HIV-associated nephropathy: a diagnosis in evolution

The prevalence and immunological features of anti-glomerular basement membrane antibody in patients with HIV

Background

Anti-glomerular basement membrane disease (GBM) is an autoimmune disease caused by the deposition of circulating anti-GBM antibodies. Non-collagen region of α3 chain of type IV collagen (α3(IV)NC1) is one of the main target antigens, in which E_A and E_B are the most classical antigen epitopes. It has been reported that anti-GBM antibodies can be detected in HIV patients; however, its immunological characteristics are still unclear.

Objectives

In this study, the positive rate of the anti-GBM antibodies in HIV and the immunological characteristics of the target antigens were clarified.

Methods

A total of 93 HIV patients diagnosed in Beijing Youan Hospital from November 2017 to January 2018 were included. Enzyme-linked immunosorbent assay was used to measure the serum IgG autoantibodies specifically against GBM in these patients, as well as their subtypes and antigen spectra.

Results

It was found that five out of the 93 patients with HIV had low to moderate levels of anti-GBM antibodies. However, these patients presented with no clinical manifestation of any kidney injury or pulmonary hemorrhages. Compared with HIV patients with negative antibodies, there were no significant differences in gender, age, CD4⁺T cell count and HIV viral load. All sera of five patients recognized non-collagenous domain1 (NC1) of alpha 3 chain of type IV collagen [(α3(IV)NC1] as classic anti-GBM patients, followed by α5(IV)NC1. The antibodies against α3(IV)NC1 were IgG3 predominant, while these antibodies did not react with either of the classic epitopes on α3 (E_A and E_B).

Conclusion

These data suggest a distinct immunological profile of anti-GBM antibodies in patients with HIV, and might explain the non-pathogenic features of HIV associated anti-GBM antibodies.

Sonographic evaluation of kidney echogenicity and morphology among HIV sero-positive adults at Lagos University Teaching Hospital

AIM

To evaluate the role of kidney echogenicity and morphology in the diagnosis of human immunodeficiency virus-associated nephropathy (HIVAN).

SUBJECTS AND METHODS

In the cross-sectional study, a sample of 340 anti-retroviral therapy (ART)-naïve AIDS patients underwent laboratory CD4+ count, serum creatinine determination and sonographic renal echogenicity grading and size measurement. Rounded kidneys were described as bulbous while bean-shaped kidneys were described as reniform; echogenicity was categorized into grades 0, 1, 2 and 3. Kidney length, width, thickness and volume were measured in HIVAN and control groups.

RESULTS

Mean age of the population was 42.7 ± 9.4 years; 87.4% had HIVAN. Mean CD4+ count, serum creatinine and GFR for HIVAN patients were 153.1 ± 103.2 cells/mm3, 218.4 ± 147.4 mmol/L and 50.1 ± 23.6 mL/min/1.73 m2 for males and 121.9 ± 91.0 cells/mm3, and 222.0 ± 150.4 mmol/L and 39.3 ± 20.6 mL/min/1.73 m2 for females, respectively; control subjects and non-HIVAN patients had grade 0 renal echogenicity; 56.9% of HIVAN patients had echogenicity grade 3; 5.3% had kidney length < 10 cm; 73.9% had bulbous kidneys; the kidney was significantly wider and thicker in HIVAN (p < 0.05).

CONCLUSION

Sonographic evaluation of renal echogenicity and morphology can reliably predict HIVAN diagnosis. Apathy to screening and late presentation were high while HIV/AIDS remains an important public health problem in the city of Lagos. Unilateral reduction in kidney size could be a major sequela of AIDS while sonographic measurement of absolute kidney length appears inadequate in the evaluation of AIDS patients with nephropathy.

Pharmacotherapy and treatment options for HIV-associated nephropathy

INTRODUCTION

Human immunodeficiency virus (HIV) remains a worldwide disease with significant mortality and morbidity. There are a multitude of HIV-related kidney diseases including HIV-associated nephropathy (HIVAN) most prominently. The risk of developing HIVAN increases with decreasing CD4 count, higher viral load, and based on genetic factors. The mortality rate for those with HIVAN-end stage renal disease (ESRD) remains 2.5-3 times higher than ESRD patients without HIVAN.

AREAS COVERED

The epidemiology of HIVAN, particularly risk assessment, will be explored in this review. Further, the pathogenesis of HIVAN, from viral-specific renal expression to the role of genetics as well as characteristic renal pathology will be described. Diagnosis and management of HIVAN will be addressed, with an emphasis on various treatment strategies including medication, dialysis, and kidney transplantation.

EXPERT OPINION

HIVAN is associated with a high risk for progression to ESRD and increased mortality. The backbone of HIVAN therapy remains combined anti-retroviral therapy (cART), while adjunctive therapies including RAAS blockade and prednisone, should be considered. In those who progress to ESRD, dialysis remains the mainstay of management, though increasing evidence has demonstrated that kidney transplantation can be effective in those with controlled HIV disease.

Hepatic tuberculosis in human immunodeficiency virus co-infected adults: a case series of South African adults

BACKGROUND

Although Mycobacterium tuberculosis (TB) infection may cause extrapulmonary disease in HIV-infected adults, HIV-associated hepatic TB has been poorly characterized. Our objective was to describe hepatic TB in HIV-infected adults.

METHODS

Retrospective study of patients diagnosed with hepatic TB from 2005-2012 at Infectious Diseases Clinic, King Edward VIII Hospital, Durban, South Africa.

RESULTS

Among twenty cases of histology-confirmed HIV-associated hepatic TB, median CD4 count was 47 cells/μl (inter-quartile range 27-107 cells/μl) and 75% (15/20) of patients had pre-existing pulmonary TB. The most frequent clinical finding was hepatomegaly (85%). Liver enzyme abnormalities included elevated alkaline phosphatase (median 456 u/L, inter-quartile range 322-1,043 u/L) and gamma-glutamyltransferase (median 422 u/L, inter-quartile range 235-736 u/L). Acid-fast bacilli were cultured from liver tissue in 30% (6/20) of patients; 25% (5/20) identified as TB. With standard anti-TB therapy, liver enzymes improved within six months in 92% (11/12) of patients. One year after diagnosis, twelve patients resolved clinically, two patients developed drug-resistant TB and six patients died.

CONCLUSION

In our case series of HIV-infected patients, hepatic TB occurred in patients with severe immunosuppression, who presented with hepatomegaly and abnormal liver enzymes. More than half of patients had resolution of liver function by six months however the 12-month mortality remained high.

The prevalence of renal impairment in individuals seeking HIV testing in Urban Malawi

BACKGROUND

Chronic kidney disease (CKD) poses a major health threat to people living in low- and middle-income countries, especially when it is combined with HIV, antiretroviral treatment (ART) or communicable and non-communicable diseases. Data about the prevalence of CKD and its association with other diseases is scarce, particularly in HIV-negative individuals. This study estimated the prevalence of CKD in individuals who were either HIV-positive (and ART-naïve) or HIV-negative in an urban Malawian population.

METHODS

This cross-sectional study was conducted at a HIV Testing and Counselling Centre in Lilongwe, Malawi. Consecutive clients who were ≥18 years and consented to participate were enrolled over a 3-month period. Clients were screened for potential renal disease and other conditions. Their blood pressure was measured, urine examined via dipstick and albumin/creatinine ratio and blood drawn for creatinine, cystatin C and sero-markers for schistosomiasis. Estimated glomerular filtration (eGFR) rate was calculated using a cystatin C-based formula and classified according to the matching CKD stages by K/DOQI (The National Kidney Foundation Kidney Disease Outcome Quality Initiative). We performed a descriptive analysis and compared differences between HIV-positive (and ART naïve) and -negative participants.

RESULTS

Out of 381 consecutive clients who were approached between January and March 2012, 366 consented and 363 (48% female; 32% HIV-positive) were included in the analysis. Reasons for exclusion were missing samples or previous use of ART. HIV-positive and negative clients did not differ significantly with regard to age, sex or medical history, but they did differ for BMI-21.3 (±3.4) vs. 24 (±5.1), respectively (p < 0.001). Participants also differed with regard to serum cystatin C levels, but not creatinine. Reduced kidney function (according to CKD stages 2-5) was significantly more frequent 15.5 vs. 3.6%, respectively (p < 0.001) among HIV-positive clients compared to the HIV-negative group. Differences in renal function were most pronounced in the eGFR range 60-89 ml/min/1.73 m2 accompanied by proteinuria with results as 11.2% vs. 1.2%, respectively for clients who were HIV-positive vs. HIV-negative (p = 0.001).

CONCLUSIONS

Reduced glomerular filtration and/or proteinuria occurred in 15.5% of HIV-positive, and 3.6% of HIV-negative patients in this urban Malawian cohort. Since generalized renal monitoring is not feasible in Malawi or other resource-limited countries, strategies to identify patients at risk for higher stages of CKD and appropriate preventive measures are needed for both HIV-positive and HIV-negative patients.

Multiple facets of HIV-associated renal disease

HIV infection has a broad spectrum of renal manifestations. This study examined the clinical and histological manifestations of HIV-associated renal disease, and predictors of renal outcomes. Sixty-one (64% male, mean age 45 years) HIV patients were retrospectively evaluated. Clinical presentation and renal histopathology were assessed, as well as CD4 T-cell count and viral load. The predictive value of histological lesion, baseline CD4 cell count and viral load for end-stage renal disease (ESRD) or death were determined using the Cox regression model. The outcomes of chronic kidney disease (CKD) and ESRD or death were evaluated by baseline CD4 cell count. The percent distribution at initial clinical presentation was non-nephrotic proteinuria (54%), acute kidney injury (28%), nephrotic syndrome (23%), and chronic kidney disease (22%). Focal segmental glomerulosclerosis (28%), mainly the collapsing form (HIVAN), acute interstitial nephritis (AIN) (26%), and immune complex-mediated glomerulonephritis (ICGN) (25%) were the predominant renal histology. Baseline CD4 cell count ≥ 200 cells/mm3 was a protective factor against CKD (hazard ratio=0.997; 95%CI=0.994-0.999; P=0.012). At last follow-up, 64% of patients with baseline CD4 ≥ 200 cells/mm3 had eGFR >60 mL·min-1·(1.73 m2)-1 compared to the other 35% of patients who presented with CD4 <200 cells/mm3 (log rank=9.043, P=0.003). In conclusion, the main histological lesion of HIV-associated renal disease was HIVAN, followed by AIN and ICGN. These findings reinforce the need to biopsy HIV patients with kidney impairment and/or proteinuria. Baseline CD4 cell count ≥ 200 cells/mm3 was associated with better renal function after 2 years of follow-up.

Urinary biomarkers of kidney diseases in HIV-infected children

A significant number of children infected with the human immunodeficiency virus 1 (HIV-1) virus all over the world are at risk of developing renal diseases that could have a significant impact on their treatment and quality of life. It is necessary to identify children undergoing the early stages of these renal diseases, as well as the potential renal toxicity that could be caused by antiretroviral drugs, in order to prevent the development of cardiovascular complications and chronic renal failure. This article describes the most common renal diseases seen in HIV-infected children, as well as the value and limitations of the clinical markers that are currently being used to monitor their renal function and histological damage in a noninvasive manner. In addition, we discuss the progress made during the last 10 years in the discovery and validation of new renal biomarkers for HIV-infected children and young adults. Although significant progress has been made during the early phases of the biomarkers discovery, more work remains to be done to validate the new biomarkers in a large number of patients. The future looks promising, however, the new knowledge needs to be integrated and validated in the context of the clinical environment where these children are living.

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

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

[Hypertension, chronic kidney disease and genetics in patients with African ancestry]

The incidence and prevalence of hypertension is markedly elevated in Afro-American populations vs Caucasians. The development of end-stage renal disease is also more frequent in Afro-American subjects, independently of blood pressure control. As compared to Caucasians, Afro-American subjects have a higher risk of end-stage renal disease when they are infected with HIV or have lupus. For decades, these data remained mysterious. Within the last 3 years, results from studies in the field of genetics and infectious diseases have transformed our view on this problem. The aim of this paper is to explain how these results have changed our understanding of hypertension and its consequences in Afro-American subjects.