Citations

AbstractEmbryonic stem cells or their progeny inevitably differ genetically from those who might receive the cells as transplants. We tested the barriers to engraftment of embryonic stem cells and the mechanisms that determine those barriers. Using formation of teratomas as a measure of engraftment, we found that semiallogeneic and fully allogeneic embryonic stem cells engraft successfully in mice, provided a sufficient number of cells are delivered. Successfully engrafted cells did not generate immunological memory; unsuccessfully engrafted cells did. Embryonic stem cells reversibly, and in a dose-dependent manner, inhibited T-cell proliferation to various stimuli and the maturation of antigen-presenting cells induced by lipopolysaccharide. Inhibition of both was owed at least in part to production of transforming growth factor-β by the embryonic stem cells. Thus, murine embryonic stem cells exert “immunosuppression” locally, enabling engraftment across allogeneic barriers.Disclosure of potential conflicts of interest is found at the end of this article.

Abstract Isolated central nervous system (CNS) relapse involving the brain parenchyma is a rare complication of systemic non-Hodgkin lymphoma. We retrospectively analyzed patient characteristics, management, and outcomes of this complication. After complete response to initial non-Hodgkin lymphoma treatment, patients with isolated CNS relapse with the brain parenchyma as initial relapse site were eligible. Patients with isolated CNS relapse involving only the cerebrospinal fluid were not eligible. Information on 113 patients was assembled from 13 investigators; 94 (83%) had diffuse large B-cell lymphoma. Median time to brain relapse was 1.8 years (range, 0.25-15.9 years). Brain relapse was identified by neuroimaging in all patients; in 54 (48%), diagnostic brain tumor specimen was obtained. Median overall survival from date of brain relapse was 1.6 years (95% confidence interval, 0.9-2.6 years); 26 (23%) have survived 3 years or more. Median time to progression was 1.0 year (95% confidence interval, 0.7-1.7 years). Age less than 60 years (P = .006) at relapse and methotrexate use (P = .008) as front-line treatment for brain relapse were significantly associated with longer survival in a multivariate model. Our results suggest systemic methotrexate is the optimal treatment for isolated CNS relapse involving the brain parenchyma. Long-term survival is possible in some patients.