Distinct Cytokine Profiles Correlate with Disease Severity and Outcome in Longitudinal Studies of Acute Hepatitis B Virus and Hepatitis D Virus Infection in Chimpanzees

Abstract

Historical studies conducted in chimpanzees gave us the opportunity to investigate the basis for the different severities of liver damage and disease outcome associated with infection with wild-type hepatitis B virus (HBV) versus a precore HBV mutant, HBV/hepatitis D virus (HDV) coinfection, and HDV superinfection. Weekly samples from 9 chimpanzees were studied for immune responses by measuring plasma levels of 29 cytokines in parallel with alanine aminotransferase (ALT) levels and viral kinetics. Comparison of classic acute hepatitis B (AHB) with severe or progressive AHB and HBV/HDV coinfection or superinfection identified distinct cytokine profiles. Classic AHB (mean ALT peak, 362 IU/liter) correlated with an early and significant induction of interferon alpha-2 (IFN-α2), IFN-γ, interleukin-12 p70 (IL-12 p70), and IL-17A. In contrast, these cytokines were virtually undetectable in severe AHB (mean ALT peak, 1,335 IU/liter), characterized by significant elevations of IL-10, tumor necrosis factor alpha (TNF-α), and MIP-1β. In progressive AHB (mean ALT peak, 166 IU/liter), there was a delayed and lower-magnitude induction of cytokines. The ALT peak was also delayed (mean, 23.5 weeks) compared to those of classic (13.5 weeks) and severe AHB (7.5 weeks). HBV/HDV coinfection correlated with significantly lower levels of IFN-α2, IFN-γ, and IL-17A, associated with the presence of multiple proinflammatory cytokines, including IL-1α, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-10, and IL-15. Conversely, HDV superinfection induced the highest ALT peak (1,910 IU/liter) and was associated with a general suppression of cytokines. Our data demonstrate that the most severe liver damage, caused by an HBV precore mutant and HDV, correlated with restricted cytokine expression and lack of Th1 response, raising the question of whether these viruses are directly cytopathic. IMPORTANCE Studies performed in chimpanzees at the National Institutes of Health (NIH) demonstrated a significant difference in ALT levels during acute hepatitis of different viral etiologies, with a hierarchy in the extent of liver damage according to the infecting virus: the highest level was in HDV superinfection, followed by infection with a precore HBV mutant, HBV/HDV coinfection, and, lastly, wild-type HBV infection. Our study demonstrates that both the virus and host are important in disease pathogenesis and offers new insights into their roles. We found that distinct cytokine profiles were associated with disease severity and clinical outcome. In particular, resolution of classic acute hepatitis B (AHB) correlated with a predominant Th1 response, whereas HBV/HDV coinfection showed a predominant proinflammatory response. Severe AHB and HDV superinfection showed a restricted cytokine profile and no evidence of Th1 response. The lack of cytokines associated with adaptive T-cell responses toward the precore HBV mutant and HDV superinfection argues in favor of a direct cytopathic effect of these viruses.

The incidence rate, serological characteristics and cytokines profile of occult HBV infection in clinic

“…Studies have shown that IFN-γ and IL-4, as the main cytokines of Th1 and Th2, play a key role in the balance of Th1/Th2. Th1 cells and cytokines are dominant, tend to occur HBV clearance, Th2 cells and cytokines are dominant, and tend to have persistent chronic HBV infection [40][41][42]. The level of IFN-γ was higher in OBI patients, which resulted in HBsAg and viral clearance and low HBV DNA replication level.…”

Novel Biomarkers of Hepatitis B Virus and Their Use in Chronic Hepatitis B Patient Management

“…Genetic markers (single nucleotide polymorphisms) have been associated with the risk of developing cirrhosis, fibrosis or HCC [ 160 ], while host miRNA regulation can indicate the development of fibrosis or HCC [ 161 , 163 ]. Additionally, certain cytokines have been observed to correlate with severity of HBV disease and clinical outcomes [ 162 , 164 , 165 , 166 , 167 ]. Finally, the phenotype and functionality of HBV-specific CD8+ T cells and NK cells have been investigated for predicting HBsAg seroclearance [ 162 ].…”

Interferon and interferon-stimulated genes in HBV treatment

“…Moreover, some studies have used the human liver chimeric mouse model and shown that HBV/HDV infection significantly induced ISG expression ( 38 ). Chimpanzees are the only immunocompetent animals that are naturally susceptible to HBV, and they are the main animal model for studying HBV infection ( 39 ). However, their HBV-related studies were limited because of ethical issues.…”