Massive clonal expansion of polycytotoxic skin and blood CD8+ T cells in patients with toxic epidermal necrolysis

Toxic epidermal necrolysis (TEN) is a life-threatening cutaneous adverse drug reaction. To better understand why skin symptoms are so severe, we conducted a prospective immunophenotyping study on skin and blood. Mass cytometry results confirmed that effector memory polycytotoxic CD8⁺ T cells (CTLs) are the main leucocytes in TEN blisters at the acute phase. Deep T cell receptor (TCR) repertoire sequencing identified massive expansion of unique CDR3 clonotypes in blister cells. The same clones were highly expanded in patient's blood, and the degree of their expansion showed significant correlation with disease severity. By transducing α and β chains of the expanded clonotypes into a TCR-defective cell line, we confirmed that those cells were drug specific. Collectively, these results suggest that the relative clonal expansion and phenotype of skin-recruited CTLs condition the clinical presentation of cutaneous adverse drug reactions.

[Relevance of antibodies in hematopoietic stem cell transplantation: Antibodies anti-HLA, anti-platelets, anti-granulocytes, anti-erythrocytes and anti-MICA. Guidelines from the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]

The presence of allo-antibodies in the serum of a recipient awaiting hematopoietic stem cell transplantation (HSCT) may have an impact on transfusion efficiency and/or donor choice, especially in the absence of an identical sibling donor. Prior to transplantation, donor specific anti-HLA (Human Leukocyte Antigen) antibodies (DSA) have a recognized effect on transplant outcome, correlated with the increasing MFI value and with the ability of such antibody to fix the complement fraction. Anti-platelet antibodies (anti-HLA class I and anti-HPA [Human Platelet Antigen]) are better involved in transfusion inefficiency and can be responsible for refractory status. ABO incompatibilities require a specific treatment of the graft in presence of high titer to avoid hemolytic adverse effects. Investigations of these antibodies should be carried out on a regular basis in order to establish appropriate transfusion recommendation, select an alternative donor when possible or adapt the source of cells. After transplantation, in case of delayed recovery or graft rejection, long term aplasia, persistent mixed chimerism or late release, and after elimination of the main clinical causes, a biological assessment targeted on the different type of antibodies will have to be performed in order to orient towards the cause or the appropriate therapy. Further studies should be carried out to determine the impact of anti-MICA antibodies and recipient specific anti-HLA antibodies, on the outcome of the transplantation.

[Haploidentical hematopoietic stem cell transplant: How to choose the best donor? Guidelines from the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]

Haploidentical hematopoietic stem cell transplantation has been growing steadily since 2012. The SFGM-TC has twice published guidelines concerning T-cell repleted haploidentical grafts with high dose cyclophosphamide post-transplantation. The 2013 workshop recommended using the non-myeloablative Baltimore protocol with bone marrow and developed prospective protocols to evaluate these transplantations. The 2015 workshop reported improved results of reduced conditioning regimens in Hodgkin's lymphoma and intensive conditioning in myeloid hemopathies, and a similar outcome with 10/10 HLA matched donor with the same disease-risk score thus raising the question of the qualifier "alternative" for haploidentical transplants. The current work concerns the criteria for selecting the donor. The main criterion remains the absence of anti-HLA antibodies directed against the donor present in the recipient sera (DSA - Donor Specific Antibodies). In case of DSA and in the absence of an alternative donor, desensitization protocols exist. The other criteria are impossible to prioritize: age, sex, CMV, and blood type. The degree of relatedness and the number of HLA incompatibilities do not seem to be a criterion of choice. The 'ideal' donor would be a young man, CMV-matched, without major ABO incompatibility with a marrow transplant. There is insufficient data for the KIR-ligand and NIMA/NIPA mismatch. Peripheral stem cell grafts appear to yield more acute GVHD than bone marrow grafts after intensive conditioning, but with comparable survival rates. Based on the literature review, the comparison of haploidentical with unrelated donors encourages inclusion in existing national protocols randomizing these different donors.

Placental histological lesions in fetal and neonatal alloimmune thrombocytopenia: A retrospective cohort study of 21 cases

BACKGROUND

Alloimmunization against human platelet antigens (HPAs) can occur prenatally and induce fetal/neonatal alloimmune thrombocytopenia (FNAIT). The aim of this study was to identify placental histological features associated with platelet alloimmunization and their clinical significance.

METHODS

This study examined 21 placentas from FNAIT-affected pregnancies and 42 age-matched control cases, all collected from pathology departments in the Rhône-Alpes region. Clinical and laboratory findings were collected for each FNAIT case. Two pathologists reviewed the placental slides of each FNAIT and control case. Histological features, with special emphasis on chronic inflammatory lesions, were evaluated. Differences between the two groups were calculated with odds ratios (ORs) and assessed with Wald's chi-square.

RESULTS

FNAIT was associated with a significantly higher frequency of chronic chorioamnionitis (CC) (OR 14, 95%CI 1.7-113.8), basal chronic villitis (BCV) (OR 17, 95%CI 2-145.6) and chronic intervillositis (CIV). Chronic villitis (CV) (OR 3.7, 95%CI 0.9-15.2) and chronic deciduitis (CD) (OR 4.7, 95%CI 0.79-28.2) were also more frequent in the FNAIT than the control group, but these differences were not statistically significant.

CONCLUSIONS

FNAIT is significantly associated with CC, BCV, and CIV. This chronic inflammatory reaction is preferentially localized on the maternofetal interface. Anti-HPA alloimmunization may trigger an immunological conflict similar to graft-versus-host disease.

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.

Systematic donor blood qualification by flow cytometry would have been able to avoid CLL-type MBL transmission after unrelated hematopoietic stem cell transplantation

The current screening for eligibility of unrelated volunteer marrow donors comprises a complete clinical check-up, a blood CBC and serum protein immunoelectrophoresis. This allows to eliminate acute leukemias, myeloproliferative and myelodysplastic disorders, myelomas and MGUS. To date, the risk of transmission of chronic lymphocytic leukemia (CLL) disease is only evaluated by the clinical evaluation and CBC. We report here the case of a CLL-type MBL disease occurring in a 12-year-old boy after unrelated BMT. Deep biological investigations, as Immunophenotyping, cytogenetic and molecular biology allow us to determine the donor origin of the CLL clone. In 2010, 14.2% donor (105/737) for unrelated hematopoietic stem cell transplantation were over 45y. It is currently estimated (USA) that 1 in 210 men and women will be diagnosed with CLL during their lifetime. Given the long asymptomatic phase of CLL, this raises the case for a detection strategy analog to that used for MGUS and myeloma through serum protein electrophoresis. This case-report, to our knowledge, of a CLL-type MBL unrelated donor-to-recipient transmission through BMT raises ethical and practical questions, such as the proper information about disease transmission risk. The cost-effectiveness of a systematic peripheral blood Immunophenotyping in donors elder than 40y at time of stem cell donation should be evaluated.

[The immunological conflict in the transfusion-related acute lung injury or 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]

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.

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.

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.

[Application of the gel test using and anti-IgA antiglobulin for the immunologic diagnosis of autoimmune hemolytic anemia with a negative direct Coombs test]

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.