Andreas L. Petzer

Evidence from a leukaemia model for maintenance of vascular endothelium by bone-marrow-derived endothelial cells

BACKGROUND Vascular endothelial cells lost from the blood-vessel endothelium through necrosis or apoptosis must be replaced. We investigated in a leukaemia model whether bone-marrow-derived endothelial cells contribute to this maintenance angiogenesis. METHODS We studied six patients with chronic myelogenous leukaemia (CML) carrying the BCR/ABL fusion gene in their bone-marrow-derived cells. We screened endothelial cells generated in vitro from bone-marrow-derived progenitor cells and vascular endothelium in myocardial tissue for the BCR/ABL fusion gene by in-situ hybridisation. For detection of donor-type endothelial cells after transplantation of haemopoietic stem cells, recipient tissue was stained with monoclonal antibodies against donor-type HLA antigens. FINDINGS We identified the BCR/ABL fusion gene in variable proportions (0-56%) of endothelial cells generated in vitro. Endothelial cells expressing the fusion gene were found in the vascular endothelium of a patient. In a recipient of an allogeneic stem-cell transplant, normal donor-type endothelial cells were detected in the vascular endothelium. INTERPRETATION These findings suggest that CML is not solely a haematological disease but originates from a bone-marrow-derived haemangioblastic precursor cell that can give rise to both blood cells and endothelial cells. Moreover, normal bone-marrow-derived endothelial cells can contribute to the maintenance of the blood vascular endothelium. The integration of bone-marrow-derived endothelial cells into the vascular endothelium provides a rationale for developing vascular targeting strategies in vasculopathies, inflammatory diseases, and cancer.

Epidemiology and outcome of infections due to Aspergillus terreus: 10-year single centre experience.

Aspergillus terreus, a less common pathogen, appears to be an emerging cause of infection at our institution, the Medical University Hospital of Innsbruck. Thus the epidemiology and outcome of A. terreus infections over the past 10 years was assessed. We analysed 67 cases of proven invasive aspergillosis (IA) according to the European Organisation for Research and Treatment of Cancer/Mycoses Study Group criteria, investigated antifungal susceptibility of amphotericin B (AMB), voriconazole and caspofungin and performed molecular typing of A. terreus. Patients with proven IA caused by A. terreus (n = 32) and non‐A. terreus (n = 35) were evaluated. The two groups were comparable in terms of age, gender, underlying disease, antifungal prophylaxis and duration of neutropenia (P > 0·05). Leukaemia was the most common underlying malignancy. Fungal dissemination occurred in 63% of the patients. Aspergillus terreus infections were associated with a lower response rate to AMB therapy (20%), compared with 47% for patients with non‐A. terreus infections (P < 0·05). In vitro, A. terreus was found to be resistant to AMB and molecular typing discriminated between patients isolates, showing a high strain diversity with 26 distinct types (I‐XXVI) identified by combination of three primers. Aspergillus terreus infections displayed evidence of AMB resistance in vitro and in vivo and were associated with a high rate of dissemination and poor outcome; A. terreus causes systemic infections of endemic character in Tyrol, Austria. The onset of A. terreus infection depends not on the degree of immunosuppression but on environmental Aspergillus spp. exposure.

Prospective Evaluation of Allogeneic Hematopoietic Stem-Cell Transplantation From Matched Related and Matched Unrelated Donors in Younger Adults With High-Risk Acute Myeloid Leukemia: German-Austrian Trial AMLHD98A

PURPOSE To assess the impact of allogeneic hematopoietic stem-cell transplantation (HSCT) from matched related donors (MRDs) and matched unrelated donors (MUDs) on outcome in high-risk patients with acute myeloid leukemia (AML) within a prospective multicenter treatment trial. PATIENTS AND METHODS Between 1998 and 2004, 844 patients (median age, 48 years; range, 16 to 62 years) with AML were enrolled onto protocol AMLHD98A that included a risk-adapted treatment strategy. High risk was defined by the presence of unfavorable cytogenetics and/or by no response to induction therapy. RESULTS Two hundred sixty-seven (32%) of 844 patients were assigned to the high-risk group. Of these 267 patients, 51 patients (19%) achieved complete remission but had adverse cytogenetics, and 216 patients (81%) had no response to induction therapy. Allogeneic HSCT was actually performed in 162 (61%) of 267 high-risk patients, after a median time of 147 days after diagnosis. Graft sources were as follows: MRD (n = 62), MUD (n = 89), haploidentical donor (n = 10), and cord blood (n = 1). The 5-year overall survival rates were 6.5% (95% CI, 3.1% to 13.6%) for patients (n = 105) not proceeding to HSCT and 25.1% (95% CI, 19.1% to 33.0%; from date of transplantation) for patients (n = 162) receiving HSCT. Multivariable analysis including allogeneic HSCT as a time-dependent covariable revealed that allogeneic HSCT significantly improved outcome; there was no difference in outcome between allogeneic HSCT from MRD and MUD. CONCLUSION Allogeneic HSCT in younger adults with high-risk AML has a significant beneficial impact on outcome, and allogeneic HSCT from MRD and MUD yields similar results.

Thrombocytes Are the Major Source for Soluble Vascular Endothelial Growth Factor in Peripheral Blood

Serum levels of vascular endothelial growth factor (VEGF-S) have been reported to correlate with tumor stage and prognosis in various human malignancies. The source of soluble VEGF in peripheral blood remains obscure. We therefore measured the concentration of immunoreactive VEGF in 241 serum samples and 61 plasma samples (VEGF-P) from 20 subjects undergoing myeloablative chemotherapy and from 3 normal platelet donors. A significant correlation between the peripheral blood platelet count (PC) and VEGF-S (r = 0.86) but not VEGF-P was found. VEGF-S levels were 58.43 ± 42.50 pg/ml (mean ± SD) in patients with a PC < 50 × 109/l, 203.29 ± 176.56 pg/ml for a PC of 50–150 × 109/l, and 457.42 ± 475.41 pg/ml for a PC > 150 × 109/l. Interestingly, VEGF-P levels were substantially lower than the corresponding VEGF-S values, namely below the detection limit in most cases. Supernatants from platelet-rich plasma contained no VEGF, but after in vitro lysis of the platelets very high VEGF levels were found. The VEGF content per 109 platelets was calculated at 2.51 ± 2.39 pg and was dependent on the mean platelet volume. In summary, VEGF release from platelets during blood clotting was found to be the main source of VEGF in serum samples. Cancer patients in clinical remission have negligible amounts of soluble VEGF in peripheral blood, and myeloablative chemotherapy causes a significant drop in VEGF-S levels corresponding to the decrease in PC. Thus, studies addressing the diagnostic and prognostic value of VEGF-S in cancer patients must be interpreted with caution. Our data provide the basis for predicting VEGF-S in relation to PC in vivo, and for reevaluating former studies of VEGF-S in patients with malignant or nonmalignant disease.

Diagnosing Invasive Aspergillosis during Antifungal Therapy by PCR Analysis of Blood Samples

ABSTRACT We evaluated the value of Aspergillus PCR as a tool for diagnosing invasive aspergillosis from whole-blood samples during antifungal therapy. In a 3-year study, 36 patients receiving antifungal therapy due to chest radiographic findings highly suggestive of fungal pneumonia were evaluated. The PCR results from whole-blood samples were compared to those obtained from bronchoalveolar lavage fluids and/or tissue specimens. A total of 205 whole-blood samples, 15 fine-needle aspirations or tissue biopsy specimens, and 21 bronchoalveolar lavage fluids and tracheal secretions were analyzed using PCR. Of the 36 patients, 15 had proven, 9 had probable, and 12 had possible invasive Aspergillus infection according to European Organization for Research and Treatment of Cancer/Mycosis Study Group definitions. For patients with proven infection the sensitivity values of PCR in lung and blood samples were 100 and 40%, respectively. The negative predictive value of blood monitoring under conditions of antifungal treatment was 44%. Clearance of fungal DNA from blood was associated with resolution of clinical symptoms in six of nine patients with proven infection. Repeated positive PCR results for Aspergillus were associated with fatal outcome, as three of six patients died. For patients with probable infection the sensitivity values of PCR in lung fluid and blood were 66 and 44%, respectively. The benefit of PCR diagnosis using whole-blood samples is limited when sampling takes place after treatment has been started. Performance of Aspergillus PCR using tissue samples is recommended in addition to microscopic examination and culture technique for sensitive detection of fungal infection.

Clinical impact of DNMT3A mutations in younger adult patients with acute myeloid leukemia: results of the AML Study Group (AMLSG).

In this study, we evaluated the frequency and prognostic impact of DNMT3A mutations (DNMT3A(mut)) in 1770 younger adult patients with acute myeloid leukemia (AML) in the context of other genetic alterations and the European LeukemiaNet (ELN) classification. DNMT3A(mut) were found in 20.9% of AMLs and were associated with older age (P < .0001), higher white blood cell counts (P < .0001), cytogenetically normal AML (CN-AML; P < .0001), NPM1 mutations (P < .0001), FLT3 internal tandem duplications (P < .0001), and IDH1/2 mutations (P < .0001). In univariable and multivariable analyses, DNMT3A(mut) did not impact event-free, relapse-free (RFS), or overall survival (OS) in either the entire cohort or in CN-AML; a negative prognostic effect was found only in the ELN unfavorable CN-AML subset (OS, P = .011). In addition, R882 mutations vs non-R882 mutations showed opposite clinical effects-unfavorable for R882 on RFS (all: hazard ratio [HR], 1.29 [P = .026]; CN-AML: HR, 1.38 [P = .018]) and favorable for non-R882 on OS (all: HR, 0.77 [P = .057]; CN-AML: HR, 0.73 [P = .083]). In our statistically high-powered study with minimized selection bias, DNMT3A(mut) represent a frequent genetic lesion in younger adults with AML but have no significant impact on survival end points; only moderate effects on outcome were found, depending on molecular subgroup and DNMT3A(mut) type.

Screening for Aspergillus spp. using polymerase chain reaction of whole blood samples from patients with haematological malignancies

Sensitive screening for Aspergillus spp. using polymerase chain reaction (PCR) of whole blood samples in patients with haematological disorders has not been performed to date. In a 2‐year study, 121 patients admitted to the University Hospital of Innsbruck for cancer chemotherapy without clinical signs of fungal infection were prospectively screened for Aspergillus spp. In 28 out of 121 (23%) patients, Aspergillus DNAaemia was detected. Of these patients, 16 (57%) were positive only once for Aspergillus DNA, but positivity was never associated with invasive aspergillosis. PCR positive episodes were short and resolved without antifungal treatment. Five patients (18%) had intermittent PCR positive results. Seven (25%) patients presented at least two consecutive positive PCR results; one of these patients developed invasive aspergillosis and another two were strongly suspected as having aspergillosis. Based on the criteria of the European Organization for Research and Treatment of Cancer case definitions, sensitivity and specificity of serial PCR monitoring were 75% and 96%. Positive PCR results became negative shortly after commencement of antifungal treatment, but the changes did not correlate with clinical responsiveness to treatment in three patients. Our results indicate the potential usefulness of PCR for screening for Aspergillus spp. in patients at risk, but without antifungal treatment.

Functional significance of the activation-associated receptors CD25 and CD69 on human NK-cells and NK-like T-cells.

The application of autologous ex-vivo expanded cytotoxic lymphocytes to cancer patients may help to control minimal residual disease. However, the number of effector cells and the resulting antitumoral activity that can be generated in vitro are remarkably variable. Thus, we separately assessed the proliferative and cytotoxic potential of CD56+ CD3- natural killer (NK) and CD56+ CD3+ T-cells in relation to their expression of CD25, CD69, and CD16 in vitro. Two-week lymphocyte cultures from peripheral blood (n = 51) and from G-CSF-mobilized progenitor cell harvests (n = 11) were performed repeatedly from 14 women with breast cancer throughout conventional- and high-dose chemotherapy. A large proportion of CD25+ cells on day 7 of the culture predicted high expandability (r = 0.69, p < 0.00001), while elevated expression of CD69 predicted augmented cytotoxicity (r = 0.72; p = 0.00001) and low expandability (r = -0.69, p < 0.00001). CD25 and CD69 expression were inversely correlated (r = -0.8, p < 0.0001). CD16 expression was not suited to predict functional properties. Additionally, NK-cells were sorted by FACS according to CD25 versus CD69 expression. In a [3H]thymidine incorporation assay the CD25+ NK-cell fraction exhibited a higher proliferation rate than did the CD69+ fraction in all of three experiments. Together, our data suggest that CD69 is a useful marker for cytotoxic activity of NK cells, whereas proliferative potential is indicated by CD25 expression. These findings should help optimizing the ex-vivo generation of large numbers of cytotoxic effector cells for immunotherapy.

Low concentrations of STI571 in the cerebrospinal fluid: a case report

Summary. We report a 53‐year‐old man with lymphoid blast crisis of Ph+ chronic myeloid leukaemia who was treated with STI571, a selective inhibitor of the enzymatic activity of BCR–ABL. He responded excellently to STI571 (600 mg/d), obtaining a complete cytogenetic remission after 3 months of therapy. Although remission in the bone marrow was sustained, the patient developed an isolated central nervous system relapse. Subsequent analyses of STI571 concentrations in the cerebrospinal fluid (CSF) revealed 2‐log lower CSF levels of STI571 than corresponding plasma levels. These are the first data demonstrating a low penetration of orally administered STI571 into the CSF in humans.

Fungal colonization in neutropenic patients: a randomized study comparing itraconazole solution and amphotericin B solution

We assessed the impact of prophylaxis with the oral itraconazole solution and amphotericin B solution on fungal colonization and infection in a randomized study among patients with hematological malignancies and neutropenia. Infecting and colonizing Candida strains of patients suffering from candidiasis were genotyped by random amplification of polymorphic DNA (RAPD) analysis. A total of 106 patients were evaluated in this study: 52 patients in the itraconazole and 54 in the amphotericin B arm. During neutropenia fungal colonization in the oropharynx occurred in 11 (19.6%) and 24 (40.6%) and in the rectum in 11 (19.6%) and 23 (38.9%) courses in the itraconazole and amphotericin B groups (P<0.05), respectively. Candida albicans was the most prevalent species in both study groups. Mixed fungal colonization with Candida krusei and Candida glabrata was increased in the amphotericin B group, yet without clinical importance since infections were due to C. albicans. The occurrence of invasive candidiasis was significantly increased in multicolonized compared to monocolonized patients. In the amphotericin B group 20 and in the itraconazole group 2 neutropenic patients showed multicolonization with Candida spp. (P<0.05). Overall fungal infections were 3.8% in the itraconazole and 14.8% in the amphotericin B group (P<0.05). RAPD typing showed oropharynx strains involved in superficial infections in four of five patients. In all four patients with deep fungal infections, it appears that the colonizing rectum strains were identical to infecting strains of Candida spp. Itraconazole solution significantly reduced Candida colonization and infection compared to amphotericin B solution. Most patients remained infected with the colonized strains for the entire study period, irrespective of antifungal prophylaxis.