Loss of protective immunity to polio, diphtheria and Haemophilus influenzae type b after allogeneic bone marrow transplantation.

Immunity to poliovirus, diphtheria and Haemophilus influenzae type b (Hib) was studied in 16 adult recipients of a bone marrow transplant from an HLA-identical sibling donor in order to evaluate the need for revaccinations. T-cell depletion was not done in any case. The donors and patients were studied before bone marrow transplantation (BMT) and the patients 1, 3, 6, and 12 months later. Prior to the BMT 10 of 11 patients were immune (titre > or = 4) to all vaccine poliovirus types by a standard microneutralization assay. At 12 months after BMT only two of seven patients were immune to all vaccine types, and none had immunity against an antigenically altered poliovirus type 3 strain Finland. The geometric means of antibody titres against poliovirus types 1, 2, and 3 strain Saukett and strain Finland declined gradually after 1 month postgrafting, being 4.4, 5.4, 3.3, and 1.3 respectively at 12 months after BMT. At 1 year 6 of 11 patients had immunity against diphtheria by a toxin neutralization method, but the antitoxin geometric mean level had decreased to a barely protective level, 0.01 IU/ml. The geometric mean Hib antibody concentration decreased during the first 6 months after BMT and thereafter increased slightly. A significant proportion of BMT recipients lose their protection against polio, diphtheria and Hib, and revaccinations are necessary.