Summary. Reduced bone mineral density (BMD) has been reported following allogeneic stem cell transplantation (alloSCT) but the effects of autologous SCT (autoSCT) are less well characterized. We performed a prospective study of BMD changes and its determinants in 44 SCT recipients (38 auto and six allo; 30 peripheral blood SCT and 14 bone marrow transplantation). Serial measurements of BMD at the lumbar spine and femoral neck were performed at baseline and at 3, 6, 12 and 24 months, and spinal radiographs were performed at baseline and 12 months. Mean baseline BMD values at the femoral neck and spine were within normal limits. At 3 months, there was a significant decline of BMD at the femoral neck (P ¼ 0AE011) and a nonsignificant trend towards reduction at the spine. BMD loss persisted for up to 2 years at the femoral neck (P ¼ 0AE005), but values returned to baseline at the spine. Reflecting the rapid initial decline in BMD, bone-specific alkaline phosphatase (a serum marker of bone formation) showed a significant initial decline at 1 month but had recovered to pretransplant levels by 3 months. No new fractures were detected at 1 year post transplant. Sex, diagnosis, use of total body irradiation, stem cell source and type of graft (auto versus allo) did not significantly predict BMD change over the first 12 months. In conclusion, significant and persistent bone loss at the femoral neck was demonstrated in this group of patients following stem cell transplantation. The implications of these findings for future fracture risk require further study.

Summary:As a consequence of the significantly larger inoculum of lymphoid cells present in peripheral blood stem cell (PBSC) harvests compared to bone marrow (BM), it is possible that autoPBSCT recipients may have an earlier and/or enhanced response to vaccines. Until data to confirm this become available, the European Blood and Marrow Transplantation Association (EBMT) recommend that all transplant recipients be immunized in the same way regardless of stem cell source. We performed a prospective study comparing serological responses to influenza, pneumococcal polysaccharide and tetanus toxoid vaccines between autoPBSCT with autoBMT recipients. Antibody responses in sibling HLA-matched allogeneic BMT (alloBMT) survivors were also evaluated. All vaccines were administered within the first 2 years after stem cell transplantation. Fifty patients were enrolled. The time of vaccination after transplant was similar between autoPBSCT (mean 11 months for each vaccine) and autoBMT recipients (mean 12 months except 13 months for tetanus toxoid) (P = NS). Serological responses were poor and no significant difference in response to any of the vaccines used was seen between the three transplant cohorts. We provide no evidence that current EBMT guidelines be modified. Large prospective vaccine studies are needed to address the issue more fully. Bone Marrow Transplantation (2001) 28, 775-781.

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