[Quality control of platelet concentrates: experience of Sousse (Tunisia) blood centre]. / Contrôle de qualité des concentrés plaquettaires: expérience du centre de transfusion de Sousse (Tunisie).

The aim of this prospective study was to control the quality of platelet concentrates prepared in Sousse blood centre: standard platelet concentrates (SPC) and apheresis platelet concentrates (APC) in order to detect anomalies and apply corrections. The quality control included three parameters: pH, volume, cells count: platelets, residual white blood cells (WBC) and red blood cells (RBC). The SPC pH was measured with pH meter, samples were obtained at the end of shelf-life by the destructive method. The control of SPC cells count was determined with a Beckman coulter, samples were collected by the stripping method. The APC quality control was assessed in the same conditions than those described for SPC but samples were collected by the transfer method. Quality control results were compared to Europe standards. During a period of six months (July-December 2002), 475 SPC (16% of the production) and 36 APC (60% of the production) were controlled. More than 95% of the SPC meet standards in regard to pH, volume and residual WBC count. However, the number of platelets and residual RBC meet standards respectively in 58% and 42% of SPC. All the APC meet standards for the three quality parameters. In conclusion, in order to improve the quality of our SPC, in regard to the number of platelets and residual RBC, two actions are respectively necessary to satisfy requirements: collecting the appropriate volume of whole blood and controlling the separation technique.

[Fever-shivers reaction and standard platelet concentrates transfusion: a prospective study]. / Réaction frissons-hyperthermie et transfusion de concentrés plaquettaires standard: étude prospective.

Fever-shivers reaction (FSR) is the most frequent transfusion immediate incident related to platelet transfusions. The aim of our prospective study was to assess the frequency of the different immediate incidents, especially the frequency and the causes of the FSR, observed during the transfusion of standard platelet concentrates (SPC). For each FSR, analysis of causes included: a bacterial culture of the implicated SPC, a blood culture and HLA antibody screening (lymphocytotoxicity assay) among the patients. In the study period, 34 patients were followed during 74 transfusions. Ten immediate incidents were noted; FSR: N = 8, erythema-urticaria: N = 1 and nausea-vomit: N = 1. The FSR was observed in 6 patients who received 56 SPC. Analysis of causes of this reaction revealed that: HLA antibodies were present in one patient; bacterial contamination was not found neither among the patients nor in the implicated SPC, and the risk of the FSR occurrence rose with increased storage time of the SPC transfused. Indeed, a significant difference was noted between the mean age of the SPC implicated in the FSR and the mean age of those not implicated (P = 0,0028). In conclusion, the FSR is a frequent incident observed during SPC transfusions. In the majority of cases, the cause of this reaction was not identified. Further studies will be necessary to better understand the physiological mechanisms of the FSR.

Treatment of haemophilia A in Tunisia: efficacy and inhibitor study.

Cryoprecipitate is the principal type of factor VIII (FVIII) concentrate used for treating haemophilia A in Tunisia. Allergic reactions, viral transmission, and inhibitor formation remain the most serious complications of FVIII therapy. The aims of the study presented here were to evaluate the efficacy of FVIII therapy, to investigate the inhibitor prevalence, and the factors which may affect inhibitor formation in our haemophilia A patients. Plasma samples were screened for FVIII inhibitors by the Bethesda method. 30 minutes FVIII recovery was also determined for each patient. In this prospective study, 18 previously treated haemophilia A patients, four with severe (FVIII concentration <2%) and 14 with moderate haemophilia, were closely followed up during administration of 223 FVIII concentrates (cryoprecipitate and/or fresh frozen plasma). The median age of the patients involved in the study was 13.5 years (range 5 to 53). Clinical response to FVIII was consistently good to excellent. In the majority of cases, actual and predicted FVIII recovery correlated' well. Adverse reactions were not observed. Five patients, aged less than 18 years and minimally treated (>36 FVIII exposure days), were found to have low titre FVIII inhibitors (<10 Bethesda units) at the end of the study. Inhibitor activity was detected in one patient with severe and in four patients with moderate haemophilia. In conclusion, FVIII therapy was effective, well tolerated, and low titre inhibitors identified did not preclude continued on demand FVIII therapy. Our study has also demonstrated that patients' age and treatment regimen do not affect inhibitor formation. Further studies are necessary to confirm these findings.

[Role of ALAT level in preventing post-transfusional hepatitis. Prospective study of 1,180 blood donors in Tunisia]. / Intérêt du dosage de l'ALAT dans la prévention des hépatites post transfusionnelles. Etude prospective à propos de 1180 donneurs de sang du sahel tunisien.

In Tunisia, regular serological tests for prevention of blood transmitted hepatitis consist in the research of HBS antigen and HCV antibodies. Our purpose in this study is to estimate the prevalence of hypertransaminasemia in blood-donors and to determinate to what extent it could prevent blood-transmitted hepatitis. Therefore we have assessed ALAT sera level in 1180 blood-donors. It rate is considered elevated if higher than twofold the normal rate (> N = 40 Ul/l). Donors with high ALAT level were summoned three months later after their blood gift to undergo clinical examination and a new serological test, researching seroconversion of HBS Ag and HCV antibodies. With regarding to estimation of residuel HCV infection risk, we were based on M.P Busch's data. Hpertransaminasemia was modified in 134 individuals (11.5%). Only 67 had replied to our summons. Alcoholism was involved in one case. Smoking was found in most of male donors. We had discovered neither weight excess nor drug or medicines consumption which could explain increasing ALAT. New serological list had revealed seroconversion for HCV antibodies in ELISA but with undeterminated profile in Immunoblot (anti NS5 solely). PCR was not carried out. Residual infection risk being considered, use of hypertransaminasemia detection in blood donors should prevent nearly 1.67 blood transmitted hepatitis per million transfusions units. However if we consider shortage in blood derivates in Tunisia, such a decision should be comprehensively weighted numerous blood donors will be moved aside.

[Transfusion practice and attitudes]. / Pratiques et attitudes transfusionnelles.

During last years, blood transfusion and transfusion security were domains which have preoccupied health authorities, the population and health professionals. Beginning with the principle that blood transfusion is a care that must be under medical responsibilities, authors analyse physician's implication in this field. To reach this objective, a study interested 199 young physicians, working in two university hospitals in Tunisia. Results indicate that physician's knowledge about blood transfusion is insufficient to guarantee quality of this medical act. In terms of attitudes and practices, physicians are not really always implicated in the different stages of blood transfusion process. Intervention is limited to prescription and blood transfusion record card writing. Transfusion herself and monitoring were, in particular, delegated to nurses. So transfusion incidents were under--declared. Transfusion medicine must occupy important place in physicians curriculum. At hospital level, quality insurance process, based on audit, have to be implemented to obtain transfusion good practices, in a domain were risks are unfortunately not yet totally circumscribed.

[Hepatitis C virus antibodies in 34130 blood donors in Tunisian Sahel]. / Les anti V.H.C chez 34130 donneurs de sang du Sahel Tunisien.

Since January 6th 1994 to december 31 1997. We researched hepatitis C Virus antibodies by second and third generation ELISA in 34,130 bloods donors living in "Sahel Tunisien". 193 were positive (0.56%). Only 171 of them were secondary tested by immunoblot assay (anticore, anti NS5, anti NS3, anti NS4). Which was positive in 53 cases (30.9%); in determined (presence of only one antibody) in 78 cases (45.6%) and negative, in 40 cases (23.3%). There was a significant relation between a ratio over than 2.5 in ELISA and immunoblot positivity. Immune response to different hepatitis virus antigens were heterogeneous with predominant in determined profile. (78/171 cases). Most of donors of the last profile had either anti NS5 (32/78) or anti NS3 (33/78) and we excluded them even through usually negative in P.C.R and associated with a very low risk of contamination.

Seroepidemiological survey of rickettsial infections among blood donors in central Tunisia.

In this report we attempt to evaluate the prevalence of antibodies against Rickettsia conorii, R. typhi, Coxiella burnettii, and Ehrlichia chaffeensis in central Tunisia. Five hundred sera from blood donors, collected between March and June 1993, were tested for these 4 antibodies using an indirect immunofluorescence antibody assay (IFA). Nine percent of the sera had antibodies against R. conorii (IgG > 1:32) by IFA, and 8% by Western blotting; with IFA, 3.6% had antibodies to R. typhi, 26% to C. burnetii (> 1:50), and none to E. chaffeensis. Infection rates with R. conorii and R. typhi did not differ significantly between the sexes, but fewer young people had antibodies to R. typhi. A significantly higher prevalence of antibodies to C. burnetii was noted for males with no difference between age classes. No significant difference was detected between urban and rural areas. This study confirmed the endemicity of rickettsioses, and revealed a high seroprevalence of Q fever, in central Tunisia.

Seropositivity to hepatitis C virus in Tunisian haemodialysis patients.

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.