Refractory cytopenias: clinical course according to bone marrow cytology and cellularity

One hundred and one patients with refractory cytopenia were reviewed for morphological classification (using bone marrow, BM, imprints for cytology and Jamshidi biopsies for BM cellularity) and clinical course. Final diagnoses were: moderate aplastic anemia (MAA), myelodysplastic syndromes (MDS) and hypoplastic acute leukemia (HAL). Ninety-two patients received high dose testosterone enanthate (TE) as first treatment (starting dose = 7-10 mg/week i.m. for at least three months). Median survival was significantly longer in MAA than in MDS and in HAL. Among MDS patients, those with primary acquired sideroblastic (AISA) and refractory (RA) anemia had median survival similar to those with MAA, but distinctly longer (p = 0.01) than patients with RA with an excess of blasts (RAEB), RAEB in transformation (RAEBtr) and chronic myelomonocytic leukemia (CMMoL). Acute leukemia (AL) developed more rarely (p less than 0.02) in MAA, AISA and RA than in RAEB, RAEBtr and CMMoL. Response to TE was seen in about two thirds of MAA and in a half of MDS and HAL patients. Among MDS patients, those with hypocellular BM developed leukemia less frequently, responded to androgens more often and survived longer than those with normocellular and, especially, with hypercellular BM. These data indicate that the cytohistological classification of refractory cytopenias identifies essentially two groups with different clinical behaviour, one (MAA, AISA and RA) having long life expectancy and a low probability of developing AL and the other (RAEB, RAEBtr, CMMoL) with a short survival and relatively frequent leukemic complication. Bone marrow hypocellularity seems to be a favourable prognostic factor in MDS. Patients with refractory cytopenias, especially those with a hypocellular BM, can be advantageously treated with androgens.     

Flow cytometric determination of ploidy and proliferative activity on isolated bone marrow particles and on total bone marrow aspirate

The nuclear DNA content distribution of peripheral blood (PB) and bone marrow (BM) cells was determined by propidium iodide flow cytometry in 33 patients who underwent BM aspiration for diagnostic purposes. Two types of BM samples were taken during every aspiration procedure: whole BM aspirate, composed of BM particles contaminated by PB cells; isolated BM particles. Proliferative activity was calculated as the percentage of cells with DNA content intermediate between the diploid (2n) and the tetraploid (4n) values (2n-4n%). Ploidy was expressed as the ratio between the modal channel of the G0-G1 peak of the probe and that of an internal reference standard (DNA index, DI). The 2n-4n% was very close to zero in all PB samples. It was significantly greater in BM particles (21.2 +/- 6.6%) than in whole BM aspirate (16.6 +/- 5.5%, p less than .0005), with a close correlation (r2 = 66; p less than .0001) between the two values. Aneuploid stem lines were found in BM but not in PB. The DI of BM stem lines were similar in whole BM aspirate and BM particles, but the percentage of aneuploid cells was usually higher in BM particles. The reduced proliferative activity and the lower percent of aneuploid cells found in whole BM aspirates, with respect to BM particles, can be attributed to the contamination of BM tissue by PB, which had a very low proliferative activity and did not show aneuploidy. BM particles are therefore an easily obtained and reliable sample for routine evaluation of proliferative activity and ploidy of BM cells by DNA flow cytometry.     

Immunophenotypic characterization of myelopoiesis in early and late myelodysplastic syndromes: use of CD44 as an aid in early diagnosis

We investigated the possibility that myeloid cells from the bone marrow (BM) of myelodysplastic patients differ in their expression of CD44 antigen compared with expression of the antigen in normal controls. In addition, two triple-surface marker assays incorporating, respectively, CD44/CD33/CD66 and CD33/CD34/HLA-DR were used to evaluate the degree of myeloid maturation and assess the number of blasts in BM by flow cytometry. Patients with early-stage myelodysplastic syndrome (MDS; RA [FAB classification]) have significantly decreased expression of CD44 on gated myeloid cells. In contrast, patients with late-stage MDS (RAEB and RAEB-T [FAB classification]) showed an elevated expression of CD44 and an increased number of CD34 blasts compared with early-stage MDS patients and normal controls. Late-stage MDS patients also had an increase in the immature myeloid compartment (CD66 weak expression) compared with early-stage MDS patients and normal controls. We have already included this assay as part of our MDS evaluation protocol alongside BM morphology and cytogenetics.     

Bone marrow macrophages are involved in the ineffective hematopoiesis of myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a group of heterogeneous myeloid clonal disorders characterized by ineffective hematopoiesis. Accumulating evidence has shown that macrophages (MΦs) are important components in the regulation of tumor progression and hematopoietic stem cells (HSCs). However, the roles of bone marrow (BM) MΦs in regulating normal and malignant hematopoiesis in different clinical stages of MDS are largely unknown. Age-paired patients with lower-risk MDS (N = 15), higher-risk MDS (N = 15), de novo acute myeloid leukemia (AML) (N = 15), and healthy donors (HDs) (N = 15) were enrolled. Flow cytometry analysis showed increased pro-inflammatory monocyte subsets and a decreased classically activated (M1) MΦs/alternatively activated (M2) MΦs ratio in the BM of patients with higher-risk MDS compared to lower-risk MDS. BM MФs from patients with higher-risk MDS and AML showed impaired phagocytosis activity but increased migration compared with lower-risk MDS group. AML BM MΦs showed markedly higher S100A8/A9 levels than lower-risk MDS BM MΦs. More importantly, coculture experiments suggested that the HSC supporting abilities of BM MΦs from patients with higher-risk MDS decreased, whereas the malignant cell supporting abilities increased compared with lower-risk MDS. Gene Ontology enrichment comparing BM MΦs from lower-risk MDS and higher-risk MDS for genes was involved in hematopoiesis- and immunity-related pathways. Our results suggest that BM MΦs are involved in ineffective hematopoiesis in patients with MDS, which indicates that repairing aberrant BM MΦs may represent a promising therapeutic approach for patients with MDS.     

Inhibition of inflammatory response in transgenic fat-1 mice on a calorie-restricted diet

Both n-3 fatty acids (n-3 FA) and calorie-restriction (CR) exert anti-inflammatory effects in animal models of autoimmunity and inflammation. In the present study we investigated the synergistic anti-inflammatory effects of n-3 FA and CR on LPS-mediated inflammatory responses using fat-1 transgenic mice that generate n-3 FA endogenously. Wild-type (WT) and fat-1 mice were maintained on ad libitum (AL) or CR (40% less than AL) diet for 5 mo; splenocytes were cultured in vitro with/without LPS. Our results show: (i) no difference in body weights between WT and fat-1 mice on AL or CR diets, (ii) lower n-6/n-3 FA ratio in splenocytes from fat-1 mice on both AL and CR diets, (iii) significant reduction in NF-kappaB (p65/p50) and AP-1 (c-Fos/c-Jun) DNA-binding activities in splenocytes from fat-1/CR mice following LPS treatment, and (iv) significant reduction in kappaB- and AP-1-responsive IL-6 and TNF-alpha secretion following LPS treatment in splenocytes from fat-1/CR mice. The inhibition of LPS-mediated effects was more pronounced in fat-1/CR mice when compared to fat-1/AL or WT/CR mice. These data show that transgenic expression of fat-1 results in decreased pro-inflammatory n-6 FA, and demonstrate for the first time that splenocytes from fat-1 mice on CR diet exhibit reduced pro-inflammatory response when challenged with LPS. These results suggest that n-3 lipids with moderate CR may confer protection in autoimmune and inflammatory diseases.     

The proliferation index of specific bone marrow cell compartments from myelodysplastic syndromes is associated with the diagnostic and patient outcome

Myelodysplastic syndromes (MDS) are clonal stem cell disorders which frequently show a hypercellular dysplastic bone marrow (BM) associated with inefficient hematopoiesis and peripheral cytopenias due to increased apoptosis and maturation blockades. Currently, little is known about the role of cell proliferation in compensating for the BM failure syndrome and in determining patient outcome. Here, we analyzed the proliferation index (PI) of different compartments of BM hematopoietic cells in 106 MDS patients compared to both normal/reactive BM (n = 94) and acute myeloid leukemia (AML; n = 30 cases) using multiparameter flow cytometry. Our results show abnormally increased overall BM proliferation profiles in MDS which significantly differ between early/low-risk and advanced/high-risk cases. Early/low-risk patients showed increased proliferation of non-lymphoid CD34⁺ precursors, maturing neutrophils and nucleated red blood cells (NRBC), while the PI of these compartments of BM precursors progressively fell below normal values towards AML levels in advanced/high-risk MDS. Decreased proliferation of non-lymphoid CD34⁺ and NRBC precursors was significantly associated with adverse disease features, shorter overall survival (OS) and transformation to AML, both in the whole series and when low- and high-risk MDS patients were separately considered, the PI of NRBC emerging as the most powerful independent predictor for OS and progression to AML. In conclusion, assessment of the PI of NRBC, and potentially also of other compartments of BM precursors (e.g.: myeloid CD34⁺ HPC), could significantly contribute to a better management of MDS.     

Using peripheral blood circulating DNAs to detect CpG global methylation status and genetic mutations in patients with myelodysplastic syndrome

Myelodysplastic syndrome (MDS) is a hematopoietic stem cell disorder. Several genetic/epigenetic abnormalities are deeply associated with the pathogenesis of MDS. Although bone marrow (BM) aspiration is a common strategy to obtain MDS cells for evaluating their genetic/epigenetic abnormalities, BM aspiration is difficult to perform repeatedly to obtain serial samples because of pain and safety concerns. Here, we report that circulating cell-free DNAs from plasma and serum of patients with MDS can be used to detect genetic/epigenetic abnormalities. The plasma DNA concentration was found to be relatively high in patients with higher blast cell counts in BM, and accumulation of DNA fragments from mono-/di-nucleosomes was confirmed. Using serial peripheral blood (PB) samples from patients treated with hypomethylating agents, global methylation analysis using bisulfite pyrosequencing was performed at the specific CpG sites of the LINE-1 promoter. The results confirmed a decrease of the methylation percentage after treatment with azacitidine (days 3-9) using DNAs from plasma, serum, and PB mono-nuclear cells (PBMNC). Plasma DNA tends to show more rapid change at days 3 and 6 compared with serum DNA and PBMNC. Furthermore, the TET2 gene mutation in DNAs from plasma, serum, and BM cells was quantitated by pyrosequencing analysis. The existence ratio of mutated genes in plasma and serum DNA showed almost equivalent level with that in the CD34+/38- stem cell population in BM. These data suggest that genetic/epigenetic analyses using PB circulating DNA can be a safer and painless alternative to using BM cells.     

TNF-α Regulates the Effects of Irradiation in the Mouse Bone Marrow Microenvironment

Background

Secondary bone marrow (BM) myelodysplastic syndromes (MDS) are increasingly common, as a result of radio or chemotherapy administered to a majority of cancer patients. Patients with secondary MDS have increased BM cell apoptosis, which results in BM dysfunction (cytopenias), and an increased risk of developing fatal acute leukemias. In the present study we asked whether TNF-α, known to regulate cell apoptosis, could modulate the onset of secondary MDS.

Principal Findings

We show that TNF-α is induced by irradiation and regulates BM cells apoptosis in vitro and in vivo. In contrast to irradiated wild type (WT) mice, TNF-α deficient (TNF-α KO) mice or WT mice treated with a TNF-α-neutralizing antibody were partially protected from the apoptotic effects of irradiation. Next we established a 3-cycle irradiation protocol, in which mice were sub-lethally irradiated once monthly over a 3 month period. In this model, irradiated WT mice presented loss of microsatellite markers on BM cells, low white blood cell (WBC) counts, reduced megakaryocyte (MK) and platelet levels (thrombocytopenia) and macrocytic anemia, phenoypes that suggest the irradiation protocol resulted in BM dysfunction with clinical features of MDS. In contrast, TNF-α KO mice were protected from the irradiation effects: BM cell apoptosis following irradiation was significantly reduced, concomitant with sustained BM MK numbers and absence of other cytopenias. Moreover, irradiated WT mice with long term (≥5 months) BM dysfunction had increased BM angiogenesis, MMPs and VEGF and NFkB p65, suggestive of disease progression.

Conclusion

Taken together, our data shows that TNF-α induction following irradiation modulates BM cell apoptosis and is a crucial event in BM dysfunction, secondary MDS onset and progression.     

Proliferation kinetics of plasma cells and of normal haemopoietic cells in multiple myeloma

DNA synthesis time (Ts) and 3H thymidine (TdR) labelling index (LI) of bone marrow (BM) myelomatous plasma cells (PC) and of the residual haemopoietic cell population (RHCP) were measured by in vitro quantitative 14C-TdR autoradiography in five patients with multiple myeloma (MM) in different phases of disease (three at presentation and two at relapse) and in one patient with solitary extra-osseous myeloma. One other patient with plasma cell leukaemia (PCL) was studied during an initial relapse phase and later during the leukaemic terminal phase. PC Ts was 18.8 +/- 3.7 (from 13.3 to 25.0) hr and PC LI was 2.5 +/- 1.8% (from 1.0 to 6.3%). In the case of PCL, circulating PC had a Ts of 14.4 hr and a LI of 3.1. From these experimental measurements, the fractional turnover rate (FTR-percentage of cells produced per unit time) and the potential doubling time (Td) of BMPC were calculated assuming that all BMPC were in a steady-state at the time of the study. BMPC FTR was 3.53 +/- 2.3% cells per day (from 1.2 to 6.72) and BMPC Td was 46.8 +/- 27.5 days (from 15.0 to 75.4). Comparison with results obtained in BM blasts of children with acute lymphoblastic leukaemia (ALL) indicated that BMPC had a lower proliferative activity (P less than 0.001), although BMPC Ts was not significantly different. In two patients a tumour doubling time of 6 and 13 months was determined by clinical follow up. Comparison of this parameter with Td showed a cell loss factor of more than 90% in both patients. Kinetic data relative to RHCP showed slight variations with respect to those found in normal subjects, with a general tendency towards a prolongation of Ts and a reduction of LI.     

In vitro culture studies of granulocyte/macrophage and erythroid progenitor cells in lymphoproliferative disorders

Granulocyte/macrophage progenitor cells (CFU-GM) and erythroid progenitor cells (BFU-E) have been assayed in peripheral blood (PB) and/or bone marrow (BM) from 12 patients with acute lymphocytic leukemia (ALL), 16 patients with chronic lymphocytic leukemia (CLL) and 31 patients with various forms of non-Hodgkin lymphoma (NHL) without BM involvement. Progenitor cell growth in PB and BM from the NHL patients did not differ statistically from controls (p greater than 0.1). CFU-GM and BFU-E per ml PB were markedly increased in ALL and CLL patients (p less than 0.001) while CFU-GM and BFU-E per plated BM cells from these patients were severely depressed (p less than 0.001). Lymphoblasts from one ALL patient failed to inhibit CFU-GM and BFU-E-derived colony growth from control PB mononuclear cells. The high levels of circulating progenitor cells in ALL and CLL patients clearly distinguish them from other cytopenic hematological malignancies, in which decreased progenitor cell levels have been demonstrated previously (acute myeloid leukemia, hairy cell leukemia). The cause of this finding and its pathophysiological implication still remains to be established.     

Rhythms in human bone marrow and blood cells

In 24h studies of bone marrow (BM), circadian stage-dependent variations were demonstrated in the proliferative activity of BM cells from subsets of 35 healthy diurnally active men. On an average, the percentage of total BM cells in deoxyribonucleic acid (DNA) synthesis phase was 188% greater at midday than at midnight (circadian rhythm: p = 0.018; acrophase or peak time of 13: 16h). Patients with malignant disease (n = 15) and a normal cortisol circadian rhythm showed higher fractions of BM cells in S-phase at midday. Colony-forming units--granulocyte/macrophage (CFU-GM), an indicator of myeloid progenitor cells, showed the same circadian variation as DNA S-phase (average range of change or ROC = 136%; circadian rhythm: p < 0.001; acrophase of 12:09h). Deoxyribonucleic acid S-phase and CFU-GM in BM both showed a circannual rhythm (p = 0.015 and 0.008) with an identical acrophase of August 12. The daily peak in BM glutathione content, a tripeptide involved in cellular defense against cytotoxic damage, preceded BM proliferative peaks by 4-5 h (ROC = 31-90%; circadian rhythm: p = 0.05; acrophase of 08:30h). Myeloid (ROC = 57%; circadian rhythm: p = 0.056; acrophase at 08:40h) and erythroid (ROC = 26%; circadian rhythm: p = 0.01; acrophase of 13:01h) precursor cells were positively correlated (r = 0.41; p < 0.001), indicating a circadian temporal relationship and equal influence on S-phase of total BM cells. Yield of positive selected CD34+ progenitor stem cells also showed significant circadian variation (ROC = 595%; circadian rhythm: p = 0.02; acrophase of 12:40h). Thus, the temporal synchrony in cell cycling renders BM cells more sensitive at specific times to hematopoietic growth factors and cell cycle-specific cytotoxic drugs. Moreover, proper timing of BM harvesting may improve progenitor cell yield. When using marker rhythms in the blood to allow for individualized timing of BM procedures, the times of low values in white blood corpuscles, neutrophils, and lymphocytes and high values in cortisol were predictive of the times of highest BM erythroid, myeloid, and total S-phase numbers occurring in the following 12 h.     

Phenotypic features and proliferative activity of B cell progenitors in X-linked agammaglobulinemia

In this study, we applied mAb and heterologous antisera in double marker combinations to investigate the phenotype and the proliferative activity of immature B lineage cells in XLA. Bone marrow (BM) samples from eight male adult patients with no circulating B lymphocytes were studied. The proportions and the phenotype of the earliest identifiable B cell progenitors, expressing nuclear terminal deoxynucleotidyl transferase (TdT), cytoplasmic CD22, and membrane CD19 and CD10 were identical to those observed in normal BM. In XLA these cells represented 1.2% to 22% of BM mononuclear cells; 5% to 42% and 1% to 45% of such cells weakly expressed CD20 and CD37, respectively, and invariably lacked CD13 and CD33. Cytoplasmic mu+ sIg- pre-B cells were seen in low numbers (0.1% to 0.3%) in four samples and were undetectable in the remaining four. Consequently, the ratio TdT+/c mu+ was greater than 100 in five out of eight samples studied in contrast to the less than 10 values seen in normal individuals. The proliferative activity of B lineage progenitor cells was studied by using Ki67 and anti-bromodeoxyuridine mAb. Although the proliferation of TdT+ cells in XLA was comparable with that seen in normal BM samples (24% to 59% of TdT+ were Ki67+ and 11% to 27% incorporated bromodeoxyuridine), this was dramatically reduced in the c mu+ cells (no c mu+, Ki67+ seen in three samples where pre-B cells were observed). Thus, the abnormalities of B cell differentiation in XLA are first seen at the c mu+ pre-B stage and suggest a maturation block in the transition between TdT+, c mu- pre-pre-B cells and c mu+ pre-B cells. The severity of this block may be variable, allowing the generation of a near normal number of pre-B cells in some patients, which nevertheless have a defective proliferative activity. Finally, our study further supports the concept that the effects of the "XLA gene" are confined within the B lineage by demonstrating that the proportions of T cells bearing TCR-alpha beta and TCR-gamma delta in XLA are similar to those seen in normal individuals.     

Increased cell proliferation in chronic Helicobacter pylori positive gastritis and gastric carcinoma--correlation between immuno-histochemistry and Tv image cytometry.

BACKGOUND: Epithelial cell proliferation activity has been reported both to be unaltered and increased in Helicobacter pylori (H. pylori) associated chronic gastritis. The proliferation rate decreased following H. pylori eradication, but results are controversial whether this change is dependent on the success of eradication. We compared the cell proliferation activity of H. pylori positive and negative gastric epithelial biopsies in chronic gastritis with and without intestinal metaplasia (IM) and gastric cancer by the expression of proliferation cell nuclear antigen (PCNA) and Tv image cytometry, and assessed the effect of H. pylori eradication on the cell proliferation rate in the gastric epithelium. METHODS: Brush smears and antral biopsies were taken from 70 patients (42 men, 28 women, mean age 58+/-15 y.o.) on routine endoscopy. Patients were divided into four groups according to the histology; normal epithelia (n = 10), chronic gastritis without IM (n = 24), chronic gastritis with IM (n = 20), and gastric carcinoma (n = 16). Thirty-three patients were H. pylori positive, and success of eradication was controlled in 24 cases. Cell proliferation was measured by immunohistochemistry using PCNA labeling index (LI) and by Tv image cytometry evaluating 12 morpho- and densitometric parameters of each nuclei and 6 additional parameters of each smear. RESULTS: PCNA LI, DNA index and S + G2 ratio were all higher in chronic gastritis than in the normal epithelium, and were further increased in carcinoma. The lower PCNA LI observed in chronic gastritis with IM corresponds to the lower S phase ratio determined by Tv image analysis. In H. pylori positive cases, the proliferation activity was 69.3+/-13.05% prior to the eradication and it decreased to 55.8+/-23.31% after the successful eradication therapy. When immunohistochemistry was compared with Tv image cytometry, PCNA LI significantly correlated with the percentage of cells in GL phase (r = -0.415) and S phase (r = 0.385), Integrated Optical Density mean (r = 0.598), density maximum (r'= 0.608), surface (r = 0.670), layers (r = 0.638), diameter minimum (r = 0.619), diameter maximum (r = 0.730) and perimeter (r = 0.501), respectively (p < 0.05). CONCLUSIONS: Epithelial cell turnover is increased in chronic gastritis with or without IM, and in gastric carcinoma. The lower PCNA LI observed in chronic gastritis with IM corresponds to the lower S phase ratio determined by Tv image analysis. Cell proliferation decreases after successful H. pylori eradication. Both methods proved to be reliable for the determination of epithelial cell proliferation.     

Functional maturation of murine B lymphocyte precursors. I. Selection of adherent cell-dependent precursors from bone marrow and fetal liver

A cell culture assay is described which is suitable to explore interactions between cells of the bone marrow (BM) microenvironment on one side and B lymphocyte progenitors on the other. First, a heterogeneous adherent BM (aBM) cell population was established on Cytodex 1 microcarriers. Then, adherent cell and surface IgM+(sIgM+) cell-depleted BM precursors or adherent cell-depleted day 12 fetal liver cells were added. The generation of B cells in these cultures was monitored by staining with fluorochrome-labeled anti-mu-chain antibody and by lipopolysaccharide (LPS) induction of protein A plaque-forming cells at limiting dilution. In the absence of aBM cells, some B cells arose after 24 hr from BM precursors but not from day 12 fetal liver cells. With aBM cells, BM precursors gave rise to a distinct second wave of B cells starting after 5 days of culture. When fetal liver cells were cultured on aBM cells, B cells appeared after a delay of 4 to 5 days. By using Ig allotype-congenic mouse strains (C.AL 20, BALB/c) and an allotype-specific plaque assay, we established that mature B cells originate from the putative progenitors and not from the aBM cell population. In an attempt to eliminate the aBM cell-independent progenitor subset, mice were pretreated with 5-fluorouracil 5 days before BM cells were collected. The remaining cells still contained B cells, but the frequency of c mu+ sIgM- pre-B cells was less than 10(-5). Remaining B cells were removed by anti-mu panning. In cultures of this precursor cell population, LPS-responsive B cells appeared after a delay of about 1 wk, and their generation was totally aBM cell-dependent and was maintained for more than 2 wk.     

Apoptotic index by Annexin V flow cytometry: adjunct to morphologic and cytogenetic diagnosis of myelodysplastic syndromes

The myelodysplastic syndromes (MDS) are clonal hematologic malignancies characterized by pancytopenia, dysplastic hematopoiesis, and a propensity to leukemic transformation. Increased apoptosis has been noted in MDS as a possible explanation for ineffective hematopoiesis, with lower levels in progression to and in de novo acute leukemia. Apoptosis can be measured by binding of Annexin V to exposed membrane phosphatidylserine. We postulated that the apoptotic index would aid in the differential diagnosis of MDS versus other hematopoietic diseases. We examined 33 bone marrow aspirates suspected of hematopoietic malignancy for apoptotic index by Annexin V analysis using a Becton Dickinson FACStar+ flow cytometer. The apoptotic index was expressed as the percentage of Annexin V-positive cells divided by total mononuclear cells in the gate. By standard morphologic analysis, 16 cases were diagnosed as MDS (9 refractory anemia [RA], 2 refractory anemia with ringed sideroblasts [RARS], 1 refractory anemia with excess of blasts [RAEB], 3 chronic myelomonocytic leukemia [CMML], and 1 unclassified), 11 as acute leukemia (AL), 6 as myeloproliferative disorders (MPD). Eight cases (uninvolved marrow of five patients with lymphoproliferative disorders [LPD], one patient with multiple myeloma, and two patients with anemia of chronic disease) served as nonneoplastic controls. A higher degree of apoptosis was observed in MDS (mean = 44.7%; range = 29.5--60%) compared with MPD (mean = 8.2%; range = 2.3--15.4%), AL (mean = 16.1%; range = 5.1--29.4%), and control marrow samples (mean = 11.6%; range = 1.5--21%). Additionally, the apoptotic index was significantly higher in MDS compared with MPD (P < 0.0001). In conclusion, a high apoptotic index occurs in MDS, supporting previous reports and suggesting that Annexin V analysis can be used as an adjunct in the diagnosis of MDS versus MPD. This would be particularly useful for the often-difficult distinction between early MDS and early MPD cases with equivocal morphology.     

Rate and time of DNA synthesis of human leukaemic blasts in bone marrow and peripheral blood

We have evaluated DNA synthesis rate (S rate) and time (Ts) and tritiated thymidine labelling index (LI) of peripheral blood (PB) and/or bone marrow (BM) leukaemic blasts (Bl) in nineteen cases of acute leukaemia (twelve non-lymphoblastic, AnLL, and seven lymphoblastic, ALL), in one case of non-Hodgkin's leukaemic lymphoma and in a case of plasma cell leukaemia. The LI of PB-Bl was significantly lower than that of BM-Bl (range 0.1-6.2% and 1.9-19.5%, respectively; P less than 0.01). The S rate was higher for PB-Bl than for BM-Bl (range 3.5-11.3 and 2.5-9.5 mol X 10(-18)/min; P less than 0.02) and the Ts of PB-Bl was shorter than that of BM-Bl (range 7.6-22.1 and 10.8-34.7 hr, respectively; P less than 0.02). In eight cases where S rates of both BM-Bl and PB-Bl were available, a linear correlation (r = 0.82; P less than 0.01) was found between the two parameters. This suggests that the DNA synthetic rate is a property of the leukaemic cell line in individual patients and differs from case to case. It further indicates that the environmental influences on the DNA synthesis rate in BM or PB are always of the same order of magnitude. From the results of this study we speculate that the DNA synthesis rate of leukaemic blasts is slowed down in the BM by environmental factors such as cell density.     

Comparative genomic hybridization in combination with flow cytometry improves results of cytogenetic analysis of spontaneous abortions

More than 50% of spontaneous abortions (SAs) have abnormal chromosomes; the most common abnormalities are trisomy, sex chromosome monosomy, and polyploidy. Conventional cytogenetic analysis of SAs depends on tissue culturing and is associated with a significant tissue culture failure rate and contamination by maternally derived cells. Comparative genomic hybridization (CGH), in combination with flow cytometry (FCM), can detect numerical and unbalanced structural chromosomal abnormalities associated with SAs while avoiding the technical problems associated with tissue culture. Routine cytogenetic and CGH analysis was performed independently on tissue from 301 SAs. Samples shown to be chromosomally balanced by CGH were analyzed by FCM to determine ploidy. Of 253 samples successfully analyzed by both approaches, there was an absolute correlation of results in 235 (92.8%). Of the 18 cases with discrepancies between cytogenetic and CGH/FCM results, an explanation could be found in 17. Twelve samples produced a 46,XX karyotype by cytogenetics, whereas CGH/FCM demonstrated aneuploidy/polyploidy or a male genome, indicating maternal contamination of the tissue cultures. In two cases, where tetraploidy was demonstrated by cytogenetics and diploidy by FCM, tissue culture artifact is implied. In three cases, CGH demonstrated an aneuploidy, and cytogenetics demonstrated hypertriploidy. In one unexplainable case, aneuploidy demonstrated by CGH could not be detected by repeat CGH analysis, conventional cytogenetic, or FISH analysis. These results demonstrate that CGH supplemented with FCM can readily identify chromosomal abnormalities associated with SAs and, by avoiding maternal contamination and tissue culture artifacts, can do so with a lower failure rate and more accuracy than conventional cytogenetic analysis.     

Effects of PUVA on a human skin epithelial cell line

An established human epithelial cell line was exposed to photoactivated 8-methoxy psoralen (PUVA) during exponential growth. Effects of PUVA treatment on cell growth were measured by cell kinetic methods (counting of cell numbers, flow cytometric measurements (FCM) of DNA and calculations of labelling indices (LI)). Doses of 8-methoxy psoralen and UVA were comparable to those used in patients. The cell number in PUVA treated cultures remained almost constant, and very few mitoses were seen for 144 h. About 9 h after PUVA, both FCM and LI showed an increase in the fraction of cells in S-phase, reaching a maximum of 85-90% after 24 h. DNA synthesis took place at a low rate in these cells. FCM showed an increasing fraction of polyploid cells after PUVA treatment. The possibility that inhibition of cell proliferation is one of the main effects of PUVA, is discussed.