Effects of recombinant interleukin-2 and revaccination for hepatitis B in previously vaccinated, non-responder, chronic uraemic patients. Collaborative Group of Girona.
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.