Günther Gastl

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.

Ep-CAM overexpression in breast cancer as a predictor of survival

The epithelial glycoprotein Ep-CAM is overexpressed in colon cancer and breast cancer. We assessed the frequency and prognostic significance of Ep-CAM in tissue specimens from 205 patients with invasive breast cancer, by immunohistochemical staining with a monoclonal antibody specific for the Ep-CAM antigen. Ep-CAM overexpression was found in 35.6% of samples and was associated with poor disease-free and overall survival.

The Value of Computed Tomography-Guided Percutaneous Lung Biopsy for Diagnosis of Invasive Fungal Infection in Immunocompromised Patients

We assessed Calcofluor white staining, Aspergillus polymerase chain reaction, and a galactomannan enzyme immunoassay for diagnosis of fungal infection with use of computed tomography-guided percutaneous lung biopsy specimens obtained from 61 patients. The sensitivity and specificity of computerized tomography, Aspergillus polymerase chain reaction, and galactomannan enzyme immunoassay were 100% and 50%, 100% and 86%, and 88% and 94%, respectively.

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.

Bacillus Calmette‐Guérin mycobacteria stimulate human blood dendritic cells

Bacillus Calmette‐Guérin (BCG) mycobacteria have been used as adjuvant in the active immunotherapy of various human cancers. In addition, dendritic cells, which are the most potent antigen‐presenting cells, have been shown to be capable of initiating anti‐tumor immune responses. Here we investigated the effects of BCG on dendritic cells cultured from human blood. Addition of BCG resulted in rapid homotypic adhesion of dendritic cells. Moreover, BCG concentrations ranging from 104 to 106 bacteria/ml enhanced expression of the dendritic‐cell‐maturation antigen CD83 and of the T‐cell co‐stimulator CD86 (B7‐2) in a dose‐dependent manner. Concomitant with the increase of CD83 and CD86 expression, the cells lost the ability to capture soluble antigens, as determined by the exclusion of fluoresceinated Dextran molecules. Strikingly, the same dosages of BCG‐bacteria stimulated TNF‐α‐gene transcription and TNF‐α‐protein release from dendritic cells in a dose‐dependent fashion. BCG infection of dendritic cells in the presence of a neutralizing antibody directed against TNF‐α inhibited CD83 expression by more than 50% indicating that the BCG‐induced maturation of dendritic cells was at least partially mediated by dendritic‐cell‐derived TNF‐α. The finding that BCG activates the most potent antigen‐presenting cells reveals a plausible immunological mechanism of the occasionally observed anti‐tumor activity of BCG.

Successful treatment of metastatic renal cell carcinoma with a biologically active dose of recombinant interferon-gamma.

We tested the clinical efficacy of a biologically active dose (BAD) of interferon (IFN)-gamma for treatment of progressive renal cell carcinoma (RCC). Twenty-two RCC patients with disease progression subsequent to nephrectomy were entered on a phase II clinical trial. During an initial dose-finding phase, biochemical responses to repeated once-weekly subcutaneous injections of 10, 100, or 500 micrograms of recombinant IFN-gamma were tested in 16 patients. Results indicated that 100 micrograms IFN-gamma applied once weekly was biologically active with induction of serum beta 2-microglobulin and neopterin. Such a dose induced a nearly maximum response of both markers lasting more than 4 days. This dose was also associated with minimal side effects. A dose of 100 micrograms IFN-gamma given once weekly was, therefore, subsequently given weekly for long-term treatment. During a median time of therapy of 10 months (range, 2 to 32 months) two complete (CR; 20+, 20+ months) and four partial tumor responses (PR; 6+, 7+, 8+, 24+ months) were seen (30% CR plus PR; 95% confidence limits, 12% to 54%) among 20 patients evaluable for response. Patients with refractory disease had significantly lower IFN-gamma-induced increments of serum beta 2-microglobulin than those who achieved clinical remission or stable disease.

Mammaglobin gene expression : A superior marker of breast cancer cells in peripheral blood in comparison to epidermal-growth-factor receptor and cytokeratin-19

Various molecular markers have been used for the detection of circulating breast cancer cells in blood by reverse transcriptase-polymerase chain reaction (RT-PCR). Using nested RT-PCR, we compared the specificity and sensitivity of human mammaglobin (hMAM), epidermal-growth-factor receptor (EGF-R), and cytokeratin 19 (CK-19) expression as markers for circulating carcinoma cells in the peripheral blood of patients with breast cancer. Blood samples from 12 patients with ductal carcinoma in situ, 133 patients with invasive breast cancer, 20 patients with hematological malignancies, 31 healthy volunteers, and tumor tissues from 40 patients with invasive breast cancer were screened for mRNA encoding hMAM, EGF-R, or CK-19 by nested RT-PCR. In all breast cancer tissues, mRNA for hMAM, EGF-R, and CK-19 was detectable. In blood samples from patients with invasive breast cancer, 11 (8%), 13 (10%), and 64 (48%) were positive for mRNA encoding hMAM, EGF-R, or CK-19, respectively. Blood samples from none of the healthy volunteers and patients with hematological disorders were positive for hMAM, while CK-19 mRNA was found in the blood of 12 (39%) healthy volunteers and transcripts for EGF-R and CK-19 were detectable in 5 (25%) and 2 (10%), respectively, of the patients with hematological malignancies. Only hMAM mRNA expression in blood correlated with clinical parameters such as nodal status, metastasis, and CA 15–3 serum levels. In summary, hMAM transcripts detectable in blood by RT-PCR represent the most specific molecular marker for hematogenous spread of breast cancer cells. With the nested RT-PCR method, aberrant EGF-R mRNA expression might occasionally be found in hematological malignancies, whereas CK-19 mRNA expression proved to be rather nonspecific. The prognostic value of hMAM RT-PCR–based tumor cell detection in peripheral blood should be further tested and validated in prospective studies.

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.

Endogenous IFN-gamma during human bone marrow transplantation : analysis of serum levels of interferon and interferon-dependent secondary messages

Serum levels of interferon-gamma and the IFN-dependent marker molecules neopterin and beta 2-microglobulin were assessed in BMT recipients. Concentrations of the latter two markers were corrected for creatinine levels in order to eliminate the impact of alteration of kidney function. Serum levels were assessed daily using commercially available radioimmunoassays. Twelve patients were studied during the early phase of allogeneic bone marrow transplantation and eleven additional patients during complications of BMT. Results indicated that both the conditioning regimen for BMT as well as major clinical complications such as infection and acute graft-versus-host disease strongly influence the endogenous patterns of the lymphokine and its secondary messages. During allogeneic BMT IFN-gamma and neopterin levels exhibited a biphasic pattern with a first peak during conditioning with high-dose cyclophosphamide and a second still higher peak at the time of hemopoietic regeneration. beta-2-microglobulin ratios increased during conditioning and remained elevated throughout observation. Serious infections of bacterial and viral origin as well as GvHD were accompanied by elevated levels of all three serum parameters studied. The kinetics of enhanced endogenous production, however, differed between infectious complications and GvHD. Increasing concentrations were observed during infections subsequent to clinical manifestation, whereas they preceded disease manifestation in GvHD.

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.