Low Positive Rates for HBeAg and HBV DNA in Rheumatoid Arthritis Patients—A Case-Control Study

Background The rates of hepatitis B virus (HBV) infection in rheumatoid arthritis (RA) patients were controversial when considering the reported outcomes. It was speculated that HBV infection status altered after suffering from RA, and variations over HBV infection rates became apparent. Methods To compare the positive proportions of hepatitis B e antigen (HBeAg) and HBV DNA, a case-control study was performed between the 27 chronic hepatitis B (CHB) patients with RA and the 108 age-and gender-matched CHB patients. In addition, the positive rates of hepatitis B surface antigen (HBsAg) and hepatitis B core antibody (anti-HBc) were surveyed among the 892 RA patients. 44.6% 34.1%.


Introduction
It was observed that the HBV infection affected rheumatoid arthritis (RA), where HBV was considered as the suspected trigger for arthritis in the genetically susceptible individuals [1]. The rates of positivity for RF and ACPA were as high as 14.4% and 4.1%, respectively, in patients with chronic hepatitis B (CHB) [2].
Hepatitis B core antigen (HBcAg) was found in the synovium of RA patients with CHB, indicating that HBV may involve in the pathogenesis of local lesions [3]. In RA patients, immune dysregulation and the immunosuppressive therapies also in uenced HBV infection [4,5].
HBV infection with a high endemicity was reported in various regions of the Asia-Paci c and Sub-Saharan Africa [6,7]. It also affects approximately 10 million people in China [8]. Unfortunately, the HBV infection rates was reported differently for RA patients in the previous studies. Yilmaz et al. reported a lower HBV infection prevalence in RA patients according to Turkish national data in comparison with the general population [9]. Mahroum et al. performed a case-control study and showed the RA patients had a greater proportion of chronic HBV infection than the age-and sex-matched controls [10]. Hsu et al. observed that RA patients were characterized with an increased risk of HBV infection when comparing with that of the aged ≥ 18 years non-RA cohort [11]. The reasons for these differences were complicated, especially when these were no studies assessing the HBV infection status in the RA patients, including HBeAg-positive, HBV DNA load and ALT level.
Herein, a case-control study was performed to clarify the effect of RA on the HBV infection status. The positive rates of hepatitis B e antigen (HBeAg) were compared between the RA patients with CHB and the age-and gender-matched general CHB patients, in addition to positive rates of HBV DNA.

Study design
This was a case-control study. A total of 27 CHB patients with RA were enrolled from the department of The medical records of patients were reviewed, and the data of the following variables were collected: age, gender, diagnosis, duration of disease, HBsAg, HBeAg, anti-HBc, ALT, HBV DNA load. All the test data of RA patients were collected at the rst visit time and the data of CHB patients were collected before their antiviral treatment.
The primary outcome was the comparison of the positive rates of HBeAg and HBV DNA between the CHB patients with RA and the age-and gender-matched CHB patients. The secondary outcomes were the followings: (i) the comparison of the elevated ALT rates between the CHB patients with RA and the CHB patients, (ii) the comparison of the HBeAg titer, HBV DNA load and ALT levels between CHB patients with RA and the CHB patients, (iii) the comparison of HBsAg-positive rates between the RA patients and Chinese general population (CGP), (iv) the comparison of anti-HBc-positive rates between the RA patients and CGP.

Laboratory methods
The titers of HBsAg, HBeAg and anti-HBc were quanti ed by The Abbott ARCHITECT assays (Abbott Laboratories, Chicago, IL, USA). The lower limit of detection for HBsAg was 0.05 IU/mL, HBeAg was 1 s/co and anti-HBc was 1 s/co. The HBV DNA load was measured by the Roche COBAS AmpliPrep/COBAS TaqMan HBV test (Roche Molecular Systems, California, IL, USA), and the lower limit of detection was 12 IU/mL. Liver function tests were performed with an automated bioanalyzer (Olympus AU5400, Japan).

Statistical analysis
The analyses were performed by SPSS software 13.0 (SPSS Inc. Chicago, IL, USA). Conditional logistic regression was used to compare the proportions between 2 groups. Quantitative data were analyzed with Shapiro-Wilk test and Levene statistic for normality and homogeneity of variance, respectively. According to situation, Paired-Samples t test or Signed rank Wilcoxon test was used to evaluate differences between two groups. P value < 0.05 was considered statistically signi cant.

Results
Basic characteristics of the CHB patients with RA 27 (3.0%) RA patients were HBsAg-positive and enrolled in this study. Among these, seven patients (25.9%) had HBV family history, seventeen patients (63.0%) had the HBV infection duration more than 10 years, and one patient (3.7%) had the RA duration more than 10 years (Table 1).   Figure 1C). In addition, HBV DNA load in the RA patients was lower than the CHB patients (1.5 ± 2.4 vs. 4.4 ± 3.3 Log 10 IU/ml, t = -3.859, P = 0.001, Figure 1D).

Discussion
For RA patients, the reported difference of the HBV infection rates may associate with the alteration of HBV infection status after suffering from RA. To elucidate this issue, the current case-control study was performed. Compared to the age-and gender-matched general CHB patients, low proportions of positivity for HBeAg and HBV DNA were observed for the CHB patients with RA.
The HBeAg positivity often represents a high replicative phase of the chronic HBV infection, and HBeAg loss is considered as a partial immune control of the chronic HBV infection [15]. In this study, the CHB patients with RA exhibited lower positive rates of HBeAg and titers of HBeAg when comparing with the matched CHB patients. HBV DNA directly indicates HBV replication. The positive rate of HBV DNA in the CHB patients with RA was less than that of the matched CHB patients, as well the HBV DNA load. It demonstrated that CHB patients with RA had more probability of HBeAg seroconversion and HBV DNA load decline, which may associate with immune control after suffering from RA.
Immune dysregulation is the characteristics of RA. It plays a complicated role in HBV infection for abnormal innate and adaptive immune activation of RA patients. First, the type I interferons (IFNs) play a critical role in defending against HBV, and the type I interferon signature is detectable in the peripheral blood of RA patients [16]. Second, CD8+ T cells are capable to control HBV infection and eliminate HBV infected cells [17]. For RA patients, CD8+ T cells are abundant and associated with disease activity, due to pro-in ammatory cytokines production[18] and self-antigens response upon cross-presentation [19]. Third, the humoral immune response has protective role against pathogens [20]. Abnormalities in B cells not only participates in pathogenesis of RA [21] (including production of autoantibody, presentation of autoantigens and secretion of proin ammatory cytokines) [22], but also affects HBV elimination.
The elevated ALT is an important characteristic of immune clearance [23], and inactive HBsAg carrying status can be obtained after immune clearance. Compared to the matched CHB patients, low proportion of ALT > 40U/L and low ALT levels were found for the CHB patients with RA. This suggested that CHB patients with RA were more prone to obtain immune control for HBV after immune clearance.
HBsAg positivity is a de nite HBV infection marker. In the present work, low HBsAg(+) rate of 3.0% was found in the RA patients, which was consistent with the previous study [9]. Then, survey outcomes also indicated that RA patients exhibited low HBsAg(+) rate according to the second Chinese National Hepatitis Seroepidemiological Survey[8] and the estimated China prevalence of HBsAg [12,13]. Hepatitis B core antigen (HBcAg) is an inner nucleocapsid component, the production of anti-HBc is induced by a cellular and humoral immune response to HBcAg during natural HBV infection. Anti-HBc positivity mostly occurs in chronic HBV infection or resolved infection [14]. We found that the positive rate of anti-HBc was 44.6% in the RA patients, higher than the rate of Chinese general population from the China national data [8]. Consistent with the previous studies [10,11], the RA patients may have higher risk of HBV infection in comparison with the general population, due to receiving disease modifying antirheumatic drugs and complicated immunity related to the disease itself [4,5]. During the natural history of HBV, HBsAg seroclearance can emerge in 0.5 -1.0% patients per year after immune clearance phase [24]. It was expected that low positive rate of HBsAg suggested HBsAg seroclearance was more common in the RA patients. The susceptible ages were different for RA and CHB patients. The mother-to-infant transmission was the main route of HBV infection in China. HBV infected early in life, and conferred a high risk of chronicity [25]. In contrast, RA occurred much frequently in the elderly women. Hence, RA was supposed to be later than HBV infection for most patients. We speculated that HBV infection status altered after suffering from RA. Among the 27 patients in this study, 62.9% of them had the HBV duration more than 10 years, and 96.3% of them had the RA duration less than 10 years. This indicates that the majority suffered from RA after HBV infection. After suffering from RA, HBV DNA declines, HBeAg and even HBsAg lose as consequent.
Here, some limitations of the study were as follows: the numbers of patients were limited, a prospective cohort study with large sample size is necessary to evaluate the difference in the natural history of chronic HBV infection between RA and general CHB patients.
In conclusion, HBV infection status altered after suffering from RA. Compared to the matched CHB patients, variations were signi cant, including low positive proportions of HBeAg and HBV DNA, due to immune dysregulation of RA patients. Figure 1 The   [12] and CGP from 2013 to 2017 [13]. Abbreviations: anti-HBc, hepatitis B core antibody; CGP, Chinese general population; HBsAg, hepatitis B surface antigen; RA, rheumatoid arthritis.