Haematopoietic abnormalities after autologous stem cell transplantation in lymphoma patients.

Haematopoietic reconstitution after autologous stem cell transplantation (ASCT) was evaluated at different times in 26 lymphoma patients. All of the patients showed a significant decrease in the number of both committed (CFU-C) and more primitive progenitor cells (LTC-IC). The expansion of bone marrow progenitor cells in a 'stroma-free' long-term liquid culture system supplemented with SCF, IL-3, IL-6 and GM-CSF from 19 transplanted patients was significantly reduced compared to normal controls. The stromal cell compartment, evaluated by means of a CFU-F assay, was also greatly reduced. The number of haematopoietic and stromal cell progenitors was, nevertheless, very similar to their pre-transplant values. Bone marrow histology, which was evaluated at different times after transplant, showed an increase in reticulin fibres, the dilatation of parenchymal sinusoids and some morphological evidence of trilineage dysplasia in 11 patients; however, the same abnormalities were seen in the majority of pre-transplant samples. No cytogenetic abnormalities were observed in 15 patients before transplant, but four subsequently developed persistent clonal karyotypic alterations and five showed non-clonal abnormalities that generally disappeared over time. Our data suggest that both the stromal and the haematopoietic compartments are somehow damaged after ASCT for lymphoma; however, these defects generally pre-exist the transplant conditioning regimen and seem to become less pronounced over time.

Response of myelodysplastic syndrome marrow progenitor cells to stimualtion with cytokine combinations in a stroma-free long-term culture system.

The effect of an ex vivo expansion culture system using multiple cytokine combinations was evaluated in 38 cases of myelodysplastic syndrome (MDS) with the aim of overcoming the defective in vitro growth of haemopoietic progenitor cells. A combination of four growth factors (GF) including SCF, IL-3, IL-6 and GM-CSF was identified as the optimal combination for expanding clonogenic progenitor cells in MDS bone marrow liquid cultures. The cultures of 50% of the patients (19/38) responded to GF stimulation (mean CFU-GM fold increase 15.65+/-48 at week 4) and showed morphological features of normal and/or dysplastic myeloid differentiation. In 12/38 cases (31%), complete unresponsiveness to multiple cytokine stimulation was observed; a small number of patients (7/38) showed progressive leukaemic growth along the cultures with the presence of 100% immature blasts at week 4. GM-CSF and c-kit receptors, analysed by immuno-histochemistry in 10 patients, were over-expressed in responding patients and either lacking or down-regulated in non-responders. Fluorescence in situ hybridization (FISH) analysis of cultured interphase cells of nine patients (trisomy 8 in eight patients) showed a clear-cut increase in the percentage of cells with three signals in the two responding patients, thus indicating the expansion of a MDS clone. Multiple cytokine liquid cultures seem to be able to override the refractoriness of MDS progenitor cells to GF stimulation in many cases, revealing a heterogeneity which may have prognostic implications and should be considered in ex-vivo and in vivo clinical trials with cytokine combinations.

CD34 immunohistochemistry of bone marrow biopsies: prognostic significance in primary myelodysplastic syndromes.

Bone marrow (BM) biopsies from 58 patients with primary myelodysplastic syndrome (MDS) were studied using QBEND10, a monoclonal antibody that recognizes the human progenitor CD34 antigen in routine aldehyde-fixed paraffin-embedded samples. FAB subtypes were RA (5 patients), RARS (9 patients), RAEB (20 patients), RAEBt (11 patients), CMML (3 patients). In addition, 10 MDS patients whose BM biopsies revealed heavy reticulum fibrosis were included. Neither the percentage of CD34+ cells nor the number of CD34+ aggregates (defined as clusters of 3 or more cells) correlated with the presence and morphology of abnormal localizations of immature precursors (ALIP). When all patients were considered, median survival was 69 months in those with less, and 25 months in patients with more than 1% CD34+ cells (P < 0.05). Median survival was 15 months in patients with CD34+ aggregates and 41 months in those without aggregates (P = 0.0017). When RAEB patients were considered median survival was 41 months in those with less than 1%, and 29 months in those with more than 1% CD34+ cells; the 4-year survival chance was 45% in the former and 18.3% in the latter group. Therefore, CD34 positivity of more than 1% identifies a subset of RAEB patients with shorter life expectancy. In addition, leukemic transformation was observed in 11 of 35 patients (31%) with no CD34 aggregates, but in 14 of 23 patients (60%) with aggregates (P < 0.05). CD34 immunostaining, which can be easily performed on routinely prepared BM biopsies, was found to be a powerful prognostic tool for predicting survival and outcome in MDS.

Selective mitochondrial alterations induced by a single dose of daunorubicin or 4-demethoxydaunorubicin in mouse ventricular myocardium.

The ventricular myocardium of CD1 mice given a single high dose (LD50) of daunorubicin (DNR) or its derivative, 4-demethoxydaunorubicin (4DD), was studied under the electron microscope. Severe degenerative alterations were observed, but only in the mitochondria in myocardial tissue samples taken 3 and 7 days after treatment. This suggests that mitochondrial lesions might play an important role in the pathogenesis of anthracycline myocardipathy. Furthermore, the nucleolar segregation phenomenon, already described in experimental doxorubicin myocardiopathy, was not observed in the myocardial samples taken 1 and 3 h after DNR or 4DD injection: this fact may be interpreted, without excluding a possible DNA-mediated toxic mechanism, as the result of different kinetic behaviour of DNR and 4DD compared to doxorubicin.