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 fr om an HLA-identical sibling donor in order to evaluate the need for re vaccinations. T-cell depletion was not done in any case. The donors an d patients were studied before bone marrow transplantation (BMT) and t he patients 1, 3, 6, and 12 months later. Prior to the BMT 10 of 11 pa tients were immune (titre greater than or equal to 4) to all vaccine p oliovirus 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 typ e 3 strain Finland. The geometric means of antibody titres against pol iovirus types 1, 2, and 3 strain Saukett and strain Finland declined g radually after 1 month postgrafting, being 4.4, 5.4, 3.3, and 1.3 resp ectively at 12 months after BMT. At 1 year 6 of 11 patients had immuni ty against diphtheria by a toxin neutralization method, but the antito xin geometric mean level had decreased to a barely protective level, 0 .01 IU/ml. The geometric mean Hib antibody concentration decreased dur ing 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.