Immune Insights from Malawi: The Dual Challenge of HBV and Liver Disease

Introduction: The interaction between the Hepatitis B Virus (HBV) and the immune system plays a critical role in determining the outcomes of infection, but also influences the progression of liver disease (LD) towards cirrhosis and hepatocellular carcinoma (HCC). As the HBV field advances towards novel therapies (including immunoregulatory drugs), enhanced risk stratification, and cancer prevention, there is a pressing need to better understand the immunological profiles that underlie diverse disease outcomes. While accounting for almost 70% of all new HBV infections worldwide, African populations have been significantly under-represented in clinical studies. Aiming to improve understanding of HBV-related liver disease in these communities, we analysed circulating levels of ten cytokines in relation to host demographics and viral biomarkers in a cohort based in Malawi.

Method: We selected 60 community participants, which were part of a wider randomly selected census, and 104 individuals presenting in clinic with cirrhosis or HCC in Blantyre, Malawi (ethics ref: 16/11/1698 and 15/5/1599). Patients were excluded if they were living with HIV and no one was on treatment at the time of analysis. Patients and community members were selected to be age and sex matched and divided into 6 subgroups for analysis, based on LD (noLD (n=60), cirrhosis (n=59) (liver stiffness >12kPa and clinical signs of chronic liver disease) and HCC (n=45)), with each of these divided further according to HBV status (positive (n=89) and negative (n=75) (Table 1). GM-CSF, IFNa2a, IL-2, IL-6, IL-8, IL-10, IL-21, IP-10, PD-1 and TNF-a were quantified using multiplex ELISA (K151AEL-1, MesoScaleDelivery). P values were calculated using Kruskal-Wallis, Fisher’s Exact Test and Pearson’s test in R 4.3.3.

Results: Both by representing the distribution of numerical variable from the cohort (cytokines quantification, age, HBV VL and elastography scores, and by hierarchically clustering the cytokine values, we observed that the main parameter explaining cytokine distribution seems to be disease status. We compared the generated clusters and in multivariable analysis, no differences were observed except for liver stifness scores and disease status, confirming that the main driver of these immune profiles is liver disease. Cluster 1 was mainly associated with cirrhosis, cluster 2 with noLD and 3 with HCC.

Conclusion: These findings highlight distinct immunological changes linked to liver disease outcomes, as previously observed in non-African populations. We show a minor impact of HBV status on the immune system in this controlled cohort. However, as the main driver of cirrhosis and HCC in this population, HBV is certainly indirectly impacting the immune system. Despite the high burden of HBV in the WHO Africa region, little research has focused on the immune profiles within these populations, creating significant gaps in our understanding of the role of immunity in HBV replication and disease progression. Bridging this knowledge gap is essential for advancing equitable HBV management strategies on a global scale.