[Chimerism analysis after allogeneic haematopoietic stem cell transplantation. Interest of cell sorting: general review]. / Étude de chimérisme post-greffe de cellules souches hématopoïétiques. Intérêt du tri cellulaire : revue générale.

Haematopoietic stem cells transplantation, widely used these last decades, represent the ultimate treatment resource for patients with haematological malignancies. Long range success of this treatment is particularly affected by relapse of the initial disease, graft rejection or graft versus host disease. Chimerism analysis after transplantation had been used since several years to document engraftment, to determine the risk of relapse and to adapt therapy promptly when necessary. Usefulness of this analysis for the outcome of transplanted patients, as well as the impact of using high sensitive techniques coupled with specific cell populations sorted have been demonstrated by retrospective studies. Follow-up of chimerism would allow to operate efficiently before the onset of clinical signs in leukaemic patients with high risk of relapse and to control the expression of minimal residual disease when specific molecular markers could not be monitored.

[Monitoring of chimerism in myeloid cells sorting of transplanted patients with acute myeloid leukaemia: a study from Lyon (France)]. / Suivi de chimérisme des populations cellulaires myéloïdes chez des patients allogreffés atteints de leucémie aiguë myéloïde : étude lyonnaise.

Chimerism analysis after allogeneic haematopoietic stem cell transplantation has been used to document engraftment and to adapt therapy promptly. The aim of this study was to document engraftment and to detect as soon as possible relapse in patients with acute myeloid leukaemia who underwent stem cell transplantation. Real-time quantitative polymerase chain reaction is a highly sensitive and reproducible technology. It is useful in some disease to target selected sub-populations in order to have an earlier detection of relapse on cell fractions. In the acute myeloid leukaemia (n=65), analysis of the chimerism on whole peripheral blood cells and bone marrow cells, CD3+ cells, specific myeloid CD33+ cells (from blood) and CD34+ cells (from bone marrow) is of importance. After transplant, 25 patients relapsed (38%), three massively, with chimerism detection in whole blood and bone marrow and 22 insidiously following two different schemes (GRI and GRII). In GRI, (n=13): chimerism of CD33+ and CD34+ cellular fractions allowed an early detection of relapse in 100% of cases undetected in whole cells whereas in GRII (n=9): myeloid cells could identified relapse in 89% of cases when whole blood cells and CD3+ cells expressed a mixed chimerism. This study highlighted the importance of sub-cellular population chimerism documentation enable to ascertain a stable engraftment and to detect early relapse. The selection of sub-cellular population studied with high sensitive technology allows a rapid and efficient intervention before the onset of clinical signs in patient with acute myeloid leukaemia and could improve the patient's follow-up.

Impact of pretransplant human leukocyte antigen-C and -DP antibodies on kidney graft outcome.

The aim of our study was to determine whether the presence of specific human leukocyte antigen (HLA)-C and -DP antibodies before transplantation influenced graft outcomes in immunized recipients. Two groups of pretransplant immunized recipients were studied: patients with only classical HLA-A, -B, -DR, -DQ antibodies (n = 176) and those with classical plus HLA-C and/or -DP antibodies (n = 27). Acute antibody-mediated rejection was preferentially associated with the presence of pretransplant anti-HLA-C and -DP antibodies (5/6 cases). In four cases, acute rejection episodes were followed by graft loss within 15 months after transplantation. There was a significant increase in the number of acute rejection episodes especially antibody-mediated acute rejections (P = .036) and in the number of graft losses for immunologic reasons (P < .001) among the group with pretransplant anti-C and -DP antibodies. Pretransplant anti-DP antibodies seemed to be involved more frequently in poor graft outcomes as shown in several recent published cases. We need to investigate their specific role among a larger cohort, taking into account an epitope analysis.

Sequencing-based typing identifies three new HLA alleles: C*02:29, C*06:29 and DQB1*03:24.

Two new HLA-C alleles, C*02:29 and C*06:29, and one new HLA-DQB1 allele, DQB1*03:24, are described.

[The immunological conflict in the transfusion-related acute lung injury or TRALI]. / Le conflit immunologique dans l'œdème pulmonaire lésionnel aigu post-transfusionnel ou trali.

Despite its underrated incidence, transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-related morbidity and mortality worldwide. The pulmonary edema in TRALI occurs in the course of the transfusion of apheresis products or erythrocyte concentrates. Its pathogenesis is attributed to the infusion of donor antibodies that recognize leucocyte antigens in the transfused host, with subsequent sequestration of leucocytes in the pulmonary vessels. It is also associated with the passive transfer of lipids and other biological response modifiers that accumulate during the storage or processing of blood components. The innate immunity and inflammatory kinins are key components. The knowledge of its etiopathogenesis must come into play for improving prevention and diagnosis and for application of adapted care of the patient.

[HLA and transfusion: new approaches with Luminex™ technology]. / HLA et transfusion: nouvelles approches à l'ère du Luminex™.

The major histocompatibility complex is a multigenic system highly polymorphic coding for human leukocyte antigen (HLA) molecules, which are the strongest antigens for immune response and play a major role in allograft rejection. Class I antigens are expressed on almost all nucleated cells and platelets, whereas HLA class II antigens are mostly on antigen presenting cells. During transfusion, anti-HLA antibodies can induce transfusion incidents like fever, transfusion-related acute lung injury TRALI and refractoriness to the platelets transfusion. Identification of HLA class I antibodies is very important to find HLA compatible platelets concentrates. Since the end of 1960s, the complement-dependent microlymphocytotoxicity assay has been the standard internationally recognized method for cross matching and screening of HLA antibodies. It became necessary to improve the test sensitivity because some clinical relevant antibodies were not detected. Sensitive methods appeared in the 1990 s: flow cytometry, enzyme-linked immunosorbent assay and now Luminex™. This latter is the most sensitive method with single HLA antigen panel assays to generate the most informative reactivity pattern of antibodies. The high sensitivity and specificity of the Luminex™ technology performed to screen HLA antibodies allows the best selection of platelets donors. When no compatible concentrates are available for highly immunized recipients, the cross-matching method could be used to select a platelet concentrate.

Three new HLA-B alleles determined by sequence-based typing: B*9551, B*5161 and B*5317.

Three new alleles with polymorphisms located in exons 2 and 3.

Three new HLA-A alleles determined by sequence-based typing: A*2493, A*2918 and A*0342.

In this study, we report the identification of three new human leukocyte antigen class I alleles: A*2493, A*2918 and A*0342 found by routine typing using commercial kits. The names A*2493 (HWS 10005702), A*2918 (HWS 10005703) and A*0342 (HWS 10005705) have been officially assigned by the World Health Organization Nomenclature Committee in August 2008.

Two new HLA-DQB alleles routinely identified by sequence-based typing: DQB1*030103 and DQB1*0505.

Here, we report the identification of two novel human leukocyte antigen-DQB1 alleles, DQB1*030103 and DQB1*0505, found by routine typing using commercial kits.

High pretransplantation soluble CD30 levels: impact in renal transplantation.

In a retrospective study, the impact of the level of pretransplantation soluble CD30 molecule (sCD30) was evaluated on 3 year transplant survival, as well as the number and grade of acute rejection episodes among kidney recipients engrafted between 2000 and 2002. One hundred and ninety sera of 190 patients sampled on the cross-match day were tested for sCD30 concentrations using an enzyme-linked immunosorbent assay (ELISA) kit (Biotest). For the analysis, a sCD30 cutoff level of 100 U/mL was chosen: 87 (46%) recipients had a level >100, and 103 (54%) <100. All cases (5) of immunological graft loss showed a high sCD30 level. The rate of biopsy-proven acute rejection was 26% in the sCD30 >100 group versus 22% in the sCD30 <100 groups. Among the first graft population (n = 157), the rate was 27% for sCD30 >100 versus 20% for the lower level. The difference was more important for grade II acute rejection (Banff criteria): 6/87 (7%) showed high sCD30 versus 2/103 (2%) with sCD30 <100. This analysis became significant for anti-HLA immunization: 11 (13%) recipients developed anti-HLA class II antibodies in the first group (sCD30 >100) versus 1 (1%) in the second group (sCD30 <100; P < .01). A high pretransplantation sCD30 was not a significant risk factor for an acute rejection episode, but it seemed to be more predictive for antibody-mediated acute rejection and immunological graft loss. However, many recipients showed an increased pretransplantation concentration without any rejection episode or graft loss. Consequently, sCD30 pregraft measurements cannot be used as a predictor for acute kidney rejection among our transplant center, nor as an aid to adapt the immunosuppressive regimen.

[Ambroxol-induced immune hemolytic anemia]. / Anémie hémolytique immunoallergique due à l'ambroxol.

INTRODUCTION: Drug-induced immune hemolytic anemia is a rare cause of hemolytic anemia. CASE RECORD: A 68-year-old male patient developed an acute intravascular hemolysis with acute renal failure. Common causes of hemolysis were ruled out and the patient rapidly improved. An immune mechanism was confirmed by the positivity of the direct antiglobulin test with anti-IgA in the presence of ambroxol only, one of the drug the patient had received during 6 days before hospitalization. DISCUSSION: To our knowledge, this is the first report of ambroxol-induced immune hemolytic anemia. This case also underlined that the direct antiglobulin test should also be performed with anti-IgA to rule out any false negative.

[Application of the gel test using and anti-IgA antiglobulin for the immunologic diagnosis of autoimmune hemolytic anemia with a negative direct Coombs test]. / Application du gel test utilisant une antiglobuline anti-IgA au diagnostic immunologique d'anémie hémolytique auto-immune à test de Coombs direct négatif.

Autoimmune hemolytic anemias (AIHA) are characterized by hyperhemolysis associated with the presence of the immunoglobulins IgG, IgM or IgA on the red cell membrane. These immunoglobulins react as auto-antibodies against the red cell auto-antigens of the patient. The diagnosis is supported by clinical and biological signs of hemolysis, and by the identification of the auto-antibodies using the direct antiglobulin test (DAT). Here we report 14 cases of patients who showed the clinical and biological profile of AIHA, but who gave a negative DAT. We therefore tried to determine the presence of IgA on the red cell membrane with a method more sensitive than the DAT: the gel test using anti-IgA. With such a gel test, we demonstrated that there were IgA auto-antibodies on the red cell membrane in the 14 cases, therefore confirming the diagnosis of AIHA. We discuss the interest of performing a gel test with anti-IgA in each case where AIHA is suspected, but in which a negative DAT has been observed.

Prevalence of GBV C/HGV RNA and GBV C/HGV antibodies in French volunteer blood donors: results of a collaborative study.

BACKGROUND AND OBJECTIVES: Posttransfusion hepatitis still occurs at an incidence of about 1 in 118,000 for HBV and 1 in 220,000 for HCV. This collaborative study aimed to determine the prevalence of a novel flavivirus, GBV-C/HGV, even though its role in transfusion-associated hepatitis is uncertain. MATERIALS AND METHODS: GBV-C/HGV RNA was detected by PCR using either the Boehringer detection kit or by primers previously described. HGV antibodies were detected by a serological assay from Boehringer. RESULTS: The observed GBV-C/HGV RNA frequency was 3.4%. HGV antibodies occurred in 9.5% of donors. CONCLUSION: In our study, 12. 9% of the donors had been in contact with the GBV-C/HGV virus.