Humoral and cellular immune response to the hepatitis B virus vaccine in health care workers.

HERNAN JULIN; ANDREA SALOMONE; NATALIA ALOISI; PATRICIA BARÉ; CARMEN CABELLO; CARMEN STANGANELLI; CLAUDIA FERRARIO; GOLDSTEIN DE FINK SUSANA

Los Cocos, Córdoba

Congreso; LXI Reunión Anual Sociedad Argentina de Inmunología.; 2013

Sociedad Argentina de Inmunología.

Hepatitis B virus (HBV) is the main infectious hazard for healthcare workers (HCW). The HBV vaccine based on the recombinant surface virus antigen (HBs) protects a high proportion of the vaccinees. All HCW should be immunized. Response is evaluated by serum antibody (Ab) titers tested 30-60 days after the third dose. A titer >10 mUI/mL is considered protective. HCW have a much higher risk of getting HBV than the general population, so a higher titer is often suggested for them (>100 mUI/mL). Many HCW were never evaluated after immunization, so they are unaware of their vaccination status. Countries differ in requiring or not booster shots. Our objective was to study the immune memory in vaccinees at different times after completion of a full course of 3 HBV vaccinations. Serum levels of anti-HBs Abs were evaluated by ELISA(anti-HBs, Radim, Italy) in 228 individuals. In vitro cellular immune responses were evaluated using an HBsAg-specific proliferation assay with tritiated thymidine in 11 samples so far. Participants work at one of two institutions in Buenos Aires and signed an informed consent. This study was approved by the ethics committees of both centers. Participants were classified by their Ab titers in three groups: G1: <10 mIU / mL, G2: 10-100 mUI/mL and G3: >100 mUI/mL. Of all cases 84.2% presented Abs>10 mIU / mL. In the literature 5-20% non-responders (NR) are reported. Here 15.8% are in G1. They must be reassessed after a secondcourse of vaccinations to be defined or not as NR. Some HCW with previous high Ab titers showed decrease or lack of them. To assess immunological memory despite low titer, proliferation was tested. Proliferation was observed in those HCW initially in G3 (high response), even with Ab levels dropped over time: (Previous/Present group) 6 G3/G3; 2 G3/G2; one G3/G1, while no proliferation was observed in two G1/G1 (no response). These preliminary data suggest that cellular parameters could be considered as markers of protection in HCW.