A critical review of diagnostic and prognostic markers of chronic hepatitis B infection

Surface antigen of hepatitis B

One important diagnostic indicator for hepatitis B infection is HBsAg. Its presence confirms the diagnosis of persistent infection and points to ongoing viral replication. When diagnosing CHB infection, HBsAg is a useful diagnostic tool. It is advised for CHB patient diagnosis and follow-up [14]. During an HBV infection, HBsAg is generated in excess and released into the blood, acting as a signal for infectivity and active infection [15]. To determine the treatment prognosis and HBV chronicity, quantitative HBsAg (qHBsAg) quantification is crucial [16]. For HBV e antigen-positive patients only, there is no significant association found between qHBsAg and HBV DNA levels [17]. One plausible therapeutic objective in the management of CHB is HBsAg seroclearance, which is linked to lower qHBsAg levels [18]. Nevertheless, because HBsAg seroclearance occurs at a low yearly rate, attempts are being made to increase it and use biomarkers like qHBsAg to forecast it early. In summary, qHBsAg can offer extra information for evaluating the course of the disease and the effectiveness of treatment, while HBsAg is a valuable diagnostic marker for CHB infection. There are restrictions on the use of HBsAg as a diagnostic marker for persistent hepatitis B infection. One disadvantage is that HBsAg can be detected in both acute and chronic infections, making it impossible to differentiate between the two [15]. Another drawback is that heterophilic antibody interference might cause HBsAg seropositivity to be a false-positive result, which could result in a misdiagnosis [16]. Furthermore, the illness stage may affect the efficacy of HBsAg as a diagnostic sign. A study indicated that the late cohort had a poorer sensitivity of HBsAg in predicting severe hepatitis activity than the early cohort [18]. As a result, although HBsAg is a useful marker for detecting the hepatitis B virus, its limitations should be taken into account. Furthermore, further testing might be required to accurately diagnose and treat CHB infection.

HBV DNA quantification

Assessing the level of viral replication in the blood requires quantifying the HBV DNA. A greater risk of progression of disease and transmission is linked to higher viral loads. As diagnostic indicators for chronic HBV infection, HBV DNA levels have significant clinical ramifications. It can be used to ascertain the infection’s phase, evaluate the effectiveness and duration of therapy, and provide guidance for the safe cessation of antiviral medication with a decreased risk of recurrence [19]. Elevated HBV DNA levels are a major risk factor for the emergence of serious long-term consequences and the advancement of chronic HBV infection, which is why HBV DNA levels are also linked to the progression of the disease [20]. Furthermore, in untreated HBV-infected patients, HBV DNA levels may indicate natural illness phases, emphasising the need for clinical management techniques and liver inflammation [21]. HBV DNA quantification can assist in clinically classifying CHB patients and directing treatment choices in addition to other clinical markers such as HBsAg levels [22]. In general, the levels of HBV DNA offer significant insights into the diagnosis, treatment, and outlook of persistent HBV infection. One of the possible drawbacks of utilising HBV DNA levels as markers of diagnosis is that they may not be able to identify viral genome mutations that lead to diagnostic escape [23]. Moreover, low antigen titres in research samples may cause the viral burden to be underestimated [24]. Developing highly homologous oligonucleotide sets for quantitative PCR assays is difficult due to the significant genetic variability of the virus, which can lead to lower primer/probe affinity for binding and misdetection of some HBV variants [25]. Another major obstacle to expanding HBV diagnostic services is the restricted availability of nucleic acid testing (NAT) to measure HBV DNA levels in nations with limited resources [26]. Liver histology, the most commonly used method for HBV diagnosis, is non-standardized and invasive, which can make it unfeasible [27]. The sporadic reproduction of HBV in individuals with hidden HBV infection and the sensitivity limitations of serological testing add to the inaccuracy of these tests for diagnosing HBV infection.

Antibody to hepatitis B core

Anti-HBc, or the hepatitis B core antibody, is frequently used to diagnose or confirm hepatitis B infection. It could be IgM, which denotes an acute infection, or IgG, which denotes a persistent or healed illness. When diagnosing CHB infection, anti-HBc is essential. Mostly present throughout life, it is a highly immunogenic particle antigen that first occurs in the early stages of infection [28]. It has been demonstrated that liver pathology, the prognosis of the disease, and HBV-related hepatitis activity are correlated with quantitative anti-HBc (qAnti-HBc) levels [29, 30]. In addition to predicting therapy response and providing a prognosis for the disease, qAnti-HBc can distinguish between distinct phases of CHB [31]. It is also linked to the inflammatory condition of the host liver and the immunological activation associated with HBV infection [32, 33]. The diagnostic and prognostic potential of qAnti-HBc can be increased by combining it with other diagnostic indicators including HBV DNA, HBeAg, qHBsAg, and anti-HBs antibodies. Better treatment outcomes, such as HBeAg loss, prolonged response, and HBsAg reduction or clearance, are linked to higher levels of anti-HBc. Anti-HBc is a useful marker for identifying and tracking CHB infection as a result. The potential of Anti-HBc as a non-invasive biomarker for forecasting clinical outcomes and treatment success is one of the prospects for the use of HBcAb in the detection of CHB infection [28, 34]. Promising correlations have been found between HBcAb quantification (qAnti-HBc) and infection phases, hepatic fibrosis and inflammatory levels, flare-ups throughout chronic infection, and the existence of occult infection [29, 35]. Additionally, it is predictive of recurrence following medication cessation, viral reactivation upon immunosuppression, re-infection following liver transplantation, and spontaneous or treatment-induced seroclearance of HBeAg and HBsAg [36]. Nevertheless, qAnti-HBc should not be used as a stand-alone diagnostic test; in fact, when paired with other biomarkers including HBV DNA, HBeAg, qHBsAg, and anti-HBs antibodies, its diagnostic and prognostic potential can be increased [37]. Standardisation of cut-off values is required for improved result comparison, and getting hold of commercially available qAnti-HBc test kits needs to be improved [14, 38]. The following are the restrictions on the use of anti-HBc in the diagnosis of CHB infection. (1) Since anti-HBc can also be seen in people with cured or occult hepatitis B infection, it is not a reliable indicator of CHB infection [29]. (2) Anti-HBs antibodies, HBV DNA, HBeAg, qHBsAg, and other indicators can enhance the diagnostic efficacy of anti-HBc [9]. (3) There is a need to increase the accessibility of commercial diagnostic kits for measuring anti-HBc [32]. (4) The use of semi-quantitative methodologies impedes the ability to compare data from various investigations and create standard cut-off values for anti-HBc. Finally, those with “anti-HBc only” status may be at risk for reactivation. Anti-HBc alone does not suggest immunological control of HBV.

Aminotransferase alanine

As indicated in Table 2, elevated alanine transaminase (ALT) levels are indicative of liver inflammation and are used to gauge the severity of liver disease. Normal ALT values do not, however, rule out serious liver disorders in CHB patients. In individuals with CHB infection, ALT levels are crucial biomarkers for the development of the disease [39]. High ALT and HBV DNA levels are important risk factors for the development of CHB infection and are linked to dangerous long-term consequences [40]. Hepatic cancer, cirrhotic events, and death can still be risks for patients with normal or slightly elevated ALT levels [41]. Antiviral therapy is advised by the most recent Chinese guidelines for CHB patients who have identifiable HBV DNA and consistently have ALT levels over the threshold of normal [42]. On the other hand, new research has demonstrated that liver biopsies from HBeAg-negative individuals who consistently have normal ALT levels may exhibit severe inflammation and fibrosis. As a result, there is disagreement regarding whether these individuals should begin antiviral therapy. Antiviral therapy has been proposed as a potential treatment for CHB patients who have normal or slightly elevated ALT levels, particularly those who underwent interferon-based treatment. It is crucial to remember that ALT levels might change over time and that the degree of liver damage or the course of the disease may not be completely captured by a single measurement. Furthermore, for a thorough evaluation of CHB infection, ALT levels need to be analysed together with other clinical indicators and diagnostic testing. Acute liver inflammation and damage are indicated by a substantial rise in ALT values. It is frequently seen in patients with severe hepatic disease, like cirrhosis or hepatocellular carcinoma, who have a CHB infection.

Non-invasive testing and liver biopsy

Predicting the course of liver disease can be aided by measuring liver inflammation and fibrosis using a tissue sample from the liver or non-invasive testing methods like FibroScan. The prognosis of a CHB infection can be predicted more accurately by non-invasive diagnostics than by liver biopsy. The prognostic efficacy of liver biopsy and non-invasive testing in determining the prognosis of chronic liver disease has been assessed. Because liver biopsy is invasive and has limits, non-invasive fibrosis markers have become popular as an alternative to the procedure [43]. To predict the severity of chronic liver disorders, such as hepatitis C virus (HCV) and non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH), several tissues and circulating markers of angiogenesis have been studied [44]. Several non-invasive fibrosis markers have been assessed for biopsy findings in patients with CHB [45]. These markers include the Goteburg University cirrhosis index (GUCI), Hui score, AST platelet ratio index (APRI), AST ALT ratio (AAR), and fibrosis four scores (FIB-4). Despite the increased use of non-invasive techniques, liver biopsies remain the most common method for grading and grading several chronic liver disorders [46].

Guidelines on the use of non-invasive tests have been published by the European Association for the Study of the Liver [47], emphasising their value in diagnosing and classifying chronic liver disease. Numerous studies have demonstrated the accuracy with which non-invasive models, such as the FIB-4 and APRI indices [45], the ALT, Age, PLT, and LS model [48], the AAR, API, APRI, KING, Zeugma scores, and Hudu’s score [49, 50], can evaluate liver histology and forecast substantial liver injury. It has been discovered that these non-invasive models exhibit remarkable accuracy, with values of the area under the curve ranging from 0.595 to 0.870 [51, 52]. They can assist in determining whether antiviral therapy is necessary without requiring an invasive biopsy of the liver, which carries some risk. Though these non-invasive diagnostics have shown potential, it needs to be noted that they ought to be employed together with clinical judgement as they could still not be able to replace liver biopsy. The conventional approach to determining the prognosis of CHB infection involves liver biopsy; however, there are several drawbacks to this method, including cost, potential problems, and invasiveness [45, 48, 49]. An alternate method that has benefits including becoming kinder to the body, safer, and more economical is to use non-invasive diagnostics [51, 52]. To forecast liver histological alterations and fibrosis in CHB patients, several non-invasive models were created utilising various indicators [53], [54], [55]. With no requirement for a liver biopsy, these models have demonstrated encouraging outcomes in precisely evaluating liver histology and forecasting the requirement for antiviral medication. Though these non-invasive procedures have demonstrated high diagnostic performance, it is crucial to remember that they might not always be able to fully replace liver biopsy. To ascertain the best application and constraints of non-invasive testing in assessing the likelihood of CHB infection, more investigation and validation are required.

Antigen for hepatitis B e

The presence of HBeAg is a significant predictive factor [10]. Patients who test positive for HBeAg are more likely to have increased infectivity and active viral replication (Table 1). An inverse relationship exists between the advancement of liver disease and HBeAg seroconversion to anti-HBe. A predictive marker for CHB infection is thought to be HBeAg [10]. High replication of viruses and enhanced contagiousness are linked to it [15]. Research has demonstrated a correlation between HBeAg seropositivity and more advanced phases of liver fibrosis, such as cirrhosis, severe fibrosis, and substantial fibrosis [56]. Furthermore, there is a correlation between HBV DNA viral load and HBeAg status, whereby individuals who test positive for HBV DNA have higher quantities of HBV circulating DNA [10, 57]. HBeAg seroconversion, however, was not discovered to be connected to liver function tests, transmission routes, chronicity duration, marriage history, gender, or age [58]. In general, HBeAg can be utilised as a marker to forecast the severity and course of a CHB infection, especially when it comes to fibrosis of the liver and viral load [12]. Regarding the prospects of CHB infection, HBeAg is a major factor. Its presence is connected to increased levels of HBV serum DNA and is linked to enhanced replication of viruses and infectivity [58]. Loss of HBeAg, or HBeAg seroconversion, is a sign of either the reactive or inactive stages of CHB [59]. Further research is needed to fully understand the relationship between HBeAg seroconversion and various factors, such as liver function tests, mode of transmission, duration of chronicity, marital status, gender, and age [60]. Lower levels of HBsAg are linked to a higher likelihood of a sustained response in HBeAg-negative individuals. The level of HBsAg after completion of treatment can be used to predict prolonged off-treatment response [61]. Furthermore, in HBeAg-positive patients, the degree of hepatitis B core-related antigen (HBcrAg) helps forecast the clinical phase and response to treatment [62]. In patients with CHB infection, HBeAg level is an indicator of disease progression. HBeAg-negative individuals may be in an inactive or aggressive phase of the disease, whereas HBeAg-positive patients have increased replication of viruses and infectivity [63]. A better prognosis is linked to HBeAg seroconversion, which is a significant treatment outcome where HBeAg turns negative [58]. HBeAg seroconversion is predicted by HBcrAg levels at the beginning and two years following antiviral medication, where lower levels are linked to a higher chance of seroconversion [64]. In HBeAg-negative individuals, HBsAg levels at the end of therapy can also predict a persistent off-treatment response; lower levels are linked to a decreased likelihood of virological resurgence [59]. HBV DNA levels and quantitative HBsAg have different capacities for defining the natural history stages of long-term HBV infection [18].

Genotype of the hepatitis B virus

Variations in HBV genotype can affect how an antiviral treatment works and how quickly the disease progresses. For instance, in certain groups, genotype C is linked to an increased risk of hepatocellular cancer (HCC). Table 3 illustrates that the HBV genotype does not seem to have a substantial impact on the clinical manifestations of hepatitis B patients [65]. Numerous investigations have demonstrated that there is no meaningful correlation between HBV genomes and clinical characteristics such as liver histology, ALT levels, liver fibrosis, and HBeAg status [66, 67]. Nonetheless, some research has indicated that a greater viral load may be linked to specific HBV genotypes [68]. Furthermore, a study discovered that HBV genotypes can affect the longitudinal HBsAg serodecline and the extent of HBsAg seroclearance, indicating a potential interaction between HBV genotype and HLA variations [69]. In general, further investigation is required to precisely ascertain the influence of the HBV genome on the clinical progression of hepatitis B. The given abstracts don’t seem to specifically address the HBV genotype. The relevance of HBV mutations and HLA genes in the risk of hepatocellular carcinoma (HCC) is covered in the abstracts, nevertheless. According to one study, there is a correlation between a higher risk of HCC and HBV mutations at the core promoter region, namely A1762T/G1764A, C1653T, and T1753V [70]. An elevated risk of HBV-related HCC was found to be significantly correlated with an HLA gene haplotype that is common in Asian populations [71]. Furthermore, an uncommon signal within the CDK14 gene was found to be associated with the prognosis and susceptibility of HBV-related HCC by a genome-wide association investigation [72]. Although the HBV genotype alone might not be a reliable indicator of the likelihood of developing HCC, these results imply that HBV mutations and HLA genes might influence an individual’s susceptibility to HCC in those with HBV infection. The HBV genotype is not a reliable indicator of HBV infection. The levels of HBV DNA do not exhibit significant variations based on the HBV genotype. Nevertheless, the levels of qHBsAg, which serve as prognostic indicators, are subject to influence. To ensure proper interpretation, genotype-specific cut-off levels must be established, as different genotypes exhibit variances in qHBsAg levels [73]. HBV DNA and qHBsAg levels can also be impacted by mutations in the preCore, basal core promoter, and preS sections of the HBV genome [74]. These alterations can impact the virus’s ability to replicate and release HBsAg, and they are genotype-dependent [75]. As such, using the HBV genotype alone for prognostication may not yield reliable findings; instead, a thorough evaluation of HBV infection necessitates taking into account the effects of certain mutations and qHBsAg levels [76].