Polymorphisms of Dectin-1 and TLR2 Predispose to Invasive Fungal Disease in Patients with Acute Myeloid Leukemia.

BACKGROUND: Patients with acute myeloid leukemia (AML) who undergo induction chemotherapy are at high risk for invasive fungal disease (IFD). Dectin-1, a C-type lectin family member represents one of the most important pattern recognition receptors of the innate immune system and single nucleotide polymorphisms (SNPs) in the Dectin-1 gene have been associated with an increased risk of infectious complications. We sought to investigate the impact of three different Dectin-1 SNPs and one TLR2 SNP on developing IFD in 186 adult patients with newly diagnosed AML following anthracycline-based induction chemotherapy. PATIENTS AND METHODS: Genotyping of Dectin-1 SNPs (rs16910526, rs3901533 and rs7309123) and TLR2 SNP (rs5743708) was performed by TaqMan method and pyrosequencing. IFD was defined according to the EORTC/MSG consensus guidelines. Multiple logistic regression analyses were applied to evaluate the association between the polymorphisms and the occurrence of pulmonary infections. Dectin-1 expression studies with SNP genotyped human monocytes were performed to elucidate susceptibility to IFD following chemotherapy. RESULTS: We could demonstrate that patients carrying the Dectin-1 SNP rs7309123 G/G (n = 47) or G/G and C/G (n = 133) genotype revealed a significant higher risk for developing both pneumonia in general (adjusted odds ratio (OR): 2.5; p = 0.014 and OR: 3.0, p = 0.004) and pulmonary IFD (OR: 2.6; p = 0.012 and OR: 2.4, p = 0.041, respectively). Patients carrying the TLR2 SNP rs5743708 (R753Q, GA/AA genotype, n = 12) also revealed a significantly higher susceptibility to pneumonia including IFD. Furthermore, Dectin-1 mRNA expression in human monocytes was lower following chemotherapy. CONCLUSION: To our best knowledge, this study represents the first analysis demonstrating that harbouring polymorphisms of Dectin-1 (rs7309123) or TLR2 (rs5743708) represents an independent risk factor of developing IFD in patients with AML undergoing induction chemotherapy.

Efficacy and feasibility of cyclophosphamide combined with intermediate- dose or high-dose cytarabine for relapsed and refractory acute myeloid leukemia (AML).

BACKGROUND: Approximately, 70 % of adult patients with de novo acute myeloid leukemia (AML) achieve a complete remission (CR) while 10-20 % of AML are refractory to induction chemotherapy. Furthermore, a significant proportion of AML patients in CR will relapse during or after consolidation treatment. There is no evidence for a standard salvage regimen and most centers use a combination of an anthracycline and cytarabine (AraC). The aim of this study was to investigate the impact of two age-adjusted regimens containing AraC and cyclophosphamide applied for the treatment of relapsed or refractory AML. PATIENTS AND METHODS: We retrospectively analyzed 60 patients (24 male, 36 female; median age 56 years) with relapsed or refractory AML who were treated with a combination of AraC and cyclophosphamide monocentrically between October 2000 and January 2013. Two different protocols containing either high-dose (hAC) or intermediate-dose cytarabin (iAC) have been applied dependent on age and performance status. RESULTS: We demonstrate an overall response rate (CR + PR) induced by hAC and iAC of 56.7 %. Importantly, a complete remission rate (CR + CRp) of 52.2 % was found in patients who received the hAC regimen while only 8.8 % of patients achieved a CR following the iAC protocol (p < 0.001). The rate of refractory disease was 26.1 and 47.1 %, respectively. High-risk cytogenetics, i.e., a complex aberrant or monosomal karyotype had no effect on achievement of CR after hAC. In addition, there was no impact of activating FLT3 mutations on response to treatment according to the hAC regimen. In the cohort of patients treated with the iAC protocol, treatment-related mortality of 11.8 % within 60 days was observed but none of the patients who received the hAC regimen died within the first 2 months following chemotherapy. The toxicity profile was acceptable at both cytarabine dose levels. Importantly, 19 patients (82.6 %) of the hAC cohort underwent allogeneic hematopoietic stem cell transplantation (HSCT) as consecutive treatment. CONCLUSION: The hAC regimen represents a promising therapeutic approach to induce a second CR in younger patients with relapsed or refractory AML prior to HSCT without using anthracyclines.

Lack of association of platelet-derived growth factor (PDGF) receptor autoantibodies and severity of chronic graft-versus-host disease (GvHD).

PURPOSE: The existence of platelet-derived growth factor (PDGF) receptor autoantibodies in systemic sclerosis is conflicting, and such antibodies were also detected in patients with chronic graft-versus-host disease (GvHD) after allogeneic peripheral blood stem cell transplantation (PBSCT). We therefore aimed to screen for PDGF receptor autoantibodies in patients with chronic GvHD. PATIENTS AND METHODS: We evaluated the existence of PDGF receptor autoantibodies in 39 patients, while 17 patients presented with a limited and 8 patients with an extensive chronic GvHD, respectively. Furthermore, 14 out of 39 patients had no chronic GvHD. RESULTS: We detected at least low levels of PDGF receptor autoantibodies in nearly all (35 of 39) patients after allogeneic PBSCT. Interestingly, only one of six patients with high levels of PDGF receptor autoantibodies presented with an extensive chronic GvHD, while the remaining six patients had no clinical signs of chronic GvHD. Thus, there was no correlation between the quantitative detection of antibodies directed against the PDGF receptor and the presence or severity of chronic GvHD. CONCLUSION: Platelet-derived growth factor receptor autoantibodies could easily be detected in patient sera. Nevertheless, we did not observe any correlation between the presence of PDGF receptor autoantibodies and the severity of chronic GvHD in patients who underwent allogeneic PBSCT.

Reconstitution and functional analyses of neutrophils and distinct subsets of monocytes after allogeneic stem cell transplantation.

PURPOSE: The aim of the study was to investigate the recovery of the innate immune system within the first 100 days after allogeneic peripheral blood stem cell transplantation (PBSCT) and to elucidate a potential correlation with such important events as severe infectious complications or graft-versus-host disease (GvHD). METHODS: In 30 consecutive patients who underwent allogeneic PBSCT, absolute numbers of neutrophils and monocytes were determined and different functional analyses performed at different time points (day +30, +60 and +90, respectively). The capacity to phagocyte Escherichia coli (E. coli) as well as the induction of oxidative burst after incubation with different stimuli (Phorbol-12-myristate-13-acetate; PMA, the chemotactic peptide N-formyl-Met-Leu-Phe; f-MLP or opsonized E. coli) were analysed after engraftment. RESULTS: There was a rapid reconstitution concerning the capability of both neutrophils and monocytes to phagocyte E. coli without a significant increase between day +30 and +90. In contrast, a twofold increase of monocyte oxidative burst after incubation with PMA at day +90 was observed (P = 0.017). Furthermore, the ability of neutrophils to induce oxidative burst after ingestion with E. coli was impaired on day +30 with a significant functional reconstitution on day +60 (P = 0.01). The oxidative burst activity following incubation with f-MLP did not show significant changes after stem cell engraftment. Analysis of numeric reconstitution of CD14+CD16+ monocytes demonstrated a potential correlation with a decreased incidence of chronic GvHD. CONCLUSION: The functional recovery of neutrophils and monocytes in the early period after allogeneic PBSCT differs not only concerning phagocytosis and oxidative burst but also with respect to the stimulus and the cell population that was analysed for oxidative burst activity. The subset of CD16+CD14+ monocytes might be a predictor for a reduced risk of chronic GvHD.

Specific pattern of protein expression in acute myeloid leukemia harboring FLT3-ITD mutations.

FLT3 activating mutations can be detected in about 35% of acute myeloid leukemia (AML). FLT3 internal tandem duplications (FLT3-ITD) represent the majority of FLT3 mutations (25 - 30%) while FLT3-TKD (tyrosine kinase domain) mutations can be found in about 7% of AML patients. In this study, we addressed the question whether especially primary AML cells carrying FLT3-ITD mutations show differences in terms of their protein expression pattern compared to FLT3 wild-type blasts. We investigated bone marrow samples that were isolated at diagnosis from 36 AML patients expressing either FLT3 wild-type (n = 16) or an activating FLT3 mutation (FLT3-ITD, n = 15; FLT3-TKD, n = 5). Proteomic analysis was performed by means of surface enhanced laser desorption/ionization-time of flight (SELDI-TOF) mass spectrometry which has shown its high efficiency in finding biomarkers in solid tumors. Here, we demonstrate that a large series of proteins is differently expressed in primary AML blasts harboring FLT3-ITD mutations. Furthermore, there are also significant differences of the protein expression profile between FLT3-ITD and FLT3-TKD mutations. Interestingly, further analysis of FLT3-ITD positive AML according to its response to the induction chemotherapy demonstrates putative prognostic markers for this subgroup of AML. We suggest that SELDI-TOF mass spectrometry represents a promising tool of proteomic analysis of AML that might help to establish new prognostic markers in AML.