Background: Growing evidence suggests that it is possible to seroconvert chronic renal failure patients who are absolute non-responders to hepatitis B vaccine by means of either additional booster vaccine doses or associated IL-2 administration or both. We have studied the possibilities of hepatitis B seroconversion by revaccination and its dependence on vaccine dose, and the effects of a concurrent low-dose rHuIL-2 regime.
Methods: Forty known absolute non-responders with chronic renal failure were entered into a complete revaccination protocol. Patients were randomly assigned to two dosage groups of either 20 or 40 micrograms hepatitis B vaccine administered at 0, 1, 2 and 6 months. Further randomly selected patients from each dosage group were given 500,000 U of rHuIL-2 in the same deltoid area 4 h after vaccine administration.
Results: Sixty-seven per cent of patients revaccinated with 40 micrograms attained antibody protecting levels compared to only 20% of those receiving doses of 20 micrograms (P < 0.025). When compared with initial values, the ThCD4/CD25 cell count was significantly reduced immediately after HuR-IL2 administration (P < 0.003) and significantly increased 1 month after the last dose was given (P < 0.0003). A definite rHuIL-2 effect on HBV antibody synthesis could not be demonstrated, nor was erythropoietin found to enhance seroconversion.
Conclusions: From these results we suggest that more intense and frequent antigenic stimulation as obtained by revaccination using four doses of 40 micrograms may effectively reduce the pool of hepatitis B vaccine nonresponders in chronic renal failure patients.