Polysaccharide antibody responses are impaired post bone marrow transplantation for severe combined immunodeficiency, but not other primary immunodeficiencies.

Established treatment of severe combined immunodeficiencies (SCID) and other primary immunodeficiencies (PID) is bone marrow transplantation (BMT). Normal lymphocyte numbers and protein antigen responses are present within 2 years of BMT, polysaccharide antibody responses appear last. Streptococcus pneumoniae infection causes significant morbidity and mortality post-BMT. Previous studies have shown good protein antigen responses post-BMT for SCID and PID, but had not examined the polysaccharide responses. We retrospectively analysed pneumococcal polysaccharide (PPS) responses in our patient series. In total, 22 SCID and 12 non-SCID PID were evaluated, all >2 years post BMT: 17 SCID, 12 PID received chemotherapy conditioning; 17 SCID, three PID had T-cell depleted (TCD) BMT, others had nonconditioned whole marrow BMT. All had normal Haemophilus influenza B and tetanus antibody responses. Of 22 SCID, 13 vs 11/12 PID responded to PPS vaccine (P=0.05). There was no association with donor age, GvHD, B-cell chimerism, or IgG2 level. Fewer TCD marrow recipients responded to PPS (P=0.04). Analysis of the SCID group showed no association of PPS response with type of marrow received. This is the first study to specifically examine PPS antibody responses following SCID and PID BMT. Pneumococcal conjugate vaccine antibody responses should be examined in these children.