Background: Heavy-chain diseases (HCDs) are human lymphoproliferative neoplasias that are characterized by the secretion of truncated immunoglobulin heavy chains devoid of light chains. We have ...previously proposed — by analogy to the process by which mutated growth factor receptors can be oncogenic — that because the genetic defects in HCDs result in the production of abnormal membrane-associated heavy chains lacking an antigen-binding domain, these abnormal B-cell antigen receptors might engage in ligand-independent signalling. Normal pre-B-cell development requires the presence of the pre-B-cell receptor, formed by the association of μ heavy chains with two polypeptides — so-called surrogate light chains, Vpre-B and λ5 — that are homologous to the variable and constant portions of immunoglobulin light chains, respectively. To assess whether amino-terminal truncation of membrane-associated heavy chains results in their constitutive activation, we have examined the ability of a HCD-associated μ protein to promote pre-B-cell development in transgenic mice.
Results When the μ HCD transgene is introduced into SCID mice, CD43− pre-B cells develop normally. To determine whether this pre-B-cell development requires surrogate light chains, we backcrossed mice expressing full-length or truncated μ transgenes with λ5-deficient mice. Our results show that the truncated heavy chain, but not the normal chain, is able to promote pre-B-cell development in the absence of λ5. We also show that truncated μ chains spontaneously aggregate at the surface of bone marrow cells.
Conclusion Expression of the truncated μ heavy chain overrides a tightly controlled step of pre-B-cell development, which strongly suggests that a constitutive signal is delivered by the truncated μ chain disease protein. The self-aggregation of μ chain disease proteins might account for this constitutive activation. We conclude that amino-terminal truncation of heavy chains could play a role in the genesis of HCD neoplasia if it occurs at an appropriate stage of B-cell differentiation, namely in a mature B cell.
Background: Matching for all alleles of the HLA-A, -B, -C, and -DRB1 loci (8/8 match) is associated with the highest overall survival (OS) rates after unrelated donor (URD) hematopoietic stem cell ...transplantation (HSCT). In Europe, patients (pts) are also matched at the HLA-DQB1 loci (10/10 match) with no overall evidence of improved OS. HLA-DPB1 mismatching has been associated with a higher risk of acute graft-versus-host disease (aGvHD) and a decreased risk of relapse. A detrimental role of additional HLA-DQB1, HLA-DPB1 and HLA-DRB3/4/5 mismatches (MM) has been recently identified on OS but only in 7/8 HLA-A, -B, -C, and -DRB1 loci URDs HSCT. We investigated the impact of HLA-DPB1 and HLA-DRB3/4/5 MM on outcomes in a large cohort of 10/10 matched URD HSCTs.
Patients and methods: 2,393 pts who received an initial HSCT from a 10/10 matched URD in 35 French centers were included between January 2000 and October 2012. Informed consent was obtained in accordance with the Declaration of Helsinki. High-resolution typing was performed for HLA-A, -B, -C, -DRB1, -DQB1, -DPB1 and -DRB3/4/5 loci for all donor/recipient pairs. Clinical data were obtained through ProMISe (Project Manager Internet Server), an internet-based system shared by all French transplantation centers. Impact of HLA-DRB3/4/5 and -DPB1 MM was quantitatively and qualitatively evaluated. For quantitative evaluation, patients were classified into 5 different groups according to their global matching level for the 7 considered loci (14/14, 13/14, 12/14, 11/14, 10/14). For qualitative evaluation, MM type and directionality (GvH and host versus graft (HvG) directions) were evaluated. HLA-DPB1 MM were classified as permissive or non-permissive (K Fleischhauer, Lancet Oncol. 2012). The primary composite endpoint for the analysis was GvHD-free and relapse-free survival (GRFS). We defined early GRFS as being alive at 3 months after HSCT with no previous grade III-IV aGvHD and no relapse and late GRFS as being alive >3 months with no previous grade III-IV aGvH, no relapse and no moderate or severe chronic GvHD (cGvHD). Late GRFS was evaluated at months 6, 12, 24 and 36 after HSCT. Acute GvHD, cGvHD, relapse and OS were also studied. Models were adjusted for HSCT period, disease risk, age, sex matching, stem cell source, and conditioning regimen.
Results: Table 1showspopulation characteristics and distribution of cumulative MM. The median follow-up was 59 months. Compared to 14/14 pairs, quantitative evaluation showed a significantly lower early GRFS for pts who received a 10-11/14 (Hazard Ratio HR 2.0, 95% CI 1.4 to 2.9, p=0.0003) or a 12/14 URD HSCT (HR 1.4, 95% CI 1.1 to 1.8, p=0.01). This was related to a significantly increased risk of grade III-IV aGVHD associated with 10-11/14 (HR 2.3, 95% CI 1.5 to 3.7, p=0.0004) and 12/14 pairs (HR 1.7, 95% CI 1.2 to 2.4, p=0.003). 10-11/14 pairs were also associated with a higher risk of death at 3 months (HR 2, 95% CI 1.1 to 3.6, p=0.024). Qualitatively, in pts matched for HLA-DRB3/4/5 but MM for HLA-DPB1 (n=1846, 77.1%), 2 HLA-DPB1 MM and non-permissive HLA-DPB1 MM were associated with a lower early GRFS (HR 1.4, 95% CI 1.1 to 1.9, p=0.01 and HR 1.3, 95% CI 1.0 to 1.7, p=0.02 respectively) due to an increased risk of aGvHD (HR 1.7, 95% CI 1.2 to 2.5, p=0.002 and HR 1.50, 95% CI 1.08 to 2.08, p= 0.017 respectively). Outcomes were not influenced by either GvHD or HvG mismatch directions. Late GRFS analyses once adjusted were not significantly different according to MM numbers, type and directions. Only 19 pairs (0.8%) were DPB1 matched and DRB3/4/5 mismatched (high linkage disequilibrium between DRB3/4/5 and DRB1); HLA-DRB3/4/5 MM could thus not be qualitatively analyzed.
Conclusion: MultipleHLA-DPB1 and HLA-DRB3/4/5 MM have an early impact after 10/10 matched URDs HSCT. The best outcomes are seen in 13 and 14/14 pairs. Early GRFS is significantly impacted by 10-11/14, 12/14, 2 DPB1 MM as well as non-permissive HLA-DPB1 MM URD HSCT which is related to an increased risk of grade III-IV aGvHD. There is a significantly increased risk of mortality for 10-11/14 pairs at 3 months. Prospective evaluation of matching for HLA-DPB1 and HLA-DRB3/4/5 is warranted to reduce early post-HSCT toxicity in donor-recipient 10/10 matched pairs.
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Michallet:Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Astellas Pharma: Consultancy, Honoraria; MSD: Consultancy, Honoraria; Genzyme: Consultancy, Honoraria. Peffault De Latour:Pfizer: Consultancy, Honoraria, Research Funding; Alexion: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Amgen: Research Funding.
Les angioedèmes (AE) bradykiniques sont soit associés à un déficit héréditaire ou acquis en C1Inhibiteur (C1Inh) soit associés à un C1Inh normal dans certaines formes héréditaires et en cas ...d’iatrogénie (AE secondaire aux inhibiteurs de l’enzyme de conversion de l’angiotensine). Quand il existe une forte suspicion clinique d’angioedème bradykinique, une exploration de C1Inh doit être réalisée. Cette exploration doit toujours comporter un dosage fonctionnel et pondéral de C1Inh ainsi qu’un dosage du C4. Un déficit pathologique en C1Inh peut être affirmé lorsque les taux sont inférieurs à 50 % des valeurs normales sur 2 prélèvements distincts. Si le déficit en C1Inh se confirme, des examens plus approfondis doivent être réalisés afin de déterminer le caractère héréditaire ou acquis du déficit. Le dosage du C1q et la recherche d’un anticorps anti-C1Inh peuvent alors être proposés. La recherche d’une mutation sur le gène SERPING1 s’impose, même en l’absence d’antécédents familiaux. L’absence de déficit en C1Inh n’exclut pas un angioedème héréditaire. Dans ce cas-là, après validation du tableau clinique par un expert du CREAK, la recherche de mutation sur les gènes F12 et PLG sera proposée.
Bradykinin mediated angioedema (BK-AE) can be associated either with C1Inhibitor deficiency (hereditary and acquired forms), either with normal C1Inh (hereditary form and drug induced AE as angiotensin converting enzyme inhibitors…). In case of high clinical suspicion of BK-AE, C1Inh exploration must be done at first: C1Inh function and antigenemy as well as C4 concentration. C1Inh deficiency is significant if the tests are below 50 % of the normal values and controlled a second time. In case of C1Inh deficiency, you have to identify hereditary from acquired forms. C1q and anti-C1Inh antibody tests are useful for acquired BK-AE. SERPING1 gene screening must be done if a hereditary angioedema is suspected, even if there is no family context (de novo mutation 15 %). If a hereditary BK-AE with normal C1Inh is suspected, F12 and PLG gene screening is suitable.
SCID-hu mouse models are of interest in the pathologic investigation of HIV infection, but obtaining a T cell response in SCID-hu-PBL mice is still controversial. We have developed a SCID model by ...engrafting human skin and autologous PBLs from HIV-seronegative individuals. The study describes the ability of this human-mouse chimera to generate in vivo a primary T lymphocyte response against HIV Ag. The injection of human autologous PBLs was performed 4 to 5 wk after the skin engraftment. Two weeks after injection of PBLs, chimeric mice were immunized with recombinant canary pox virus expressing HIV-1 LAIgp160 (vCP-LAIgp160) and supplemented or not with rIL-2. Intradermal vCP-LAIgp160 injection induced an intradermal perivascular human lymphocytic infiltrate and an epidermic network of CD1a+, CD80+, and CD86+ cells. We derived CD4+ T cell lines (STLs) from the human skin graft of immunized mice, showing that STLs mediated an MHC class II-restricted cytolytic activity directed against HIV-LAIgp160 Ags. Cytokine gene expression in both human skin cells and in STLs showed a predominance of IL-2, IFN-gamma, and IL-12 transcripts. Finally, the T cell repertoire analysis using the immunoscope technique showed a very limited CDR3 length polymorphism in the skin infiltrating lymphocytes suggesting an Ag-specific repertoire. The ability to induce a primary Th1 cell response in vivo affords a useful preclinical model for testing vaccine strategies.
The parasite Schistosoma mansoni infects its definitive mammalian host through an obligatory cutaneous penetration. In this work, we studied early immune response following migration of larvae ...through human skin, the first immunocompetent organ encountered by the parasite. For this purpose we used an experimental model of severe combined immunodeficient mice engrafted with human skin and injected with autologous PBL. Six days after percutaneous infection, we observed an infiltration of lymphocytes within the human skin, predominantly composed of CD4+ T cells. Moreover, among the cytokines potentially present in the infected skin, immunohistochemistry analysis revealed an in vivo expression of IL-7 in the epidermal layers and strikingly at the level of vascular endothelium. Using an in vitro coculture system, we showed that the S. mansoni larvae directly trigger IL-7 production by human dermal microvascular endothelial cells but not by keratinocytes. Finally, measurements of IL-7 concentrations in plasma of 187 S. mansoni-infected individuals showed that the youngest, which are also the most infected, displayed the highest IL-7 levels. Together, these findings describe dermal endothelial cells as a novel source of IL-7, a cytokine particularly important in schistosomiasis.
Bradykinin mediated angioedema (BK-AE) can be associated either with C1Inhibitor deficiency (hereditary and acquired forms), either with normal C1Inh (hereditary form and drug induced AE as ...angiotensin converting enzyme inhibitors…). In case of high clinical suspicion of BK-AE, C1Inh exploration must be done at first: C1Inh function and antigenemy as well as C4 concentration. C1Inh deficiency is significant if the tests are below 50 % of the normal values and controlled a second time. In case of C1Inh deficiency, you have to identify hereditary from acquired forms. C1q and anti-C1Inh antibody tests are useful for acquired BK-AE. SERPING1 gene screening must be done if a hereditary angioedema is suspected, even if there is no family context (de novo mutation 15 %). If a hereditary BK-AE with normal C1Inh is suspected, F12 and PLG gene screening is suitable.
Peripheral blood mononuclear cells (PBMC) from healthy donors were injected into C.B.-17 severe combined immunodeficiency (scid) mice which were subsequently immunized with crude Schistosoma mansoni ...adult worm antigenic preparation (SWAP) or with recombinant S. mansoni 28-kDa glutathione transferase (r-Sm-28-GST) antigen. PBMC from a S. mansoni-infected patient were also transferred. The specific human anti-SWAP and anti-Sm-28-GST antibody responses were monitored. The presence in both cases of human specific antibodies in scid mouse sera was determined by enzyme-linked immunosorbent assay and Western blotting techniques using anti-human immunoglobulin reagents. No antibodies were detected in these sera using anti-mouse immunoglobulin antisera. These antibodies were functional since a cytotoxic activity against schistosomula was observed when monocytes were incubated with scid mouse sera positive for anti-Sm-28-GST antibodies.
A new model for systemic and multifocal HIV-1 infection was developed in severe combined immunodeficient (SCID) mice to study the alterations of thymocytes and of the thymic microenvironment that ...occur during a disseminated HIV infection.
We grafted SCID mice with the classical human fetal thymus/liver co-implants together with fragments of autologous lungs (SCID-huLLT). These organs achieved normal differentiation and were productively infected after an intraperitoneal inoculation of two HIV-1 primary isolates. At time of sacrifice, thymic biopsies and thymic cell suspensions were analysed by immunohistochemistry, flow cytometry and lymphocyte function assays.
At weeks 2-4 post-inoculation we observed the following thymocyte abnormalities: a minor to severe depletion of the immature CD1+CD4+CD8+ T cells (range, 0-73% thymocytes), compared with the persistence of mature CD4+ cells (11-50%) and amplification of CD8+ T cells (6-92%). The immature subset depletion was inversely related to the thymic HIV-1 viral load, suggesting the preferential infection of this subset. The residual mature thymocytes were functional as assessed by their sustained proliferative responses to CD3-triggering which contrasted with the lack of HIV-specific cytotoxic activity. A quantitative analysis of immunostained thymic sections revealed a disorganization and a densification of the thymic epithelial cells (TEC) network which occurred in all HIV-infected SCID-hu mice independently of the thymic CD1+CD4+CD8+ T-cell depletion.
These results suggest that a systemic HIV infection induces in human thymuses from SCID-huLLT mice a preferential depletion of the immature thymocytes in the absence of mature CD4+ T-cell depletion, HIV-specific cytotoxic T-lymphocyte activity or thymic epithelial cell death, but is associated with dysplasia of the thymic microenvironment, and is therefore opening new perspectives for studying immune cell reconstitution strategies in HIV infection.
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