Human gastrointestinal neoplasia-associated myofibroblasts can develop from bone marrow-derived cells following allogeneic stem cell transplantation.

This study characterized the contribution of bone marrow-derived cells to human neoplasia and the perineoplastic stroma. The Australasian Bone Marrow Transplant Recipient Registry was used to identify solid organ neoplasia that developed in female recipients of male allogeneic stem cell transplants. Eighteen suitable cases were identified including several skin cancers, two gastric cancers, and one rectal adenoma. Light microscopy, fluorescence and chromogenic in situ hybridization, and immunohistochemistry were performed to determine the nature and origin of the neoplastic and stromal cells. In contrast to recent reports, donor-derived neoplastic cells were not detected. Bone marrow-derived neoplasia-associated myofibroblasts, however, were identified in the rectal adenoma and in a gastric cancer. Bone marrow-derived cells can generate myofibroblasts in the setting of human gastrointestinal neoplasia.

Imatinib as a potential antiresorptive therapy for bone disease.

Osteoclasts (OCs) are large multinucleated cells derived from progenitor cells of the monocyte-macrophage lineage. Signal transduction via the macrophage-colony-stimulating factor (M-CSF) receptor, c-fms, is essential for OC formation. Since we have previously demonstrated inhibition of c-fms by imatinib, we examined the effect of imatinib on OC formation and activity. OC formation was not affected by concentrations of 1.0 microM imatinib and lower, but was reduced by 75% at 3.0 microM imatinib. In contrast, both the area of resorption and the number of resorption lacunae were reduced by 80% at 0.3 microM imatinib, and no resorption was observed at concentrations above 3.0 microM. A dose-dependent decrease in receptor activator of nuclear factor kappaB (RANK) expression was observed in OCs when cultured in the presence of imatinib, providing a mechanism for the decrease in OC function. In vivo analysis of the effect of imatinib on OC activity in adult mice following 8 weeks of imatinib treatment also demonstrated a decrease in OC activity. These results suggest that imatinib may have therapeutic value as an antiosteolytic agent in diseases such as osteoporosis, metastatic bone disease, and multiple myeloma.

Mannose-binding lectin gene polymorphisms are associated with major infection following allogeneic hemopoietic stem cell transplantation.

Life-threatening complications such as graft versus host disease and infection remain major barriers to the success of allogeneic hemopoietic stem cell transplantation (SCT). While pretransplantation conditioning and posttransplantation immunosuppression are important risk factors for infection, the reasons that similarly immunosuppressed transplant recipients show marked variation in frequency of infection after allogeneic SCT are unclear. Mannose-binding lectin (MBL) deficiency is a risk factor for infection in other situations where immunity is compromised. We investigated associations between MBL2 gene polymorphisms and risk of major infection following allogeneic SCT. Ninety-seven related allogeneic donor-recipient pairs were studied. Clinical data including survival, days of fever, graft versus host disease incidence and severity, and infection were collected by case note review. Five single-nucleotide polymorphisms in the MBL2 gene were genotyped using the polymerase chain reaction and sequence-specific primers. MBL2 coding mutations were associated with an increased risk of major infection following transplantation. This association was seen for donor (P =.002, odds ratio [OR] 4.1) and recipient (P =.04, OR 2.6) MBL2 genotype. MBL2 promoter variants were also associated with major infection. The high-producing haplotype HYA was associated with a markedly reduced risk of infection (recipient HYA P =.0001, OR 0.16; donor HYA P =.001, OR 0.23). Donor MBL2 coding mutations and recipient HYA haplotype were independently associated with infection in multivariate analysis. These results suggest that MBL2 genotype influences the risk of infection following allogeneic SCT and that both donor and recipient MBL2 genotype are important. These findings raise the possibility that MBL replacement therapy may be useful following transplantation.