Altered communication between the immune and nervous systems may influence the clinical severity of viral hepatitis, suggesting the disease involves systemic mechanisms beyond the liver.

Researchers identified a molecular neuroimmune signature — called the “neuroimmunome” by the authors — across multiple types of patient samples. The same pattern was also seen in hepatocellular carcinoma, suggesting it may contribute to the development of chronic hepatitis and to disease progression.

The study, published in the Journal of Medical Virology, shows that this network of genes associated with the interaction between the nervous and immune systems may help explain variations in the clinical course of hepatitis. It also points to avenues for discovering new biomarkers and potential therapeutic targets.

Analysis of Genetic Patterns

To analyze how viral hepatitis is associated with changes in communication between the immune and nervous systems, the researchers used a systems biology approach capable of integrating large volumes of data and revealing consistent patterns across different biological contexts.

The analysis followed structured steps to assess the clinical relevance of the findings:

Sample diversity. In vitro models, liver tissue samples from patients with hepatitis, and peripheral blood mononuclear cells were combined, allowing for the examination of pathophysiologic processes.

Integration of international data. Samples from public databases in multiple countries were analyzed to identify genes with consistent changes in expression, increasing the robustness of the results.

Transcriptomic meta-analysis. Genes whose expression remained altered across all sample types were selected to reduce individual bias and highlight stable molecular signals.

Neuroimmunome function. The identified genes are involved in both immune processes — cytokine signaling, T‑cell activation, and the interleukin‑1 response — and neural processes such as synaptic transmission, glutamatergic signaling, noradrenergic activity, and the neuregulin pathway.

Clinical relevance. The team applied linear discriminant analysis to evaluate whether the gene expression patterns could distinguish patients with mild, moderate, or severe hepatitis.

Association with hepatocellular carcinoma. The genes were compared with data from The Cancer Genome Atlas (TCGA), allowing analysis of potential connections to liver cancer development.

Cellular interactions in the liver. Ligands and receptors were analyzed to map changes in communication between immune cells and hepatocytes, offering clues about mechanisms that may influence disease progression.

Neuroimmune Alterations and Clinical Course

In viral hepatitis, changes were observed in genes related simultaneously to the nervous and immune systems. The identified genes participate in neuron-to-neuron communication and neurotransmission while also playing essential roles in the immune response, including cytokine‑mediated inflammation and T‑cell activation.

These findings suggest immune cells can respond in an integrated way to neural and immune signals. This interaction may influence the organism’s response to infection and help explain, at least in part, why some patients develop more severe disease.

The neuroimmune signature was consistently detected across blood, liver tissue, and experimental models, reinforcing the observed pattern and suggesting these findings may help explain why some patients progress to more severe disease.

The study also found that the magnitude of genetic alterations correlates with clinical markers of hepatitis severity, such as liver enzyme levels and the systemic inflammatory response. These findings suggest the neuroimmune gene network may reflect the organism’s functional state during viral infection.

Expression Predicts Severity

Some of the identified genes correlated with hepatitis severity, suggesting that expression profiles could be used for clinical risk stratification. This molecular approach could, in the future, complement conventional clinical tests, enabling earlier and more personalized monitoring. It could also inform therapeutic decisions for patients at risk for progression to severe disease.

Comparisons with TCGA data indicated that similar alterations occur in hepatocellular carcinoma, suggesting these pathways may influence both chronic disease evolution and tumor progression.

Additionally, changes in communication between immune cells and other liver cell types — including adrenergic pathways and inflammatory mediators — may affect disease severity and hepatic inflammatory response. These findings also point to potential therapeutic targets for future clinical interventions.

A Systemic Perspective on Hepatitis

Traditionally, viral hepatitis has been treated as a liver‑restricted disease, but the study’s results suggest it should be viewed as a systemic pathology in which communication networks between the immune and nervous systems modulate clinical severity.

Identifying this neuroimmune signature expands opportunities to discover molecular biomarkers and new therapeutic targets and offers clues about mechanisms involved in liver oncogenesis.

Characterizing this molecular network may also help identify dysfunctional immune responses early and guide new prevention and treatment strategies.

The study suggests that patients with specific gene‑expression profiles could benefit from intensified clinical monitoring or targeted treatments, including immunomodulatory approaches.

Potential Impacts on Mental Health 

According to the authors, the results suggest alterations in the neuroimmunome may be related to stress and mood disorders in patients with hepatitis. Previous studies have shown that people with chronic hepatitis have higher rates of anxiety and depression, which can influence disease progression through immunomodulatory pathways.

In this context, the molecular network may indicate a biological link between the liver and the brain, supporting the integration of psychotherapeutic strategies into the clinical care of patients with liver disease.

Changes in genes such as NRG1 and DBH were also linked to hepatocellular carcinoma severity. Analyses of DBH, which encodes dopamine-beta‑hydroxylase and is responsible for norepinephrine synthesis, suggest stress‑related pathways may be more active in the tumor microenvironment, pointing to a possible connection between stress and progression of liver disease.

Other neuroimmunome genes, such as OLFM1 and WDR62, were associated with both hepatocellular carcinoma progression and depressive and anxiety disorders. These findings reinforce that communication between the immune and nervous systems can influence multiple aspects of disease.

Mortality and Incidence

The global burden of viral hepatitis remains significant. According to the World Health Organization, the disease causes about 1.3 million deaths per year, making it the second‑leading cause of death from infectious diseases worldwide.

Data from Brazil’s Ministry of Health indicate that between 2000 and 2024, more than 826,000 cases of viral hepatitis were confirmed, with types B and C predominating and accounting for most infections and deaths. During that period, 49,999 deaths were recorded with hepatitis listed as the underlying cause, and 45,959 deaths with hepatitis listed as a contributing cause.

These numbers underscore the importance of investigating mechanisms that modulate hepatitis severity and the need to develop more effective strategies for diagnosis, monitoring, and treatment, both globally and nationally.

This story was translated from Medscape’s Portuguese edition.