Red blood cells from donors with sickle cell trait: a safety issue for transfusion?

Sickle cell trait (SCT) affects approximately 8% of the population in Martinique (FWI) and about the same rate is found among the African Americans. In several regions of tropical Africa, up to 40% of individuals are also affected. SCT has been characterized as a benign condition and patients are currently asymptomatic or run a benign course. However, life-threatening complications may occur. SCT can be detected in patients hospitalized for various complaints, and SCT likely causes serious morbidity and mortality in some people. Moreover, these clinical observations have been supported by several in vitro studies in which haemoglobin AS red cells showed abnormalities of their filterability. These problems are revisited with the implementation of universal leucoreduction in several countries. The question of the screening of all blood donors for SCT and the use of their red blood cells (RBCs) has yet to be resolved.

[Assessment of the use of transfusion therapy and complications in orthopedic surgery in patients with sickle-cell anemia: retrospective study]. / Analyse des pratiques transfusionnelles et complications chez le patient drépanocytaire en situation de chirurgie orthopédique: étude rétrospective.

Red blood cells (RBCs) transfusion is a common practice in the treatment or for the prevention of complications of patients with sickle-cell disease. In surgery, pre-operative transfusions are frequently given to prevent peri-operative complications. There is no consensus however on the best regimen of transfusion for this purpose. The transfusion techniques are muliple. In addition, pre-operative transfusion therapy is reported to be largely responsible for an increased morbidity and mortality in patients with sickle cell anemia undergoing surgery. During the period 1990-2000, 16 patients (4 men and 12 women) with a mean age of 37 years and various major sickle cell hemoglobinopathies underwent 32 total hip arthroplasty for femoral head necrosis. Nine patients with sickle-cell trait were included as control group. Twelve of them had haemoglobin SS (HbSS), 2/16 had HbSC, 2/16 had HbS/betathalassemia. Operative transfusion were given in only 12/32 procedures, 4 were performed pre-operatively and 8 intra-operatively. Simple transfusion (mean: 2.5 packed red cells) were administered in all the procedures. The main complications observed in our patients were anemia by hemolysis and haemorrhagic shock, vaso-occlusive crisis and chest syndrome. Anemia requiring transfusions was significatively related to the procedures with pre-operative transfusion. In the light of our result, we would like to propose transfusional protocol--if needed--only intra-operatively.

[The role of yaws in the serologic screening of treponematoses in blood donors in Martinique]. / La place du pian dans le dépistage sérologique des tréponématoses chez les donneurs de sang de la Martinique.

Using TPHA instead of VDRL for syphilis blood-screening since 1995 showed an important increase of positive blood donors in Martinique. Yaws, another treponema disease, has been present on the island until 1975-1980. Usual tests are unable to identify which type--venereal or non venereal--of treponema is involved. Our study, carried out from January 1995 to May 1999, compares actual serological and epidemiological characteristics of TPHA reactive donors to former studies. In our results, the frequency of reactive TPHA is about 1.04% in blood donations. Donors are carrying serological tracks of a past treponema disease with very low rate of antibodies, sometimes linked to yaws. Among donors aged 18 to 30, prevalence is low and is going to become similar to the rate observed in Continental France. This means that this problem will disappear in new donor generations. We suggest the possibility for them to continue blood donation, if their personal preliminary enquiry fits the admission criteria for blood giving.

Seroindeterminate patterns and seroconversions to human T-lymphotropic virus type I positivity in blood donors from Martinique, French West Indies.

BACKGROUND: Screening for human T-lymphotropic virus type I (HTLV-I) antibodies in volunteer blood donors has been systematic in the French West Indies since 1989. Western blot-indeterminate results are commonly obtained. The significance of these indeterminate serologic patterns in HTLV-I-endemic areas is still unclear. STUDY DESIGN AND METHODS: During a 2-year period, 9759 blood donors were tested for HTLV-I antibodies. The epidemiologic features of HTLV-I-seropositive, -seroindeterminate, and -seronegative donors were compared. A lookback investigation was performed for the HTLV-I-seropositive donors, and the HTLV-I-seroindeterminate individuals were followed up. RESULTS: Thirty-nine donors (0.4%) were HTLV-I seropositive and 49 (0.5%) were seroindeterminate. The age and sex ratio characteristics of the seroindeterminate donors are divergent from those of the HTLV-I-seropositive group and are more like those of the seronegative population. However, during the study period, three cases of seroconversion after an initial seroindeterminate profile were reported. Two cases were detected through follow-up of 38 HTLV-I-seroindeterminate donors over a mean of 8 months (2-24 months). The third seroconverter belonged to the HTLV-I-seropositive group and was identified through lookback investigation. This case is atypical, with p19 reactivity for several months before HTLV-I seropositivity. CONCLUSION: These findings indicate that, although HTLV-I-seroindeterminate donors mainly are HTLV-I-noninfected, the rate of seroconversion in a repeat blood donor population from an endemic region must be taken into consideration. Moreover, the case of delayed seroconversion observed in this study suggests the difficulty of counseling seroindeterminate blood donors in endemic regions.

[AS heterozygote hemoglobinopathy and coronary risk]. / Hémoglobinopathie hétérozygote AS et risque coronaire.

There have been several reports of vaso-occlusive events and sudden death in subjects with sickle cell trait. However, the precise mechanism underlying these episodes remains unclear. The clinical observations have been supported by in vitro studies in which haemoglobin AS (Hb AS) red cells showed abnormalities of their filterability, probably related to gelling or polymerisation of the Hb AS. These in vitro studies and reports in the literature of sickle-cell hearts led the authors to investigate the possible association between AS subject and coronary risk. The results of coronary angiography in 9 patients with Hb AS, paired with respect to the usual cardiovascular risk factors, were compared with those of 18 AA subjects. The number of patients who underwent coronary bypass surgery for three-vessel disease was much greater in the AS subjects. However, the difference was not statistically significant. This tendency of AS subjects to develop thrombosis and coronary artery disease requires further study with larger numbers of patients.

Assessment of qualitative functional parameters of stored red blood cells from donors with sickle cell trait (AS) or with heterozygote (AC) status.

We have compared the storage quality of three groups of 10 red blood cell concentrates of the AA, AS and AC haemoglobin phenotype. The 30 samples were drawn on CPD on day 0, and were centrifuged 6 hours later. Leukocytes were removed on D1 and the samples were kept at +4 degrees C for 42 days in SAG-mannitol. Viability tests were performed using a series of in vitro tests, including: ATP, 2,3-DPG, K+, glucose, lactic acid, pH, osmotic fragility tests and erythrocytic morphology determination. Results demonstrated a good functional quality for AS and AC haemoglobin RBCs. Higher 2,3-DPG levels were found in Hb AS and Hb AC. A lower osmotic fragility in Hb AC and AS RBCs versus Hb AA was observed; no significant difference was found in terms of ATP levels and other parameters. In addition no variation in S and C haemoglobin levels and no sickling were observed. In conclusion, these results indicate an overall good quality for haemoglobin AS and AC RBCs. Further in vivo studies must now be performed in order to confirm the transfusional quality of haemoglobin AS and AC RBCs.