Virological features of hepatitis B virus-associated nephropathy in Japan

IFI16 induces inflammation in hepatitis B virus-associated glomerulonephritis by regulating the Caspase-1/ IL-1 ß pathway

Aims and background

IFI16 plays an important role in innate immunity against invasive microbial infection by sensing double-stranded DNA viruses due to caspase-1-dependent inflammasome activation and subsequent maturation and secretion of IL-1β. However, the role of IFI16 in regulating the immune response to viruses in Hepatitis B Virus-Associated Glomerulonephritis (HBV-GN), especially in sensing hepatitis B virus (HBV), has not been determined. In this study, we investigated the inflammatory role of IFI16 in HBV-GN.

Methods

A total 75 kidney tissue including 50 HBV-GN and 25 chronic glomerulonephritis (CCN) were collected to determine the expression of IFI16, Caspase-1 and IL-1β using immunohistochemistry (IHC), then the correlation between them was analyzed. In vitro, the primary human glomerular mesangial (HGM) cells and HEK-293 T cell lines were used in this study. The cell lines were both co-transfected with HBVDNA and overexpression or silencing IFI16. Quantitative Real-time PCR and western blotting were used to determine the expression of IFI16, Caspase-1 and IL-1β.

Results

IFI16 expression in HBV-GN biopsies (80.0%) was significantly higher than in CGN (24.0%) and positively correlated with HBVDNA,caspase-1 and IL-1β expression in HBV-GN. Meanwhile, over expression of IFI16 increased caspase-1 and IL-1β expression in HBV-infected HGM and HEK-293 T cell lines, knockdown of IFI16 mRNA by siRNA resulted in downregulation of the caspase-1 and IL-1β expression in both cell lines.

Conclusions

The elevation of IFI16 during HBV infection or replication may contribute to renal damage due to inflammation, thus providing a putative therapeutic target and a new avenue for researching the pathogenesis of HBV-GN.

Hepatitis B-related glomerulonephritis and optimization of treatment

Introduction: Multiple studies have revealed a strong relationship between the development of nephropathy and hepatitis B virus (HBV) infection. The underlying pathogenesis of hepatitis B-related glomerulonephritis (HBV-GN) involves immune complexes, which can be isolated from kidney tissues. Clearance of HBV antigenemia improves renal impairment and proteinuria in HBV-GN patients.Areas covered: In this review, we present our current understanding of the epidemiology, pathogenesis, pathology, diagnosis, and treatment of HBV-GN. We discuss the advantages and disadvantages of oral nucleoside/nucleotide analogs (NAs), and the main pharmaceutical treatment for hepatis B.Expert opinion: Currently, antiviral agents are the main HBV-GN therapeutic agents. Although no randomized controlled clinical trials have compared the efficacy of interferon (IFN) and NA, we suggest IFN treatment for pediatric patients (IFN-α in patients ≥1 year; pegIFN-α in patients ≥3 years) considering treatment duration and absence of resistance. Novel NAs have brought about promising treatment options involving high efficacy viral suppression and low resistance rates. NAs with a high barrier to resistance (e.g. entecavir) are recommended as first-line therapy of HBV-GN. Immunosuppression monotherapy, such as corticosteroids, is of little benefit and potentially harmful to HBV-GN patients due to the possibility of viral reactivation.

Analysis of clinical features and pathology of serum HBsAg positive glomerulonephritis

To analyze the relationship between the factors related to the occurrence of HBV-GN and serum HBsAg-positive glomerulonephritis. A total of 56 patients were enrolled in the present study. All enrolled cases were divided into two groups according to whether HBsAg and/or HBcAg was present in renal kidney tissue: patients with Hepatitis B virus-associated nephritis (HBV-GN group, 30 cases) and patients with hepatitis B virus-combined nephritis (HBV-CG group, 26 cases). We sought to analyze the differences in clinical features and pathological characteristics in both groups. The rate of HBeAg positivity in the HBV-GN group was considerably increased in the HBV-CG group (P < 0.05), and the number of patients with HBsAg+HBeAg+HBcAb+ in the HBV-GN group was considerably increased in the HBV-CG group (21 cases vs 10 cases) (P < 0.05). Moreover, the number of MCD patients diagnosed by renal biopsy in the HBV-GN group was reduced compared with the HBV-CG group (1 case vs 7 cases) (P < 0.05). HBV infection and high-virus proliferation status were closely related with HBV-GN.

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.

Glomerular Diseases Associated With Hepatitis B and C

Infections with hepatitis B virus (HBV) and hepatitis C virus (HCV) are prevalent worldwide. In this review, we discuss the epidemiology, pathogenesis, clinical manifestations, and treatment of HBV- and HCV-related glomerulonephritis (GN). The most common histopathologic presentation of HBV-GN is HBV-associated membranous nephropathy, which usually manifests clinically with varying grades of proteinuria and microscopic hematuria. The pathogenesis is likely to be immune complex mediated; however, other host and viral factors have been implicated. The treatment of HBV-GN revolves around antiviral therapy. Various histologic types of glomerular diseases are reported in association with HCV infection, the most frequent being Type 1 membranoproliferative glomerulonephritis, usually in the context of Type 2 mixed cryoglobulinemia. The pathogenesis of HCV-GN can be attributed to glomerular deposition of cryoglobulins or noncryoglobulin-immune complexes. Cryoglobulins typically comprised immunoglobulin Mκ with rheumatoid factor activity. Clinically, patients may present with proteinuria, microscopic hematuria, hypertension, and acute nephritic and/or nephrotic syndrome. The treatment of HCV-GN, especially cryoglobulinemic membranoproliferative glomerulonephritis, encompasses various options including contemporary antiviral therapy with or without conventional and novel immunomodulatory agents.

Hepatitis B virus-associated glomerulonephritis in HBsAg serological-negative patients

OBJECTIVE

The main objective of this study is to report the clinical and pathological characteristics of hepatitis B virus (HBV)-associated glomerulonephritis (HBV-GN) in serum hepatitis B surface antigen (HBsAg)-negative patients in China. HBV-GN is caused by the HBV's attack on the kidney tissues, but definitive diagnostic criteria are still lacking. The diagnostic criteria used in China require HBsAg positivity in the serum, but research on occult HBV infection has shown that HBV infection is also found in serum HBsAg-negative patients. Clinical and pathological characterization of HBV-GN in serum HBsAg-negative patients is required.

MATERIALS AND METHODS

Serologic and clinical findings and pathological characteristics of renal tissues in 18 HBV-GN patients (11 men and seven women) with serum HBsAg negativity were analyzed retrospectively. Thirty-three HBV-GN patients with serum HBsAg positivity and 59 patients with membranous nephropathy (MN) without any HBV infection markers in serum and renal tissues during the same period were included as controls.

RESULTS

Among the 18 HBsAg-negative patients with GN, 12 had HBsAb positivity in their sera. None of the patients was positive for serum HBeAg. Proteinuria was the major clinical manifestation and the renal histopathology was characterized as MN. Immune fluorescence deposits in renal tissues consisted mainly of HBsAg. The degree of renal injury and the decrease in the C3 level were less than those in HBsAg-positive patients and idiopathic membranous nephropathy patients.

CONCLUSION

We propose to use the HBV marker in renal tissues as a new diagnostic criterion for HBV-GN. If MN patients have HBV marker positivity in renal tissues, HBV-GN can be diagnosed even without HBsAg in the serum. This would improve the diagnostic accuracy and potential treatment efficiency.

The genotype C could play a key role in hepatitis B virus associated nephritis among the northwest Chinese children

BACKGROUND

Hepatitis B virus-associated glomerulonephritis (HBV-GN) is a kind of immune complex-induced glomerulonephritis. The present study was designed to determine whether Hepatitis B virus (HBV) genotype is associated with glomerulonephritis in north-west Chinese children.

METHODS

A total of 296 HBV-infected patients were enrolled in this study. The serum of patients was subjected to DNA extraction and the HBV genotypes were determined by PCR.

RESULTS

The results showed that genotype C (49%) was predominant within the subjects, compared to HBV/B (38.5%), B/C recombinant (7.4%) and none B/C (5.1%). The serum tests showed that the changes of Complement 3 (C3) and alanine amino transferase (ALT) levels in the genotype C patients were significantly greater than those in the genotype B patients. The frequency of genotype C in HBV-GN patients was higher than that in non HBV-GN patients (χ2 value=30.239, P<0.001). But, it was not associated with renal dysfunction. Furthermore, The genotype C was associated with high HBV-DNA load (82.9% vs 17.1%, P<0.001), which is seen more frequently in the HBV-GN children (86.3% vs 13.3%, P=0.004).

CONCLUSIONS

The genotype C may play a role in HBV-GN children, via favoring HBV replication.

Meta-analysis of combined therapy for adult hepatitis B virus-associated glomerulonephritis

AIM: To investigate the efficacy and safety of combined antiviral and immunosuppressant therapy in adult hepatitis B virus-associated glomerulonephritis (HBV-GN) patients.

METHODS: A computerized literature search was carried out in the PubMed database, Embase, the Cochrane Library, Chinese BioMedical Literature on disc, Chinese Medical Current Contents, Chinese National Knowledge Infrastructure, Wanfang and VIP (Chinese Technological Journal of Database) to collect articles between June 1980 and December 2010 on therapy with immunosuppressants, e.g., glucorticosteroids, mycophenolate mofetil and leflunomide, combined with antivirals, e.g., interferon, lamivudine, entecavir and adefovir dipivoxil, in adult HBV-GN patients. The primary outcomes were remission of proteinuria, clearance of HBV e-antigen, and elevation of serum albumin. The secondary outcomes were blood levels of alanine aminotransferase, serum creatinine, and HBV-DNA titer. Meta-analysis was performed using Review Manager 5.1. Fixed or random effect models were employed to combine the results after a heterogeneity test. The effects of the combined therapy were analyzed for different doses of glucorticosteroid and different types of HBV-GN.

RESULTS: Twelve clinical trials with 317 patients were included. A significantly higher incidence of HBV-GN was found in male patients (relative risk = 2.40, 95% CI: 1.98-2.93). Combined therapy reduced the proteinuria significantly with a mean difference of 4.19 (95% CI: 3.86-4.53) and increased the serum albumin concentration significantly with a mean difference of -11.95 (95% CI: -12.97-10.93) without significant alterations of liver function (mean difference: 4.62, 95% CI: -2.55-11.79) and renal function (mean difference: 10.29, 95% CI: 0.14-20.45). No significant activation of HBV-DNA replication occurred (mean difference: 0.12, 95% CI: -0.37-0.62). There was no significant difference between the high dose glucorticosteroid group and the low dose glucorticosteroid group in terms of proteinuria remission (P = 0.76) and between different pathological types of HBV-GN [membranous glomerulonephritis (MN) vs mesangial proliferative glomerulonephritis, P = 0.68; MN vs membranoproliferative glomerulonephritis, P = 0.27].

CONCLUSION: Combined antiviral and immunosuppressant therapy can improve the proteinuria in HBV-GN patients without altering HBV replication or damaging liver and renal functions.

Hepatitis B virus-associated glomerular nephritis in East Asia: progress and challenges

BACKGROUND

Hepatitis B virus-associated glomerular nephritis (HBV-GN) is the most common secondary glomerulonephritis in East Asia. Part of the patients developed to renal insufficiency within 10 years, which cause a great burden for patients' family and society.

METHODS

We reviewed basic and clinical research work in China, Japan, Korea, and Mongolia, eastern part of Asia. Comparisons between data from East Asia and those from other regions were made.

RESULTS

The genetic variations conferring susceptibility to HBV-GN and disease progression as well as the pathogenic role in HBV-GN progression were investigated. Clinical features of HBV-GN in East Asia were different from that of other regions in the world. Clinical trials showed that treatment with anti-viral agents was effective to promote the disease remission.

CONCLUSION

HBV-GN remains a great challenge to East Asian nephrologists. In-depth basic studies and multi-centered clinical trials are needed in the future.

Hepatitis B and Renal Disease

Glomerulonephritis is an important extrahepatic manifestation of chronic hepatitis B virus (HBV) infection. The uncommon occurrence, variability in renal histopathology, and heterogeneity in clinical course present challenges in clinical studies and have resulted in a relative paucity of data and uncertainty with regard to the optimal management of HBV-related glomerular diseases. The advent of nucleos(t)ide analogue medications that effectively suppress HBV replication has markedly altered the clinical outcomes of kidney transplant recipients with HBV infection, but the emergence of drug resistance is an escalating problem. This article reviews the recent knowledge of the pathogenesis and treatment of HBV-related membranous nephropathy, and discusses the management of hepatitis B in kidney transplant recipients, which is continuously evolving.

Membranous nephropathy associated with chronic hepatitis B occurring in a short period after acute hepatitis B virus infection

We herein present a case of membranous nephropathy associated with chronic hepatitis B following acute hepatitis B virus (HBV) infection. A 22-year-old man was admitted to our hospital for evaluation of proteinuria, pitting edema on both legs, and increased body weight in December 2002. At the age of 18, he had suffered from acute hepatitis A and syphilis, and was found to be negative for hepatitis B surface antigen (HBsAg). Furthermore, he suffered from acute hepatitis B (AH-B) at the age of 21; he was found to be positive for HBsAg and anti-IgM antibody to core antigen (IgM HBcAb). However, he discontinued outpatient treatment before confirmation of HBsAg clearance or the appearance of antibody to HBsAg (HBsAb). At the present admission, HBsAg, antibody to hepatitis B e antigen (HBeAg), and HBcAb were positive, while IgM HBcAb was negative. His genotype of HBV was type A (HBV/A). Histopathological findings of the renal biopsy specimen confirmed glomerulonephritis and glomerular deposition of HBsAg. Thus, he was diagnosed as having nephrotic syndrome caused by membranous nephropathy (MN) associated with chronic hepatitis B (CH-B) following AH-B. Although interferon-alpha (IFN-alpha) administration was started for the treatment and temporary improvement of proteinuria was observed, remission of MN was not achieved.