IMMUNE-RESPONSE OF IMMUNOCOMPROMISED CHILDREN WITH MALIGNANCIES TO A RECOMBINANT HEPATITIS-B VACCINE

The aim of this study was to interpret the antibody response to hepati tis B vaccination following an intensified four-dose schedule in 140 c ancer patients who presented at our clinic between January 1, 1993 and December 31, 1994. According to therapy status, the patients were div ided into two groups: group A consisted of 76 patients undergoing chem otherapy and group B of 64 patients in complete remission and off trea tment. The eligibility requirements were negative hepatitis B virus (H BV), HCV and human immunodeficiency virus serologic markers. A total o f four doses (20 mu g per dose) of recombinant HB vaccine was administ ered intramuscularly in the deltoid region at 0, 1, 2, and 6 months. B lood from the vaccinated subjects was obtained at months 1, 2, 3, and 7 in order to measure anti-HBs titer levels. Protective anti-HBs titer s were considered to be those greater than or equal to 10 mI/mL. The o verall seroconversion rate I month after the fourth dose was 57% (80/1 40 patients), and the seroconversion rates for groups A and B were 31. 5% (24/76 patients) and 87.5% (56/64 patients), respectively. Our resu lts indicated that immunocompromised children undergoing chemotherapy (although less responsive than children in complete remission and off treatment) still preserved their potential to produce protective titer s of anti-HBs. On this basis we recommend (1) HB vaccination after dia gnosis of malignancy in pediatric patients whenever a high prevalence of HB infection exists and (2) vaccination of patients off therapy and in complete remission.