Nouvelle revue francaise d'hematologie最新文献

A survey was carried out of the attitudes adopted in French laboratories with regard to the diagnosis of heparin-induced thrombocytopenia (HIT). The platelet aggregation assay is used in 100% of laboratories, aggregation being measured by light transmission in an aggregometer (3/4). Blood is drawn either in emergency (1/4) or after heparin discontinuation (1/4). The nature of the samples for testing is a fresh citrated plasma (100%) although frozen plasma is occasionally employed, while 40% of laboratories use less than 3 control platelet donors. Platelet response is verified in the presence of a non immune agonist (18%) or an immune challenge (known positive plasma or platelet activating monoclonal antibody) (13%). Heparin is of the same type as received by the patient and is tested at two or more concentrations of approximately 0.5 and 1.0 IU/ml, but rarely at high concentration (100 IU/ml). The platelet count is adjusted to 250-350 x 10(9)/l (18%), the ratio of patient plasma to PRP is 1:1 (59%), the time of observation is about 20 min (50%) and control platelets are tested with heparin to rule out any false positive results (9/10). Standardization is nevertheless required if the platelet aggregation assay is to be considered as a reference test.

The present study was carried out to determine the evidence of alloimmunization against red blood cells in 364 patients transfused in our center over a period of 4 years (1990-1993). Among these patients, 127 were thalassemic and 182 had sickle cell disease (SCD). In 55 control patients, who received blood matched for the ABO, Rhesus and Kell antigen systems from the outset of transfusion, no immunization was detected. However, in the study group, who initially received blood matched only for ABH and Rh D antigens, the frequency of alloimmunization was 7.76% (24/309). Only one antibody was detected in 15 patients (62.5%) and two or more in 9 patients (37.5%). Alloimmunization concerned the Rhesus system in 58.82% of cases and the Kell system in 26.47%, while the frequency of immunization was significantly lower in patients of less than 5 years as compared to those in the age range 5-10 years (p < 0.001).

The prevalence of anti-hepatitis C virus (anti-HCV) antibodies and of hepatitis B markers (HBs antigen, anti-hepatitis B core antigen) was assessed in 63 haemodialysis patients from the Tunisian Sahel. As measured by second generation ELISA assays (Ortho and Organon), the frequency of anti-HCV antibodies was 42% (27/63), while 4 patients (6.3%) were HBs Ag positive and 30 (47.6%) anti-HBc positive. Anti-HCV seropositivity was significantly correlated with duration of dialysis (p = 0.007) and number of blood transfusions (> 10 units, p = 0.0004). Among 12 subjects with a history of abnormal ALAT levels, 10 were anti-HCV positive (p = 0.0016) and the results suggest hepatitis C viral infection to be the main cause of liver disease in haemodialysis patients in Tunisia.

In a fuzzy set, the probability that a result for a patient is increased (or decreased) is equal to the probability of incidence of reference values equal and lower (or higher) than the evaluated result. Application of fuzzy logic to computer analysis of haematological data enables more appropriate interpretation of continuous pathological changes.

Protein C activity was determined in 70 patients with liver disease, 30 with acute viral hepatitis and 40 with liver cirrhosis. Statistical comparison of the values for patients with those for healthy Ivorians showed a significant decrease in protein C activity, positively correlated with a prolongation of the prothrombin time.

Since the treatment of leukaemia by autologous bone marrow transplantation is becoming increasingly frequent, a retrospective study was undertaken to ascertain factors influencing the evolution of the disease (death and relapse). Data were collected over a period of 11 years for 105 patients with acute leukaemia (60 lymphoid cases and 45 myeloid cases). Multivariate analysis by the Cox model was used to determine prognostic factors for survival and disease free survival (DFS). Overall survival for the entire population was 35% after 8 years while DFS was 33% after 3 years. The major prognostic criteria were granulocyte recovery time (p < 0.001 at 5 weeks) and platelet recovery time (p < 0.02 at 6 weeks). Patients conditioned by an association of polychemotherapy and total body irradiation (TBI) showed a better survival rate than those conditioned by polychemotherapy alone (p < 0.01), with an overall survival of 48% after 3 years for the former group as compared to 19% for the latter. Other parameters influencing survival were the number of graft CFU-GM, sex and age. A knowledge of these factors could provide a means of predicting the long term evolution of leukaemia following autologous bone marrow transplantation. However, the present results require validation by a prospective study taking into account recent therapeutic protocols with haematopoietic growth factors.

A male patient of 24 years who had experienced thrombotic episodes since the age of 15 displayed an unusually low antithrombin III (AT III) activity measured as heparin cofactor (13% of the normal), while a similarly decreased value (16% of normal) was found in a 26 year old brother who had suffered from thrombotic events since the age of 12 years. AT III heparin cofactor activities were close to 50% of normal in the father, mother, another brother and a sister, none of whom had experienced thrombotic episodes. Since all available members of the family, including the patient, displayed near normal AT III antigen levels (73-85%) normal total progressive antithrombin activities (92-110%) as assessed by the thrombin agarose diffusion technique and normal total progressive anti-Xa activities, the propositus and his brother could be considered to be homozygotes or compound heterozygotes for a qualitative familial AT III deficiency probably caused by an abnormality of the heparin binding site. Molecular techniques would be required to elucidate the precise mutation giving rise to the deficiency.

Erythrocyte-endothelial cell interactions were rediscovered using endothelial cells in culture and radiolabelled erythrocytes. Increased adherence of erythrocytes from patients with sickle cell anaemia was found to be related to the occurrence of vaso-occlusive episodes. In diabetes mellitus and sickle cell anaemia, the adhesion was shown to be potentiated by plasmatic factors such as fibrinogen and fibronectin and to induce endothelial cell activation and enhanced prostacyclin production. The molecular basis of the abnormal adherence of diabetic erythrocytes was shown to be linked to Advanced Glycosylated End-products (AGE) present on the cell membrane and to RAGE 35 receptors exposed by the endothelium. Intercellular Adhesion Molecule (ICAM) was identified as an ubiquitous receptor present on endothelium and involved in leucocyte adhesion and it was more recently demonstrated that erythrocytes infested by Plasmodium falciparum bind to ICAM. This adhesion may be important for the dissemination of Plasmodium falciparum and the complications of the disease. In summary, interactions between endothelium and erythrocytes appear to be involved in the pathophysiology of a number of affections and could constitute a new therapeutic target.

This report presents the case of a patient with PRCA in CLL where in vitro culture studies correlated well with successful CS-A treatment. Before initiating CS-A therapy, coculture studies showed that T-cells from peripheral blood of the patient suppressed the formation of CFU-E and BFU-E colonies by normal bone marrow cells. Normal erythropoiesis reappeared in the bone marrow of the patient 3 weeks after the start of CS-A therapy. At this time, cocultures demonstrated that peripheral blood T-cells no longer inhibited the growth of normal BFU-E, although there was persistent suppression of CFU-E. Six months later the patient was in stable remission from PRCA on maintenance therapy with CS-A. Moreover, cocultures showed no T-cell inhibition of normal BFU-E or CFU-E colony formation. The strong correlation between in vitro culture studies and a beneficial clinical outcome observed in this case suggests that in vitro cultures could be used to monitor CS-A treatment in patients with PRCA in CLL.