[Measurement of d-dimers in non-valvular atrial fibrillation. First prospective Tunisian study]. / Intérêt du dosage des d-dimères dans la fibrillation atriale non valvulaire. Première série prospective tunisienne.

Atrial fibrillation can expose to thrombo-embolic complications. Many biomarkers have been tested to refine the stratification of thrombo-embolic risk. The study aim was to assess the interest of the d-dimer testing in this pathology. We conducted a prospective observational study including 50 cases and 19 controls, enrolled at the cardiology department of the Mongi Slim Hospital, from July to November 2012. The d-dimer assay was performed on mini-VIDAS(®) and analyzed according to clinical, echocardiographic and biological data. The mean age of patients was 61.8±10.6years. The mean CHA2DS2-VASc score was 2.58±1.31. The average of D-dimer levels was 590±506ng/ml in patients and 225.26±112.95ng/ml in controls (P=0.02). No significant difference has been found between the d-dimer level and age, sex, type and etiology of atrial fibrillation, the CHA2DS2-VASc score, the left atrial surface. Among patients on acenocoumarol, d-dimer levels was significantly higher in patients with an INR<2 compared to those with an INR≥2 (P=0.004). We identified a positive d-dimer threshold (300ng/ml) in patients distinguishing them significantly with controls (P<0.001). In conclusion, the measurement of d-dimers could help clinicians to identify patients with atrial fibrillation having an increased coagulability and, therefore, an increased thrombo-embolic risk. It could be complementary to the determination of INR in monitoring anticoagulation therapy: d-dimers level refines the thrombo-embolic risk and INR measurement assesses the level of anticoagulation and the bleeding risk.

[Anti-erythrocyte and anti-HLA immunization in hemoglobinopathies]. / Immunisation anti-érythrocytaire et anti-HLA au cours des hémoglobinopathies.

AIM: Evaluate the anti-erythrocyte and anti-HLA immunization rates in hemoglobinopathies. PATIENTS AND METHODS: Cross-sectional study (October 2009-March 2010) on 83 patients followed for hemoglobinopathies. The irregular antibodies research is realized by two techniques: indirect Coombs and enzymatic technique on gel cards. The search for anti-HLA class I antibodies is done by complement dependent lymphocytotoxicity. RESULTS: The mean age was 30 years (14-64 years), the sex ratio M/F is 0.84. Our series included 42 cases of sickle cell disease (29 homozygous sickle cell anemia and 13 sickle-thalassemia) and 41 cases of thalassemia syndromes (26 major and 15 intermediate). The anti-erythrocyte alloimmunization rate is 10.84% without difference between thalassemia syndromes and sickle cell disease. The autoimmunization rate (22.89%) is higher in thalassemia syndromes (41.46%) than in the sickle cell disease (7.14%) (P<0.001). The anti-HLA immunization rate is 31.6% without difference between thalassemia syndromes and sickle cell disease. The young age, transfusion at a young age and the total number of transfusions are the factors that increase the risk of anti-erythrocyte autoimmunization. No clinicobiological parameter does influence the anti-erythrocyte and anti-HLA alloimmunization. There is no significant association between anti-erythrocyte and anti-HLA immunization. CONCLUSION: The erythrocyte and anti-HLA anti-immunization rates are high in our series. Preventive strategy is needed to ensure optimal blood safety.

[Lineage assignment in acute leukemia: confrontation between cytology and immunophenotyping]. / Diagnostic de lignée dans les leucémies aiguës : confrontation entre cytologie et immunophénotypage.

OBJECTIVE: The determination of the cellular lineage in acute leukemia is a crucial step in the diagnosis and the later therapeutic conduct. In Tunisia, emerging country, some cases of acute leukemias are still treated on the basis of an only cytologic study because of lack of cytometry. Our objective is to realize a confrontation between cytology and flow cytometry in the diagnosis of AL and to analyze discrepancies. PATIENTS AND METHODS: The study concerns 100 cases of AL. A second double-blind examination of the bone marrow smears of acute leukemias is realized by two cytologists and confronted to immunophenotyping. RESULTS: In two cases of AML, flow cytometry reassigned lineage into T ALL and biphenotypic AL. In three cases of ALL the lineage was reassigned into undifferentiated acute leukemia (2 cases) and biphenotypic acute leukemia (1 case). Lineage was not established in four cases, immunophenotyping allowed the diagnosis of B ALL in 3 cases, and of biphenotypic acute leukemia in 1 case. In both cases of discrepant findings, flow cytometry allowed the diagnosis of biphenotypic acute leukemia in a case and of AML in the other one. CONCLUSION: The cytological study remains insufficient in the diagnosis of lineage even with experimented cytologists. Immunophenotyping is essential in lineage assignment and reassignment.

[Medical knowledge in immunological security of red blood cells transfusion in Tunisia: evaluation of a CD-ROM of auto-learning]. / Connaissances médicales en matière de sécurité immunologique en transfusion érythrocytaire en Tunisie : évaluation d'un CD-ROM d'auto-enseignement.

In Tunisia, red blood cells (RBC) transfusion joins in a statutory frame but remains subject to failures because of the misunderstanding of legislation and regulations. Our purpose is to estimate the knowledge of the medical staff in the immunological safety of RBC transfusion before and after reading an auto-education CD-ROM. It is a study of evaluation of an intervention. Eighty physicians participated to the study. The evaluation was done using an anonymous questionnaire, containing seven questions with multiple choices (QMC) relating to several items. The rate of good answers (RGA) calculated by questions and by items took into account the impact of the CD-ROM on the improvement of the answers after reading. The global average mark is 2.9/7. The RGA to questions varies from 22.5 % to 76.3%. All participants answered correctly to more than 50% of all items. Two answered correctly to all items. Among the participants, 31.3% answered to all "important" items, concerning ABO blood groups compatibility and ultimate bedside test. The rate of participation to the final evaluation was 83%. The impact of the CD-ROM was important and statistically significant. In the final evaluation, the global mark raised from 2.9 to 5.8/7, 31.5% (vs 2%) answered correctly all the questions and 95.5% (vs 31.3%) answered correctly all "important" items. This study revealed a misunderstanding of the doctors in immunological safety of RBC transfusions. Auto-teaching by CD-ROM was efficient. An improvement of the knowledge by continuous training is necessary in our country.

The contribution of HLA class I and II alleles and haplotypes to the investigation of the evolutionary history of Tunisians.

The frequencies of HLA class I and class II alleles and haplotypes of 104 healthy unrelated Tunisians were analyzed by high-resolution PCR-reverse dot blot hybridization, and was compared with other Mediterranean and Sub-Saharan Africans using genetic distances measurements, Neighbor-joining dendrograms, correspondence, and extended haplotypes analysis. The most frequent HLA class I A alleles were A*02, A*24, and A*30, while the most frequent B alleles were B*44, followed by B*50, B*51, and B*07. Among HLA class II DRB alleles analyzed, the most frequent were DRB1*0301, DRB1*0701, DRB1*1501, followed by DRB1*1303 and DRB1*0102; for DQB1, they were DQB1*0301 and DQB1*0201. Three-locus haplotype analysis revealed that A*03-B*07-DRB1*1503 and A*02-B*44-DRB1*0402 were the most common HLA class I and II haplotypes in this population. Compared with other communities, our result indicate that Tunisians are very related to North Africans and Western Europeans, particularly Iberians, and that Tunisians, Algerians, and Moroccans are close to Berbers suggesting little genetic contribution of Arabs who populated the area in 7th to 8th century AD. The similarities and differences between Tunisians and neighboring and related communities in HLA genotype distribution provide basic information for further studies of the MHC heterogeneity among Mediterranean and North African countries, and as reference for further anthropological studies.

[HFE gene mutations in Tunisian major beta-Thalassemia and iron overload]. / Mutations du gène HFE chez des beta-thalassémiques majeurs tunisiens et surcharge en fer.

OBJECTIVES: In this study we have determined the allele frequency of HFE mutations H63D and C282Y in a group of Tunisian beta-thalassemia major patients. These two mutations are implicated in hereditary hemochromatosis among Caucasians. In this study we wanted to correlate these mutations with the iron status in major beta-thalassemia patients. DESIGN AND METHODS: Fifty Tunisian major beta-thalassemia were screening for the C282Y and H63D by digestion of polymerase chain reaction products (RFLP). Serum ferritin level was measured by immunoenzymatic microparticular essay. RESULTS: The allele frequency of H63D mutation was 17%. C282Y mutation was not present in our studied patients. No statistically significant difference of serum ferritin level was found between major beta-thalassemia with and without HFE mutations. CONCLUSION: Our results suggest that H63D mutation is so frequent in Tunisian major beta-thalassemia patients than in the general population and that the coinheritance of H63D mutation does not influence the severity of iron overload in these patients.

[RT-PCR use for the diagnostic of chronic myeloid leukaemia]. / Contribution de la RT-PCR au diagnostic de la leucémie myéloïde chronique.

The molecular analysis of chromosomal abnormalities associated with hematological malignancies allowed the identification of genes involved in theses rearrangements as well as of some recurrent mechanisms. Polymerase chain reaction (PCR) tools are now available to detect these rearrangements, allowing a better follow-up of these diseases. Chronic myeloid leukemia is a myeloproliferative disorder characterized by a reciprocal translocation t(9;22)(q34;q11) which results in a bcr-abl fusion gene. Retro-transcription polymerase chain reaction (RT-PCR) is used to detect bcr-abl to establish diagnosis and to monitor patients. We report here the results of 30 patients samples tested in the hematology laboratory at Pasteur Institute, diagnosed as chronic myeloid leukemia and monitored with RT-PCR. Our results highlight the interest of molecular tools to diagnose and monitor patients mainly when cytogenetic techniques are irrelevant such as cases with complex chromosomal rearrangements or when patients achieve Philadelphia negativity after treatment.