Assessing hepatitis B immunity using dried blood spot samples from HIV+ individuals

Area of Science:

• Immunology
• Virology
• Clinical Diagnostics

Background:

• Hepatitis B virus (HBV) infection remains a global health concern.
• Monitoring immunity to Hepatitis B surface antigen (HBsAg) is crucial for vaccination programs.
• Dried blood spots (DBSs) offer a minimally invasive alternative to serum for serological testing.

Purpose of the Study:

• To evaluate an optimized enzyme immunoassay (EIA) for detecting and quantifying antibodies against hepatitis B surface antigen (anti-HBs) in DBSs.
• To assess the utility of DBS testing for anti-HBs in individuals with and without human immunodeficiency virus (HIV) infection.

Main Methods:

• Serum and DBS samples were collected from 56 HIV-positive and 99 HIV-negative patients.
• An optimized EIA was employed for anti-HBs detection in DBSs, with modified sample volume and cutoff values.
• Sensitivity and concordance between serum and DBS anti-HBs results were analyzed.

Main Results:

• The sensitivity of anti-HBs detection in DBSs was 79.8% in HIV-negative and 76.8% in HIV-positive subjects.
• Concordant results correlated with higher CD8 cell counts, HIV viral load, and anti-HBs optical density (OD) values.
• Anti-HBs titers were consistently higher in serum compared to DBS, though DBS could detect levels as low as 17.4 IU/mL (HIV+) and 27.3 IU/mL (HIV-).

Conclusions:

• Optimized EIA for DBS is a feasible method for detecting and quantifying anti-HBs.
• DBS testing for anti-HBs is applicable in HIV-infected individuals.
• This approach could enhance access to hepatitis B diagnosis and vaccination monitoring, particularly in resource-limited settings.