Bone marrow may be the preferable graft source in recipients homozygous for HLA-C group 2 ligands for inhibitory killer Ig-like receptors

HLA class I molecules participate in natural killer cell regulation by acting as ligands for inhibitory killer cell Ig-like receptors (KIRs). One individual may express one or more inhibitory KIR lacking the corresponding HLA ligand. The role of this 'missing KIR ligand' constellation in hematopoietic SCT (HSCT) remains controversial and depends on incompletely defined transplant variables. We have retrospectively analyzed the effects of missing HLA-C group 1/2 and Bw4 KIR ligands in the recipients on the outcome in 382 HSCT, comparing 118 BMT to 264 PBSC transplants (PBSCT). In the multivariate Cox analysis of PBSCT, poor PFS was observed in homozygous HLA-C group 2 (C2/2) recipients (risk ratio (RR), 1.59; P=0.026). In contrast, C2 homozygosity was not unfavorable after BMT (RR, 0.68; P=0.16). C2 homozygous recipients (n=68) had better PFS after BMT than after PBSCT (RR, 0.17; P=0.001), due to fewer relapses (RR, 0.27; P=0.018). Missing Bw4 favorably influenced PFS after BMT (RR, 0.56; P=0.04), but not after PBSCT. These data suggest opposite effects of missing KIR ligands in BMT vs PBSCT. Larger studies are required to reassess whether BMT should be preferred to PBSCT as an option for C2/C2 recipients.

The rat in basic therapeutic research in homeopathy

The Similia Principle, the basis of homeopathy, implies that substances initiating symptoms when applied to healthy biological systems can be utilized as remedies to treat a diseased system with similar symptoms. Depending whether the remedy substance was of the same type as the etiologic agent, treatment is classified as either homologous or heterologous. The intact rat is the biological system most utilized in basic science homeopathic research. The Homeopathy Basic Research experiments (HomBRex) database (about 1300 experiments on model biological systems in homeopathic research) was analyzed for homologous and heterologous treatments of disease states of intact rats. The relationship between the Similia Principle and hormesis is discussed.

Significant alterations in the epidemiology and treatment outcome of invasive fungal infections in patients with hematological malignancies

Invasive fungal infections (IFI) remain a leading cause of morbidity and mortality in immunocompromised patients. This retrospective single-center study analyzed incidence, treatment and outcome of invasive fungal infections in 1,095 patients with hematological malignancies receiving either cytoreductive chemotherapy or autologous or allogeneic hematopoietic stem cell transplantation at our institution between 1995 and 2004. IFI occurred in 167/1,095 (15%) patients with a significant increase over time (12.7% between 1995 and 2000 vs. 18.1% in the later IFI cohort, P = 0.0134). Fifty-four (32%) patients had proven, 70 (42%) patients had probable, and 43 (26%) patients suffered from possible IFI according to EORTC/MSG criteria. In 108/124 (87%) cases with proven or probable IFI, moulds were the causative pathogens. Both, Aspergillus fumigatus (n = 46) and Aspergillus terreus (n = 41) were predominant. Yeast infections (Candida spp.) were documented in 16/124 (10%) cases with proven or probable IFI. Median overall survival of the entire IFI cohort was 7 (3-17) months. Overall survival was significantly better in patients with probable or possible IFI (37 and 38%, respectively) compared with patients with proven IFI (28%, P = 0.019). In 35% of patients, IFI was the principal cause of death with a significant decrease over time (44% in time cohort 1995-2000 vs. 28% in the later IFI cohort, P = 0.018) accompanied by an increased use of novel antifungals. By multivariate analysis, only proven IFI was significantly predictive for death (HR 1.7, P = 0.018). A significant decrease in fungus-related deaths was observed despite a significant increase of IFI over time, probably due to improved diagnostic and therapeutic approaches.

Fludarabine/intermediate-dose cytarabine with or without allogeneic hematopoietic stem cell transplantation in poor-risk leukemia: a single center experience

Disease recurrence has been and remains the leading cause of treatment failure in patients with high-risk leukemia. We retrospectively analyzed outcome in 61 patients with high-risk leukemia receiving a combination of fludarabine and intermediate-dose cytarabine as induction (n = 11) or salvage therapy (n = 35). Thirty-six patients having a suitable stem cell donor proceeded to allogeneic hematopoietic stem cell transplantation (HSCT). Ten patients received fludarabine-based salvage therapy without consecutive allogeneic transplantation and 15 patients received fludarabine/intermediate-dose cytarabine because of disease relapse following allogeneic stem cell transplantation. In patients without prior allogeneic HSCT (n = 46) the complete remission rate (CR) was 41% with a CR rate of 46 and 14% in patients with acute myeloid leukemia (AML) and with acute lymphoblastic leukemia (ALL), respectively. Overall survival for patients achieving a CR was 41 versus 0% for patients not achieving CR (P < 0.0001). The best outcome was observed in patients receiving an allogeneic HSCT in CR following fludarabine/ intermediate-dose cytarabine (47 vs. 0% for patients not in CR at the time of allografting, P = 0.01). All 10 patients receiving fludarabine/intermediate-dose cytarabine without subsequent allogeneic HSCT died within 3 years either of disease relapse/progression or infection. Only 1/15 (7%) patients receiving fludarabine/intermediate-dose cytarabine because of relapse following allogeneic HSCT became a long-term survivor. By multivariate analysis achieving CR, receiving an allogeneic HSCT, and being in first relapse or untreated were the only parameters that significantly determine the outcome. Although preliminary only high-risk AML patients having a stem cell donor are candidates for fludarabine/intermediate-dose cytarabine and only those achieving a CR should be referred to subsequent allogeneic HSCT. All other patients with high-risk leukemia are candidates for experimental therapies within controlled trials.

The roles of growth factors and neural activity in the development of the neocortex

Previous research on primarily the peripheral nervous system has shown that soluble growth factors help control key developmental events by contributing to dynamic autocrine and paracrine signalling systems. Much less is known about the roles of these substances in neocortical development. Using cell and tissue culture paradigms, we have demonstrated that soluble growth factors are produced by the neocortex and its subcortical targets, and that these tissues can respond to them. There are several possible functions for these factors in neocortical development in vivo: they may initiate axonal growth from neocortical neurons and/or their afferents; accelerate or guide that growth; and/or play a role in the later refinement of connections. Although none of these possibilities can be excluded, the existing evidence strengthens the hypothesis that soluble growth factors are important for the early postnatal growth and refinement of neocortical connections, when their levels of release may be regulated by neocortical activity. At present we do not know which growth factors are involved in these processes, but the results of preliminary experiments indicate that neurotrophins and fibroblast growth factor are prime candidates.

Vascular Endothelial Growth Factor and Activin-A Serum Levels Following Allogeneic Hematopoietic Stem Cell Transplantation

Allogeneic hematopoietic stem cell transplantation is frequently complicated by syndromes characterized by a disruption of the endothelial integrity such as graft-versus-host disease or liver toxicity. Vascular endothelial growth factor and activin-A, a member of the transforming growth factor beta (TGF-beta) superfamily, are important for endothelial integrity and tissue repair. We retrospectively measured endogenous vascular endothelial growth factor and activin-A serum levels in 70 patients following allogeneic stem cell transplantation. Vascular endothelial growth factor serum levels were significantly decreased within the first 2 weeks after the transplant and returned to pre transplant levels by day +15. Activin-A serum levels were significantly elevated from day +7 with peak levels reached on day +10. By using the median value as cutoff high vascular endothelial growth factor levels on day +15 were associated with significantly better overall survival, less liver toxicity, faster neutrophil recovery, and a trend towards less severe acute graft-versus-host disease. No correlation was found between activin-A serum levels and survival, liver toxicity, neutrophil recovery, or graft-versus-host disease. Monitoring of vascular endothelial growth factor levels following allogeneic hematopoietic stem cell transplantation might help to identify patients with a very high risk for early transplant-related complications.

Impact of natural killer cell dose and donor killer-cell immunoglobulin-like receptor (KIR) genotype on outcome following human leucocyte antigen-identical haematopoietic stem cell transplantation

To define the role of quantitative graft composition and donor killer-cell immunoglobulin-like receptor (KIR) genotype in clinical outcome following unmanipulated peripheral blood stem cell transplantation (PBSCT) from human leucocyte antigen (HLA)-identical siblings, 43 consecutive transplants for haematological malignancies were analysed retrospectively. Twenty-four patients underwent myeloablative conditioning and 19 received busulphan/fludarabine-based reduced intensity conditioning (RIC). In patients with acute myelogenous leukaemia or myelodysplastic syndrome (AML/MDS; n = 18), no relapse occurred following transplants meeting both a high (above median) natural killer (NK) cell count and missing HLA-ligand(s) to donor's KIR(s), compared to all other AML/MDS patients (0% versus 44%; P = 0.049). Missing HLA-B and/or HLA-C ligand combined with missing HLA-A3/11 (KIR3DL2 unblocked) predicted for reduced relapse incidence regardless of diagnosis or conditioning type (P = 0.028). Moreover, in AML/MDS patients, this constellation predicted superior overall survival (OS) (P = 0.046). Transplants with more than two different activating donor KIRs were associated with an increased risk for non-relapse mortality (NRM), both by univariate and multivariate analysis. Quantitative graft composition had a significant impact exclusively in RIC transplants. Here, a trend towards reduced relapse incidence was found in patients receiving high numbers of NK cells (16% versus 54%; P = 0.09). In patients receiving high versus low T cell numbers, OS was superior (83% versus 37%; P = 0.01), due mainly to reduced NRM (0% versus 33%; P = 0.046). By multivariate analysis, relapse risk was decreased significantly in patients receiving high NK cell numbers (P = 0.039). These data suggest that both the number of transplanted NK cells and the donor KIR genotype play a role in graft-versus-malignancy mechanisms in HLA-identical PBSCT.