Clinical trial NCT06876467: Study of the Cellular Response Induced After Vaccination Against the Hepatitis B Virus
Official title: Etude de la réponse Cellulaire Induite Post-vaccination Contre le Virus de l'hépatite B
Study type: OBSERVATIONAL
Overall status: NOT_YET_RECRUITING
Conditions: Hepatitis B Vaccination
Immune Response
T Cells
Keywords: PBMCs isolation
Serology
Spectral cytometry
RNA sequencing
Lead sponsor: Assistance Publique - Hôpitaux de Paris
Sponsor class: OTHER
First posted: 2025-03-14
Enrollment: 115
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Observational model: COHORT
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Healthy individuals receiving HBV vaccination

Brief summary: 296 million people worldwide are infected with the hepatitis B virus (HBV), despite the existence of an effective prophylactic vaccine. Current treatments (nucleoside analogues and pegylated interferon-α) do not prevent chronic hepatitis B (CHB) patients from developing liver fibrosis or hepatocellular carcinoma.

Vaccination is the best way to prevent HBV infection. The first generation of plasma-based vaccines, introduced in the 1980s, has now been superseded by protein vaccines, which are the only ones authorized in France. They are safe and effective. After an initial series of three out of four doses, protective levels of antibodies to the HBV surface antigen (anti-HBsAg; ≥10 IU/mL) are achieved in over 95% of infants, children and young adults.

HBV antigen (Ag)-specific CD4+ and CD8+ T lymphocytes play a major role in the control of HBV infection, contributing to viral clearance and the pathophysiology of acute hepatitis B. However, during HBC, these HBV-specific T cells develop a dysfunctional phenotype and become 'exhausted'. T lymphocytes directed against surface protein antigens (HBsAg) are the most affected by depletion mechanisms - these disappear completely in chronically infected patients, suggesting an important role for these T lymphocytes in infection control. Interestingly, recent studies of rare patients undergoing functional recovery from chronic infection following antiviral treatment have shown a re-emergence of T lymphocytes directed against HBsAg, confirming the importance of these cells in controlling viral replication. Although the protection induced by hepatitis B vaccination has mainly been attributed to the humoral response, a few studies have documented the presence of HBsAg-specific T lymphocytes. These could contribute to the maintenance of a long-term post-vaccination humoral response. The aim of this study is therefore to determine the frequency of healthy individuals receiving HBV vaccination who have a detectable HBsAg-specific T-cell response post-vaccination. We will also study the potential correlation between the frequency of HBsAg-specific T lymphocytes and the level of serum anti-HBsAg antibodies, and we will finely characterize the functional phenotype of these cells using cutting-edge methods and technologies (spectral cytometry, sequencing of mRNA and TCRs). These data will contribute to a better understanding of the biological mechanisms associated with HBV vaccine-induced protection.


Eligibility criteria: Inclusion Criteria:

* Adults ≥18 years
* Pre-vaccination HBV serology carried out within 4 weeks prior to vaccination
* Collection of no objection

Exclusion Criteria:

* Opposition of the person or inability to give opposition
* Pregnant or breast-feeding women
* Chronic illnesses affecting the individual's immune system (asplenia; hyposplenia; haematological cancer; auto-immune disease requiring immunosuppressive treatment, HIV infection).
* Non-affiliation with a social security scheme, Universal Medical Coverage or any equivalent scheme

Primary outcomes:
measure: Proportion of individuals with a cellular response
timeFrame: At inclusion
Secondary outcomes:
measure: Frequency of pehotypes of T lymphocytes post-HBV vaccination
timeFrame: At inclusion
measure: Anti-HBsAg antibody levels
timeFrame: At inclusion
measure: Percentage of LT CD4 circulating cells
timeFrame: At inclusion
measure: Percentage of LT CD8 circulating cells
timeFrame: At inclusion
Other outcomes:
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