Immunopathogenesis of Liver Injury During Hepatitis C Virus Infection

The present report describes current concepts about the mechanism of liver cell injury caused by host immune response against hepatitis C virus (HCV) infection in human beings. This report is based on the observations from experimental studies and follow-up actions on human liver diseases. The results from different investigations suggest that liver injury depends on the presentation of viral antigen and the level of host immune response raised against HCV-related peptides. Both innate and adaptive immunity are triggered to counter the viral onset. During development of host immunity, the cell-mediated immune response involving CD4⁺ Th1 cells and CD8⁺ cytotoxic T-lymphocyte (CTL) cells were found to play a major role in causing liver damage. The hepatic Innate lymphoid cells (ILCs) subsets are involved in the immune regulation of different liver diseases: viral hepatitis, mechanical liver injury, and fibrosis. Humoral immunity and natural killer (NK) cell action also contributed in liver cell injury by antibody-dependent cellular cytotoxicity (ADCC). In fact, immunopathogenesis of HCV infection is a complex phenomenon where regulation of immune response at several steps decides the possibility of viral elimination or persistence. Regulation of immune response was noted starting from viral-host interaction to immune reaction cascade engaged in cell damage. The activation or suppression of interferon-stimulated genes, NK cell action, CTL inducement by regulatory T cells (Treg), B cell proliferation, and so on was demonstrated during HCV infection. Involvement of HLA in antigen presentation, as well as types of viral genotypes, also influenced host immune response against HCV peptides. The combined effect of all these effector mechanisms ultimately decides the progression of viral onset to acute or chronic infection. In conclusion, immunopathogenesis of liver injury after HCV infection may be ascribed mainly to host immune response. Second, it is cell-mediated immunity that plays a predominant role in liver cell damage.

Molecular basis of hepatocellular carcinoma induced by hepatitis C virus infection

Present study outlines a comprehensive view of published information about the underlying mechanisms operational for progression of chronic hepatitis C virus (HCV) infection to development of hepatocellular carcinoma (HCC). These reports are based on the results of animal experiments and human based studies. Although, the exact delineated mechanism is not yet established, there are evidences available to emphasize the involvement of HCV induced chronic inflammation, oxidative stress, insulin resistance, endoplasmic reticulum stress, hepato steatosis and liver fibrosis in the progression of HCV chronic disease to HCC. Persistent infection with replicating HCV not only initiates several liver alterations but also creates an environment for development of liver cancer. Various studies have reported that HCV acts both directly as well as indirectly in promoting this process. Whereas HCV related proteins, like HCV core, E1, E2, NS3 and NS5A, modulate signal pathways dysregulating cell cycle and cell metabolism, the chronic infection produces similar changes in an indirect way. HCV is an RNA virus and does not integrate with host genome and therefore, HCV induced hepatocarcinogenesis pursues a totally different mechanism causing imbalance between suppressors and proto-oncogenes and genomic integrity. However, the exact mechanism of HCC inducement still needs a full understanding of various steps involved in this process.

A Single-step Multiplex Quantitative Real Time Polymerase Chain Reaction Assay for Hepatitis C Virus Genotypes

BACKGROUND AND OBJECTIVES

The variable response of hepatitis C virus (HCV) genotypes towards anti-viral treatment requires prior information on the genotype status before planning a therapeutic strategy. Although assays for typing or subtyping of HCV are available, however, a fast and reliable assay system is still needed. The present study was planned to develop a single-step multiplex quantitative real time polymerase chain reaction (qPCR) assay to determine HCV genotypes in patients' sera.

METHODS

The conserved sequences from 5' UTR, core and NS5b regions of HCV genome were used to design primers and hydrolysis probes labeled with fluorophores. Starting with the standardization of singleplex (qPCR) for each individual HCV-genotype, the experimental conditions were finally optimized for the development of multiplex assay. The sensitivity and specificity were assessed both for singleplex and multiplex assays. Using the template concentration of 10² copies per microliter, the value of quantification cycle (Cq) and the limit of detection (LOD) were also compared for both singleplex and multiplex assays. Similarly, the merit of multiplex assay was also compared with sequence analysis and restriction fragment length polymorphism (RFLP) techniques used for HCV genotyping. In order to find the application of multiplex qPCR assay, it was used for genotyping in a panel of 98 sera positive for HCV RNA after screening a total number of 239 patients with various liver diseases.

RESULTS

The results demonstrated the presence of genotype 1 in 26 of 98 (26.53%) sera, genotype 3 in 65 (66.32%) and genotype 4 in 2 (2.04%) sera samples, respectively. One sample showed mixed infection of genotype 1 and 3. Five samples could not show the presence of any genotype. Genotypes 2, 5 and 6 could not be detected in these sera samples. The analysis of sera by singleplex and RFLP indicated the results of multiplex to be comparable with singleplex and with clear merit of multiplex over RFLP. In addition, the results of multiplex assay were also found to be comparable with those from sequence analysis. The sensitivity, specificity, Cq values and LOD values were compared and found to be closely associated both for singleplex and multiplex assays.

CONCLUSION

The multiplex qPCR assay was found to be a fast, specific and sensitive method that can be used as a technique of choice for HCV genotyping in all routine laboratories.

Multiplex qPCR for serodetection and serotyping of hepatitis viruses: A brief review

The present review describes the current status of multiplex quantitative real time polymerase chain reaction (qPCR) assays developed and used globally for detection and subtyping of hepatitis viruses in body fluids. Several studies have reported the use of multiplex qPCR for the detection of hepatitis viruses, including hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV), and hepatitis E virus (HEV). In addition, multiplex qPCR has also been developed for genotyping HBV, HCV, and HEV subtypes. Although a single step multiplex qPCR assay for all six hepatitis viruses, i.e., A to G viruses, is not yet reported, it may be available in the near future as the technologies continue to advance. All studies use a conserved region of the viral genome as the basis of amplification and hydrolysis probes as the preferred chemistries for improved detection. Based on a standard plot prepared using varying concentrations of template and the observed threshold cycle value, it is possible to determine the linear dynamic range and to calculate an exact copy number of virus in the specimen. Advantages of multiplex qPCR assay over singleplex or other molecular techniques in samples from patients with co-infection include fast results, low cost, and a single step investigation process.

Cloning and expression of N22 region of Torque Teno virus (TTV) genome and use of peptide in developing immunoassay for TTV antibodies

Background

Torque Teno Virus (TTV) is a DNA virus with high rate of prevalence globally. Since its discovery in 1997, several studies have questioned the role of this virus in causing disease. However, it still remains an enigma. Although methods are available for detection of TTV infection, there is still a need for simple, rapid and reliable method for screening of this virus in human population. Present investigation describes the cloning and expression of N22 region of TTV-genome and the use of expressed peptide in development of immunoassay to detect anti-TTV antibodies in serum. Since TTV genotype-1 is more common in India, the serum positive for genotype-1 was used as source of N22 for expression purpose.

Methods

Full length N22 region of ORF1 from TTV genotype-1 was amplified and cloned in pGEM®-T Easy vector. After cloning, the amplicon was transformed and expressed as a fusion protein containing hexa-histidine tag in pET-28a(+) vector using BL21 E. coli cells as host. Expression was conducted both in LB medium as well as ZYP-5052 auto-induction medium. The expressed peptide was purified using metal-chelate affinity chromatography and used as antigen in developing a blot immunoassay.

Results

Analysis of translated product by SDS-PAGE and western blotting demonstrated the presence of 25 kDa polypeptide produced after expression. Solubility studies showed the polypeptide to be associated with insoluble fraction. The use of this peptide as antigen in blot assay produced prominent spot on membrane treated with sera from TTV-infected patients. Analysis of sera from 75 patients with liver and renal diseases demonstrated a successful implication of N22 polypeptide based immunoassay in screening sera for anti-TTV antibodies. Comparison of the immunoassay developed using expressed N22 peptide with established PCR method for TTV-DNA detection showed good coherence between TTV-DNA and presence of anti-TTV antibodies in the sera analysed.

Conclusions

This concludes that TTV N22 region may be expressed and safely used as antigen for blot assay to detect anti-TTV antibodies in sera.

Novel single-step multiplex real-time polymerase chain reaction assay for simultaneous quantification of hepatitis virus A, B, C, and E in serum

BACKGROUND AND AIM

Viral hepatitis needs an earliest diagnosis for its proper and timely treatment. Although serodiagnosis of viral hepatitis is in regular practice, however, it has certain limitations and points to alternate procedures of diagnosis. Present study was designed to develop a single-step multiplex real-time polymerase chain reaction (PCR) assay for detection of hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV) and hepatitis E virus (HEV) related nucleic acids in sera from infected patients.

METHODS

The PCR was standardized to detect HAV, HBV, HCV and HEV in serum using variables including annealing temperature, extension temperature, MgCl2 , and primer concentrations. The conserved regions of all viral genomes were used as targets for amplification.

RESULTS

This novel assay was found to be a fast, sensitive, specific, and reproducible system for detection of HAV, HBV, HCV, and HEV in serum. The detection limit for different viral genomes at 100% level was found to be 280 copies/mL for HAV, 290 copies/mL for HBV, 30 copies/mL for HCV, and 300 copies/mL for HEV in a single-tube assay system.

CONCLUSION

Present multiplex real-time PCR is the first report on single-step nucleic acid detection of HAV, HBV, HCV, and HEV in sera samples. It is an alternate diagnostic assay for common use in laboratories analyzing viral hepatitis cases.

An insight into the diagnosis and pathogenesis of hepatitis C virus infection

This review focuses on research findings in the area of diagnosis and pathogenesis of hepatitis C virus (HCV) infection over the last few decades. The information based on published literature provides an update on these two aspects of HCV. HCV infection, previously called blood transmitted non-A, non-B infection, is prevalent globally and poses a serious public health problem worldwide. The diagnosis of HCV infection has evolved from serodetection of non-specific and low avidity anti-HCV antibodies to detection of viral nucleic acid in serum using the polymerase chain reaction (PCR) technique. Current PCR assays detect viral nucleic acid with high accuracy and the exact copy number of viral particles. Moreover, multiplex assays using real-time PCR are available for identification of HCV-genotypes and their isotypes. In contrast to previous methods, the newly developed assays are not only fast and economic, but also resolve the problem of the window period as well as differentiate present from past infection. HCV is a non-cytopathic virus, thus, its pathogenesis is regulated by host immunity and metabolic changes including oxidative stress, insulin resistance and hepatic steatosis. Both innate and adaptive immunity play an important role in HCV pathogenesis. Cytotoxic lymphocytes demonstrate crucial activity during viral eradication or viral persistence and are influenced by viral proteins, HCV-quasispecies and several metabolic factors regulating liver metabolism. HCV pathogenesis is a very complex phenomenon and requires further study to determine the other factors involved.

Expression of the full-length HCV core subgenome from HCV gentoype-1a and genotype-3a and evaluation of the antigenicity of translational products

BACKGROUND

Hepatitis C virus (HCV) infection is a major public health problem in India. Detection of HCV and its genotypes by simple and economic assays is a prime requirement in the planning of antiviral treatments for patients infected with this virus. Although commercial assays are available for the detection of both HCV RNA and genotypes, efforts aimed at the development of simple and economical systems for these measurements are still going on.

AIM

The present study was designed to clone and express the HCV CORE gene from HCV genotype-1a and genotype-3a and use the peptides to develop immunoassays for the detection of genotype-specific antibodies in sera samples.

METHODS

One hundred and thirty-five serum samples from patients with liver and renal diseases were screened for HCV RNA by real-time PCR, followed by HCV genotyping in RNA-positive sera by restriction fragment length polymorphism, sequencing, and phylogenetic analysis. The HCV CORE gene was amplified from sera carrying HCV genotype-1a and genotype-3a and cloned and expressed in the pET19b vector. The translational products were used to develop a western blot assay for the detection of genotype-specific anti-HCV antibodies.

RESULTS

The HCV CORE gene, from both genotypes, was cloned and expressed successfully, with production of a 26 kDa recombinant protein in either case. Using peptides in a western blot assay, 101 sera samples were tested for the anti-HCV CORE antibody. Each peptide showed a reaction with anti-HCV total antibody without showing any genotype-specific binding. This indicates that individual peptides obtained from different genotypes do not have a genotype-specific epitope to bind with antibodies.

CONCLUSION

Cloning and expression of the HCV CORE gene from genotype-1a and genotype-3a was successful. However, the peptides formed did not show genotype-specific binding with anti-HCV.

HCV-genotypes: a review on their origin, global status, assay system, pathogenecity and response to treatment

The present report is a review article on various aspects of Hepatitis C virus (HCV) genotypes and their subtypes. HCV has six genotypes and several subtypes showing important epidemiological and clinical implications. The information based on previous studies and presented through this article highlight the origin, classification and causes of genetic diversity, global status, detection assays, pathogenicity and response to treatment of HCV-genotypes. The six genotypes differ in 30-35% of nucleotide sites over the complete genome. The difference in genomic composition of sub-types of genotype is usually found to be 20-25%. The variability remains more frequent in structural genes as compared to non-structural or untranslated genes. Both genotypes and their sub-types show a varied prevalence globally and raise several issues related to their transmission and treatment of HCV-infection. All this information has a great significance while planning future strategies for eradication and therapeutic management of HCV. In addition, these reports produce a further scope for more studies to unravel the mystery behind HCV-genotypes and formulate guidelines to resolve this public health problem noted worldwide.

Hepatitis C virus (HCV): a review of immunological aspects

The present manuscript represents an updated review on different aspects of immunology involved during hepatitis C virus infection in human beings. This includes a brief mention of HCV structure, presentation of viral components to host immune system, and ensuing immune response and immunopathogenesis occurring during HCV infection. The present article also highlights immunodiagnosis of HCV infection and the current status of immunotherapy available for HCV eradication. Its envelope protein, E2, is the primary mediator of virus attachment and cell entry. CD81 molecule on cell surface acts as a major receptor for viral entry into the host cells. Mature dendritic cells play an important role in presenting viral antigen, activate T-cells, and initiate anti-viral immune response. Relative T-cell populations and release of different cytokines from activated T-cells ultimately determine the clearance or persistence of HCV viremia through cellular and humoral immune responses. Natural killer (NK) cells constitute the first line of host defense against invading viruses by recruiting virus-specific T-cells and inducing antiviral immunity in liver. Diagnosis of acute or chronic hepatitis C virus (HCV) infection is established by serological assays for presence of antibodies against different sets of viral proteins during varied periods post infection. An effective immunotherapy and vaccine against HCV is still awaited.

Torque teno virus: Its prevalence and isotypes in North India

AIM: To investigate the prevalence and genotype distribution of Torque teno virus (TTV) in patients with different liver diseases and chronic renal failure treated at a referral hospital in North India.

METHODS: Whereas prevalence of TTV was based on amplification of conserved region of ORF2 of TTV genome, the genotyping of TTV was carried out using restriction fragment length polymorphism (RFLP) procedure on the N22 region of ORF1.

RESULTS: TTV-DNA was detected in 137 of 513 (26.7%) patients with liver diseases and 38 of 65 (58.5%) patients with chronic renal failure. TTV was also detected in 27% of healthy controls. The sequence analysis of the PCR product from 10 randomly selected cases failed to show a significant sequence divergence when compared with that of the TRM1 isolate of TTV genotype 1. The results of genotyping in 55 randomly selected patients showed the presence of genotype 1 (G1) in 53 (96.4%) and genotype 2 (G2) in 2 cases (3.6%), respectively. Other genotypes were not identified in this patient subgroup, suggesting that G1 is predominant in this area. The results of genotyping by RFLP were also supported by phylogenetic tree analysis, where G1 was found to be the major genotype.

CONCLUSION: These results indicate that TTV is moderately present in Indian patients, with G1 to be the major genotype in North India. The pathogenicity and etiological role of TTV in different diseases is still a question mark and warrant further studies.

Correlation of serum HCV core concentration with blood level of lipid and antioxidants in various forms of liver diseases

BACKGROUND/AIMS

The present study was designed to investigate the effect of hepatitis C virus (HCV) core protein expression on the blood level of lipids, lipoproteins and apolipoprotein in various forms of liver diseases. At the same time, effect of HCV core protein was also studied on the level of antioxidants in these patient groups. The aim behind this study was to explore the possibility of HCV core induced lipid changes and ensuing oxidative liver damage in these liver diseases.

METHODOLOGY

We studied a total number of 130 patients including 50 patients with acute viral hepatitis (AVH), 30 with chronic hepatitis (CH), 30 with hepatic cirrhosis and 20 patients with fulminant hepatic failure (FHF). Sera from all these patients were analyzed for hepatitis viral markers and HCV core protein using EIA assays. Sera/plasma from them were simultaneously analyzed for total cholesterol, triglyceride, low density lipoprotein (LDL), high density lipoprotein (HDL), apolipoprotein A-1 and B, and also for antioxidants.

RESULTS

Analysis of data demonstrated the presence of viral hepatitis B, C and E infections in these cases. Hepatitis A and D infections were absent in all the patients. When data on lipid and lipoprotein were analyzed in relation to HCV core expression, we could not observe a significant change in the serum level of total cholesterol, triglyceride, LDL, HDL, apolipoprotein A-1 and apoprotein B in core positive patients as compared to core negative cases. However, lipoprotein (a) [Lp(a)] level was significantly reduced in core positive patients as compared to core negative cases. Furthermore, analysis of Superoxide dismutase (SOD), Total antioxidant (TAO) and Uric Acid in these patients demonstrated only a minor change in SOD and TAO levels in relation to HCV core, though at the same time, Uric Acid was found raised in all the groups.

CONCLUSIONS

These observations clearly indicate that core expression does not bring a significant change in serum level of lipids, lipoprotein and apoproteins. Similarly, HCV core expression also does not show a major change in SOD and TAO levels suggesting an insignificant impact of core on oxidative stress during liver diseases.

Impact of viral hepatitis on apo- and lipoprotein status in blood

OBJECTIVES

To investigate the effect of viral hepatitis on serum levels of apo- and lipoproteins in different forms of liver diseases.

MATERIALS AND METHODS

One hundred and thirty adult patients and 100 healthy age- and gender-matched control individuals participated in this study. Patients were grouped according to four types of liver disease: acute viral hepatitis, chronic active hepatitis (CAH), cirrhosis of the liver and fulminant hepatic failure.

RESULTS

Hepatitis B virus, C virus and E virus (HEV) infections were recorded in different combinations in these patients, but viral infections of hepatitis A and D were not seen in any of the patient groups. The results of lipo- and apoprotein analysis showed different patterns. The low-density lipoprotein value was high in the CAH group. In the other three groups, low-density lipoprotein level was comparable to the control value. The high-density lipoprotein level (p = 0.02) was significantly low in all groups except in the cirrhosis group. Apo-A was significantly reduced in the acute viral hepatitis and fulminant hepatic failure groups, whereas Apo-B level was low in the CAH and cirrhosis groups. The lipoprotein (a) level in these groups was low, compared to control.

CONCLUSION

No apparent relationship was observed between etiological viruses and ensuing changes in lipid/lipoprotein profile..

Significance of hepatitis C virus core protein in the diagnosis of hepatitis C virus infection in different liver diseases

The present article describes the presence of hepatitis C virus (HCV) core protein in relation to HCV antibody in different types of liver diseases caused by hepatitis viral infections. One hundred thirty patients with various types of liver diseases, including those with acute viral hepatitis (n = 50), chronic viral hepatitis (n = 30), cirrhosis of the liver (n = 30), and fulminant hepatic failure (n = 20), were analyzed for HCV core protein, HCV-ribonucleic acid (RNA) and anti-HCV antibodies using enzyme immunoassays and reverse transcriptase-polymerase chain reaction. All patients were also simultaneously analyzed for other hepatitis markers to diagnose hepatitis A to E in all cases. Patients with HCV infection were additionally tested for HCV core protein and HCV-RNA. The results of analysis demonstrated the presence of hepatitis B, C, and E in different proportions of patients with these liver diseases. Hepatitis A and D infections were absent in all cases. Analysis of sera from acute viral hepatitis demonstrated the presence of HCV core protein, HCV-RNA, anti-HCV antibodies, and both core protein and anti-HCV together in 18%, 16%, 6%, and 2% of cases, respectively. In fulminant hepatic failure patients, these markers were recorded in 20%, 10%, 10%, and 5% of cases, respectively. In the chronic viral hepatitis group, the pattern was reversed, and their presence was recorded in 13.3%, 13.3%, 46.6%, and 10% of cases, respectively. Similarly, in cirrhosis patients, these markers were noted in 23.3%, 23.3%, 23.3%, and 13.3% of cases, respectively. None of the control sera were positive for any hepatitis marker. The significance of HCV core protein in relation to HCV-RNA and anti-HCV for the diagnosis of HCV infection in different liver diseases has been discussed.

Transfusion transmitted virus: A review on its molecular characteristics and role in medicine

The present review gives an updated overview of transfusion transmitted virus (TTV), a novel agent, in relation to its molecular characteristics, epidemiological features, modes of transmission, tissue tropism, pathogenesis, role in various diseases and its eradication from the body. TTV, a DNA virus, is a single stranded, non-enveloped, 3.8 kb long DNA virus with a small and covalently closed circular genome comprising 3852 bases. It was tentatively designated Circinoviridae virus. TTV genome sequence is heterogeneous and reveals the existence of six different genotypes and several subtypes. TTV has been reported to transmit not only via parenteral routes, but also via alternate routes. This virus has been detected in different non-human primates as well. At present, TTV is detected by polymerase chain reaction (PCR) with no other available diagnostic assays. It shows its presence globally and was detected in high percent populations of healthy persons as well as in various disease groups. Initially it was supposed to have strong association with liver disease; however, there is little evidence to show its liver tropism and contribution in causing liver diseases. It shows high prevalence in hemodialysis patients, pointing towards its significance in renal diseases. In addition, TTV is associated with several infectious and non-infectious diseases. Although its exact pathogenesis is not yet clear, TTV virus possibly resides and multiplies in bone marrow cells and peripheral blood mononuclear cells (PBMCs). Recently, attempts have been made to eradicate this virus with interferon treatment. More information is still needed to extricate various mysteries related to TTV.

Transfusion-transmitted virus in association with hepatitis A-E viral infections in various forms of liver diseases in India

AIM: To describe the prevalence of transfusion-transmitted virus (TTV) infection in association with hepatitis A-E viral infections in different forms of liver diseases in North India.

METHODS: Sera from a total number of 137 patients, including 37 patients with acute viral hepatitis (AVH), 37 patients with chronic viral hepatitis (CVH), 31 patients with cirrhosis of liver and 32 patients with fulminant hepatic failure (FHF), were analyzed both for TTV-DNA and hepatitis A-E viral markers. Presence of hepatitis B virus (HBV), hepatitis C virus (HCV) and hepatitis E virus (HEV) infections was detected in different proportions in different groups. Moreover, TTV-DNA was simultaneously tested in 100 healthy blood donors also.

RESULTS: None of the patients had hepatitis A virus (HAV) and hepatitis D virus (HDV) infections. Overall prevalence of TTV-DNA was detected in 27.1% cases with AVH, 18.9% cases with CVH, 48.4% cases with cirrhosis and 9.4% cases with FHF. TTV-DNA simultaneously tested in 100 healthy blood donors showed 27% positivity. On establishing a relation between TTV infection with other hepatitis viral infections, TTV demonstrated co-infection with HBV, HCV and HEV in these disease groups. Correlation of TTV with ALT level in sera did not demonstrate high ALT level in TTV-infected patients, suggesting that TTV does not cause severe liver damage.

CONCLUSION: TTV infection is prevalent both in patients and healthy individuals in India. However, it does not have any significant correlation with other hepatitis viral infections, nor does it produce an evidence of severe liver damage in patients with liver diseases.

Hepatitis C virus core protein: an update on its molecular biology, cellular functions and clinical implications

The present review article is an update on various features of hepatitis C virus (HCV) core protein including its molecular biology, role in HCV replication, involvement in HCV pathogenesis, etiological role in hepatocellular carcinogenesis, significance in diagnosis and vaccination against HCV infection. Core protein is a structural protein of HCV virus and has only recently been characterized. It was found to play a major role in HCV-induced viral hepatitis. Although published information shows a lot about the clinical significance of HCV core protein, several studies are still needed to demonstrate its exact significance in viral biology and underlying HCV pathogenesis.

Apolipoproteins and their role in different clinical conditions: an overview

Apolipoproteins or apoproteins are a group of proteins associated with lipoproteins in different proportions and play significant roles in several diseases. Different types of apolipoproteins, including apolipoproteins A, B, C, D, E, H and J and their subclasses have been reported, in addition to a few more apolipoproteins reported recently. These proteins have varied, but definite roles in normal physiology in our body. Moreover, their blood levels have strong association with clinical conditions during different diseases and are used as diagnostic and prognostic markers and to compute index of risk for some serious disease entities. Present article gives an overview of the structural features, physiological significance and diagnostic and clinical implications of apolipoproteins.

Serum lipoprotein (a) levels in liver diseases caused by hepatitis

Lipoprotein (a) [LP(a)] is a genetic variant of low density lipoprotein (LDL) and is mainly synthesized in liver. We conducted a study to evaluate the association of serum [Lp(a)] level with hepatitis viral infections. A total of 130 patients including 50 patients with acute viral hepatitis (AVH), 30 with chronic active hepatitis (CAH), 30 with cirrhosis of liver and 20 patients with fulminant hepatic failure (FHF) were analysed for different hepatitis viral markers and Lp(a) level in their serum samples. For comparison, 50 healthy persons were also tested for Lp(a) level. Serum Lp(a) level in patients in all the disease groups was significantly reduced compared to that observed in controls. Lp(a) level could not be detected in 40 per cent cases with AVH, 46.6 per cent with CAH, 70 per cent with cirrhosis and 80 per cent of FHF patients. On correlating Lp(a) level to viral etiology in these patients, it was found that the extent of diminution in Lp(a) level did not follow any trend with some particular viral infection and was recorded nearly same in all the infections. The findings of this study suggested that serum Lp(a) level was significantly (P<0.001) reduced in patients with liver diseases irrespective of the viral etiology.