Abstract Invasive aspergillosis (IA) remains a major complication following allogeneic hematopoietic stem cell transplant (HSCT). In contrast to conventional HSCT, few investigators have examined ...risk factors of IA associated with nonmyeloablative (NMA) regimens characterized by outpatient administration, immunosuppression rather than cytoreduction, and short duration of neutropenia posttransplant. We report our results on a cohort of 125 patients treated homogenously who received a 6/6 matched sibling NMA HSCT designed to be performed on an outpatient basis. Conditioning regimen included fludarabine (30 mg/m2 × 5 days) and cyclophosphamide (300 mg/m2 × 5 days) followed by reinfusion of a minimum of 4 × 106 CD34+ cells/kg. Acute graft-versus-host disease (aGVHD) prophylaxis consisted of tacrolimus and mycophenolate mofetil (MMF). Overall, 13 patients developed IA (5 proved, 6 probable, 2 possible) 44-791 days (median 229) after NMA HSCT, with a risk of 7% at 1, 11% at 2, and 15% at 3 years. Patients who suffered from IA had poorer overall survival (crude hazard ratio 2.3; 95% confidence interval CI 1.0-5.4; P = .045). Intestinal aGVHD or chronic GVHD (cGVHD) was significantly associated with IA at 1 (27% versus 3%, P = .003), 2 (27% versus 8%, P = .01), and 3 years (37% versus 10%, P = .005). The use of daclizumab was also significantly associated with IA at 3 years (47% versus 12%, P = .02). Age, sex, diagnosis, previous autologous transplant, duration of neutropenia, occurrence of cytomegalovirus viremia, duration of steroids or MMF intake, aGVHD, cGVHD, and cumulative number of days spent in hospital were not associated with IA. After multivariate analysis, intestinal GVHD remained the only statistically significant risk factor for IA at 1 ( P = .003), 2 ( P = .01), and 3 years ( P = .005). We conclude that in NMA HSCT, the risk of IA increases over time and is significantly associated with intestinal GVHD. Because there is currently no surrogate in vitro markers of immunocompetence following NMA HSCT, this clinical finding is of particular importance to identify a population at higher risk who should be targeted for antimold prophylaxis.
Molecular basis for stem-cell self-renewal Krosl, Jana K; Faubert, Amelie; Sauvageau, Guy
The hematology journal : the official journal of the European Haematology Association,
2004, Letnik:
5 Suppl 3
Journal Article
In 1977 we showed that cells of a human lymphocytic leukaemia-derived T line (Molt-4) have receptors for Epstein-Barr virus (EBV). More recently, EBV-positive human T cell lymphomas have been ...recognized and human T cell lines containing the EBV genome have been established in vitro. To understand better the interaction of EBV with T cells, we decided to determine first whether human peripheral blood T lymphocytes express receptors for EBV. Using flow cytometry we examined the binding of both lymphocyte-transforming (B95-8) and non-transforming (P3HR-1) strains of EBV to T lymphocyte subpopulations, using a double labelling technique with T cell-specific phycoerythrinated monoclonal antibodies (Leu 2a) and fluoresceinated viral preparation. Our results suggest that, in general, about 50% of the CD8+ (or suppressor/cytotoxic) T cell subpopulation from both EBV-seropositive and -seronegative individuals can bind EBV. EBV receptor expression on these T cells was about 10 and 51 times less than that on Molt-4 and Raji (an EBV receptor-positive B cell line) cells, respectively. The specificity of this binding was demonstrated by the inhibition of attachment of viral preparations preincubated with a monoclonal antibody directed against the viral ligand (gp240/350), and by preincubating these target T cells with unlabelled virus. We were unable to detect EBV-induced antigens in infected T cells, suggesting that, as in Molt-4 cells, virus internalization may not occur in fresh T cells and/or that the virus receptor may not be completely functional. We were also unable to detect C3d (or CR2) receptors on these T cells, or to inhibit virus attachment by treating the targets with an anti-CR2 monoclonal antibody (OKB7), suggesting that the EBV receptor on CD8+ peripheral blood lymphocytes is different from that on B cells.
A study documents expression of multiple Hox genes in primitive normal hematopoietic cells and identifies striking differences in the patterns of expression of certain Hox genes within functionally ...distinct subpopulations of these cells.
•MLL-AF9–driven AML originating from JAM-C deleted mouse hematopoietic stem and progenitor cells is characterized by an AP-1/TNF-α transcriptional program.•Stratification of patients with AML with ...LSC score (LSC-17) is improved by the AP-1/TNF-α initiating cell score associated with AP-1/TNF-α gene signature.
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The leukemic stem cell (LSC) score LSC-17 based on a stemness–related gene expression signature is an indicator of poor disease outcome in acute myeloid leukemia (AML). However, our understanding of the relationships between LSCs and preleukemic cells is still incomplete. In particular, it is not known whether “niche anchoring” of preleukemic cells affects disease evolution. To address this issue, we conditionally inactivated the adhesion molecule JAM-C expressed by hematopoietic stem cells (HSCs) and LSCs in an inducible mixed-lineage leukemia (iMLL)-AF9–driven AML mouse model. Deletion of Jam3 (encoding JAM-C) before induction of the leukemia–initiating iMLL-AF9 fusion resulted in a shift from long-term to short-term HSC expansion, without affecting disease initiation and progression. In vitro experiments showed that JAM-C controlled leukemic cell nesting irrespective of the bone marrow stromal cells used. RNA sequencing performed on leukemic HSCs isolated from diseased mice revealed that genes upregulated in Jam3-deficient animals belonged to activation protein-1 (AP-1) and tumor necrosis factor α (TNF-α)/NF-κB pathways. Human orthologs of dysregulated genes allowed to identify a score based on AP-1/TNF-α gene expression that was distinct from, and complementary to, the LSC-17 score. Substratification of patients with AML with LSC-17 and AP-1/TNF-α genes signature defined 4 groups with median survival ranging from <1 year to a median of “not reached” after 8 years. Finally, coculture experiments showed that AP-1 activation in leukemic cells was dependent on the nature of stromal cells. Altogether, our results identify the AP-1/TNF-α gene signature as a proxy of LSC anchoring in specific bone marrow niches, which improves the prognostic value of the LSC-17 score. This trial was registered at www.ClinicalTrials.gov as #NCT02320656.
This study was aimed at quantitating, by means of fluorescence-activated cell sorter (FACS), EBV binding to different types of target cells, and at learning about a possible relation between EBV ...receptor density and the fate of cell-surface bound virus. We used fluoresceinated virus preparations of two strains of EBV (B95-8: lymphocyte transforming strain; P3HR-1: non-transforming strain) to analyze quantitatively the expression and density of EBV receptors on different human lymphoid cell lines and on B lymphocytes from both EBV-seropositive and -seronegative donors. FACS analysis was also used as a tool to approximate the cell surface area of the different lymphoid cells examined. Our results indicate that: (a) after accounting for the difference in cell surface dimensios, the fluorescence intensity of EBV-bound Raji (a B line) cells was three to four times higher per unit area than that of EBV-bound fresh B lymphocytes from an EBV-seropositive donor; (b) Molt-4 (a T line) cells bound about 21-fold less P3HR-1 EBV and 6-fold less B95-8 EBV than Raji cells per unit area; (c) B lymphocytes from EBV-seronegative adult donors bound only about one third as much virus as B cells from seropositive individuals; (d) two B lymphocyte sub-populations can be identified in the peripheral blood in regard to their ability to bind EBV, regardless of the EBV antibody status of the donor; (e) the EBV receptor on Molt-4 cells appears structurally different from the one found on Raji cells since EBV binding to Molt-4 cells was not blocked by a monoclonal antibody (OKB7) specific to the complement receptor (CR2). Further, in contrast to Raji cells, Molt-4 expressed a differential binding activity for each of the two EBV strains used. Taken together, the important differences observed in regard to EBV attachment to various targets also appear to relate to the fate of cell-surface bound virus: i.e., virus penetration might be determined, at least in part, by the density of EBV receptors on the target cell surface; thus the receptor density may play a major role in viral infection.
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