[Dose-reduced conditioning before allogeneic stem cell transplantation: principles, clinical protocols and preliminary results]

Long-term control of HIV by CCR5 Delta32/Delta32 stem-cell transplantation

Infection with the human immunodeficiency virus type 1 (HIV-1) requires the presence of a CD4 receptor and a chemokine receptor, principally chemokine receptor 5 (CCR5). Homozygosity for a 32-bp deletion in the CCR5 allele provides resistance against HIV-1 acquisition. We transplanted stem cells from a donor who was homozygous for CCR5 delta32 in a patient with acute myeloid leukemia and HIV-1 infection. The patient remained without viral rebound 20 months after transplantation and discontinuation of antiretroviral therapy. This outcome demonstrates the critical role CCR5 plays in maintaining HIV-1 infection.

Prediction of individual response to chemotherapy in patients with acute myeloid leukaemia using the chemosensitivity index Ci

As the response to chemotherapy in patients with acute myeloid leukaemia (AML) may still not be accurately determined by known prognostic factors, such as karyotype, the ex vivo chemosensitivity profile may help to predict the individual response. The predictive accuracy of an ex vivo assay should be assessed by correlation of assay results with both response rate and survival. We prospectively investigated the prognostic relevance of pre-therapeutic ex vivo chemosensitivity testing in primary cell cultures from adult AML patients by applying a new evaluation methodology, designated the chemosensitivity index, C(i). This C(i) was designed as a prognostic index by taking the area under the curve as an exact measure of the total dose-response relationship. We found an overall predictive accuracy of 98.2% concerning treatment response, which compares favourably with previously published data ranging from 75% to 92%. Moreover, the C(i) proved to be the strongest prognostic factor for overall survival in a multivariate Cox regression analysis including karyotype grouping and age (P < 0.001), and enabled the evaluation of response to combination therapies and selection of possible treatment alternatives. Our data suggest that ex vivo chemosensitivity testing evaluated by the C(i) could serve as a powerful tool for assay-directed therapy strategies in AML.

Proteomics applied to the clinical follow-up of patients after allogeneic hematopoietic stem cell transplantation

A phase 1 diagnostic study was performed to evaluate a novel technology for clinical proteomic research based on capillary electrophoresis and mass spectrometry. Urine from 40 patients after hematopoietic stem cell transplantation (HSCT; 35 allogeneic, 5 autologous) and 5 patients with sepsis was collected for a period of 100 days and analyzed. More than 1000 different polypeptides could be detected in individual samples. Polypeptide patterns excreted in the urine of patients were significantly different from those of healthy volunteers. No significant differences were detected comparing different conditioning regimens. The aim of this study was to identify polypeptide patterns functioning as early indicators of graft-versus-host disease (GVHD). Eighteen patients developed GVHD after allogeneic HSCT. Sixteen differentially excreted polypeptides formed a pattern of early GVHD markers, allowing discrimination of GVHD from patients without complications with 82% specificity and 100% sensitivity, cross-validated. Inclusion of 13 sepsis-specific polypeptides allowed us to distinguish sepsis from GVHD with a specificity of 97% and a sensitivity of 100%. Sequencing 2 prominent GVHD-indicative polypeptides led to the identification of a peptide from leukotriene A4 hydrolase and a peptide from serum albumin. The data reveal that capillary electrophoresis and mass spectrometry allow identification of biomarkers for a variety of diseases or related complications.