Membranoproliferative glomerulonephritis associated with hepatitis C virus infection

The 2010 nephrology quiz and questionnaire: part 2

Presentation of the Nephrology Quiz and Questionnaire (NQQ) has become an annual "tradition" at the meetings of the American Society of Nephrology. It is a very popular session judged by consistently large attendance. Members of the audience test their knowledge and judgment on a series of case-oriented questions prepared and discussed by experts. They can also compare their answers in real time, using audience response devices, to those of program directors of nephrology training programs in the United States, acquired through an Internet-based questionnaire. As in the past, the topics covered were transplantation, fluid and electrolyte disorders, end-stage renal disease and dialysis, and glomerular disorders. Two challenging cases representing each of these categories along with single best answer questions were prepared by a panel of experts (Drs. Hricik, Palmer, Bargman, and Fervenza, respectively). The "correct" and "incorrect" answers then were briefly discussed, after the audience responses and the results of the questionnaire were displayed. The 2010 version of the NQQ was exceptionally challenging, and the audience, for the first time, gained a better overall correct answer score than the program directors, but the margin was small. Last month we presented the transplantation and fluid and the electrolyte cases; in this issue we present the remaining end-stage renal disease and dialysis and the glomerular disorder cases. These articles try to recapitulate the session and reproduce its educational value for a larger audience--that of the readers of the Clinical Journal of the American Society of Nephrology. Have fun.

Hepatitis C virus and kidney: a strong association with different clinical aspects

The most frequent kidney disease associated with chronic hepatitis C virus (HCV) infection is membranoproliferative glomerulonephritis in patients with type II mixed cryoglobulinaemia. The principal clinical manifestations of glomerular disease in HCV-infected patients are the presence of proteinuria and haematuria with or without impaired kidney function. Pharmaceutical regimens vary because the main pathogenesis of renal dysfunction often mediated by cryoglobulins has not been fully elucidated. HCV infection remains common in patients on renal replacement therapy and has an adverse impact on their survival. Safe and effective pharmaceutical regimens have not been yet established and nosocomial spread within dialysis units continues to occur. Monotherapy with interferon for HCV infection is probably more effective in dialysis than in non-uraemic patients, while experience with ribavirin is limited because of its adverse haemolytic effect. Based on shortage of cadaver kidneys and the fact that HCV renal transplant recipients have better survival than stay on maintenance haemodialysis or at list for transplantation, health organization proposed the use of cadaver kidneys from anti-HCV-positive donors, bringing up concerns and conflicting views. This present review describes the main renal manifestations of HCV infection, the epidemiological and clinical characteristics of chronic kidney disease population and comments on the limitations and shortcomings of current therapeutical regiments.

Hepatitis C virus infection among patients with chronic immune thrombocytopenic purpura in northern India

BACKGROUND

Hepatitis C virus (HCV) has been reported to be associated with the occurrence of autoimmune disorders, including immune thrombocytopenic purpura (ITP). This has suggested that HCV could be responsible for thrombocytopenia in these patients. This study was performed to estimate the frequency of HCV infection in patients of chronic ITP (cITP), and to find the frequency of thrombocytopenia in chronic HCV infection.

MATERIALS

A total of 150 subjects were included in the study. Fifty consecutive adult patients with cITP (< 6 months' duration) and 50 age-matched patients with chronic HCV were included for comparison of platelet counts in two groups. Fifty age-matched healthy subjects were also included in the control group. All patients' sera were tested for the presence or absence of HCV-RNA. Anti-HCV antibodies were tested in patients as well as in controls. Complete blood count and examination of peripheral blood smear were done followed by bone-marrow aspiration to confirm the diagnosis of ITP.

RESULTS

Three patients (6%) were tested positive for anti-HCV antibodies while no subject was positive in control group (P=0.24). The prevalence of severe thrombocytopenia (platelet counts <50,000/mL) was significantly higher in ITP patients compared with that in chronic HCV patients (P=0.0001). Thrombocytopenia occurred more frequently in patient with moderate to severe than mild stage of fibrosis (P=0.001).

CONCLUSION

In conclusion, thrombocytopenia in ITP patients was not associated with HCV infection. The prevalence of thrombocytopenia was more common and more severe in ITP patients when compared with that in patients with chronic HCV. Thrombocytopenia in chronic HCV patients was related to the stage of fibrosis and to the duration of HCV infection.

Treatment of hepatitis C-mediated glomerular disease

Chronic kidney disease (CKD) is becoming a major public health issue worldwide, mainly due to the increasing prevalence of hypertension, diabetes and aging population. Chronic hepatitis C virus (HCV) infection commonly involves the kidneys, can be a cause of CKD, and significantly impacts morbidity and mortality in these patients. Prompt recognition and knowledge of how to best manage these patients are essential in order to have a successful renal outcome. Patients with HCV and kidney involvement can often be managed with a specific combination of antiviral drugs, immunosuppressants, plasmapheresis, and newer monoclonal antibodies. However, no large randomized controlled trials have been conducted in this patient population, optimal management of HCV-mediated kidney diseases is not well defined, and treatment itself can be associated with significant toxicity in patients with CKD. This article reviews the recent literature, discusses the limitations of current therapies, as well as toxicity associated with treatment, and suggests future areas for research.

Higher prevalence of chronic kidney disease and shorter renal survival in patients with chronic hepatitis C virus infection

BACKGROUND

The role of hepatitis C virus infection (HCV) in the etiology and progression of chronic kidney disease (CKD) is controversial.

AIM

To measure the prevalence of CKD and evaluate its course in patients with chronic HCV infection.

METHODS

A retrospective analysis was done after excluding patients with nephrolithiasis, structural kidney disease, and those with missing clinical information on 552 anti-HCV-positive patients and 313 patients without known HCV infection matched for age, race, and gender. CKD was defined as estimated glomerular filtration rate value of <60 mL/min/1.73 m(2) and/or persistence of proteinuria (>3 months) on urine analysis by dipstick. Viral load obtained during the initial evaluation was defined as "baseline viral load".

RESULTS

The prevalence of CKD in the anti-HCV-positive group was significantly higher compared to control group [53 (9.6%) vs. 16 (5.1%), P = 0.02]. On multivariate regression analysis, higher age, hypertension, HCV PCR > 7 × 10(5) cps/mL, and diabetes mellitus were significant independent positive predictors, whereas history of interferon treatment was significant independent negative predictor for CKD. Male gender, human immunodeficiency virus status, body weight, intravenous drug use, and HCV genotype were not predictors of CKD. Analysis of renal survival through Kaplan-Meyer curves revealed significantly shorter time to develop CKD (74 vs. 84 months, P < 0.001; log rank) and end-stage renal disease (79.9 vs. 86.5 months, P = 0.005; log rank) in the HCV group compared to the control group.

CONCLUSION

Chronic HCV infection was associated with a significantly higher prevalence of CKD compared with controls, as well as significantly shorter renal survival. A higher baseline viral load is an independent predictor of CKD.

Effect of kidney transplantation on outcomes among patients with hepatitis C

The long-term outcome of kidney transplantation in patients infected with hepatitis C virus (HCV) and end stage renal disease (ESRD) is not well described. We retrospectively identified 230 HCV-infected patients using enzyme immunoassay and nucleic acid testing obtained during the transplant evaluation. Of 207 patients who had a liver biopsy before transplant, 44 underwent 51 follow-up liver biopsies at approximately 5-year intervals either while on the waitlist for a kidney or after kidney transplantation. Advanced fibrosis was present in 10% of patients biopsied, identifying a population that may warrant consideration for combined liver-kidney transplantation. Kidney transplantation does not seem to accelerate liver injury; 77% of kidney recipients who underwent follow-up biopsies showed stable or improved liver histology. There was a higher risk for death during the first 6 months after transplant, but undergoing transplantation conferred a long-term survival advantage over remaining on the waitlist, which was evident by 6 months after transplant (HR, 0.32; 95% CI, 0.17 to 0.62). Furthermore, the risk for death resulting from infection was significantly higher during the first 6 months after transplant (HR, 26.6; 95% CI, 5.01 to 141.3), whereas there was an early (≤6 months) and sustained decrease in the risk for cardiovascular death (HR, 0.20; 95% CI, 0.08 to 0.47). In summary, these data suggest the importance of liver biopsy before transplant and show that kidney transplantation confers a long-term survival benefit among HCV-infected patients with ESRD compared with remaining on the waitlist. Nevertheless, the higher incidence of early infection-related deaths after transplant calls for further study to determine the optimal immunosuppressive protocol.

A causative link between periodontal disease and glomerulonephritis: a preliminary study

Background:

Periodontal disease has been associated with a number of systemic diseases. A high prevalence of periodontitis among individuals with chronic kidney diseases and end-stage renal disease has been reported. However, no association between periodontal diseases and glomerulonephritis has previously been investigated.

Objective:

The aim of this study was to assess the severity and possible role of periodontitis in a group of patients with unknown primary glomerulonephritis.

Methods:

Ten patients with unknown primary glomerulonephritis, and who had a renal biopsy with stable renal function and serum creatinine <1.6 mg/dL, were recruited. Severity of the periodontal disease was clinically measured with plaque index (PI), gingival index (GI), and periodontal pocket depth (PD). The subjects received appropriate dental treatments where indicated. The patients were also put on angiotensin-converting enzyme inhibitor or angiotensin receptor blockers for controlling blood pressure and proteinuria. Six months following appropriate periodontal treatment, renal function, degree of proteinuria, and level of C-reactive protein (CRP) were measured in each individual.

Results:

The median age of the patients was 30 (15.8) years. The median urine protein excretion was lower following the periodontal therapy (P=008). Prior to the dental and/or periodontal therapies, the median PI, PD, and GI were 57.5%, 4.3, and 1.1, respectively. The majority of the patients had advanced periodontal disease. In four patients, +2/+3 CRP turned negative after periodontal treatment.

Conclusions:

The present study revealed that a causative link might exist between periodontal disease and glomerulonephritis.

Kidney grafts from HCV-positive donors: advantages and disadvantages

The Organ Procurement and Transplantation Network database (2001-2006) was reviewed for kidney transplant (KT) recipients, to evaluate the effects of use of grafts from donors positive for hepatitis C virus (HCV) on recipient outcome. Data for 76,787 de novo adult KT recipients were included in the analysis. Serologic tests revealed HCV positivity in 6.25% of cadaver kidneys and 2.97% of living-donor kidneys. Median follow-up in patients still alive was 36 months. At multivariable Cox regression analysis in recipients of cadaver kidney, HCV serostatus was significantly associated with overall and graft survival (both P < .001), with a hazard ratio for HCV-positive patients of 1.43 for overall survival and 1.48 for graft survival. Similar results were obtained for living-donor kidney recipients. Recipients of HCV-positive organs tended to be male and African American and to have a shorter waiting time. Infection was the most commonly reported cause of death in recipients of organs from HCV-positive donors. In patients willing to accept HCV-positive grafts (929 [25.6%]), waiting time was significantly shortened (P < .001). However, this benefit was offset by decreased patient survival (P < .001) and graft survival (P = .007).

Distinctive gene expression profiles characterize donor biopsies from HCV-positive kidney donors

BACKGROUND

Because of the shortage of organs for transplantation, procurement of kidneys from extended criteria donors is inevitable. Frequently, donors infected with hepatitis C virus (HCV) are used. To elucidate an initial compromise of molecular pathways in HCV graft, gene expression profiles were evaluated.

METHODS

Twenty-four donor allograft biopsies (n=12 HCV positive (+) and n=12 HCV negative (-)) were collected at preimplantation time and profiled using microarrays. Donors were age, race, gender, and cold and warm ischemia time matched between groups. Probe level data were read into the R programming environment using the affy Bioconductor package, and the robust multiarray average method was used to obtain probe set expression summaries. To identify probe sets exhibiting differential expression, a two sample t test was performed. Molecular and biologic functions were analyzed using Interaction Networks and Functional Analysis.

RESULTS

Fifty-eight probe sets were differentially expressed between HCV (+) versus HCV (-) donors (P<0.001). The molecular functions associated with the two top scored networks from the analysis of the differentially expressed genes were connective tissue development and function and tissue morphology (score 34), cell death, cell signaling, cellular assembly, and organization (score 32). Among the differentially affected top canonical pathways, we found the role of RIG1-like receptors in antiviral innate immunity (P<0.001), natural killer cell signaling (P=0.007), interleukin-8 signaling (P=0.048), interferon signaling (P=0.0 11; INFA21, INFGR1, and MED14), ILK signaling (P=0.001), and apoptosis signaling.

CONCLUSIONS

A unique gene expression pattern was identified in HCV (+) kidney grafts. Innate immune system and inflammatory pathways were the most affected.

Allograft failure in kidney transplant recipients with membranoproliferative glomerulonephritis

BACKGROUND

Membranoproliferative glomerulonephritis types I (MPGN-I) and II (MPGN-II) are rare diseases that in limited case series have been reported to recur frequently in kidney transplants and have a negative impact on allograft survival.

STUDY DESIGN

Retrospective database review.

SETTING & PARTICIPANTS

189,211 primary kidney transplants in the United Network for Organ Sharing (UNOS) database from September 1987 to May 2007.

PREDICTOR OR FACTOR

MPGN-I (811 patients; 0.4%), MPGN-II (179 patients; 0.1%), other GN (58,129 patients; 30.7%), and all other diagnoses (130,092 patients; 68.7%).

OUTCOMES

Death-censored and non-death-censored allograft survival.

RESULTS

Compared with controls, patients with MPGN-I and MPGN-II were significantly younger at the time of transplant, with a median age of 36 and 27 years compared with 44 years in the GN group and 46 years in all other disease groups, respectively (all P < 0.001). Mortality in patients with MPGN-I (8.8%) was significantly lower compared with the GN (11.3%; P = 0.02) and other disease (16.6%; P < 0.001) populations and lower in those with MPGN-II (9.5%) compared with the other disease (16.6%; P = 0.01) population. Graft failure rates were significantly higher in the MPGN-I (44.5%) cohort, but not in the MPGN-II (45.3%) cohort compared with the GN (38.0%) population (P < 0.001 and P = 0.05, respectively); neither MPGN cohort differed from the other disease (43.0%) population (P = 0.4 and P = 0.5). Overall, 10-year death-censored graft survival was similar for MPGN-I (56.2%) and MPGN-II (57.5%); both were significantly worse than for GN (65.2%; P < 0.001 and P = 0.003, respectively), and only MPGN-I was significantly worse than the other disease (60.0%) population (P = 0.004). Of allograft failures with a reported cause, disease recurrence was the primary cause in 36 (14.5%) MPGN-I and 18 (29.5%) MPGN-II transplant recipients and was significantly higher compared with 879 (6.6%) GN and 1,319 (4.4%) all-other-disease recurrence failures (P < 0.001).

LIMITATIONS

Limited pretransplant clinical and biopsy data.

CONCLUSIONS

A diagnosis of MPGN-I or MPGN-II has a significant negative impact on overall primary allograft survival compared with other forms of glomerulonephritis, whereas only MPGN-I has a significant, but modest, negative effect compared with other causes of end-stage renal disease.

Clinical features of acute renal failure associated with hepatitis A virus infection

Acute hepatitis A (AHA) is one of the most common infectious diseases; it is usually a self-limiting disease affecting the liver. Although extrahepatic manifestations are not common, some cases have been reported associated with acute renal failure. We reviewed the clinical features of patients with AHA complicated by acute renal failure (ARF group) and compared them with patients with noncomplicated AHA (non-ARF group). The medical records of 208 consecutive patients with AHA who were diagnosed between January 2003 and October 2008 were reviewed. We identified 15 patients (7.2%) with ARF associated with AHA. There were no differences between the ARF and non-ARF group with regard to gender and age. The peak value of alanine aminotransferase (ALT) (median: 6060 IU/L vs 1792 IU/L, P < 0.001), prothrombin time (PT) (International normalized ratio, median 1.72 vs 1.10, P < 0.001), and total bilirubin level (median: 9.6 mg/dL vs 6.3 mg/dL, P = 0.04) were significantly higher in the ARF than in the non-ARF group. Twelve patients (80%) recovered completely with haemodialysis (seven patients, 46.7%) or only conservative management (five patients, 33.3%), while one patient underwent liver transplantation because of fulminant hepatic failure, and two patients died because of fulminant hepatic failure. There were no deaths among patients with noncomplicated AHA in the non-ARF group. Five patients underwent kidney biopsy; two patients were diagnosed with acute tubular necrosis, two patients with acute interstitial nephritis with IgA nephropathy and one patient with acute tubulointerstitial nephritis. All patients in the ARF group had microscopic haematuria and proteinuria (100%vs 31.1%, P < 0.001). Urine sodium levels were more than 10 mEq/L in 10 patients. The findings of high urinary sodium concentrations, microscopic haematuria and proteinuria did not support the diagnosis of hepatorenal syndrome (HRS). Patients with AHA with ARF had higher ALT levels, more prolonged PTs, and higher total bilirubin levels. The prognosis for these patients was poorer than for those without ARF. However, the patients with ARF and nonfulminant AHA had recovered with proper treatment and should not be confused with patients that have HRS.

Hepatitis C and kidney disease

Multiple extrahepatic manifestations have been associated with chronic hepatitis C, the most important among them being cryoglobulinemia, glomerulonephritis, porphyria cutanea tarda, lichen planus, seronegative arthritis, and lymphoproliferative disorders as in the sudies of Bonkovsky and Mehta (2001) and El-Serag et al. (2002). We will discuss in this paper chronic hepatitis C- related kidney disease and course and management of patients with chronic hepatitis C in special circumstances like hemodialysis and kidney transplantation.

Hepatitis C increases the risk of progression of chronic kidney disease in patients with glomerulonephritis

BACKGROUND/AIMS

We have shown that hepatitis C does not increase the risk of developing chronic kidney disease (CKD), but it is not known if hepatitis C worsens progression of existing CKD.

METHODS

We retrospectively identified patients with primary glomerulonephritis on biopsy over 4 years, evaluating the progression of CKD over time.

RESULTS

The cohort consisted of 111 patients: 21% were positive for hepatitis C, 61% were negative for hepatitis C and 18% were not tested. The hepatitis C-positive subjects were more likely to be African American (p = 0.031), followed for fewer days (p = 0.007) and have diabetes and focal segmental glomerulosclerosis on biopsy (p < 0.001). Longitudinal follow-up of CKD progression using multiple creatinine measures analyzed by repeated measures ANCOVA demonstrated that patients with hepatitis C had a worsening creatinine over time compared to the hepatitis C-negative and not tested groups (p < 0.001). By Cox hazards regression analyses, risk of death/end-stage renal disease (ESRD) was decreased in patients who tested negative for hepatitis C compared to testing positive (0.46, CI 0.27-0.88), but this became nonsignificant after adjustment for mean arterial pressure and hemoglobin.

CONCLUSION

Our results support that infection with hepatitis C in patients with glomerulonephritis is associated with an increased risk of progression of CKD. Prospective studies are required to confirm these observations.

Chronic viral hepatitis and chronic kidney disease

Chronic kidney disease (CKD) has become a major public health problem worldwide over the past few decades because of the increasing prevalence of hypertension, diabetes mellitus, and elderly individuals in most countries. Chronic viral hepatitis (due to hepatitis B virus (HBV) and hepatitis C virus (HCV)) also poses significant morbidity and mortality globally. Both these viruses can cause CKD and these infections can occur as a consequence of CKD management. CKD patients acquiring HBV or HCV infection have higher morbidity and mortality rates, and the management of these infections among CKD patients with antiviral agents is associated with high rates of adverse effects. The optimal management of CKD associated with HBV and HCV is not well defined because of insufficient data from clinical trials. This review discusses the pathogenesis, clinical characteristics and management issues related to chronic viral hepatitis and CKD.

Immunity and immunopathology to viruses: what decides the outcome?

Many viruses infect humans and most are controlled satisfactorily by the immune system with limited damage to host tissues. Some viruses, however, do cause overt damage to the host, either in isolated cases or as a reaction that commonly occurs after infection. The outcome is influenced by properties of the infecting virus, the circumstances of infection and several factors controlled by the host. In this Review, we focus on host factors that influence the outcome of viral infection, including genetic susceptibility, the age of the host when infected, the dose and route of infection, the induction of anti-inflammatory cells and proteins, as well as the presence of concurrent infections and past exposure to cross-reactive agents.

Relationship between hepatitis C virus infection and pulmonary disorders: potential mechanisms of interaction

Recently, an increasing number of reports have suggested that chronic hepatitis C virus (HCV) infection is associated with pulmonary disorders. The effects of HCV on the lung may present as worsening of lung function and impaired responses to therapy in patients with chronic obstructive pulmonary disease and asthma. Moreover, chronic HCV infection may be associated with the pathogenesis of interstitial lung disease. It is believed that chronic HCV infection may contribute to the immune responses modulating the pathogenic processes underlying pulmonary disorders and, therefore, may lead to a wide spectrum of clinical presentations. Potential candidates for a role in these immune responses are the CD8(+) T lymphocytes and inflammatory cytokines. In this review, the effects of HCV on the lung and the potential mechanisms of interaction between chronic HCV infection and pulmonary disorders will be discussed.

Delayed spontaneous resolution of nephrotic syndrome in a patient with hepatitis C virus-associated membranoproliferative glomerulonephritis

Treatment with antiviral and/or immunosuppressive therapy is considered the standard care in patients with hepatitis C virus (HCV)-associated membranoproliferative glomerulonephritis (MPGN). However, even with an adequate therapy, a favourable response is not always guaranteed. In patients with HCV-associated MPGN, a delayed spontaneous remission of nephrotic syndrome is rare. We present here one such case. Our patient refused antiviral (and immunosuppressive) therapy throughout the course of his illness and was thus managed symptomatically. More than 8 months after presentation, an unexpected gradual resolution of his nephrotic syndrome was noted. The urine protein/creatinine ratio decreased from ~16 000 mg/g of creatinine on presentation to 500 mg/g of creatinine in the 12th month. This was however not accompanied by resolution of HCV or cryoglobulinaemic activity. Our case demonstrates the possibility of a delayed spontaneous remission occurring in this disease. This must be considered when weighing treatment options in such patients.

Infection: a hypothesis on active susceptibility and species immunity with implications for AIDS prevention

There is no fundamental difference in contagiousness or pathogenicity between the normal and pathogenic microfloras: both are contagious, and both may either cause illness or persist in the body of a healthy carrier. The contagiousness of the normal microflora is determined by its positive function in the host. In addition to the normal microflora, endogenous retrovirus genes are also useful for a macroorganism: they have been found to be integral elements of many animal and plant genomes and participate in vital functions, such as genome activity control, antiviral defense, and formation of the placenta; dysfunction of some endogenous retrovirus genes causes pathology. Components of bacterial cells cause protective effects with respect to noninfectious somatic diseases. Therefore, it is reasonable to assume that natural susceptibility to both "normal" and "pathogenic" microfloras results from vital necessity for a macroorganism to interact with them. The necessity to interact with specific microorganisms and, hence, susceptibility to them is the cause of their infectivity. In this connection, studies on the positive functions of specific "pathogenic" microflora in a macroorganism with the use of SPF animals would be of interest. Even more interesting would be experiments with transfer of specific microbial genes into the genomes of susceptible species, which may help to understand the causes and mechanisms of susceptibility/insusceptibility as a basis of species immunity and develop fundamentally new and more natural methods for preventing and treating infectious diseases.

Systemic lupus erythematosus and Sjögren's syndrome induced in a case by interferon-α used for the treatment of hepatitis C

A 57-year-old Japanese woman developed skin eruption, pleuritis, pancytopenia, parotid gland swelling and glomerulonephritis after 7-month treatment with pegylated interferon-α and ribavirin for chronic hepatitis C. Disease-specific autoantibodies such as anti-SSA, anti-SSB, anti-Sm and anti-dsDNA antibodies became positive. The diagnosis of systemic lupus erythematosus and Sjögren’s syndrome was made and treatment with glucocorticoid pulse followed by oral glucocorticoid was started. It is highly probable that interferon-α-induced systemic lupus erythematosus and Sjögren’s syndrome in this case. Interferon-α might be important pathogenically in these diseases. Lupus (2010) 19, 753—755.

Clinicopathological study on hepatitis C virus-associated glomerulonephritis without hepatitis C virus in the blood

PURPOSE

Patients with hepatitis C virus (HCV)-associated glomerulonephritis in whom HCV RNA was not detected in the blood have been reported. We attempted to uncover the differences between HCV RNA-negative and HCV RNA-positive cases.

METHODS

The clinical and pathological findings for 5 patients with HCV-associated glomerulonephritis without HCV in the blood were compared with those for 23 patients with HCV RNA-positive HCV-associated glomerulonephritis.

RESULTS

The HCV RNA-negative cases were characterized by advanced age, female dominance, no cryoglobulinemia and no glomerular deposition of IgG compared with the HCV RNA-positive cases, although no differences were observed in amount of urinary protein, frequency of nephrotic syndrome, serum levels of total protein, creatinine level, presence of hypocomplementemia and rheumatoid factor. The prognosis was similar for both groups.

CONCLUSION

These cases point to the need for further study of the pathogenesis of this disease.

The complement system in systemic autoimmune disease

Complement is part of the innate immune system. Its major function is recognition and elimination of pathogens via direct killing and/or stimulation of phagocytosis. Activation of the complement system is, however, also involved in the pathogenesis of the systemic autoimmune diseases. Activation via the classical pathway has long been recognized in immune complex-mediated diseases such as cryoglobulinemic vasculitis and systemic lupus erythematosus (SLE). In SLE, the role of complement is somewhat paradoxical. It is involved in autoantibody-initiated tissue damage on the one hand, but, on the other hand, it appears to have protective features as hereditary deficiencies of classical pathway components are associated with an increased risk for SLE. There is increasing evidence that the alternative pathway of complement, even more than the classical pathway, is involved in many systemic autoimmune diseases. This is true for IgA-dominant Henoch Schönlein Purpura, in which additional activation of the lectin pathway contributes to more severe disease. In anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis the complement system was considered not to be involved since immunoglobulin deposition is generally absent in the lesions. However, recent studies, both in human and animal models, demonstrated complement activation via the alternative pathway as a major pathogenic mechanism. Insight into the role of the various pathways of complement in the systemic autoimmune diseases including the vasculitides opens up new ways of treatment by blocking effector pathways of complement. This has been demonstrated for monoclonal antibodies to C5 or C5a in experimental anti-phospholipid antibody syndrome and ANCA-associated vasculitis.

Clinical and morphologic spectrum of renal involvement in patients with mixed cryoglobulinemia without evidence of hepatitis C virus infection

Hepatitis C virus (HCV) infection represents, by far, the major cause of mixed cryoglobulinemia (MC). The renal disease associated with this pathological condition is now well described. By contrast, renal involvement in patients with MC not associated with HCV has been only poorly described, and few cases have been reported. We analyzed the demographic, clinical, and laboratory features and outcome in patients presenting with renal disease associated with MC not related to HCV infection. Records of 20 patients with MC and renal disease, with no evidence of HCV by serology and polymerase chain reaction analysis, were retrospectively analyzed. Renal biopsies and extensive searches for lymphoproliferative disorder were performed in all patients at presentation. MC was related to primary Sjögren Syndrome (pSS) in 9 patients, and to non-Hodgkin lymphoma in 1 patient, while MC was classified as essential in the remaining 10 cases. Renal involvement was characterized by microscopic hematuria in all patients, nephrotic range proteinuria in 75% of patients, hypertension in 80% of patients, and renal failure in 85% of patients (mean glomerular filtration rate, 46 mL/min per 1.73 m). Membranoproliferative glomerulonephritis with subendothelial deposits was observed in all kidney specimens. Skin vasculitis was the main extrarenal manifestation. In all patients, cryoglobulinemia was classified as type II MC, characterized by monoclonal IgMkappa and polyclonal IgG. Most patients (17/20) were treated with steroids or immunosuppressive agents, or both. Initial renal remission was observed in 94% of patients. However, renal relapse occurred in most patients, with 10% reaching end-stage renal disease. Three patients with essential MC developed B-cell lymphoma 36-48 months after the diagnosis of MC. Unexpectedly, B-cell lymphoma induced by Epstein-Barr virus infection occurred in only 1 of the 9 pSS patients. Forty percent of patients died as a result of extrarenal causes.Renal disease associated with MC unrelated to HCV is characterized by the high prevalence of pSS (45%), the finding of CD20+ B-lymphocyte nodular infiltrates in the kidney interstitium, and a high incidence of overt B-cell lymphoma during follow-up. These findings emphasize the need for repetitive clinical evaluation in those patients.

Hepatitis C virus-induced cryoglobulinemia

In this review we discuss the clinical manifestations, pathogenesis, and treatment of hepatitis C virus (HCV)-related cryoglobulinemia. HCV is a major cause of liver-related morbidity and is increasingly recognized as an instigator of B-cell lymphoproliferative disorders such as mixed cryoglobulinemia and non-Hodgkin lymphoma. Cryoglobulinemia is characterized by the clonal expansion of rheumatoid factor-expressing B cells in the liver, lymph nodes, and peripheral blood, resulting in the presence of cryoglobulins in the circulation. Cryoglobulins are cold-insoluble immune complexes containing rheumatoid factor, polyclonal IgG, and HCV RNA that precipitate and deposit on vascular endothelium, causing vasculitis in organs such as the skin, kidneys, and peripheral nerves. A subset of patients develops a low-grade lymphoma composed of B cells that are immunophenotypically similar to the expanded B cells seen in cryoglobulinemia. HCV-related B-cell lymphoproliferative disorders likely comprise a spectrum of disease, ranging from asymptomatic clonal B-cell expansions to pathogenic cryoglobulinemia and lymphoma. It is unclear how B cells become dysregulated during the course of chronic HCV infection, and continued patient-centered research is necessary to elucidate the pathogenesis of HCV-related B-cell dysregulation.

Anti-Soluble Liver Antigen (SLA) Antibodies in Chronic HCV Infection

Hepatitis C infection is associated with autoimmune disorders, such as the production of autoantibodies. Anti-LKM1 and anti-LC1, immunomarkers of type 2 autoimmune hepatitis, have been previously associated with a HCV infection. Anti-Soluble-Liver-Antigen autoantibodies (SLA) are specifically associated with type 1 and type 2 autoimmune hepatitis and more closely related to patients who relapse after steroid therapy. The recent molecular cloning of the soluble liver antigen provides the opportunity to develop more specific tests for the detection of antibodies against it. The aim of this work is to characterize anti-soluble-liver autoantibodies in sera from patients chronically infected by HCV. A recombinant cDNA from activated Jurkat cells coding for the full length tRNP(Ser)Sec/SLA antigen was obtained. ELISA, Western Blot and immunoprecipitation tests were developed and used to search for linear and conformational epitopes recognized by anti-SLA antibodies in sera from patients chronically infected by HCV. Anti-soluble liver antigen antibodies were found in sera from 10.4% of HCV-infected patients. The prevalence was significantly increased to 27% when anti-LKM1 was also present. Most anti-SLA reactivity was directed against conformational epitopes on the antigen. The means titers by ELISA were lower than those obtained in type 2 AIH. The result of autoantibody isotyping showed a subclass restriction to IgG1 and also IgG4. This study shows the presence of anti-SLA antibodies in approximately 10% of HCV infected patients. The prevalence of SLA autoantibodies in HCV infected patients increases when LKM1 autoantibodies are also present. The relationship between the prevalence of this characteristic autoimmune hepatitis autoantibody and the implication of an autoimmune phenomenon in the liver injury of patients chronically infected by HCV needs further investigation.

Hepatitis C seropositivity and kidney function decline among women with HIV: data from the Women's Interagency HIV Study

BACKGROUND

How coinfection with hepatitis C virus (HCV) impacts on the trajectory of kidney function in human immunodeficiency virus (HIV)-infected patients is unclear. This study examined the effect of HCV infection on kidney function over time in women infected with HIV.

STUDY DESIGN

Retrospective observational cohort.

SETTING & PARTICIPANTS

Study sample included participants from the Women's Interagency HIV Study who were HIV infected and had undergone HCV antibody testing and serum creatinine measurement at baseline.

PREDICTOR

HCV seropositivity.

OUTCOMES & MEASUREMENT

Estimated glomerular filtration rate (eGFR) calculated from semi-annual serum creatinine measurements using the 4-variable Modification of Diet in Renal Diseases (MDRD) Study equation. Linear mixed models were used to evaluate the independent effect of HCV seropositivity on eGFR over time, adjusting for demographic factors, comorbid conditions, illicit drug use, measures of HIV disease status, use of medications, and interactions with baseline low eGFR (<60 mL/min/1.73 m(2)).

RESULTS

Of 2,684 HIV-infected women, 952 (35%) were found to be HCV seropositive. In 180 women with chronic kidney disease (CKD) at baseline (eGFR < 60 mL/min/1.73 m(2)), HCV seropositivity was independently associated with a fully adjusted net decrease in eGFR of approximately 5% per year (95% confidence interval, 3.2 to 7.2) relative to women who were seronegative. In contrast, HCV infection was not independently associated with a decrease in eGFR in women without low eGFR at baseline (P < 0.001 for interaction).

LIMITATIONS

The MDRD Study equation has not been validated as a measure of GFR in persons with HIV or HCV infection. Proteinuria was not included in the study analysis. Because the study is observational, effects of residual confounding cannot be excluded.

CONCLUSIONS

In HIV-infected women with CKD, coinfection with HCV is associated with a modest, but statistically significant, decrease in eGFR over time. More careful monitoring of kidney function may be warranted for HIV-infected patients with CKD who are also coinfected with HCV.

Detection of the hepatitis C virus antigen in kidney tissue from infected patients with various glomerulonephritis

BACKGROUND

Several studies have postulated a causal link between hepatitis C virus (HCV) infection and renal diseases through the induction of cryoglobulinaemia. However, the detection of viral antigens within kidneys of HCV-infected patients has proved to be difficult. We studied a cohort of Chinese HCV-infected patients with various glomerulonephritis (GN) in an attempt to detect HCV antigens within their kidneys.

METHODS

Twenty-one patients with various GN were found to be serum HCV-antibody positive (seven serum HCV-RNA positive simultaneously), at the time of renal biopsy, from January 2005 to April 2008 in our hospital. A murine monoclonal antibody against the HCV-NS3 protein was employed to detect the HCV antigen using immunohistochemistry and immunogold labelling. Their clinical and pathological data were collected and further analysed.

RESULTS

The HCV-NS3 antigen was detected in six (6/21, 28.6%) HCV-antibody-positive patients by immunohistochemistry and four out of the six were serum HCV-RNA positive (4/7 in HCV-RNA positive, 57.1%). The HCV antigen mainly displayed a linear or granular deposition along glomerular capillary walls and/or mesangial region. Immunoelectron microscopy showed that the labelling of HCV-NS3 was localized mainly in electronic dense deposits. In the HCV-NS3 detectable patients, three patients were with membranoproliferative glomerulonephritis (MPGN), one with membranous nephropathy, one with IgA nephropathy and one with amyloid nephropathy. The age and urinary protein were significantly greater in HCV-NS3-positive patients than those in HCV-NS3 negative, while serum C3 level was significantly lower in the former group. No significant difference was found in serum ALT, albumin and creatinine level between the two groups.

CONCLUSION

HCV-NS3 antigens could be detected in kidney tissue of HCV-infected patients with various GN, but mainly in those with MPGN and HCV-RNA positive. HCV itself might be involved directly in the pathogenesis of HCV-associated GN.

Development of novel treatments for hepatitis C

Hepatitis C virus (HCV) infection is a major and growing global health problem, affecting about 170 million people worldwide, and is a leading cause of liver cirrhosis and hepatocellular carcinoma. Currently, treatment is restricted to interferon alfa and ribavirin, which leads to a successful outcome in only about 50% of individuals. New effective treatments with tolerable side-effect profiles are needed urgently, but development has been hindered by an inability to culture HCV and a scarcity of animal models. Herein, we review progress in HCV biology, including cell culture and new animal models, and the contribution of this work to our understanding of the virus' life-cycle and pathogenesis and development of specifically targeted antiviral treatment. We also discuss changes in our understanding of HCV epidemiology, clinical manifestations, and diagnostics.

Sustained virological response reduces incidence of onset of type 2 diabetes in chronic hepatitis C

Diabetes is present in patients with chronic hepatitis C virus infection. The aim of this retrospective cohort study was to assess the cumulative development incidence and predictive factors for type 2 diabetes after the termination of interferon therapy in Japanese patients positive for hepatitis C virus (HCV). A total of 2,842 HCV-positive patients treated with interferon (IFN) monotherapy or combination therapy with IFN and ribavirin were enrolled. The mean observation period was 6.4 years. An overnight (12-hour) fasting blood sample or a casual blood sample was taken for routine analyses during follow-up. The primary goal was the onset of type 2 diabetes. Evaluation was performed by using the Kaplan-Meier method and Cox proportional hazard analysis. Of 2,842 HCV patients, 143 patients developed type 2 diabetes. The cumulative development rate of type 2 diabetes was 3.6% at 5 years, 8.0% at 10 years, and 17.0% at 15 years. Multivariate Cox proportional hazard analysis revealed that type 2 diabetes development after the termination of IFN therapy occurred when histological staging was advanced (hazard ratio 3.30; 95% confidence interval [CI] 2.06-5.28; P < 0.001), sustained virological response was not achieved (hazard ratio 2.73; 95% CI 1.77-4.20; P < 0.001), the patient had pre-diabetes (hazard ratio 2.19; 95% CI 1.43-3.37; P < 0.001), and age was >or=50 years (hazard ratio 2.10; 95% CI 1.38-3.18; P < 0.001).

CONCLUSION

Our results indicate sustained virological response causes a two-thirds reduction in the risk of type 2 diabetes development in HCV-positive patients treated with IFN.

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.

Viruses and kidney disease: beyond HIV

SUMMARY

Human immunodeficiency virus (HIV)-infected patients may acquire new viral co-infections; they also may experience the reactivation or worsening of existing viral infections, including active, smoldering, or latent infections. HIV-infected patients may be predisposed to these viral infections owing to immunodeficiency or risk factors common to HIV and other viruses. A number of these affect the kidney, either by direct infection or by deposition of immune complexes. In this review we discuss the renal manifestations and treatment of hepatitis C virus, BK virus, adenovirus, cytomegalovirus, and parvovirus B19 in patients with HIV disease. We also discuss an approach to the identification of new viral renal pathogens, using a viral gene chip to identify viral DNA or RNA.

Hepatitis C infection and chronic renal diseases

More than 170 million people worldwide are chronically infected with the hepatitis C virus (HCV), which is responsible for over 1 million deaths resulting from cirrhosis and liver cancers. Extrahepatic manifestations are also relevant and include mixed cryoglobulinemia, lymphoproliferative disorders, and kidney disease. HCV infection is both a cause and a complication of chronic kidney disease, occurring largely in the context of mixed cryoglobulinemia. This infection also represents a major medical and epidemiologic challenge in patients with end-stage renal disease on renal replacement therapy with dialysis or transplantation. In these settings the presence of HCV correlates with higher rates of patient mortality than in HCV-negative subjects on dialysis or undergoing kidney transplant. The major concern is the lack of safe and effective drugs to treat HCV-infected patients with chronic kidney disease. Unfortunately, there are no large-scale clinical trials in this population, especially those receiving renal replacement therapy, so that strong evidence for treatment recommendations is scant. This review article provides the readers with the most recent insights on HCV infection both as cause and complication of chronic kidney disease, discusses pitfalls and limitations of current therapies, and reports on preliminary experience with novel therapeutic agents, as well as directions for future research.

Liver-kidney pathophysiological interrelationships in liver diseases

On the basis of several clinical and experimental researches, it is possible today to deepen the different mechanisms regarding kidney and liver relationships. However, the most studied field remains the renal function during liver disease. These alterations can be divided into: 1. Renal functional impairment is mainly considered due to hemodynamic derangement with a progressive decrease in peripheral vascular resistance (PVR) and an increase in cardiac output and rate, characteristic of hyperdynamic circulation, and outer cortex renal ischemia. Two principal forms of RFI characterize the hepatorenal syndrome (HRS) while in the first stage is based on the simple decrease in renal clearances with avid sodium retention. 2. Metabolic renal damage is principally due to abnormal serum levels of bile acids, bilirubin and perhaps toxic hepatic molecules which induce tubular dysfunction leading to RTA, of which type I, in the incomplete form, is the most common, varying between 30% and 50% of cases. It is mainly studied during cholestatic disease. 3. Organic renal impairment is principally based on immunological response to viral antigens and abnormal hepatic products which lead to the presence of immunocomplexes and cryoglobulins on the blood which tend to be deposited in the subendothelial and subepithelial glomerular areas, inducing complement activation, mesangial cell proliferation and monocyte-macrophage cell infiltration.

Hepatitis C virus enhances incidence of idiopathic pulmonary fibrosis

AIM: To investigate the cumulative development incidence and predictive factors for idiopathic pulmonary fibrosis in hepatitis C virus (HCV) positive patients.

METHODS: We studied 6150 HCV infected patients who were between 40-70 years old (HCV-group). Another 2050 patients with hepatitis B virus (HBV) were selected as control (HBV-group). The mean observation period was 8.0 ± 5.9 years in HCV-group and 6.3 ± 5.5 years in HBV-group. The primary goal is the development of idiopathic pulmonary fibrosis (IPF) in both groups. The cumulative appearance rate of IPF and independent factors associated with the incidence rate of IPF were calculated using the Kaplan-Meier method and the Cox proportional hazard model. All of the studies were performed retrospectively by collecting and analyzing data from the patient records in our hospital.

RESULTS: Fifteen patients in HCV-group developed IPF. On the other hand, none of the patients developed IPF in HBV-group. In HCV-group, the cumulative rates of IPF development were 0.3% at 10th year and 0.9% at 20th year. The IPF development rate in HCV-group was higher than that in HBV-group (P = 0.021). The IPF development rate in patients with HCV or HBV was high with statistical significance in the following cases: (1) patients ≥ 55 years (P < 0.001); (2) patients who had smoking index (package per day × year) of ≥ 20 (P = 0.002); (3) patients with liver cirrhosis (P = 0.042).

CONCLUSION: Our results indicate that age, smoking and liver cirrhosis enhance the development of IPF in HCV positive patients.

Etiology and clinical characteristics of membranous nephropathy in Chinese patients

BACKGROUND

Membranous nephropathy (MN) is a common cause of proteinuria and can be subdivided into idiopathic and secondary classifications. Most patients with MN present with associated systemic diseases that need to be identified before appropriately diagnosing idiopathic MN. However, the cause and clinical characteristics of MN in Chinese patients have not been investigated.

STUDY DESIGN

Case series.

SETTING & PARTICIPANTS

Patients with biopsy-proven MN at the Research Institute of Nephrology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China.

OUTCOME

The diagnosis of idiopathic and secondary MN was based on clinical, initial laboratory, and histological findings.

RESULTS

390 patients with MN were identified from 1985 to 2005. Of 390 patients with MN, 124 (31.8%) had idiopathic MN and 266 had secondary MN (68.2%). Of patients with idiopathic MN, 75 (60.5%) were men and 49 (39.5%) were women. Mean age was 43.9 +/- 13.2 years (range, 14 to 78 years). Common presentations of idiopathic MN were 60.5% with proteinuria (39.5% of whom presented with nephrotic syndrome), 29.8% with hypertension, 17.7% with hematuria, and 0.8% with decreased kidney function. In patients with secondary MN, causes were autoimmune diseases (73.3%), infections (17.7%), tumors (4.5%), and drugs or toxins (4.5%). Systemic lupus erythematosus was the most common autoimmune disease (predominately in younger women). Hepatitis B predominated in younger men. Greater levels of proteinuria were found in patients who presented with drugs or toxins compared with patients with other secondary MNs (P < 0.05).

LIMITATIONS

Not all patients underwent all tests, particularly serum tumor markers, hepatitis C virus antibody, and hepatitis C virus RNA tests.

CONCLUSION

Proteinuria was a common presentation in patients with idiopathic MN, which was predominately found in middle-aged to elderly men. Secondary MN was more common than idiopathic MN, and most secondary MN diagnoses were secondary to systemic lupus erythematosus and hepatitis B infection.