Antibody level after hepatitis B vaccination in hemodialysis patients: Influence of hepatitis C virus infection

Seroconversion after hepatitis B vaccine has been estimated to occur when the level of anti-HBs is higher than 10 IU/l, but recently is has been considered that an antibody titer above 100 IU/l is necessary to guarantee an efficacious protection. We prospectively studied the evolution of anti-HBs after primary vaccination (3 doses; Engerix B, 40 mu g each) in 56 seronegative and not previously vaccinated hemodialysis patients. Three months after vaccine administration, seroconversion (anti-HBs >10 IU/l) was found in 43 patients (76.7%), but an adequate response (titer > 100 IU/l) was observed only in 30 (53.5%). At 1 year after vaccination only 1 (3.3%) of the 30 cases with an effective response had lost his anti-HBs, while 12 of the 13 patients (92.3%) with an inadequate response (anti-HBs between 10 and 100 IU/l) had no detectable antibodies (p < 0.01, chi(2)). Considering that an antibody titer above 100 IU/l following vaccination is necessary in order to maintain that level of antibody 1 year later, we analyzed the factors which influenced obtaining this level of antibody. Age, time on hemodialysis, serum albumin, Kt/V and protein catabolic rate did not affect the response to the vaccine. Females had a better response than males, and interestingly we found that hepatitis C virus (HCV) infection influenced the level of immunity. 27 out of the 43 HCV-negative cases (62.7%) obtained anti-HBs levels greater than 100 IU/l, but only 3 out of the 13 HCV-infected patients (23%) had an anti-HBs above 100 IU/l (p < 0.01, chi 2). Our results suggest that after hepatitis B vaccine, an antibody titer higher than 100 IU/l is necessary to maintain the antibody level 1 year later, and that HCV infection may reduce the effectiveness of hepatitis B vaccine in hemodialysis patients.