Epidemiology, clinical picture and long-term outcomes of FIP1L1-PDGFRA-positive myeloid neoplasm with eosinophilia: Data from 151 patients

FIP1L1-PDGFRA-positive myeloid neoplasm with eosinophilia (F/P+ MN-eo) is a rare disease: robust epidemiological data are lacking and reported issues are scarce, of low sample-size and limited follow-up. Imatinib mesylate (IM) is highly efficient but no predictive factor of relapse after discontinuation has yet been identified. One hundred and fifty-one patients with F/P+ MN-eo (143 males; mean age at diagnosis 49 years; mean annual incidence: 0.18 case per million population) were included in this retrospective nationwide study involving all French laboratories who perform the search of F/P fusion gene (study period: 2003-2019). The main organs involved included the spleen (44%), skin (32%), lungs (30%), heart (19%) and central nervous system (9%). Serum vitamin B12 and tryptase levels were elevated in 74/79 (94%) and 45/57 (79%) patients, respectively, and none of the 31 patients initially treated with corticosteroids achieved complete hematologic remission. All 148 (98%) IM-treated patients achieved complete hematologic and molecular (when tested, n = 84) responses. Forty-six patients eventually discontinued IM, among whom 20 (57%) relapsed. In multivariate analysis, time to IM initiation (continuous HR: 1,01 [0.99-1,03]; P = .05) and duration of IM treatment (continuous HR: 0,97 [0,95-0,99]; P = .004) were independent factors of relapse after discontinuation of IM. After a mean follow-up of 80 (56) months, the 1, 5- and 10-year overall survival rates in IM-treated patients were 99%, 95% and 84% respectively. In F/P+ MN-eo, prompt initiation of IM and longer treatment durations may prevent relapses after discontinuation of IM.

Intravenous immunoglobulin or high-dose methylprednisolone, with or without oral prednisone, for adults with untreated severe autoimmune thrombocytopenic purpura: a randomised, multicentre trial

BACKGROUND

Treatment of adults with autoimmune thrombocytopenic purpura (AITP) is based more on individual experience than on results of controlled studies. We compared intravenous immunoglobulin with high-dose methylprednisolone in untreated adults with severe AITP and assessed efficacy of subsequent oral steroids compared with placebo. Primary outcome was number of days with platelet count greater than 50 x 10(9)/L within the first 21 days.

METHODS

We did a randomised multicentre trial based on a 232 design. 122 adults with severe AITP (platelet count < or =20 x 10(9)/L) were randomly assigned to receive either intravenous immunoglobulin or high-dose methylprednisolone on days 1-3 (randomisation A), and then to receive either oral prednisone or placebo (randomisation B) on days 4-21. Analysis was by intention to treat.

FINDINGS

Six patients were excluded from the analysis. The number of days on which platelet counts were above 50 x 10(9)/L was 18 in 56 patients receiving intravenous immunoglobulin and 14 in 60 receiving high-dose methylprednisolone (p=0.02). Percentage of patients who had platelet counts over 50 x 10(9)/L on days 2 and 5 was 7% and 79%, respectively, in the intravenous immunoglobulin group compared with 2% and 60%, respectively, in the high-dose methylprednisolone group (p=0.04). During the second treatment period, prednisone was more effective than placebo for all short-term endpoints. Patients who received intravenous immunoglobulin and prednisone had platelet count greater than 50 x 10(9)/L for 18.5 days (p=0.005), and those treated with high-dose methylprednisolone and prednisone had this count for 17.5 days.

INTERPRETATION

Intravenous immunoglobulin and oral prednisone seems to be more effective than high-dose methylprednisolone and oral prednisone in adults with severe AITP, although the latter treatment is effective and well tolerated.

Embolized ischemic lesions of toes in an afibrinogenemic patient: possible relevance to in vivo circulating thrombin

Fibrinogen plays a complex role in hemostasis, thrombosis, and vascular disease. Hyperfibrinogenemia is an independent vascular risk factor and dysfibrinogenemia can provoke thrombosis. Afibrinogenemia is usually responsible for hemorrhagic diathesis, and unexpected ischemic lesions are intriguing. We report the case of an afibrinogenemic patient, who at the age of 30 developed ischemic lesions of the feet related to severe stenosis of the iliac and hypogastric arteries. The biopsy of the iliac artery lesion showed an intense myointimal hyperplasia. We performed standard hemostatic analysis and analyzed the activation markers of platelets and coagulation factors and the kinetics of thrombin generation in the patient and in normal control plasmas treated or not with reptilase. Occlusive arterial lesions were attributed to a disruptive hematoma penetrating the vascular lumen. Thrombin concentration after calcium addition increase markedly in the afibrinogenemic patient and in defibrinated normal plasma, as compared to untreated normal plasma. Thrombin-antithrombin complexes (T-AT) were markedly enhanced while F1+2 prothrombin fragments stayed in the normal range. These results suggested activation of coagulation and in vivo circulating thrombin. Thrombin activates the platelets that secrete growth factors for smooth muscle cells and generate the intimal hyperplasia. Recurrent hemorrhage within the vessel wall might induce injury and local thrombin generation. Thrombin not trapped by the clot is available for platelet activation and smooth muscle cell migration and proliferation. The absence of a protective fibrin cap on the intima might account for intima vulnerability and embolization. Afibrinogenemia appears in this paradoxical situation as a vascular risk factor.

Erythroblastic synartesis: an auto-immune dyserythropoiesis

Erythroblastic synartesis is a rare form of acquired dyserythropoiesis, first described by Breton-Gorius et al in 1973. This syndrome is characterized by the presence of septate-like membrane junctions and "glove finger" invaginations between erythroblasts, which are very tightly linked together. This phenomenon, responsible for ineffective erythropoiesis, leads to an isolated severe anemia with reticulocytopenia. In the following report, we describe 3 new cases of erythroblastic synartesis associated with dysimmunity and monoclonal gammapathy. In all cases, the diagnosis was suggested by characteristic morphological appearance of bone marrow smears, and further confirmed by electron microscopy. Ultrastructural examination of abnormal erythroblast clusters showed that these cells were closely approximated with characteristic intercellular membrane junctions. The pathogenesis of the dyserythropoiesis was modeled in vitro using crossed erythroblast cultures and immunoelectron microscopy: when cultured in the presence of autologous serum, the erythroblasts from the patients displayed synartesis, whereas these disappeared when cultured in normal serum. Moreover, synartesis of normal erythroblasts were induced by the patient IgG fraction. Immunogold labeling showed that the monoclonal IgG were detected in, and restricted to, the synartesis. A discrete monoclonal plasmacytosis was also found in the patient bone marrow. The adhesion receptor CD36 appeared to be concentrated in the junctions, suggesting that it might be involved in the synartesis. These experiments indicated that a monoclonal serum immunoglobulin (IgG in the present cases) directed at erythroblast membrane antigen was responsible for the erythroblast abnormalities. Specific therapy of the underlying lymphoproliferation was followed by complete remission of the anemia in these cases.

A phase II trial of induction and consolidation therapy of acute myeloid leukemia with weekly oral idarubicin alone in poor risk elderly patients

We have conducted a phase II outpatient trial testing weekly oral administration of idarubicin (ZAVEDOS-ZVD) alone to determine the rate of objective response and toxicity in poor risk acute myeloid leukemia (AML) patients over 60 years of age. The treatment consisted of three phases: induction, with 20 mg/m2 of ZVD on days 1, 8, 15 and 22; consolidation with 20 mg/m2 of ZVD for 4 weeks; and maintenance with six cycles lasting 3 months and consisting of oral 6 mercapto-purine 2 mg/kg/day, 4 days a week for 2 months; subcutaneous cytarabine 1 mg/kg, once a week for 2 months; and oral ZVD 20 mg/m2 on day 1 and day 8 of the third month. In case of failure after induction course, patients received salvage treatment with 4 weekly oral doses of 40 mg/m2 ZVD. Fifty-one patients with a median age of 76 years were enrolled and could receive induction course. Of these 51 patients, 37 could receive subsequent courses, which consisted either of consolidation, or salvage. Only 11 patients underwent maintenance treatment. Sixty-three percent of patients had to be hospitalized during induction, for a median duration of 14.5 days, and 87% required hospitalization during salvage for a median duration of 17.5 days. Only five patients (38%) required hospitalization during consolidation. There were three toxic deaths (6%), two from hemorrhage and one from pulmonary embolism. The overall response rate was 29%, with 12 patients in complete response (25%) and two in partial response (4%). The median overall survival rate is 4 months for the whole population, and the median DFS is 9.6 months among the 14 responding patients. The results of this trial show that this new weekly schedule of oral ZVD chemotherapy is feasible and effective in poor risk elderly patients with AML. This regimen may be helpful for patients unable to tolerate intensive intravenous regimens, and is a real alternative to palliative treatments.

Angioimmunoblastic-like T-cell non Hodgkin's lymphoma: outcome after chemotherapy in 33 patients and review of the literature

We analyzed 33 patients with AILD T-NHL in a retrospective multicentric study. The median age was 62 yr (35-84 yr) (19 patients over 60 yr). Advanced disease (n = 31) and B-symptoms were consistently found (n = 29) and 20 patients had bone marrow involvement. The main laboratory abnormalities were: anemia (n = 13), hypereosinophilia (n = 13), lymphopenia (n = 14), hypergammaglobulinemia (n = 17), elevated lactate dehydrogenase (LDH) level (n = 24). First-line therapy was chemotherapy (ChT) alone (n = 25) or ChT after steroids (n = 8). Most patients received a CHOP-like regimen for a median number of 6 cycles and 3 patients received interferon alpha (IFN alpha) as consolidation after chemotherapy. With a median follow-up of 46 mo, 60% achieved a complete response but the outcome was poor with a relapse rate at 56%, a median survival referring to the total population was of 36 mo (2-108+ mo) and an overall survival at 5 yr of 36%. Two patients received high-dose chemotherapy (with total body irradiation) and autologous progenitor-cell transplantation for chemosensitive relapse and were free of disease at, respectively, 76 and 24 mo+. In conclusion AILD T-NHL still has a poor prognosis compared to other NHL. The role of intensive therapy and IFN alpha still remains to be evaluated.

Induction of endothelial cell adhesion molecules by serum and immunoglobulins G from a patient with vasculitis and monoclonal gammapathy: potential relevance to vasculitis

Interactions between endothelial cell adhesion molecules and their beta2 integrin adhesive receptors on leukocytes are thought to play a role in the pathogenesis of inflammatory diseases and probably vasculitis. We describe a case in whom leukocytoclastic vasculitis was associated to a monoclonal immunoglobulin G2 kappa (IgG2K). During the vasculitic crisis, the patient's serum and the isolated IgG from this serum induced the expression of E-selectin, VCAM-1 and ICAM-1 at the HUVEC surface, but not tissue factor activity, whereas normal, control serum and patient serum at remission were without any effect. A close relationship between the vasculitis and the serum level of the monoclonal IgG was observed. We suggest that the monoclonal IgG might induce the vasculitis by increasing the expression of E-selectin, VCAM-1 and ICAM-1 which facilitate the interaction of leukocytes with vascular endothelium.

[Pulmonary mucormycosis in a leukemia patient. Diagnostic and therapeutic difficulties]

The observation of pulmonary mucormycosis occurring in a patient presenting with aplasia induced therapeutically during treatment for acute myeloblastic leukaemia, has led to a review of the characteristics of this rare opportunistic fungal infection: it occurs in a particular condition; the clinical manifestations are characterised by the thrombotic character and the rapidly necrosing nature of the histological lesions; the diagnosis is usually very difficult to make and is linked to the rarity of the pathology and the frequently negative mycological specimens apart from tissue biopsies; the value of a medicosurgical therapeutic strategy on which the prognosis of the infection depends.

Aplastic anaemia in a case of hereditary neutrophil Fcgamma receptor IIIb deficiency

CD16 antibodies recognize Fcgamma receptors III of a and b types. In a patient with severe idiopathic aplastic anaemia (AA), polymorphonuclear cells, which in normal subjects express FcgammaRIIIb, were found to be CD16 negative. The FcgammaRIIIb gene configuration was analysed by PCR on peripheral blood mononuclear cells. Bi-allelic deletion encompassing at least part of the coding exon 5 was found in the patient and his brother, suggesting a hereditary defect. The patient underwent successful bone marrow transplantation from his HLA-matched brother despite a similar phenotype and genotype. This observation suggests that FcgammaRIIIb hereditary deficiency in donor and/or recipient does not impair engraftment and justifies the use of other monoclonal antibodies in addition to CD16 in the study of GPI-anchored antigen expression.

Results of three courses of adriamycin, bleomycin, vindesine, and dacarbazine with subtotal nodal irradiation in 189 patients with nodal Hodgkin's disease (stage I, II and IIIA)

AIM OF THE STUDY

To evaluate in a prospective trial three courses of an ABVD-like chemotherapy (CT) regimen given before radiation therapy (RT) (subtotal nodal irradiation (STNI) in favorable stage Hodgkin's disease (HD). The efficacy, risk factors and medium-term toxicities are reported.

PATIENT CHARACTERISTICS

Stage I or II with at least one of the following factors, mediastinal involvement, histological type 3, age > 40 years, ESR rate > 50 mm, or stage IIIA. 189 patients with newly diagnosed HD were treated between 01/89 and 01/94 (stage I, n = 33; stage II, n = 129, stage IIIA, n = 27). Three courses of an ABVD-like regimen (adriamycin 25 mg/m2, bleomycin 10 mg, vindesine 2 mg/m2 and dacarbazine 250 mg/m2 day 1 and 8) were given before STNI at 36/40 grays. At diagnosis, prognostic factors were distributed as follows: B symptoms (n = 54), bulky mediastinum (n = 41), hemoglobin < 12 g/dl (n = 37), ESR > 50 (n = 65), age > 45 (n = 24).

RESULTS

After chemotherapy, 90% had an objective response (partial response > 75%) and 98% were in complete remission (CR) at the end of RT. Three patients had primary refractory disease and 13 patients (7%) relapsed, 3 at the initial site, 4 at previously uninvolved sites and 6 at both. With a median follow-up of 60 months, 170 patients are in 1st CR, 5 in 2nd or greater CR and 11/14 patients have died from HD. Bulky mediastinum (p = 0.009), age > 45 years (p = 0.03) and EST > 50 mm (p = 0.05) were adverse prognostic factors for survival. Bulky mediastinum (p = 0.009) was the only prognostic factor for freedom from progression. TOXICITIES: Two patients died from treatment related toxicity and one patient died with an osteogenic sarcoma. No secondary leukemia has so far been detected. 24 pregnancies were reported. Cardiopulmonary toxicity was always < grade 1 (WHO) in 95 patients evaluated. Two patients over 45 years old had a myocardial infarction.

CONCLUSION

With an acceptable medium-term toxicity, this treatment achieved 85% survival at 5 years.

Specific mucosal erosions in hypereosinophilic syndrome. Evidence for eosinophil protein deposition

BACKGROUND

Mucosal erosions can be a presenting feature of the hypereosinophilic syndrome. The aim of this study was to analyze in situ the presence of eosinophil proteins and the state of eosinophil activation. Biopsy specimens of mucosal lesions and normal skin were taken from two men with oral and genital erosions typical of hypereosinophilic syndrome. Tissue sections were immunohistochemically labeled with anti-major basic protein, anti-eosinophil-derived neurotoxin, and anti-eosinophil peroxidase antibodies. The same specimens were also subjected to electron microscope examination.

OBSERVATIONS

Eroded specimens displayed areas of eosinophil spongiosis within which extracellular deposits of eosinophil peroxidase, major basic protein, and eosinophil-derived neurotoxin were present. In normal skin, only a few eosinophils were present within the capillary lumen, and no extracellular deposits of these proteins were seen. Under the electron microscope, the cytoplasmic membranes of eosinophils located around the erosion were disrupted. Remnants of necrotic keratinocytes were found near these lysed eosinophils.

CONCLUSION

As with other involved organs in hypereosinophilic syndrome, mucosal erosions seem to be the consequence of eosinophil protein release.

Indium-111 pentetreotide scintigraphy in malignant lymphomas

Somatostatin receptor imaging (SRI) was carried out as part of the initial staging of 26 patients with histologically proven Hodgkin's (3) and non-Hodgkin's (23) lymphoma, and in the assessment of the first treatment's efficacy in seven of these patients. Static acquisitions over the whole body were performed 4 and 24 h after intravenous administration of 150 MBq of indium-111 pentetreotide. SRI data were compared with the results of conventional methods (clinical data, abdominal and thoracic computed tomography, bone marrow biopsy). Only 50 of the 86 (58%) confirmed extra-medullary tumour sites were detected by SRI. Twelve previously unknown localizations were visualized in seven patients. The Ann Arbor clinical stage was modified in only one of them. When tumoral tracer uptake was present, a tumour uptake index (TUI) was calculated using two regions of interest (one over the tumoral hot spot and one over the shoulder) on 24-h planar images. The patients were classified into three groups: high tumour uptake (TUI > 2.5 in all tumour sites, group A, six patients), low tumour uptake (1.5 < TUI < 2.5 in all tumour sites, group B, 18 patients), and no tumour uptake (group C, two patients). The sensitivity of SRI detection was higher in group A (90%) than in group B (52%) (P < 0.001). Six weeks after the fourth chemotherapy cycle, conventional methods and SRI were concordant in five of seven investigated cases (four complete remissions and one residual active thoracic mass showing tracer uptake), and discordant in two. SRI demonstrated residual tumoral tracer uptake in these two patients, who had previously been considered to be in complete remission. In conclusion, SRI does not seem to be reliable for the initial staging of lymphomas because of the highly variable and usually low tumoral tracer uptake. It may be more useful in the diagnosis of residual masses after treatment. However, further studies are needed to assess its specificity.

High-dose methylprednisolone is an alternative treatment for adults with autoimmune thrombocytopenic purpura refractory to intravenous immunoglobulins and oral corticosteroids

Eight patients with severe chronic autoimmune thrombocytopenic purpura (AITP) refractory to high-dose intravenous immunoglobulin (IVIgG) and/or oral prednisone were treated with one to three infusions of high-dose methylprednisolone (HDMP) (15 mg/kg/day). The mean platelet count before treatment was 12 +/- 10 x 10(9)/L. HDMP therapy led to a safe platelet count (> 50 x 10(9)/L) after 2-5 days in five patients, and a minimal platelet increase (34 x 10(9)/L) able to stop bleeding in a sixth patient. The effect of HDMP was, however, transient in four of five responders. No side effects were observed, even in the four patients older than 70 years. HDMP thus appears to be a good alternative in emergency situations or prior to surgery for patients with AITP refractory to conventional therapy.

Thrombin induces endothelial cell growth via both a proteolytic and a non-proteolytic pathway

Binding of 125I-thrombin to human umbilical vein endothelial cells (HUVECs) was specifically displaced by the synthetic tetradecapeptide SFLLRNPNDKYEPF, named thrombin receptor agonist peptide (TRAP), which has recently been described as a peptide mimicking the new N-terminus created by cleavage of the thrombin receptor, and F-14, a tetradecapeptide representing residues 365-378 of the human alpha-thrombin B chain. Binding of 125I-TRAP to HUVECs was time-dependent, reversible and saturable, showing high affinity (KD = 1.5 +/- 0.4 microM) and high binding capacity (Bmax. = 7.1 +/- 0.6 x 10(6) sites/cell) (n = 3). Unlabelled thrombin and TRAP competitively and selectively inhibited the specific binding of 125I-TRAP with IC50 values of 5.8 +/- 0.7 nM and 2.8 +/- 0.4 microM respectively, whereas F-14 remained ineffective at displacing 125I-TRAP from its binding sites, suggesting the presence of at least two different types of thrombin-binding sites on HUVECs. TRAP was a potent mitogen for HUVECs in culture. Both TRAP and alpha-thrombin stimulated the proliferation of HUVECs with half-maximum mitogenic responses between 1 and 10 nM. F-14 also promoted HUVEC growth. The mitogenic effects of F-14 and TRAP were additive. N alpha-(2-Naphthylsulphonylglycyl)-DL-p-amidinophenylalanylpiper idine (NAPAP) and hirudin (two specific inhibitors of the enzyme activity of thrombin) specifically inhibited thrombin-induced HUVEC growth (IC50 values 400 +/- 60 and 52 +/- 8 nM respectively) but remained without effect on the mitogenic effect of TRAP or F-14. This demonstrated that the mitogenic effect of alpha-thrombin for HUVECs was intimately linked to its esterolytic activity but also showed that thrombin can stimulate HUVEC growth via another non-enzymic pathway. This hypothesis was further reinforced by the fact that F-14-induced proliferation of HUVECs remained unaltered by two antibodies directed against TRAP or the cleavage site on the extracellular portion of the thrombin receptor, which both strongly reduced thrombin-induced proliferation of HUVECs. Thrombin-, TRAP- or F-14-induced HUVEC proliferation was strongly inhibited by a neutralizing monoclonal antibody directed against basic fibroblast growth factor (bFGF), suggesting that thrombin regulates the autocrine release of bFGF in HUVECs.

Bradykinin regulates the expression of kininogen binding sites on endothelial cells

The vasoactive compound bradykinin (BK) is liberated by proteolytic cleavage from high molecular weight kininogen (HK) and low molecular weight kininogen (LK). Expression of kininogens on cell surface receptors may affect the delivery of BK at sites of inflammation. Therefore, we investigated whether BK itself alters the expression of binding sites for its parent molecules, HK and LK, on the surface of cultured human umbilical vein endothelial cells (HUVEC). 125I-LK and 125I-HK each bind to a single class of sites on HUVEC in reactions that are saturable, reversible, and zinc-dependent (Bmax = 9.7 +/- 0.2 x 10(5) sites/cell; kd = 43.3 +/- 8 nmol/L; n = 5 and Bmax = 10.3 +/- 0.4 x 10(5) sites/cell; kd = 40.3 +/- 0.9 nmol/L; n = 3 for LK and HK, respectively). HK and LK compete for the same binding site (Ki = 19.4 +/- 5 nmol/L HK v 125I-LK; Ki = 24.5 +/- 4 nmol/L LK v 125I-HK, n = 3). Moreover, 50-fold molar excess light chain of HK inhibits 125I-LK binding 51% and 50-fold molar excess LK and the heavy chain of HK inhibit 125I-light chain of HK binding 92% and 76%, respectively. Preincubation of HUVEC with BK produces a transient, concentration-dependent increase in the binding of HK and LK, reaching a maximum 3 to 4 hours after addition of BK (46% increase over control for HK; 57% increase over control for LK; P < .005 for each ligand). Des-Arg9-bradykinin, a B1 receptor agonist, increases kininogen binding to the same extent as BK; the upregulation of kininogen binding sites by BK is partially blocked by a B1 but not by a B2 receptor antagonist. The protein kinase C inhibitors (PKC), sphingosine and H7, completely block the induction of HK receptors by BK. Phorbol 12-myristate 13-acetate (PMA), which also activates PKC, stimulates the binding of HK and the purified light chain of HK to HUVEC as well. However, unlike HK and its light chain, binding of LK and the heavy chain of HK are increased by PMA only in the presence of added calcium ion. These studies show that BK upregulates a common binding site for HK, LK, and each chain of HK on HUVEC. Induction of kininogen receptors on endothelial cells by BK may modulate the generation of this vasoactive compound at sites of vascular injury.

Coagulation disorders associated with acute promyelocytic leukemia: corrective effect of all-trans retinoic acid treatment

The bleeding diathesis in patients with acute promyelocytic leukemia (APL) is generally attributed to disseminated intravascular coagulation (DIC), initiated by the release of procoagulant activity from leukemic cells. Primary fibrinogenolysis, mediated by the release of leukocyte proteases, may also contribute to this disorder. We analyzed coagulation parameters in 15 non-septic APL patients. Before treatment, there was evidence of thrombin activation with DIC: increased levels of circulating thrombin-antithrombin III complexes, prothrombin fragments 1 + 2 and D-Dimer complexes. This DIC syndrome was probably limited, since no prothrombin time decrease, no significant factor V consumption, and normal levels of coagulation inhibitors (antithrombin III and protein C) were observed in APL patients when compared to normal controls. In this context, marked hypofibrinogenemia suggested primary fibrinogenolysis as the predominant etiology. Despite normal or high tissue plasminogen activator (tPA) and plasminogen activator inhibitor (PAI-1) antigen levels, the plasma PAI-1 activity and the formation of tPA/PAI-1 complexes were lower in APL patients than in normal controls, suggesting a proteolytic degradation of PAI-1, not able to complex tPA. Two other fibrinolytic inhibitor molecules (alpha-2 plasmin inhibitor antigen and histidine-rich glycoprotein antigen) were also significantly reduced, as well as the two subunits of fibrin stability factor XIII, although only subunit A is known to be susceptible to thrombin action. Evidence of degraded forms of von Willebrand factor in the plasma suggested an extended proteolytic activity. Four patients treated with all-trans-retinoic acid (ATRA) as a single differentiating agent were studied serially. A dissociation between these two syndromes--DIC and fibrinogenolysis/proteolysis--was observed. The rapid correction of the lysis markers contrasted with a more prolonged persistence of the procoagulant activity. We observed persistently high elastase/alpha 1-proteinase inhibitor complex levels during ATRA therapy, despite progressive correction of all lysis markers. Thus, the release of elastase from promyelocytic leukemic cells is probably not the only determinant of the fibrinogenolytic/proteolytic syndrome. In summary, the present findings provide new arguments for the association of DIC and proteolysis syndromes in APL-associated coagulation disorders. Further prospective studies are needed in order to confirm the persistence of thrombin activation in course of ATRA therapy.

Characterization of urokinase receptor expression by human placental trophoblasts

The processes of implantation and placentation are both dependent on the invasion and remodeling of the uterine endometrium and vasculature by trophoblasts. Because the secretion and autocrine binding of urokinase (uPA) appears to be a common mechanism used by cells to facilitate plasmin-dependent tissue invasion, we measured the production of uPA and expression of uPA receptors by trophoblasts. Prourokinase bound specifically, reversibly, and with high affinity to cultured trophoblasts, via the uPA epidermal growth factor-like domain. Trophoblasts derived from two first-trimester placentae bound more prourokinase than cells isolated from term placentae. Furthermore, in vitro differentiation of cultured cytotrophoblasts into syncytiotrophoblasts was associated with diminished expression of urokinase receptors and a parallel decrease in the cellular content of uPA receptor mRNA. Trophoblasts also secreted prourokinase and plasminogen activator inhibitors types 1 and 2 (PAI-1 and PAI-2). Although prourokinase was secreted in amounts sufficient to endogenously saturate trophoblast uPA receptors, trophoblasts secreted greater amounts of PAI-1 and PAI-2 than uPA, and no net plasminogen activator activity was detected in trophoblast conditioned medium. In contrast, plasminogen added directly to cultured trophoblasts was readily converted to plasmin. Although the invasion and remodeling of uterine tissues by trophoblasts is a complex process dependent on several proteases of varying specificity, our findings suggest that the expression and modulation of urokinase receptors on the trophoblast cell surface may play an important role in this process.

Modulation of allogenic reaction by ticlopidine treatment

Ability of response in proliferation and cytotoxicity of lymphocytes, after in vitro allogeneic reaction was tested in three independent series of experiments, before and after seven days of ticlopidine treatment (500 mg daily) taken by normal adult individuals. In the third experiment, blood samples were taken twice before treatment and twice during the treatment. In two of the three series of experiments the ability of proliferation of responding cells in a mixed lymphocyte reaction was decreased (P less than 0.01). Cytotoxicity was reduced in the three series of experiments when the combination effector/target cells after treatment was compared with the combination before treatment (P less than 0.01 - 0.001), at various effector to target cells ratios for one target (50:1 and 100:1).