Search

The technology allowing freezing of RBC units has been available for many decades. The high-glycerol method for RBC storage at -8 degrees C is predominantly used. Several studies have shown satisfactory results regarding the in vitro viability and function of cryopreserved RBCs. RBC freezing is nowadays mostly encountered in rare blood programs and military deployments. Preservation time of frozen RBCs appears to be virtually indefinite, but most countries apply a 10-year outdate. There is no mandatory time restriction in France. The National Rare Blood Bank currently includes 962 (17.5%) RBC units aged to years or more and 153 (2.8%) aged 20 years or more. Since 1994, 1957 RBC units have been thawed and transfused, among which 118 were aged 10 years or more and 8 were aged 20 years or more. Discarding RBC units older than to years may be highly sensitive for very rare blood groups, e.g., U-, of which approximately 30 percent of the cryopreserved units are aged to years or more. However, the lack of nucleic acid testing for HIV and HCV may be problematic for old RBC units drawn from donors who were not subsequently tested for these markers, which is now mandatory in most countries. Regarding the 118 transfused RBC units older than 10 years, no evidence of hemolysis of thawed RBCs and no transfusion reaction, clinical or biologic hemolysis, or transfusion ineffectiveness was reported, either by any of the parties involved in the transfusion supply of rare RBC units or through the French hemovigilance program, which requires a mandatory report of any transfusion reaction. It has recently been suggested to extend the 10-year restriction in some countries. Considering our experience and observational data, we may consider it safe and efficient to transfuse rare frozen RBC units older than 10 years. An international consensus for RBC cryopreservation time should ideally be established.

For ten years, the working party of immunohaematology of the French Society of Blood Transfusion organizes a quality control. After the modification of the law about the realization of erythrocyte typing and detection of unexpected red cell allo-antibodies, the quality control was performed in order to determine the sensitivity of the indirect antiglobulin test by filtration with a standard anti-RH1(D) produces by the National Reference Center of Blood Groups.

The immunologic risk associated to erythrocyte transfusions is bound to the polymorphism of blood group systems and to the respect of blood transfusion regulations. The results of three studies are presented, which were carried out respectively by the French Society of Blood Transfusion, the National Institute of Blood Transfusion and the National Haemovigilance Network. Two hundred and twenty-seven cases of immunologic accidents are analysed using the Kaplan's interpretation model and the traditional method of process analysis. The results show three critical factors in the occurrence of this type of incident: the relevance of the clinical examinations prescribed, the way in which the biological results are taken into account, and the relationship/exchange of information between private and public hospitals, and blood transfusion centers.

The risks associated to red cell and platelet transfusions are essentially bound to the polymorphism of blood group antigens and to transfusion transmitted agents including virus, bacterias.... In France, the haemovigilance system and several investigations allowed to measure these different kinds of risks. We also developed analysis of failures in order to prevent errors and accidents to increase blood safety.

The Société Française de Transfusion Sanguine and the Centre National de Référence pour les Groupes Sanguins performed a quality control to evaluate the performances of two serological tests: the Direct Antiglobulin Test (DAT) and the Elution test. Among the 110 Blood Transfusion Centers participating in this control, 80 (73%) returned a result. Of these, 68 results were correct for the DAT (85%; positive for type IgG) and 31 results were correct for the elution (39%; anti-FY1). This control gave the opportunity to confirm the main procedures used in routine testing on a national scale. The analysis of the results underlines the importance of the choice of a standardized technique for these tests. Such controls are useful to appreciate the quality of the routine tests and to find the means to improve them.

Alloimmunization following multiple transfusions, a frequently observed complication in sickle cell anemia patients, may make subsequent transfusion attempts extremely hazardous. The case of a young woman with sickle-cell anemia is reported; she was hospitalized for the treatment of extensive invalidating leg ulcers. The transfusion program that was initiated as a prerequisite to skin allografts had to be stopped, due to rapid occurrence of multiple alloimmunization. Broad spectrum alloantibodies precluded further selection of compatible blood units. In an attempt to get round this impossibility, a treatment with Hydroxyurea was initiated in order to boost synthesis of F-hemoglobin. After one year under this treatment, the patient's clinical status has clearly improved without requiring any new blood transfusion.

In 1987-1988 the National Reference Center for Blood Groups checked samples of reagents and cards utilized in ultimate pretransfusion tests at the patient's bedside as described in the circular published on the 17th of May (1985) by the "Direction Générale de la Santé". This inquiry shaved some deficiencies concerning the storage conditions, the patency of the reagents and the absence of anti-A + B reagent. Taking these results into account, some modifications are considered in order to improve the realization of these tests which are regarded in France as the last major step for the security of the red blood cells transfusion.

The red blood cells and sera from 21 RN/RN individuals were studied. The study confirmed the Rh type D+C+E-c-e+, CW-, characterized by an increased expression of the D antigen, a markedly decreased expression of the C and e antigens, the presence of a low incidence antigen (Rh32) and the absence of a high incidence antigen (Rh46) associated with an epitope recognized by a murine monoclonal antibody (MR 432). Four individuals exposed to Rh46 cells by pregnancy and/or transfusion had an anti-Rh46 antibody. This antibody gave positive reactions with all red blood cells of common and rare Rh phenotype except Rh null, D--, D.., DC(W-) and RN/RN cells. This antibody is considered to be of clinical significance in case of transfusion or pregnancy.

Abstract: Aim of the study: Determination of blood group antigens from data obtained by using molecular methods (genotyping) has become an indispensable tool in the specialized immunohematology laboratories. The French National Reference Centre for Blood group typing (CNRGS) routinely performs genotyping of the FY, JK and MNS system (common genotyping), providing a phenotype deduced from genotyping data for FY1, FY2, JK1, JK2, MNS3 and MNS4 antigens. Patients and methods: We performed a study to evaluate the common genotyping prescriptions referred to the CNRGS over the last three years. Results: Between February2006 and February2009, the CNRGS performed 2392 genotyping, including 981 common genotyping. Analysis of 172 common genotyping performed in 2008 showed that 63.8% of the prescriptions expressed a genotyping demand. Of the latter, 42.7% were genotyping prescriptions only, whereas 57.2% were prescriptions of genotyping associated with alloantibody identification. All prescriptions refer to blood group genotyping indications issued from guidelines, with no incorrect prescription, that are patients transfused within four months before blood sampling in 63.6% of cases or a positive direct antiglobulin test in 24.5% of cases. Lastly, 36% of the blood samples referred to the CNRGS had no genotyping prescription. Yet, common genotyping was performed by the CNRGS to get complete immunohematology data for antibody identification. Conclusion: Usefulness of blood group genotyping in specialized immunohematology laboratories is obvious. However, the strategy for implementation of molecular methods remains to be defined. Use of high-throughput DNA analysis should change our way of working. [Copyright &y& Elsevier]

Abstract: Background: The use of blood group genotyping for the prediction of antigen expression has been discussed in clinical transfusion settings, but much less for reagent red blood cells selection. In France, the Centre National de Référence pour les Groupes Sanguins (CNRGS) produces a reference panel of reagent red blood cells, mainly used for red cell antibody identification. The use of high-throughput DNA analysis has never been applied to blood donors whose red blood cells are used as reagents. The aim of this study was to compare the serological phenotype and that predicted from DNA analysis in such donors, and to determine the benefit of DNA analysis in reagent red blood cells selection strategy. Study design and method: Red blood cells of 346 blood donors were typed with two different reagents for each antigen. The genotyping was performed by using HEA v1.2 BeadChips, BioArray Solutions, Immucor. The comparison between the serologically determined phenotype and that predicted from DNA analysis held on 8876 paired results obtained from 10 blood group systems and 25 antigens. Results: A 99.95% concordance was observed. Four cases of discrepancy for RH, KEL, LU and DO blood group systems were analyzed. Genotyping precisions were of special interest for the Duffy blood group system. Conclusion: Systematic DNA analysis brings important information on reagent red blood cells selection. It can be used at a routine level. Especially, the notion of “antigen of double dose” which is specified in several countries by government bodies should evolve regarding data obtained from DNA analysis. This should improve the quality of reagent red blood cells as first step for antibody identification. [ABSTRACT FROM AUTHOR]