Biological Prole of Chronic Hepatitis B and its Predictive Factors According to Liver Histological Activity at the Renaissance Hospital, N’Djamena, Chad

Background: No study in black Africa has investigated the prole of chronic hepatitis B according to the new European association for the study of the liver (EASL) classication. The aim of the study was to determine the biological prole of chronic HBsAg carriers according to the EASL classication of chronic hepatitis B. Method: This is a prospective cross-sectional study carried out in the gastroenterology outpatient department at the Renaissance Hospital in N’Djamena from January, 2018 to July, 2019. All patients with chronic HBsAg were included and documented for at least one year. Patients with hepatitis C, hepatitis D or HIV or alcoholic were excluded. The biological prole was determined according the EASL classication: HBeAg-positive chronic infection, HBeAg-positive chronic hepatitis, HBeAg-negative chronic infection, HBeAg-negative chronic hepatitis and HBsAg-negative phase. Factors associated with presence of signicant liver brosis were founded by logistical regression. Results: 106 patients were included. The average age were 42.4 years old. The sex ratio was 1.43. The median of the transaminase were 24 IU/ml (AST) and 21 IU/ml (ALT). 61 patients had HBeAg-negative chronic infection (59.8%) and 37 patients had HBeAg-negative chronic hepatitis (36.2%). HBeAg-positive chronic infection and HBeAg-positive chronic hepatitis were both seen in 2% of the cases. Signicant liver brosis was independently associated with the ALT levels (Odds ratio=1.038 [1.009-1.068]; p=0.009). Conclusion: Chronic HBeAg-negative B infection is the main form in chronic HBsAg-positive carriers. Transaminases are a predictive factor for the presence of hepatic brosis.

Transaminases are a predictive factor for the presence of hepatic brosis.

Background
Hepatitis B virus (HBV) infection is endemic in Sub-Saharan Africa (1) and is the main cause of liver cirrhosis and hepatocellular carcinoma (2). These progressive complications are linked to the chronic forms of the virus. The natural history of these chronic forms is complex, evolving in several phases which can overlap (3). The HBV treatment is variable depending on whether or not there is signi cant histological liver damage (4,5). The European Association of the Study of the Liver (EASL) currently recognizes ve phases; HBeAg-positive or negative chronic infection, HBeAg-positive or negative chronic hepatitis and HBsAg-negative phase (6). These ve forms are distinguished by the presence of the HBeAg or of the anti HBe antibody, the HBV DNA level, the transaminase values, and the presence or absence of liver in ammation or liver brosis. HBeAg positive chronic infection represents the classical early phase of infection known as the immune tolerant phase, which is characterized by the presence of HBeAg, elevated levels of HBV replication, normal transaminases, minimal histological lesions and lack of clinical signs of liver in ammation. The presence of HBeAg, elevated levels of HBV DNA replication (greater than 2000 IU/ml), elevated transaminases and moderate or severe histological lesions characterize HBeAg positive chronic hepatitis or phase two. The third phase called HBeAg negative chronic infection B (formally inactive phase) with low levels of HBV DNA replication, normal transaminases, absence of HBeAg and minimal histological damage. HBeAg negative chronic hepatitis in which transaminases are permanently elevated or uctuating, HBV viral load is elevated and moderate to severe histological lesions.
Phase 5 is the loss of the HBsAg characterized as negative, the presence of the anti-HBc antibody with or without detection of the anti-HBs antibody; which is also called the occult hepatitis B where the transaminases are normal and the HBV DNA is generally undetectable but not always. The distribution of each of these forms in a given population of chronic HBsAg carriers has not been largely studied (7). No study in black Africa has investigated the pro le of chronic viral hepatitis b according to the new EASL classi cation. The objective of our study was to determine the distribution of the different forms of chronic hepatitis B according to the de nition of EASL. Therefore, this cross-sectional study was done in the gastroenterology consultation department at the Renaissance University Hospital in Ndjamena, Chad.

Methods
This is a cross-sectional study carried out from January 2018 to July 2019 at the Renaissance University Hospital in N'djamena. It included all patients seen in the gastroenterology outpatient department for chronic carriers of HBsAg, documented for at least one year. Patients co-infected with HIV, hepatitis C or hepatitis D or alcohol abuse were excluded from the study. During the rst consultation, the following parameters collected from all the patients included; age, sex, HBeAg/anti-HBe antibody, transaminase levels, hepatitis B viral load and FibroTest ActiTest score. The enzyme linked immunosorbent assay (ELISA) technique was used for the serological markers; HBsAg and Ag/anti-HBe couple. The transaminase levels were assayed by a VIDAS automated system. Hepatitis viral load (detection threshold of HBV DNA = 10 IU/L). The FibroTest-ActiTest score (BioPredictive, Paris, France) was used for the non-invasive and biological evaluation of brosis and liver activity according to the METAVIR score.

Results
We included 102 patients and their ages ranged from 3 to 63 years old. The male/female sex ratio was 2.9, the level of ALT ranged from 7 IU/L to 323 IU/L, the viral load varied from 1 to 8.6 log while 16 patients (15.7%) had biochemical activity. Among patients with anti-HBe negative antibodies, 25.5% (n=25) had a viral load greater than 2000 IU/L. Two of the four HBeAg positive patients had a VHB DNA between 4 to 7 logs (66.7%). Moreover, according to the FibroTest-ActiTest score, brosis and activity were found in 37 and 14 patients respectively. In patients with HBeAg negative, virological and biochemical activity was noted in 25.5% (n=25) and 14.3% (n=14), respectively. Table 1 presents the characteristics of the samples.

Discussion
The predominance of HBeAg negative forms, young adulthood and males were usually found in Sub-Saharan Africa [8]. The predominance of HBeAg negative forms was also found in Asia and Europe but in lower proportions [7,9,10]. In South Asia, a quarter of children with chronic HBsAg were still HBeAg positive during adolescence; the spontaneous loss of HBsAg being faster in Africans where only 10% of them remained HBsAg positive in their thirties [11][12][13].
This geographical variation was often explained by the difference in genotypes but also by the difference in the modes of transmission; materno-fetal in Asia and early childhood in Africa [12,13]. HBeAg negative chronic infection (59.8%), also known as inactive carriage of HBV, was the major form in our sample, which was followed by chronic HBeAg negative chronic hepatitis. HBeAg positive forms (infection or hepatitis) were marginal with 2% each while the data in the literature were variable.
Hadziyannis et al [15] had also reported the prevalence of  [20]. According to Guardiola et al, the majority of subjects with chronic HBeAg negative carriers were inactive carriers [21]. Respectively, 75% and 56% of the patients had normal transaminases and a HBV DNA less than 2000 IU/ml. In our study, these proportions were 85% and 75%, respectively.
During a Fibroscan, 54% of the patients had no histological brosis activity [21]. The Fibrotest-Actitest score was zero in 36% of our patients. The only factor in our study associated with the presence of signi cant brosis activity was the high level of transaminases. The predictive nature of transaminases for the presence of signi cant hepatic brosis is recognized by several authors [10,12,22,23].

Conclusion
According to the EASL classi cation, the biological pro le of chronic hepatitis B is dominated by HBeAgnegative chronic infection. The administrative authorization of the Renaissance Hospital was obtained and the study was consistent with Helsinki Declaration. All patients had given their consent to participate.

-Consent for publication
All patients had given their consent for publication.
-Availability of data and material The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

-Competing interests
All authors declare no con icts of interest related to this article.
-Funding None of the personal or funding interests declared.
-Authors' contributions TMS, MAB, DSA and AC contributed equally to manuscript rewriting and data analysis; TMS, MAB, and AC, assisted in collecting patient data; TMS, MAB, DSA AC contributed to designing the study, providing clinical data, and reviewing the drafts and nal versions of the manuscript. All authors have read and approved the manuscript.