[Validation of antibody screening by indirect antigloblin test and ABO blood typing by filtration and microplate techniques: assessment of robustness]

According to requirements of the French Committee for Accreditation (Cofrac), it is essential to use validated and standardised methods in Immunohematology. This imposes first the knowledge of metrological tolerances for all the technics. Two multicenter studies were carried out to define the maximal acceptable deviations concerning incubation temperature and time, volumes of patient plasma and tests cells for antibody screening using indirect antiglobulin test on one hand and for reverse grouping on another hand. All equipment used (temperature test chamber, chronometer, pipettes) were calibrated according to Cofrac standards. The antibody screenings were performed manually using 3 different filtration systems: ID Diamed, Biovue Ortho and Scangel Biorad, the same tests cells, a standard 20 ng/mL anti RH1, a positive control anti KEL1 and a negative control; the reverse blood grouping was performed manually using the above mentionned filtration systems and microplate technic with the same A1 and B test cells. These two studies showed that all the tests from the multiples combinations of the above parameters gave the same results and allowed us to define a range of tolerance for 4 critical physical parameters involved in the antibody screening and blood typing.

[Red blood cell antibody screening: error analysis in a french interlaboratory comparison program survey]

The French quality control is organized by the French Health Products Safety Agency. In 2005, the immuno-haematology testing control included the screening of an anti KEL 1 antibody. 17 out of 2639 laboratories (0,64%) answered 'negative screening'. All laboratories received a questionnaire in order to understand the failure. In this paper the authors present the detailed laboratories' responses and failure explanations.

[Quality control: sensitivity of the indirect antiglobulin test by filtration]

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.

[External quality evaluation]

Since ten years, the immunohaematology working group of the French Society of Blood Transfusion has organized a quality control. Tests concern essentially the screening and identification of irregular antibodies, direct antiglobulin tests and elutions.

[Problem-solving in immunohematology: direct compatibility laboratory test ]

Cross-matching between the serum of a patient and the red blood cells to be transfused is most important for the prevention of hemolytic transfusion reactions in allo-immunized or new-born patients found positive with direct antiglobulin test. Cross-matching is a time-consuming and complex laboratory test. In order to obtain valid results, it is necessary to abide by some technical rules detailed in this article. The choice of the blood units to be cross-matched depends on the patient's clinical story and on the specificity of anti-erythrocyte antibodies present in the serum. The identification and the management of most frequent difficulties met by using the cross-match technique are discussed hereby.

[Prevention of fetal hemolytic disease: it is time to take action]

In spite of the progress made since 1970 in specific prevention by anti-rhesus immunoglobulins, and improved management of at-risk pregnancies, allo-immunization due to the erythrocytic Rh 1 antigen (formerly known as Rhesus D or Rh D) remains widespread. In fact, anti-Rh 1 antibodies currently constitute over one-third of the immune antibodies detected after pregnancy. The prevention of allo-immunization against the Rh 1 antigen is therefore still problematical, and concerns approximately one pregnant woman in seven. The etiology and pathology of fetal hemolytic disease have been recalled, and the treatment approach during pregnancy and delivery has been carefully examined. Tests for quantifying the risk of fetomaternal hemorrhage have also been described. This approach aims at improving the methods of preventing allo-immunization (e.g., during pregnancy and delivery) and the efficacy of treatment. It is also stated that if the necessary preventive action is not taken in cases of allo-immunization due to to the Rh 1 antigen, this should be considered a grave medical fault.

Decision aides in immunohematology: detection of anti-erythrocyte antibodies

Detection and identification of irregular red-cell antibody in the serum or plasma of a patient is of prime importance for the prevention of hemolytic transfusion reactions and the biological supervision of the hemolytic disease of the foetus or the newborn. Practice in these tests is replete with complex biological problems. Using problem solving strategies, we discuss the recognition and resolution of the most frequent difficulties encountered in red cell antibody identification.

[Analytical validation in erythrocyte immunohematology]

In a transfusional or foeto-maternal context, hemolysis by incompatibility due to anti-erythrocyte antibodies (regular or irregular) remains the most frequent and most serious immunological risk in the receiver. In order to prevent this risk, a number of actions must be taken, such as the realization of the immunohematologic analyses for which the methodological practices have been legislated because of their serious clinical consequences. Several elements play a role in the reliability of the analyses and their results: the selection of the reagents and their validation in the routine technique used; the validation of reception; the controls involved in secondary preparations (e.g., blood cells reagent); and the daily internal controls. All this requires the choice of adapted controls and the management of possible anomalies.

[Evolving methods in immunohematology]

The immunogenic nature of erythrocyte polymorphism is in variance with the incompatible transfusion. Indeed, the fixing of an antibody on the corresponding antigen generally condemns the cell concerned with its destruction. Therefore, in order to ensure the immunohemolytic safety of the transfusions, it is necessary to avoid an in vivo encounter between antigens and antibodies, whose feasibility study in vitro is a determining element. Because of the requirement standards of such analyses and the preoccupation with the continuous improvement of transfusion safety, the evolution of the methods used in immunohematology is a constant concern for all those involved in the process. Thus, during the last few years, new technologies have been introduced which aim at improving performance and sometimes implementing alternatives to agglutination. This improvement is not limited to the search for an overall increase in specificity-sensitivity; it also takes into account the capability to detect "the clinically significant" as well as the limitations of human reliability, which justifies the introduction of automation and computerization. The whole of these methodological evolutions associated with that of the performance of reagents, legitimate the need to reconsider the realization of erythrocyte typing and the search for anti-erythrocyte antibodies.

[Problem-solving in immunohematology: interpretation of ABO typing and its difficulties]

Practice in immunohematology is replete with complex problems that require practitioners' problem-solving performance. In immunohematology, the acquisition of the reasoning process and necessary skills for making clinical decisions is based on teaching problem-solving strategies which potentially reduce errors and improve patient outcome. We discuss the recognition and resolution of the common causes of discrepancies in ABO typing results using problem-solving strategies.

[Detection of irregular anti-erythrocyte antibodies using the indirect antiglobulin test in a low-ionic-strength medium. Immunohematology Group of the French Blood Transfusion Society]

The detection of irregular antibodies is usually performed with serum by the indirect antiglobulin test (IAT) with a polyspecific antiglobulin reagent. In a first study in 1996, we compared the results obtained with 3,264 blood samples of patients drawn with or without anticoagulant: no significant difference was observed among the 240 allo-antibodies detected and identified. In this paper we report the comparison of the results obtained by IAT on column of filtration with two kinds of reagents: polyspecific and anti-IgG antibodies. Respectively 2,927 (76 contained an antibody), and 643 (161 contained an antibody) sera of patients were tested with methods ID-Diamed and Ortho-Biovue. Titrations of 153 other antibodies were also performed with the two reagents. Results showed no significant difference using either polyspecific reagent or the anti-IgG antibodies. This study proves that it is possible to perform screening of irregular antibodies on uncoagulated blood samples. This possibility allows automation as blood typing and screening of irregular antibodies can be carried out with the same sample.

[Identification of alloantibodies associated with an autoantibody: profile of 2 quality control programs in French blood transfusion facilities]

The French Blood Transfusion Society working group Immunohaematology and the French Blood Transfusion Center of Lille performed two quality control exercises-96-01 and 97-02-in order to evaluate identification performances of alloantibodies associated with an autoantibody recognizing a high frequency antigen. Concerning control 96-01, 83 (75%) of the 110 blood transfusion centers participating at this exercise sent results. The alloantibody screening was correct for 78 of them (94%). Sixty-one (78%) blood transfusion centers correctly identified the specificities (anti-RH1 + anti-FY1). Concerning control 97-02, 82 (94%) of the 87 blood transfusion centers participating in this exercise sent results. The alloantibody screening was correct for 69 (88%) of them. Fifty-three blood transfusion centers (77%) correctly identified the specificities (anti-RH3 + anti-FY1). These exercises allowed us to confirm the main procedures used in routine for national scale testing. The analysis of the results has underlined the importance of these tests for assessing the quality of these examinations, and highlighted the means to be carried out in order to improve them.

[Fetal cells in the maternal blood: a step towards non-invasive prenatal diagnosis? Review of the literature]

Prenatal diagnosis of genetic abnormalities requires nucleated fetal cells which are currently obtained by invasive techniques such as amniocentesis, chorionic villus sampling and percutaneous umbilical blood sampling. Each of these entails a risk to the foetus and sometimes to the mother. Nucleated fetal cells have been reported to be present in maternal blood. Recovery of fetal cells from maternal blood would allow a noninvasive prenatal diagnosis. Their rarity (1 fetal cell for 10(6) to 10(8) maternal cells) presents a technical challenge. Due to the small number of fetal cells, sensitive analysis techniques such as PCR and FISH are necessary. Some degree of fetal cells enrichment in the maternal blood sample often precedes the analysis. Different techniques are used for the enrichment: discontinuous density gradient, magnetic activated cell sorting, fluorescence activated cell sorting, micromanipulator.... Several prenatal diagnosis have already been performed from maternal venous blood samples: diagnosis of gender, RhD blood genotype, Duchenne muscular dystrophy and hemoglobinopathy by PCR, diagnosis of gender and chromosome aneuploidy by FISH. Many teams are working on this subject. It is difficult to compare the studies because the techniques of enrichment and analysis vary. We review the different strategies chosen for prenatal diagnosis from maternal blood and discuss the results.

Thrombocytopenia induced by vancomycin-dependent platelet antibody

BACKGROUND AND OBJECTIVES

Many drugs are associated with thrombocytopenic purpura through immune-mediated platelet destruction. The case of a woman who suffered life-threatening thrombocytopenia during vancomycin treatment for Staphylococcus aureus septicemia is reported.

MATERIALS AND METHODS

Conventional clinical and laboratory methods, including flow cytometry.

RESULTS

After treatment of septicemia with vancomycin, severe thrombocytopenia and bleeding occurred, without detection of drug-dependent platelet antibodies (DDPA). This was followed by vegetative endocarditis, whereupon antibiotics were withdrawn so as to isolate the organism. The thrombocytopenia was corrected. On day 34, antibiotics including vancomycin were reinstituted, and three days later thrombocytopenia recurred. With a change in antibiotics, the platelet count corrected itself within four days.

CONCLUSIONS

Vancomycin may induce potentially severe immunological thrombocytopenia.

[Severe hemolysis related to an association of erythrocyte allo- and autoantibodies in a thalassemia patients]

Alloimmunization to red cell antigens and haemolytic transfusion reactions may occur after red blood cell transfusion. We describe a case of life threatening postransfusion hyperhaemolysis in a beta thalassaemia patient. For many years, transfusion therapy was stopped but the patient developed a profound anaemia which required splenectomy. At that time, the serum contained a red cell alloantibody with anti-KN3 specificity. In vivo red cell survival studies were performed trying to determine the capacity of this antibody to cause red cell destruction. Unfortunately, these studies triggered again an intense haemolytic process explained by the appearance of red cell auto- and alloantibodies. This case underlines a possible link between the development of alloimmunization and the induction of potentially serious autoimmune haemolytic anaemia.

[The direct antiglobulin and elution tests: evaluation of quality control in Blood Transfusion Centers]

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.

[Immuno-hemolytic transfusion reactions. III. Report of 61 cases]

Blood transfusion is mainly bound to immunological and infectious risks. The immunological risk originates from an incompatibility between the blood of the donor and that of the recipient; this risk remains insufficiently assessed. A multicentre study has been carried out by the French Blood Transfusion Society and the National Institute for Blood Transfusion. Sixty-one accidents due to an erythrocyte incompatibility were found: 26 cases with ABO incompatibility, and 35 cases with alloantibodies of other blood group systems. For the former category of accidents, the most frequent cause was due to a failure in the realization of the bedside ABO check. For the latter, the main problem was the achievement and the interpretation of antibody screening. The long term follow-up shows no chronic after-effects of immunological accidents. For each accident, errors have been identified and analysed. It was proven that they all originate from health care establishments.

Production of anti-endothelial cell antibodies by coculture of EBV-infected human B cells with endothelial cells

Vascular endothelial cells are suspected of being the target of autoimmune processes seen in many connective tissue diseases and in systemic vasculitis as evidenced by the detection of circulating autoantibodies against endothelial cell antigens. In order to select B cells recognizing endothelial cells antigens, Epstein-Barr virus (EBV)-infected B cells, obtained from one patient presenting a systemic vasculitis, were cocultured with human endothelial cells concurrently with a human endothelial cell line (EC-pSV1 cells). This coculture consisted of a first step of expansion of B cells specifically selected by adherence onto human umbilical vein endothelial cells (HUVEC). The adherence of selected B cells was specific to endothelial cells because no rosette formation around control cells (HeLa cells or COS cells) was observed. Adherent B cells were cloned by limiting dilution by coculture onto EC-pSV1 cells and screened for anti-HUVEC antibody production by endothelial cell ELISA. An increase in anti-HUVEC antibody production of IgM isotype was detected by endothelial cell ELISA, peaking at Day 9 and remaining constantly elevated, relative to B cell expansion. Among 21 B cell lines producing IgM, 6 presented high levels of anti-HUVEC antibodies, whereas 1 of 52 B cells cloned without EC-pSV1 cells showed such antibody production. Anti-HUVEC antibody production and B cell proliferation were dependent on the presence of endothelial cells. Two of these 6 B cell lines produced antibodies directed against an endothelial cell antigen with an apparent molecular weight of 192 kDa as determined by immunoblotting analysis. Our results demonstrate that adherence of EBV-infected B cells to endothelial cells and further cloning by adherence can efficiently select anti-HUVEC antibody-producing human B cells and might help to define antigens potentially involved in autoimmune diseases.

[Anti-Tja (PP1Pk) isoimmunization. A case, a review of the literature]

AIM

A review of the literature concerning the very rare anti-PP1Pk isoimmunisation with a personal case.

CLINICAL MATERIAL

Anti-PP1k antibody gives rise to the high risk of abortion in the first and the second trimester (in a different series the risk is 50-70%). A 19-year-old patient who had this antibody was helped by a plasmaphoresis repeatedly between the 6th and the 25th week of pregnancy. Cordocentesis was carried out to estimate fetal haemoglobin from the 25th week onwards. A set caesarean section was carried out at 36 weeks because of intrauterine growth retardation and the development of fetal anaemia.

DISCUSSION

The authors suggest research based on the known immunohaematological factors concerned with this isoimmunisation and on the main treatments available (plasmaphoresis, cordocentesis, and delivery at a set time).

CONCLUSION

Until now there have been very few cases and only four similar cases to ours have been reported in the literature. That is why it is so difficult to suggest a well defined strategy for treating these patients.

[Severe form of neonatal hemolytic disease by anti-Vel allo-immunization]

BACKGROUND

Routine detection of maternal sensitization during pregnancy sometimes reveals alloimmunization by exceptional antigens.

CASE REPORT

A first pregnancy was complicated by a severe post-partum anemia in the mother, that required a blood transfusion. Irregular agglutinins were detected during the first trimester of a second pregnancy, for which the father was different from the first. The specific antibody was not identified at that time. The newborn, born at a gestational age of 39 weeks, developed severe jaundice at 3 hours of life, with hemolytic disease, anemia and hepatomegaly. Therapy included two transfusions of packed, washed red cells obtained from the mother on days 7 and 25. Immunologic tests showed that the hemolytic disease of this newborn was due to an anti-Vel alloimmunization.

CONCLUSION

Antibodies detected during the pregnancy must be identified in order to manage properly any perinatal problems due to rare antibodies.

[Donath-Landsteiner hemolytic anemia. Physiopathological, diagnostic and therapeutic aspects]

Donath-Landsteiner hemolytic anemia accounts for one third of all immunologic hemolytic syndromes in pediatric patients. Diagnosis is suggested by results of the direct Coombs test which is positive with anti-C3d, evidence of erythrophagocytosis on admission blood smears, and results of the Donath-Landsteiner test. Anti-P specificity should be routinely looked for. Management, required once the diagnosis is established, is symptomatic. Warmed red blood cell concentrates should be used for blood transfusions. Exposure to cold should be avoided. Use of maintenance corticosteroid therapy is no longer acceptable.

[Standardization trial of ABO-Rh(D) blood typing using a U-microplate]

This study reports the results of ABO-Rh (D) typing in microplate according to a suggested protocol. 35,532 blood typings were performed by 13 laboratories, compared to usual technics. This work has proved the feasibility in routine of this protocol in order to identify the A, B, D and weak antigens. However the difficulties in detecting some weak variants reveal the interest of standards for immuno-haematology reagents, to apply in the microplate technology.

[Characterization and validation of a human anti-C monoclonal antibody]

Peripheral lymphocytes were obtained from an immunized woman against C and Ce antigens. Punction was realized 14 days after childbirth. After hetero-hybridization, a unique cell line continued secreting a monoclonal IgM antibody. Serological characterization of this antibody was determined by direct agglutination tests against 150 native and enzyme treated red blood cells including some rare phenotypes. This antibody was specific of C determinant of the Rh system. It showed strong reactions by saline and enzymatic technics, against C positive cells from Ce positive and Ce negative patients. The validation was performed by a manual direct agglutination test in saline (tube) and by an automated-hemagglutination test (in microplate) against 2,500 patients samples. No discrepancy was observed. This monoclonal IgM anti-C could be used as a potent reagent and since one year, about 30,000 patients and pregnant women have been phenotyped in our laboratory successfully.

Usefulness of electron microscopy in the diagnosis of congenital dyserythropoietic anemia type I: report of a case

This report describes a case of congenital dyserythropoietic anemia (CDA) type I diagnosed in a 22-year-old woman with a two year history of macrocytic anemia. Light microscopy study of bone marrow disclosed only minor and nonspecific findings, without erythroid hyperplasia. Electron microscopy of bone marrow erythroblasts surprisingly showed most of the classical features of CDA type I. Electron microscopy may be an important tool for the diagnosis of macrocytic anemia of obscure origin, especially in young patients.

Congenital diserythropoietic anemia type I. Report on monozygotic twins with associated hemochromatosis and short stature

We report the first occurrence of congenital dyserythropoietic anemia type I in monozygotic twins and the seventh familial occurrence to our knowledge. Mild hemochromatosis is present in the two children but has not yet required iron chelation. Moderate growth retardation, which seems to be related to pituitary failure, is also present.

Acquired loss of red-cell Wj antigen in a patient with Hodgkin's disease

A patient with Hodgkin's disease became temporarily Wj-negative with alloanti-Wj in his serum. Four human autoantibodies, and 1 of 2 murine monoclonal antibodies, with serological characteristics of anti-Wj were nonreactive with his red cells, confirming that they have anti-Wj specificity. Six siblings of the patient are all Wj-positive. The patient was also temporarily Anton-negative, and cross-testing between Wj and Anton red cells and antisera showed mutual compatibility, indicating that the antigens are the same. The patient and 3 of his 6 siblings are also of the rare Lu: - 13 phenotype, providing the first evidence that this is an inherited characteristic.

Idiotypic and anti-idiotypic determinants on lymphocytes during anti-Rh immunization

Evolution of idiotypic determinants on lymphocytes membrane and presence of other lymphocytes carrying anti-idiotypic determinants, were studied in Rh negative human volunteer blood donors during immunization towards Rh factor. For this purpose E-Rh Rosettes, direct immunofluorescence, inhibition of E-Rh Rosettes by anti-idiotypic sera as well as EA-Rh Rosettes--induced with Fab'2 fragments from anti-Rh antibodies and lymphocytes from the same subject--were examined and compared to the evolution of circulating antibodies. E-Rh Rosettes preceded or accompanied production of anti-Rh antibodies; their frequency decreased after the fifth month following immunization, meanwhile EA-Rh Rosettes increased in parallel with antibody decrease. The direct immunofluorescence and the inhibition of E-Rh Rosettes, by anti-idiotypic sera, show the presence of idiotypic determinants on lymphocyte membranes; the presence of EA-Rh Rosettes, coinciding with the decrease in antibodies demonstrate the existence of lymphocytes bearing auto-anti-idiotypic determinants.

[A new case of deficient H phenotype in a secretor]

A new case of secreting Bombay phenotype has been discovered during a routine blood grouping in a Caucasian born from consanguineous parents. In spite of the presence of an anti-HI antibody a transfusion of crossmatched O units was very well tolerated by the patient.

[Immunization with antigen D. Results obtained with 118 volunteers]

During the last four years, 118 blood donors have been immunized to obtain plasma with a high level anti-D in order to prepare anti-D immunoglobulins. The results of the immunizing schedule are very successful, as we have obtained anti-D of titer superior to 256 in 96,36% of the cases (Coombs technic). However, the development of unwanted antibodies outside the Rh system (anti-Jka: 6, anti-Fya: 5) has led us since November 1979 to use phenotyped blood without undesirable red blood cell antigens. No irregular antibody has developed since except for an anti-Yta. The anti-HLA have been observed with a frequency of 36%. The use of frozen/thawed and phenotyped blood without undesirable red blood cell antigens can allow to obtain a high level of anti-D without risk for the donors. Nevertheless, the exceptional immunization to a public antigen persists.