文摘
Forty-seven patients (age range, 7 months–18 years)with malignant (38 cases) and nonmalignant (9 cases)disorders given an allogeneic or an autologous bone marrowtransplantation (BMT) were immunized with Haemophilusinfluenzae type b (Hib) polysaccharide–diphtheriatoxoid conjugate vaccine administered in a single dose at different timepoints after transplantation. Results were compared with those of 13healthy children matched for age and sex who received the sameimmunization schedule. Serum and saliva samples for measurement of totalIgG subclass and specific antibody levels were obtained from patientsand healthy controls before and 3 weeks after vaccination. Twenty-fiveof the 47 patients (53%) had a specific anti-Hib IgGresponse, while an effective IgA and IgM response was mounted by 23(49%) and 11 (23%) children,respectively. In the control group, 13 of 13 subjects mounted a specificIgG antibody production (P < 0.005 in comparison to thepatients' response rate), while an IgA and IgM response wasdemonstrated in 12 (92%; P < 0.01compared to transplanted patients) and 7 (54%;P < 0.05 in comparison to BMT recipients) children,respectively. Lapse of time from BMT to immunization was the mostimportant factor predicting antibody response, as proved by an effectiveincrease in prevaccination specific IgG levels in the majority ofpatients vaccinated after 2 years from transplant. Our data demonstratethat BMT recipients have a reduced capacity to mount an antibodyresponse to polysaccharide antigens compared to normal controls, evenwhen a protein-conjugated vaccine is employed. Since time aftertransplant is the major factor influencing the recovery of immunereactivity to polysaccharide antigens, the ontogeny of the B cellrepertoire seems to follow a predetermined sequential program ofdevelopment.