Evaluation of platelet turnover by flow cytometry.

The number of circulating newly produced platelets depends on the thrombopoietic capacity of bone marrow as well as platelet removal from the bloodstream. Flow cytometric analysis with thiazole orange (TO), a fluorescent dye that crosses platelet membranes and binds intracellular RNA, has been used to measure circulating reticulated platelets (RPs) with high RNA content as an index of platelet turnover. We first assessed the specificity of TO flow cytometry and then applied this method in the diagnosis of thrombocytopenia caused by impaired platelet production or increased destruction. We also explored the utility of TO flow cytometry to predict thrombocytopoiesis after chemotherapy-induced bone marrow aplasia. Venous blood, anticoagulated with K(2)EDTA, was incubated with 0.6 microg/ml TO plus an anti-GPIIIa monoclonal antibody. The mean percentage of RPs in control subjects (n = 23) was 6.13 +/- 3.09%. RPs were 10.41 +/- 9.02% in patients (n = 10) with hematological malignancies during aplasia induced by chemotherapy and a significant increase in RPs (35.45 +/- 6.11%) was seen in the recovery phase. In 10 patients with idiopathic thrombocytopenic purpura, the percentage of TO positive platelets was 67.81 +/- 18.79 (P < 0.001 vs. controls). In patients with thrombocytopenia associated with hepatic cirrhosis (n = 21; 21.04 +/- 16.21%, P < 0.001 vs. controls) or systemic lupus erythematosus (n = 6, 29.08 +/- 15.57%; P < 0.001 vs. controls) increases in TO-stained platelets were also observed. Measurement of TO positive platelets may be a reliable tool for the laboratory identification of platelet disorders, with a higher sensitivity than measurement of platelet volume. Measurement of RPs may also prove useful to recognize the underlying pathogenetic mechanisms in thrombocytopenia.

VEPEMB in elderly Hodgkin's lymphoma patients. Results from an Intergruppo Italiano Linfomi (IIL) study.

BACKGROUND: In advanced age the prognosis of Hodgkin's lymphoma (HL) is poor, but, as a consequence of the low incidence of HL in the elderly, prospective studies are lacking and the best treatment strategy is difficult to define. PATIENTS AND METHODS: One-hundred and five HL patients over 65 years of age were treated homogeneously with an original reduced-intensity regimen designed for HL in the elderly containing vinblastine, cyclophosphamide, procarbazine, etoposide, mitoxantrone and bleomycin (VEPEMB). Forty-eight early stage (IA-IIA) patients received three courses of VEPEMB followed by involved field irradiation. Fifty-seven advanced stage (IIB-IV) patients received six courses followed by radiotherapy limited to the areas of bulky disease. RESULTS: Mean age was 71 years (range 66-83). Co-morbidities were present in 39 patients (37%). A treatment plan modification for poor tolerance or toxicity was needed in 18 patients. Results were satisfactory, even if they were better in early rather than in advanced stage disease: complete response rate 98% versus 58% (P <0.01); 5-year failure-free survival 79% versus 34% (P <0.01). The results were affected by advanced stage, systemic symptoms and co-morbidity but they were not influenced by age itself. CONCLUSIONS: VEPEMB is an effective and low toxic regimen for HL in the elderly. Co-morbidity is a prognostic factor more important than age itself.

Serum levels of soluble CD30 improve International Prognostic Score in predicting the outcome of advanced Hodgkin's lymphoma.

BACKGROUND: The International Prognostic Score (IPS) and circulating levels of the soluble form of CD30 molecule (sCD30) have both been associated with poor outcome in patients with advanced Hodgkin's lymphoma (HL). The aim of this study was to assess the prognostic power of the combined evaluation of sCD30 and IPS in these patients. PATIENTS AND METHODS: We included 101 patients with advanced HL, treated with ABVD (doxorubicin, bleomycin, vinblastine and dacarbazine) or MOPP (mechlorethamine, vincristine, procarbazine and prednisone)/ABVD chemotherapy with or without radiotherapy. All were tested for pre-treatment sCD30 levels. RESULTS: Six-year estimated overall survival (OS) and failure-free survival (FFS) was 89% +/- 3% and 75% +/- 4%, respectively. Thirty-three patients (33%) had IPS >2; their FFS was 60% compared with 82% in the remaining patients (P = 0.027). Serum sCD30 levels were > or =100 U/ml in 41 (41%) patients; their FFS at 6 years was 58%, compared with 87% in patients with sCD30 <100 U/ml (P = 0.003). In the 18 patients with both sCD30 > or =100 U/ml and IPS >2, FFS was significantly worse (44%) than in patients with low sCD30 and low IPS (89%) (P <0.001) or with only one of the two adverse prognostic factors (73%) (P = 0.03). CONCLUSIONS: In our study, the combination of IPS >2 and serum sCD30 levels > or =100 U/ml identifies a sizeable subgroup (18%) of advanced HL patients with very poor FFS, who might take advantage of intensified up-front treatment strategies.

Effects of sodium selenite on in vitro interactions between platelets and endothelial cells.

Selenium is an essential component of glutathione peroxidase enzymes, which protect cells against peroxidation and control concentrations of intracellular proxides. Since selenium deficiency is associated with an increased incidence of arterial thrombosis, we studied the effect of selenium on in vitro interactions between platelets and endothelial cells. Platelets from normal volunteers on a diet with (PLTSe+) or without (PLTSe-) selenium supplementation and human umbilical vein endothelial cells cultured in medium alone (ECSe-) or supplemented with Se (ECSe+) were used. The effect of in vivo administration or in vitro supplementation of selenium on platelet function was investigated in an aggregometry model designed for studying the interactions between platelets and endothelial cells using ADP and arachidonic acid as agonists. We observed that: (1) selenium-dependent glutathione peroxidase enzyme activity increased in both PLTSe+ and ECSe+, being about fivefold higher in the former; (2) platelet aggregation was inhibited by Se+ cells; (3) Se+ cells released less thromboxane B(2) (PLTSe+) and more 6-keto-prostaglandin F(1alpha) (ECSe+) than Se- cells; (4) when ECSe+ were treated with acetylsalicylic acid, the inhibitory effect of selenium on platelet aggregation disappeared; (5) the concentration of nitric oxide metabolites in Se+ culture media did not differ from that in Se- media. We suggest that an antithrombotic effect on the interactions between platelets and endothelial cells can be induced by stimulating glutathione peroxidase enzymes with selenium via a mechanism that is blocked by acetylsalicylic acid and is apparently unrelated to the biosynthesis of nitric oxide metabolites.

The Italian Consensus Conference on Diagnostic Criteria for Myelofibrosis with Myeloid Metaplasia.

The purpose of this work was to develop a definition of myelofibrosis with myeloid metaplasia (MMM) using diagnostic criteria that would remain valid within the set of patients with chronic myeloproliferative disorders or myelodysplastic syndromes. A list of 12 names for the disease and 37 diagnostic criteria were proposed to a Consensus Panel of 12 Italian experts who ranked them in order so as to identify a core set of criteria. The Panel was then asked to score the diagnosis of 46 patient profiles as appropriate or not appropriate for MMM. Using the experts' consensus as the gold standard, the performance of 90 possible definitions of the disease obtained through the core set was evaluated. 'Myelofibrosis with myeloid metaplasia' ranked as the preferred name of the disease. Necessary criteria consisted of 'diffuse bone marrow fibrosis' and 'absence of Philadelphia chromosome or BCR-ABL rearrangement in peripheral blood cells'. The six optional criteria in the core set consisted of: splenomegaly of any grade; anisopoikilocytosis with tear-drop erythrocytes; the presence of circulating immature myeloid cells; the presence of circulating erythroblasts: the presence of clusters of megakaryoblasts and anomalous megakaryocytes in bone marrow sections; myeloid metaplasia. The definition of the disease with the highest final score was as follows: necessary criteria plus any other two criteria when splenomegaly is present or any four when splenomegaly is absent. The use of this definition will help to standardize the conduct and reporting of clinical studies and should help practitioners in clinical practice.

Serum levels of p55 and p75 soluble TNF receptors in adult acute leukaemia at diagnosis: correlation with clinical and biological features and outcome.

The tumour necrosis factor (TNF)/TNF-receptor (TNFR) complex plays a role in the growth of leukaemic cells. We retrospectively investigated the relationship between pretreatment serum concentration of soluble TNFR (p55- and p75-sTNFRs) and outcome in adult acute myeloid (AML 82 cases) and lymphoid (ALL 44 cases) leukaemia. Both sTNFRs were significantly higher in AML (p55-sTNFR 4.53 +/- 3.7, median 3.75; p75-sTNFR 6.51 +/- 5.25 ng/ml, median 4.72) and ALL sera (3.31 +/- 1.5, median 2.95; 5.30 +/- 2.3 ng/ml, median 4.56, respectively) than in controls (1.89 +/- 0.5, median 1.98; 2.22 +/- 0.8 ng/ml, median 2.37) (P < 0.01 for both sTNFRs). Fresh leukaemic cells expressed p55- and p75-sTNFRs, which were modulated and released into the supernatant (SN) following short-term in vitro culture, suggesting that in vivo sTNFRs were also leukaemia-derived. Whereas no correlation was observed between sTNFRs and outcome in ALL, in AML higher p55-sTNFR levels (> 3.75 ng/ml) were associated with shorter disease-free survival (DFS) (P = 0.006) and overall survival (OS) (P = 0.0004). At multivariate analysis p55-sTNFR was the most significant predictor of DFS (P = 0.006) and OS (P < 0.001). Our data suggest that the prognostic significance of p55-sTNFR in AML could be related to relevant biological features of AML blasts.

Estimated 6-year event-free survival of 55% in 60 consecutive adult acute lymphoblastic leukemia patients treated with an intensive phase II protocol based on high induction dose of daunorubicin.

On the basis of a previous experience suggesting that daunorubicin dose in induction was an independent prognostic factor in adult ALL, we designed a chemotherapeutic regimen (ALLVR589) characterized by high doses of daunorubicin (270 mg/m2) in induction and by high-dose Ara-C in post-remission. The protocol was otherwise conventional: induction and post-remission therapy were followed by chemo-radio prophylaxis of the central nervous system (CNS) and periodical reinductions over a 3-year maintenance period. Sixty consecutive patients (male 42, female 18, median age 34 years, range 14-71; B-lineage, 35; T-lineage, 25; Ph' and bcr/abl positive, 7) recruited between 1989 and 1996, were evaluated for treatment outcome. Complete remissions were 56 (93%), one patient had refractory disease, early deaths were five (8%); 19/56 (34%) patients relapsed, five of whom were Ph'+. Median time to relapse was 11 months (range 3-47); 68% of relapses occurred within 12 months from CR. No CNS relapses were observed. After a median follow-up of 44 months (1-100), 33/60 (55%) patients remain event-free; 23/60 (38%) are off-therapy in continuous CR (median follow-up from diagnosis: 63 months; range 38-100). These results suggest that increasing DNM dosage in induction is one of the possible approaches to improve the outcome of adult ALL by decreasing the relapse occurrence.

Improved prognosis of Pseudomonas aeruginosa bacteremia in 127 consecutive neutropenic patients with hematologic malignancies.

OBJECTIVES: Although decreasing in frequency, Pseudomonas aeruginosa bacteremia is still a major challenge for neutropenic cancer patients. In patients with hematologic malignancies, the prognosis of P. aeruginosa bacteremia is particularly poor due to the prolonged and severe neutropenia, mucosal damage, and other defects in immunity related both to the underlying disease and to the cytotoxic therapy. METHODS: To verify the outcome of P. aeruginosa bacteremia and to try to define possible prognostic factors, the authors reviewed the medical records of 127 consecutive episodes of P. aeruginosa bacteremia observed in the hematologic unit of the Verona University School of Medicine. RESULTS: Presence of pneumonia and septic shock, persistence and severity of neutropenia, delayed and inappropriate antibiotic therapy, and unresponsive underlying disease had negative impact on clinical outcome of P. aeruginosa bacteremia. CONCLUSIONS: With recognition of the risk factors and more careful management, the prognosis of P. aeruginosa bacteremia in neutropenic patients with hematologic malignancies has improved in recent years.

Eighty-one percent event-free survival in advanced Burkitt's lymphoma/leukemia: no differences in outcome between pediatric and adult patients treated with the same intensive pediatric protocol.

BACKGROUND: Advanced Burkitt's lymphoma (BL) has an extremely poor prognosis in adults. With a previous protocol including CNS prophylaxis, 40% of our adult patients achieved CR and only 13% became long survivors. In 1988, following this poor experience, we adopted a very intensive pediatric-derived protocol. PATIENTS AND METHODS: Twenty-one consecutive patients, 8 adults (median age 35, stage III: 1; IV: 7; leukemias: 6) and 13 children (median age 10, state III: 8; IV: 5; leukemias: 4) were treated with the same protocol (POG 8617), based on alternate two-phase cycles with sequential high-dose CTX, VCR, ADM + CNS chemoprophylaxis (phase A) and HD MTX + HiDAC (phase B). Adults received 6 cycles, children 8; i.t. prophylaxis in phase B was omitted in adults. RESULTS: Twenty of 21 (95%) patients achieved CR (adults 100%, children 92%). Two patients died early; 2 relapsed at 4 and 9 months. With a median follow-up of 28 months (4-96), 17 patients (81%) are event free (adults 75%, children 85%). Severe infections affected 62% of adults and 15% of children. CONCLUSIONS: (1) The prognosis of adult advanced BL definitely improved with this intensive protocol. (2) There were no differences in outcome between adults and children. (3) Outcome of lymphoma and leukemia was similar. (4) Severe infections occurred frequently in adults. This intensive pediatric protocol requires a careful supportive therapy.

Preferential release of high amounts of interleukin-8 by myeloid blasts showing monocytic differentiation.

BACKGROUND: In myeloid blasts, the expression and release of the multifunctional chemokine IL-8 could be expected to be differentiation-associated. METHODS: We investigated the profile of interleukin-8 (IL-8) expression and release by leukemic cells obtained at diagnosis from 42 untreated adult patients with acute myeloid leukemia of various FAB subtypes (2 M0, 7 M1, 6 M2, 6 M3, 10 M4 and 11 M5). IL-8 transcripts were evaluated by Northern blot and densitometric analysis. IL-8 release by myeloid blasts was evaluated by a specific ELISA either in sera at diagnosis or in supernatants (SN) obtained from cultured leukemic cells. RESULTS: In basal conditions, Northern blot analysis revealed detectable IL-8 transcripts in 15/29 cases, eleven of which were classified as M4-M5 and 4 as FAB M0-M3. Densitometric analysis of IL-8 transcript bands showed higher expression in M4-M5 than in M0-M3 cases (mean values +/- SD: 16.5 +/- 21 and 0.77 +/- 1.36 densitometric units, respectively; p = 0.012). Higher IL-8 serum levels were observed in leukemic patients as opposed to normal controls (mean values +/- SD: 0.53 +/- 0.75 vs 0.003 +/- 0.014 ng/mL, respectively; p = 0.006). Furthermore, a trend (though not of statistical significance) towards higher IL-8 serum values was observed in M4-M5 as opposed to M0-M3 subtypes. After 24 hours of culture, the majority of myeloid blasts (95%) spontaneously released detectable amounts of IL-8 into SN. However, M4-M5 released substantially higher amounts of IL-8 than M0-M3 blasts (mean +/- SD: 68 +/- 46 and 8.5 +/- 12 ng/mL, respectively; p < 0.001). This difference between M0-M3 and M4-M5 blasts was already observed after 6 hours of culture and increased over 72 hours. CONCLUSIONS: Our findings confirm and further support the preferential release of high levels of IL-8 by myeloid blasts showing monocytic differentiation.

Selenium enhances glutathione peroxidase activity and prostacyclin release in cultured human endothelial cells. Concurrent effects on mRNA levels.

Selenium (Se) is an essential component of glutathione peroxidase (GSH-Px), an enzyme that protects cells by reducing intracellular peroxides. Impaired Se status and GSH-Px activity seem associated with increased risk of atherosclerotic vascular diseases. This study reports the effects of Se supplementation on GSH-Px activity, on prostacyclin (PGI2) production, on 12-hydroxy-eicosatetraenoic acid (12-HETE) levels, and on GSH-Px mRNA expression in cultured human umbilical vein endothelial cells (HUVEC). Se-enriched HUVEC showed significant increase of both GSH-Px activity and thrombin-stimulated production of PGI2 in the presence of stable concentrations of 12-HETE. On the other hand, an inverse correlation between Se concentrations in culture media and GSH-Px mRNA levels in Northern blot analysis was shown; this suggests that a major degree of regulation for GSH-Px expression by Se is most likely exerted at the posttranscriptional level. These observations may help to explain the increased incidence of atherosclerosis described in Se-deficient individuals.

Serum levels of soluble CD30 are elevated in the majority of untreated patients with Hodgkin's disease and correlate with clinical features and prognosis.

PURPOSE: To evaluate the serum levels of the soluble form of the CD30 molecule (sCD30) in patients with Hodgkin's disease (HD) to establish whether there is a correlation with clinical features at presentation and prognosis. PATIENTS AND METHODS: The sCD30 serum levels of 117 patients were measured at diagnosis with a commercial sandwich enzyme-linked immunoadsorbent assay (ELISA) test kit, and in 78 of these patients the sCD30 levels were also recorded during the follow-up period. RESULTS: sCD30 levels at diagnosis were increased (> 20 U/mL) in a high proportion of patients (87.2%; mean +/- SD, 108 +/- 134 v 5.3 +/- 5.7 U/mL in controls, P < .0001) and correlated with stage (stages I + II, 73 +/- 97 U/mL; III + IV, 162 +/- 165 U/mL; P < .0001), with presence of B symptoms (stage A, 69 +/- 82 U/mL; stage B, 162 +/- 171 U/mL; P < .0001), and, to some extent, with tumor burden (bulky presentation, 141 +/- 129 U/mL; nonbulky, 91 +/- 133 U/mL; P = .058). Patients with sCD30 levels greater than 100 U/mL at diagnosis had a significantly higher rate of poor outcome in terms of failure to achieve a complete remission (CR) or disease relapse after CR achievement. In fact, the event-free survival (EFS) duration of patients with sCD30 levels greater than 100 U/mL was significantly worse (P = .0016). Using multivariate analysis, an sCD30 level greater than 100 U/mL retained its significance after adjustment for other prognostic parameters. CONCLUSION: sCD30 in HD at presentation strictly correlates with clinical features. Serum levels greater than 100 U/mL at diagnosis entail a significantly higher risk of treatment failure, a factor that is independent of other prognostic parameters.

IL-8 mRNA expression and IL-8 production by acute myeloid leukemia cells.

Purified leukemic cells from 30 acute myeloid leukemia (AML) cases at diagnosis were investigated for the presence of interleukin 8 (IL-8) mRNA by Northern blot analysis. IL-8 specific transcripts were detected in uncultured blasts in 14/30 cases, 10/14 from patients with M4-M5 and 4/14 from cases with M0-M3 morphology. The transcript expression was associated with the detection of IL-8 molecule in blast cells by immunostaining performed on cytospin preparations. After 24-hour culture, a strong up-regulation or the appearance in cases negative before culture of IL-8 mRNA was observed in all cases tested, and culture supernatants contained high amounts of IL-8. Our data demonstrate that leukemic cells in AML are equipped with the functional apparatus for IL-8 production. Since IL-8 displays a wide range of biological activities, including the regulation of some membrane molecules relevant to adhesion and migration processes, its production by AML blasts might be of relevance for the pattern of leukemic growth.

ICAM-1 tissue overexpression associated with increased serum levels of its soluble form in Hodgkin's disease.

We investigated ICAM-1/CD54 tissue immunoreactivity and serum levels of its soluble form (sICAM-1) in patients with Hodgkin's disease (HD) at diagnosis. ICAM-1 was strongly expressed in involved tissues, and sICAM-1 serum levels were higher in HD (79 patients) than in controls (P < 0.01), and in patients with more advanced or more active disease (stages III + IV vI + II: P = 0.002; stage 'B' v 'A': P < 0.0001; 'bulky' disease v non-'bulky': P = 0.042). We suggest that tissue ICAM-1 overexpression leading to increase of circulating sICAM-1 may interfere with the lymphocyte adhesion machinery thus contributing to the well-known immune derangement of HD.

Splenectomy for patients with myelofibrosis with myeloid metaplasia: pretreatment variables and outcome prediction.

Since according to the early studies, the outcome after splenectomy in the individual patient with myelofibrosis with myeloid metaplasia (MMM) is unpredictable, we assessed retrospectively the pre-intervention characteristics that best predicted adverse events, hematological consequences, and survival in 71 splenectomized MMM patients. The findings indicate that the operative risk of splenectomy for both mortality (8.4%) and morbidity (39.3%) was unpredictable. New hemorrhagic or thrombotic complications occurred in 16.9% of surviving patients and were predicted by age < 50 years, a normal to high platelet count (> 200 x 10(9)/l) and huge splenomegaly (> 16 cm from the costal margin). Massive liver enlargement occurred in 24% of patients and has to be expected in patients splenectomized for transfusion-dependent anemia. Anemia improved substantially in 45% and 52% of patients at 3 months and at 1 year, respectively, and was predicted by severe anemia, low platelet count (< 100 x 10(9)/l) or normal to high white blood cell (WBC) count (> 4 x 10(9)/l). Survival from splenectomy was superior in patients < 45 years with WBC < 10 x 10(9)/l count. An unexpectedly high rate of blastic transformation was observed. It accounted for 42.8% of the deaths. The results suggest trials for prophylactic cytoreductive treatment in young patients and when platelet count is normal to increased. Further study is needed for elucidating the possible role played by splenectomy in inducing blastic transformation.

Soluble interleukin-2 receptor in hairy-cell leukemia: a reliable marker of disease.

The CD25 molecule, which corresponds to the p55 alpha chain of the interleukin-2 receptor, is strongly expressed by neoplastic cells in hairy-cell leukemia and is released in large amounts in the soluble form which is detectable in serum. In order to assess the reliability of the soluble interleukin-2 receptor as a disease marker in the management of patients with hairy-cell leukemia, we investigated serum levels in 35 untreated patients and in 2 patients with the hairy-cell leukemia variant. In 21 of 35 patients soluble receptor levels were also monitored during and after recombinant interferon-alpha therapy. Clinical and hematological parameters were also assessed. Soluble interleukin-2 receptor levels were extremely high at the time of diagnosis in patients with typical hairy-cell leukemia [32,722 +/- 27,001 vs. 331 +/- 145 units/ml in controls (mean +/- SD)], but not in patients with the leukemia variant. A progressive decrease in soluble interleukin-2 receptor levels paralleled the clinical response to treatment, although normal values were never detected, even in patients who achieved an apparent complete remission. After recombinant interferon-alpha discontinuation, disease recurrence was accompanied by a progressive increase to pre-treatment soluble receptor levels. Overall, a close correlation was found between soluble interleukin-2 receptor values and total tumor burden (r = 0.84, P < 0.001). On the basis of these data, soluble interleukin-2 receptor should be regarded as a key marker in the management of patients with hairy-cell leukemia.

Mechanisms of platelet activation by cultured human cancer cells and cells freshly isolated from tumor tissues.

We studied the effects on platelet function of cells isolated from freshly dissociated human tumor tissues (11 breast carcinomas, 9 colon carcinomas and 1 lymph node metastasis from melanoma) obtained at surgery as compared with cultured human tumor cells: namely, human melanoma 1402 cell line derived from a primary tumor and two lines derived from lymph node metastases (ME 7110/2 and Me 665/1) as well as a human hepatoma cell line (Hep G2). The three melanoma cell lines activated platelets by producing ADP, as evidenced by the inhibitory effect of apyrase and by the direct measurement of the agonist in the supernatants of tumor cell suspensions; this production was much greater by the cells derived from metastases than by the cells derived from the primary tumor. On the other hand, aggregation induced by Hep G2 hepatoma cells was unaffected by apyrase and was inhibited by hirudin or concanavalin A, suggesting that the cells aggregate platelets by producing thrombin, probably through tissue factor activity of the cells themselves. Cells isolated from 16 of the 21 human tumor tissues possessed a potent platelet-aggregating effect, which was not inhibited by apyrase, hirudin or concanavalin A, but was virtually abolished by the cysteine protease inhibitors iodoacetic acid or p-hydroxymercuri-phenylsulfonate. Collectively, our data demonstrate that cells isolated from freshly dissociated tumor tissues activate platelets through tumor-associated cysteine proteinases rather than by the ADP- or thrombin-dependent mechanisms characteristic of cultured human tumor cell lines.

Nicotine alters fibronectin and factor VIII/vWF in human vascular endothelial cells.

Primary cultured human endothelial cells derived from umbilical cord vein were exposed during the growth of the culture to medium containing nicotine at various concentrations (0.5-200 micrograms/ml). Patterns of cellular fibronectin and factor VIII/vWF were compared to control by immunofluorescence technique. The levels of glycoproteins released in the culture medium were quantified by ELISA method. Treated cells showed an important decrease in fibronectin content with fragmentation of the fibronectin pericellular filaments, whereas the levels of secreted fibronectin were reduced in a dose-dependent manner. This reduction of fibronectin availability was correlated with an elongation of cell shape as revealed with phase contrast microscopy. By immunofluorescence, factor VIII/vWF cytoplasmic granules appeared drastically reduced whereas the secretion of the protein was significantly increased. As shown by electron microscopy, there was a concomitant reduction in the number and size of Weibel-Palade bodies. These studies indicate that nicotine modifies fibronectin and factor VIII/vWF distributions but in different ways.