected patients from a panel of experts in HIV and nephrologists on behalf of the Spanish AIDS Study Group (GESIDA) and the National AIDS Plan.

Imaging features of renal pathology in the human immunodeficiency virus-infected patient

Renal disease in patients with acquired immunodeficiency syndrome was described before even human immunodeficiency virus was demonstrated to be the causative agent, when the now known human immunodeficiency virus associated nephropathy was first described. Several other pathologic processes mostly relating to the immunodeficiency caused by the virus, such as atypical infections, malignancies, as well as highly active antiretroviral therapy related side affects, have been shown to affect the kidneys. The mortality and morbidity burden is high; therefore, it is paramount the radiologist be familiar with the imaging features of this wide range of diseases processes.

Urinary NGAL marks cystic disease in HIV-associated nephropathy

Nephrosis and a rapid decline in kidney function characterize HIV-associated nephropathy (HIVAN). Histologically, HIVAN is a collapsing focal segmental glomerulosclerosis with prominent tubular damage. We explored the expression of neutrophil gelatinase-associated lipocalin (NGAL), a marker of tubular injury, to determine whether this protein has the potential to aid in the noninvasive diagnosis of HIVAN. We found that expression of urinary NGAL was much higher in patients with biopsy-proven HIVAN than in HIV-positive and HIV-negative patients with other forms of chronic kidney disease. In the HIV-transgenic mouse model of HIVAN, NGAL mRNA was abundant in dilated, microcystic segments of the nephron. In contrast, urinary NGAL did not correlate with proteinuria in human or in mouse models. These data show that marked upregulation of NGAL accompanies HIVAN and support further study of uNGAL levels in large cohorts to aid in the noninvasive diagnosis of HIVAN and screen for HIVAN-related tubular damage.

Tenofovir renal toxicity targets mitochondria of renal proximal tubules

Tenofovir disoproxil fumarate (TDF) is an analog of adenosine monophosphate that inhibits HIV reverse transcriptase in HIV/AIDS. Despite its therapeutic success, renal tubular side effects are reported. The mechanisms and targets of tenofovir toxicity were determined using '2 x 2' factorial protocols, and HIV transgenic (TG) and wild-type (WT) littermate mice with or without TDF (5 weeks). A parallel study used didanosine (ddI) instead of TDF. At termination, heart, kidney, and liver samples were retrieved. Mitochondrial DNA (mtDNA) abundance, and histo- and ultrastructural pathology were analyzed. Laser-capture microdissection (LCM) was used to isolate renal proximal tubules for molecular analyses. Tenofovir increased mtDNA abundance in TG whole kidneys, but not in their hearts or livers. In contrast, ddI decreased mtDNA abundance in the livers of WTs and TGs, but had no effect on their hearts or kidneys. Histological analyses of kidneys showed no disruption of glomeruli or proximal tubules with TDF or ddI treatments. Ultrastructural changes in renal proximal tubules from TDF-treated TGs included an increased number and irregular shape of mitochondria with sparse fragmented cristae. LCM-captured renal proximal tubules from TGs showed decreased mtDNA abundance with tenofovir. The results indicate that tenofovir targets mitochondrial toxicity on the renal proximal tubule in an AIDS model.

Proteinuria in children infected with the human immunodeficiency virus

OBJECTIVES

To determine the prevalence of proteinuria in a large cohort of children infected with the human immunodeficiency virus (HIV) and their longitudinal progression during treatment with highly active antiretroviral therapy.

STUDY DESIGN

In a retrospective cohort study, 286 children infected with HIV were monitored with quantitative assays of proteinuria from January 1998 through January 2007, with monitoring of viral load, lymphocyte profiles, kidney function, and mortality rates. Proteinuria was quantitated by urine protein to creatinine ratio (Upr/cr).

RESULTS

Ninety-four (33%) had proteinuria at baseline. Of these, 32 (11.2%) had nephrotic range proteinuria (Upr/cr > or = 1.0). Initial screening was at 11 +/- 0.3 years of age, with an average follow-up of 5.6 +/- 0.1 years. The mortality rate was significantly greater in those with proteinuria. During the period of observation, 15 patients with nephrotic proteinuria died or had development of end-stage renal disease, and 16 showed improvement. Of those with intermediate range proteinuria (Upr/cr > or = 0.2 < 1.0), 3 progressed to nephrotic range proteinuria, and 39 (63%) showed resolution of the proteinuria (Upr/cr < 0.2). Improvement in proteinuria was correlated with decreasing viral load (r = 0.5; P < .01).

CONCLUSIONS

Control of viral load with highly active antiretroviral therapy appears to prevent the progression of HIV-associated renal disease and improve survival rates in infected children.

HIV infection in the elderly

In the US, an estimated 1 million people are infected with HIV, although one-third of this population are unaware of their diagnosis. While HIV infection is commonly thought to affect younger adults, there are an increasing number of patients over 50 years of age living with the condition. UNAIDS and WHO estimate that of the 40 million people living with HIV/AIDS in the world, approximately 2.8 million are 50 years and older. With the introduction of highly active antiretroviral therapy (HAART) in the mid-1990s, survival following HIV diagnosis has risen dramatically and HIV infection has evolved from an acute disease process to being managed as a chronic medical condition. As treated HIV-infected patients live longer and the number of new HIV diagnoses in older patients rise, clinicians need to be aware of these trends and become familiar with the management of HIV infection in the older patient. This article is intended for the general clinician, including geriatricians, and will review epidemiologic data and HIV treatment as well as provide a discussion on medical management issues affecting the older HIV-infected patient.

Viral subversion mechanisms in chronic kidney disease pathogenesis

Viruses cannot autonomously replicate but must rely on the host cellular machinery to support their life cycle. Through natural selection, viruses have evolved strategies to co-opt the host organism to be a better site for their propagation. Some of these strategies are directed at the cellular machinery and involve complicated and ingenious solutions to optimize infection, replication, viral gene expression, and new virion assembly and shedding. Other strategies are directed at the host's innate and adaptive immune systems that permit the virus to evade clearance mechanisms. The more common pathogenic viral infections in nephrology-cytomegalovirus, HIV-1, hepatitis C virus, polyomavirus BK, and parvovirus B19-all have acquired subversion strategies that benefit the virus but because they interfere with normal cellular and immune processes also have become pathogenic to the host. In addition, the highly prevalent viruses cytomegalovirus, BK, and B19 cause severe disease only in the setting of immunosuppression, revealing the very delicate balance that some viruses have achieved with their host's immune system. Thus, selective pressure for survival drives both the evolution of more sophisticated viruses and the host immune system as it evolves to combat the environment of adapting and emerging infectious agents. Understanding the molecular mechanisms of these viral subversion strategies may reveal new targets for the development of highly specific antiviral therapies and also aid vaccine development.

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.

Cardiac transplantation in HIV-positive patients: are we there yet?

The epidemiology and clinical picture in human immunodeficiency virus (HIV) infection has evolved tremendously over the years, leaving health-care professionals having to cope with continuously transforming challenges in the management of HIV-infected patients.

HIV-1 Tat reduces nephrin in human podocytes: a potential mechanism for enhanced glomerular permeability in HIV-associated nephropathy

OBJECTIVE

To determine whether HIV-1 Tat may directly alter glomerular permeability in HIV-associated nephropathy (HIVAN).

DESIGN

Heavy proteinuria is a hallmark of HIVAN. The slit diaphragm is the ultimate glomerular filtration barrier critical for maintaining the efficiency of the ultrafiltration unit of the kidney. In this study, we evaluated the direct effect of Tat protein on the permeability of isolated glomeruli and on the expression of nephrin, the main slit diaphragm component, by human cultured podocytes.

METHODS

Permeability was studied by measuring the permeability to albumin in isolated rat glomeruli. We also evaluated the expression of nephrin in human cultured podocytes by using immunofluorescence and Western blot.

RESULTS

We found that Tat increased albumin permeability in isolated glomeruli, and rapidly induced the redistribution and loss of nephrin in cultured podocytes. Pretreatment of glomeruli and podocytes with blocking antibodies showed that Tat reduced nephrin expression by engaging vascular endothelial growth factor receptors types 2 and 3 and the integrin alphavbeta3. Pre-incubation of podocytes with two platelet-activating factor (PAF) receptor antagonists prevented the loss and redistribution of nephrin induced by Tat, suggesting that PAF is an intracellular mediator of Tat action. Tat induced a rapid PAF synthesis by podocytes. When podocytes transfected to overexpress PAF-acetylhydrolase, the main catabolic enzyme of PAF, were stimulated with Tat, the redistribution and loss of nephrin was abrogated.

CONCLUSION

The present results define a mechanism by which Tat may reduce nephrin expression in podocytes, thus increasing glomerular permeability. This provides new insights in the understanding of HIVAN pathogenesis.

Mechanisms of disease: focal segmental glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS), a subtype of "idiopathic nephrotic syndrome", is not a single disease, but a lesion that initially affects the glomerulus followed by the tubulointerstitium and renal vessels. The term 'FSGS' does not accurately encompass the various pathologic features of the glomerulus, which are not always focal, segmental or sclerotic. Particular variants of FSGS, such as collapsing glomerulopathy and the glomerular tip lesion, exemplify the nosologic uncertainty inherent in the classification of glomerular lesions. Pathologic variation notwithstanding, all pathologic processes that affect the podocyte lead to one of the histologic subtypes of FSGS. This specialized cell type has essential roles in maintaining the integrity of glomerular architecture, resisting endocapillary hydraulic pressure and hindering egress of proteins into the urinary space. Once initiated, podocyte lesions and ensuing fibrosis are usually irreversible, at least in human forms of FSGS. Remarkable progress has been made in unraveling the mechanisms of podocyte dysregulation that accompany the cellular variants of FSGS and in identifying genetic mutations affecting proteins of the slit diaphragm. Hopefully, this progress will drastically improve treatments for what is one of the most difficult therapeutic challenges to confront the nephrologist.

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 and the kidney: a status report after 20 years

The first association between HIV-1 infection and kidney disease was made in 1984 and much has been learned over the past 20 years. In recent years, more effective therapies for HIV-1 infection and its associated opportunistic infections have led to improved patient survival. However, with prolonged survival, morbidity associated with renal disease has also increased. Among the multiple glomerulopathies that can affect patients with HIV, focal segmental glomerulosclerosis (FSGS) is most common and frequently leads to end-stage renal disease. Although the precise mechanisms of HIV-associated FSGS remain to be elucidated, it appears that host genetic susceptibility, direct infection of the renal epithelium, and toxicity of one or more viral accessory protein contribute. Therapy for HIV-associated FSGS includes control of blood pressure and the use of angiotensin antagonist therapy. A randomized trial of angiotensin receptor blocker will be initiated shortly. Drug-related nephropathies are also common, manifesting as acute renal failure, nephrolithiasis, and interstitial nephritis. Tenofovir, a newer nucleoside analogue, has recently been implicated in causing tubular toxicity, although the incidence is low. Appropriate screening for renal dysfunction can minimize the likelihood of progressive renal injury in all patients with HIV-1 infection.

HIV-associated renal disorders: recent insights into pathogenesis and treatment

Renal electrolyte disorders, acute renal failure, and a variety of chronic renal diseases are common in HIV-infected patients. Glomerular disorders include IgA nephropathy, cryoglobulinemia, amyloidosis, and a lupus-like immune complex glomerulopathy. The most attention has been focused on collapsing glomerulopathy associated with nephrotic syndrome and progressive renal failure, which appears to be unique for patients with HIV/AIDS, called HIV-associated nephropathy (HIVAN), and it occurs predominantly in African American patients. Investigations in humans and in a transgenic mouse model reveal direct infection of renal epithelial cells by HIV and toxic cellular and immunologic processes mediated by HIV glycoproteins as the principal pathophysiology of HIVAN. Highly active antiretroviral treatment may be associated with an improved renal outcome and even reversal of kidney disease in some patients. Treatment with angiotensin-converting enzyme inhibitors may avert progression of HIVAN to end-stage kidney disease and result in superior patient and kidney survival as compared with untreated patients.

Seasonal variation in undiagnosed HIV infection on the general medicine and trauma services of two urban hospitals

OBJECTIVE

To examine the seroprevalence of undiagnosed HIV and variation by season among patients admitted to the general internal medicine (GIM) and trauma services of two urban hospitals.

DESIGN

A cross-sectional blinded HIV-1 seroprevalence survey.

SETTING

A 725-bed academic medical center's hospital and an affiliated 324-bed tertiary care hospital.

PARTICIPANTS

Residual serological specimens were obtained for unique patients aged 17 to 65 to study services in summer (June 16 to September 4, 2001) and fall to winter (November 1, 2001 to January 8, 2002).

METHODS

Hospital files provided data on demographics, service type, and discharge clinical categories (fall-winter group only). HIV ELISA (enzyme-linked immunosorbent assay) tests with confirmatory Western blot were linked to subjects' de-identified files. We excluded 34 subjects with known HIV. Of the remaining unique admissions in summer (n=604) and fall-winter (n=978), 60% and 55% were tested, respectively. Predictors of undiagnosed HIV infection were examined using multivariate analysis.

RESULTS

The summer cohort (n=362) had significantly lower unadjusted seroprevalence of undiagnosed HIV infection (1.4%; 95% confidence interval [CI], 0.4% to 3.2%) than the fall-winter cohort (n=539; 3.7%; 95% CI, 2.3% to 5.7%; P=.04). Overall, undiagnosed HIV was somewhat less likely in women (adjusted odds ratio [AOR], 0.45; 95% CI, 0.19 to 1.07) but more likely in black patients (AOR, 3.46; 95% CI, 0.70 to 17.06). In the fall-winter cohort, undiagnosed HIV was more likely for discharges with the following clinical categories versus those with a cardiac condition: dermatologic/breast (AOR, 14.90; 95% CI, 1.20 to 184.77), renal/urological (AOR, 22.43; 95% CI, 2.12 to 236.75), or infectious (AOR, 31.08; 95% CI, 2.40 to 402.98).

CONCLUSIONS

The higher seroprevalence of undiagnosed HIV in the fall-winter admissions to GIM and trauma services supports especially targeting HIV testing in these months.

Impact of fibronectin fragments on the transendothelial migration of HIV-infected leukocytes and the development of subendothelial foci of infectious leukocytes

Leukocyte infiltrates that can serve as viral reservoirs, and sites for viral replication are found in many organs of HIV-1-infected patients. Patients whose blood leukocytes migrate across confluent endothelial monolayers ex vivo and transmit infectious virus to mononuclear leukocytes (MNLs) lodged beneath this endothelial barrier have a worse prognosis. We evaluated the ability of 110- to 120-kDa fibronectin fragments (FNf), which are found in the blood of >60% of HIV-1-infected patients, to stimulate transendothelial migration and drive productively infected MNLs into a potential perivascular space. FNf induced MNLs to release TNF-alpha in a dose-dependent fashion; the resulting increase in lymphocyte and monocyte transendothelial migration could be blocked with soluble TNF receptor I. Rather than penetrate deeply into the subendothelial matrix, as is seen with untreated controls, FNf-treated MNLs clustered just below the endothelial monolayer. Treatment with FNf during migration increased subsequent recovery of HIV-infected cells from the subendothelial compartment. FNf treatment also significantly increased the numbers of HLA-DR(bright), dendritic-type cells that reverse-migrated from the subendothelial depot to the apical endothelial surface 48 h after migration. Fibronectin fragments can be produced by viral and host proteases in the course of inflammatory conditions. The ability of FNf to stimulate transendothelial migration of HIV-1-infected MNLs may help to explain the dissemination of this infection into cardiac, renal, and CNS tissues.

[Renal involvement in the human immunodeficiency virus infection]

BACKGROUND AND OBJECTIVE

Although renal pathologies are becoming an emergent problem in the population infected by the human immunodeficiency virus (HIV), there is very scarce information about the natural course of this problem. The objective of the present study is to describe renal lesions in an autopsy series of HIV-infected patients never treated with antiretroviral therapies.

PATIENTS AND METHOD

Autopsy information has been retrospectively retrieved from 61 HIV-infected subjects (mean age, 36,9 [8,4] years; 58,6% drug abusers, 84% males) died in our hospital between 1984 and 1997. None of the patients received antiretroviral therapy. All autopsy and clinical reports were considered, as well as basic analytical parameters about renal function. Renal autopsy samples were specifically reviewed.

RESULTS

At the time of the last admission, 9.8% of patients had renal insufficiency, who made up 44.3% of patients having renal insufficiency anytime. Infections were the main cause of death (76%). The majority of patients (93.4%) showed histopathological renal abnormalities, which were highly heterogeneous. Renal lesions were mainly located on the tubules (96.7%) and the interstitium (60.7%). Moreover, glomeruli were affected in 55.7% of patients. Most frequent histopathological diagnosis was acute tubular necrosis (16.4%) and septic nephritic abscesses (16.4%), followed by tubulointerstitial nephritis (9%). HIV-associated nephropathy was present in two patients (3.3%). There were no significant differences when considering the existent of renal failure.

CONCLUSIONS

Renal histological abnormalities are frequent in the natural evolution of HIV infection. There is an important heterogeneity of lesions, mainly involving tubules, interstitium and mesangium. The cause of renal lesions is predominantly septic, according to the chief systemic process. It does not exist any relationship between renal analytical parameters and the presence of renal damage.

Apoptosis of uninfected cells induced by HIV envelope glycoproteins

Apoptosis, or programmed cell death, is a key event in biologic homeostasis but is also involved in the pathogenesis of many human diseases including human immunodeficiency virus (HIV) infection. Although multiple mechanisms contribute to the gradual T cell decline that occurs in HIV-infected patients, programmed cell death of uninfected bystander T lymphocytes, including CD4+ and CD8+ T cells, is an important event leading to immunodeficiency. The HIV envelope glycoproteins (Env) play a crucial role in transducing this apoptotic signal after binding to its receptors, the CD4 molecule and a coreceptor, essentially CCR5 and CXCR4. Depending on Env presentation, the receptor involved and the complexity of target cell contact, apoptosis induction is related to death receptor and/or mitochondria-dependent pathways. This review summarizes current knowledge of Env-mediated cell death leading to T cell depletion and clinical complications and covers the sometimes conflicting studies that address the possible mechanisms of T cell death.