scholarly journals B Cell Reconstitution after Gene Therapy in Patients with Wiskott Aldrich Syndrome and Comparison with Mismatched Allogeneic Hematopoietic Stem Cell Transplantation

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3235-3235
Author(s):  
Alessandra Magnani ◽  
Cécile Roudaut ◽  
Aurelie Gabrion ◽  
Laure Caccavelli ◽  
Fabien Touzot ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Count ◽  
Lentiviral Vector ◽  
Cell Phenotype ◽  
Hematopoietic Stem ◽  
Allogeneic Hsct ◽  
Normal Ranges ◽  
Ivig Replacement

Abstract Background. Wiskott Aldrich Syndrome (WAS) is a rare primary immunodeficiency associated with thrombocytopenia, eczema, severe infectious and autoimmune complications, and lymphomas. Mismatched allogeneic hematopoietic stem cell transplantation (HSCT) is an alternative for patient lacking an HLA-matched donor but is associated with an increased frequency of complications. Moreover low lymphoid and myeloid chimerism is related to a higher rate of autoimmunity and thrombocytopenia. Recent gene therapy (GT) trials showed that gene-corrected autologous CD34+ cells infusion could be an appropriate therapeutic approach for these patients. It has been recently shown that B cell homeostasis is altered in WAS. As the B cell reconstitution participates to the restoration of immunological competence, a comprehensive study of this compartment after GT and the comparison with mismatched allogeneic HSCT is crucial. Objective. To perform a longitudinal study of B cell reconstitution in WAS patients after lentiviral vector-mediated GT, compared to mismatched allogeneic HSCT. Methods. Five patients (age 0.8-15.5 years) underwent GT at our center since 2011(follow-up 1.5-4.2 years) after near-myeloablative and immunosuppressive conditioning regimen with (n=3) or without (n=2) anti-CD20 administration. Patient 2 (P2) died 7 months after GT from a pre-existing infectious complication. Eleven patients undergoing mismatched allogeneic HSCT (age 0.6-10.9 years) at the same center were studied (follow-up 5.1-14.7 years). Longitudinal B cell assessment included B cell count before and after treatment, and the following subsets: switched memory (SM, CD19+ CD27+ IgD-), marginal zone (MZ, CD19+ CD27+ IgD+), naives (CD19+ CD27- IgD+), transitional (CD19+ CD27- IgD+ CD24high CD38high), circulating plasma cells (CD19+ CD27+ IgD- CD27high CD38high) and CD21low B cells (CD19+ CD21low CD38-), a subset abnormally expanded in WAS. Quantification of the B cell replication history was assessed through k-deleting recombination excision circles (KRECs). Analyses were compared to age-matched controls. WAS protein (WASP) expression and vector copy number (VCN) were measured in sorted B cells. Results. All alive GT patients show stable engraftment of functionally corrected lymphoid cells, without adverse events. Transduced B cells number and WASP expression increased progressively after GT. Absolute B cell count attained normal values in all the patients, and correlates with WASP expression and VCN in B cells. IgM levels are below normal ranges in four patients. P3 and P4 attained a B-cell phenotype within normal ranges; P3 discontinued intravenous immunoglobulin (IvIg) replacement. No expansion of CD21low B cells was observed. P1 and P5 (follow-up 18 months) present a variable defect in SM, naives and/or MZ B cells. P1 recently developed autoimmune manifestations; no significant changes were observed concomitantly. A defect in B cell lymphopoiesis was observed before GT as measured by KRECs analysis, normalizing after GT (P1, P3 and P4). Several complications were recorded in patients undergoing mismatched allogeneic HSCT, including dysimmunity, arthritis, developmental deficit and infections. Total B cell count normalized in eight patients, IgM levels were low in three. Among patients with available information, four still remain under IvIg replacement. Four patients developed a mixed lymphoid and myeloid chimerism, variably associated with low B cell count, low IgM and IvIg replacement. A complete B cell assessment for these patients is ongoing. Conclusions. B cell transgene expression is obtained after lentiviral vector-mediated GT in WAS patients and is associated with improved B cell lymphopoiesis. A correct B cell phenotype is observed in two patients who did not receive rituximab prior GT. The question whether this is related to the treatment will need a longer follow-up to be answered. Patients undergoing mismatched allogeneic HSCT present a higher frequency of complications. Although a higher proportion of these patients discontinued IvIg replacement, B cell reconstitution is not optimal. Analysis of patients in particular with mixed chimerism will provide important information in the setting of GT. The analysis of B cell reconstitution after GT and mismatched allogeneic HSCT deserves particular attention in the assessment of immunological reconstitution. Disclosures No relevant conflicts of interest to declare.

Allogeneic Hematopoietic Stem Cell Transplantation For Severe Neuromyelitis Optica

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 5539-5539 ◽  
Author(s):  
Raffaella Greco ◽  
Attilio Bondanza ◽  
Luca Vago ◽  
Lucia Moiola ◽  
Paolo Rossi ◽  
...  
Keyword(s):  
Stem Cell ◽  
Hematopoietic Stem Cell Transplantation ◽  
Stem Cell Transplantation ◽  
B Cell ◽  
High Dose ◽  
B Cell Depletion ◽  
Immune Repertoire ◽  
Hematopoietic Stem ◽  
Allogeneic Hsct

Abstract Background Neuromyelitis Optica (NMO), also known as Devic’s disease, is a rare inflammatory and demyelinating disorder of the central nervous system characterized by recurrent attacks of optic neuritis (ON) and longitudinally extensive trasverse myelitis (LETM). Previously considered as a severe variant of multiple sclerosis, NMO has been recently recognized as a distinct disorder associated with peculiar pathogenic auto-antibodies to aquaporin-4 (AQP4). Despite transient control of disease activity, standard treatments are often followed by relapses with accumulating disability and ultimately a poor prognosis. Thus, new therapeutic strategies for NMO are warranted. Hematopoietic Stem Cell Transplantation (HSCT) can induce stable remissions in patients with severe treatment-refractory Autoimmune Diseases. Here we report our investigational experience on allogeneic HSCT in two patients with severe and refractory forms of the disease. Methods Both treated patients had aggressive forms of NMO and serum positivity for AQP4 antibodies. Upn#1 is a 30 yrs old male affected by severe relapsing LETM, with paraparesis and thoracic spinal cord lesion on magnetic resonance imaging (MRI). Upn#2 is a 28 yrs female with recurrent attacks of ON and LETM. Both had received several lines of treatment without benefit, including high-dose corticosteroids, cyclophosphamide, rituximab, natalizumab, alemtuzumab, plasma exchange, high-dose thiotepa/cyclophosphamide and/or BEAM with Anti-Thymocyte Globulin (ATG) and cyclosporine followed by autologous HSCT rescue. Before HSCT the two patients showed an Kurtzke Expanded Disability Status Score (EDSS) of 6 (assistance required to walk) and 8.5 (restricted to bed, paraplegia) respectively, while both of them presented active contrast enhancing lesions on MRI and positivity for the pathogenic AQP4 auto-antibodies. Upn#1 underwent allogeneic HSCT from his HLA-identical sibling, while Upn#2 from a matched unrelated donor. Conditioning regimen consisted of full-dose treosulfan and fludarabine. Graft versus host disease (GvHD) prophylaxis combined ATG-Fresenius with cyclosporine and a short course of methotrexate (Upn#1) or mycophenolate and rapamycin (Upn#2); B cell depletion of both patients and graft was obtained by rituximab. Results Hematopoietic recovery occurred in both patients within day 30, and was accompanied by rapid achievement of full donor chimerism. Each patient experienced an episode of febrile neutropenia and one of them a CMV reactivation, both responsive to medical therapy; no serious adverse events were reported. None of the patients experienced neither acute nor chronic GvHD. MRI demonstrated the disappearance of the inflammatory lesions, without evidence of new ones. The immunological data obtained from the follow-up of these two patients suggest that allogeneic HSCT can alter the course of NMO through several concurring mechanisms: the eradication of autoreactive cell clones by high-dose chemotherapy and by the in vivo T and B cell depletion used for conditioning, the disappearance of the pathogenetic anti-AQP4 antibodies and achievement of a stable full-donor hematopoietic chimerism by donor T cell-mediated alloreactivity; the re-establishment of thymic central tolerance and renewal of the immune repertoire. Strikingly, these results correlated with a marked improvement of neurological functions in both treated patients. In UPN#1 EDSS dropped from 6 to 3.5 (fully ambulatory but with moderate disability in one functional neurological system), while in UPN#2 EDSS decreased from 8.5 to 7.5 (unable to take more than a few steps, restricted to wheelchair). At last follow-up (48 and 36 months after HSCT, respectively), both patients are alive, well and relapse-free. Conclusions These findings suggest that allogeneic HSCT may be beneficial in patients who have aggressive forms of NMO, by renewing the immune repertoire of T- and B-cells, thus reducing disease activity and arresting disability progression. The preliminary evidence of long-term disease control in these two refractory patients paves the way for further prospective phase I-II clinical trials to validate allogeneic HSCT as promising novel option for aggressive forms of NMO. Disclosures: Bonini: MolMed S.p.A: Consultancy.

scholarly journals Memory B-cell reconstitution following allogeneic hematopoietic stem cell transplantation is an EBV-associated transformation event

Blood ◽  
2015 ◽  
Vol 126 (25) ◽  
pp. 2665-2675 ◽  
Author(s):  
David M. Burns ◽  
Rose Tierney ◽  
Claire Shannon-Lowe ◽  
Jo Croudace ◽  
Charlotte Inman ◽  
...  
Keyword(s):  
Stem Cell ◽  
B Cells ◽  
Hematopoietic Stem Cell Transplantation ◽  
Stem Cell Transplantation ◽  
B Cell ◽  
Memory B Cells ◽  
Hematopoietic Stem ◽  
Allogeneic Hsct ◽  
Key Points ◽  
High Level

Key PointsCD19+CD27+ memory B cells are detectable at supranormal frequencies in patients with high-level EBV DNAemia following allogeneic HSCT. These memory B cells are frequently positive for EBV genomes and bear many of the hallmarks of lymphoblastoid transformation.

EBV-Associated Post-Transplant Lymphoproliferative Disorder after Pediatric Allogeneic Hematopoietic Stem Cell Transplantation.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4980-4980
Author(s):  
Keon Hee Yoo ◽  
Hee-Jin Kim ◽  
Chang Seok Ki ◽  
Ki Woong Sung ◽  
Hye Lim Jung ◽  
...  
Keyword(s):  
B Cells ◽  
Lymphoproliferative Disorder ◽  
B Cell Lymphoma ◽  
Complete Response ◽  
Cytotoxic T Cell ◽  
Solid Organ ◽  
Hematopoietic Stem ◽  
Allogeneic Hsct ◽  
Post Transplant

Abstract Post-transplant lymphoproliferative disorder (PTLD) is a well-recognized complication arising in recipients of solid organ or hematopoietic stem cells. In most instances, it is caused by abnormal proliferation of EBV-infected B-cells under impaired cytotoxic T-cell control against B-cells. Although pediatric recipients have been known to be more prone to the development of PTLD, no data have been published on PTLD developed in Korean children who received allogeneic HSCT. We reviewed medical records of 255 pediatric allogeneic HSCT performed from March 1998 to January 2007 at Samsung Medical Center. Ten consecutive cases developed EBV-associated PTLD at a median of 94 days (range, 17–242 days) from transplantation. Fever (10/10), hepatosplenomegaly (10/10), lymphadenopathy (7/10), nausea/vomiting (7/10), malaise/lethargy (7/10), diarrhea (7/10), neurological abnormalities (6/10) and weight loss (5/10) were the most common presenting symptoms or signs of PTLD. All patients with PTLD were EBV-seropositive before transplant. EBV genome was detected in tumor cells by in situ hybridization in all cases and 3 cases were monomorphic diffuse large B-cell lymphoma by histology. Nested PCR for immunoglobulin heavy change gene rearrangement and/or kappa and lamda immunostains were done in all cases to determine the clonality of PTLD lesions, which revealed 7 cases of monoclonality, 2 cases of oligoclonality and only 1 case of polyclonality. In all of the 6 patients whose bloods were tested for quantification of EBV genome, 136 to 465800 copies of EBV DNA were detected per 106 PB lymphocytes. The estimated cumulative incidence of PTLD in all subjects was 4.5%. No PTLD occurred following 77 matched-related transplants. The incidence of PTLD was higher after unrelated cord blood transplantation (UCBT, n=61) than that after matched-unrelated marrow transplantation (MUD-BMT, n=86) without statistical significance (10.5% vs 4.9%, P=0.36). The use of ATG in conditioning regimen was a significant risk factor for the development of PTLD (9.1% vs 0.8%, Hazard ratio 11.34, P=0.0036). Eight patients received 2 to 6 weekly doses of rituximab and 5 of those (62.5%) attained complete response. One of the 5 patients who showed complete response died of pneumonia and ARDS. One patient with polymorphic polyclonal disease underwent complete resolution of PTLD with only just withdrawal of immune suppression. There were 5 deaths, 4 of which were due to PTLD progression with or without accompanied GVHD. The estimated 3-year survival from the diagnosis of PTLD was 50% with a median follow-up of 40 months (range, 8–47 mo) among surviving patients. The incidence of PTLD was relatively high in our subjects. Considering that autopsy rate is very low in Korea, the exact incidence of PTLD might be even higher. High index of suspicion and regular follow-up using EBV quantitative PCR, especially for high-risk patients, may be beneficial not to miss the potentially curable disease and to initiate early therapeutic interventions.

Paralog 4 HOX Genes HOXA4 and HOXB4 Expand Pro-B Cells in Vitro

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1299-1299 ◽  
Author(s):  
Marilaine Fournier ◽  
Charles-Etienne Lebert-Ghali ◽  
Mona Hassawi ◽  
Janetta Jacoba Bijl
Keyword(s):  
B Cells ◽  
B Cell ◽  
Hox Genes ◽  
Cell Phenotype ◽  
Cell Compartment ◽  
Hematopoietic Stem ◽  
Potential Implication ◽  
Strong Expansion

Abstract Abstract 1299 HOX genes are known for their involvement in self-renewal of normal and malignant hematopoietic stem cells (HSC). Enforced expression of HOXB4 leads to HSC expansion in vitro and in vivo without leukemia development. We have recently shown that overexpression of its paralog HOXA4 also resulted in an increase of HSCs and myeloid progenitors in vitro. HOXA4 HSC are fully functional and reconstitute mouse chimeras with normal ratios of mature cells in the periphery. Interestingly, although the mature B-cell compartment is not enhanced, the overexpression of HOXA4 resulted in a 10-fold expansion of B-cell progenitors in the bone marrow (BM). Moreover, the number of more primitive WW-IC was not affected by the overexpression of HOXA4, indicating that this gene specifically expands IL-7 responsive B-cell progenitors. Based on these observations in vivo, we sought to determine if paralog 4 HOX genes can expand B-cell progenitors in vitro. To test this B220+ cells were sorted from BM of healthy wild type mice and transduced with MSCV retroviral vectors for HOXA4-GFP, HOXB4-GFP or control-GFP. Cells were cultured in B-cell specific medium and their growth in response to IL-7 was followed for three weeks. We observed a 15- and 10-fold increase of growth for HOXA4 and HOXB4 pro-B cells compared to control, respectively, within 16 days. FACS analysis confirmed the pro-B cell phenotype of all three cultures. These cells are currently being tested for their repopulation capacity of the B-cell compartment in irradiated hosts. To further investigate potential implication of these genes in oncogenic transformation HOXA4 and HOXB4 were overexpressed in E2APBX1 B-cells derived from E2APBX1 transgenic mice. We showed that the overexpression of HOXA4 or HOXB4 induced a strong expansion of E2APBX1 pro-B cell in vitro (2381- and 1090-fold difference over the control after 23 days, respectively), leading to an immortalization of the culture. Despite this huge expansion these cells were incapable to initiate leukemia upon transfer into irradiated recipients. B-CFC assays showed that the growth of HOXA4 or HOXB4 E2APBX1 pro-B cell cultures was supported by a strong expansion of B-cell progenitors (6138- and 15307-fold difference over the control after 20 days, respectively). Taken together, these results indicate that IL-7 responsive pro-B-cell progenitors are sensitive to paralog 4 HOX genes, an effect which is dramatically enhanced in the context of E2APBX1. Lack of clear oncogenic potential puts HOXA4 and –B4 forward as promising candidates to expand B-cell progenitors in vitro. These cells could potentially be used for B-cell complementation therapy in BM transplantation recipients. Disclosures: No relevant conflicts of interest to declare.

B Lymphocytes Emerge De Novo Independently in the YS and PSP Before E10, but Lack B-2 Potential.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1501-1501
Author(s):  
Momoko Yoshimoto ◽  
Encarnacion Montecino-Rodriguez ◽  
Prashanth Porayette ◽  
Kenneth Dorshkind ◽  
Mervin C. Yoder
Keyword(s):  
B Cells ◽  
B Cell ◽  
De Novo ◽  
Conflicts Of Interest ◽  
Heart Function ◽  
Fetal Liver ◽  
Cell Phenotype ◽  
Hematopoietic Stem ◽  
Marginal Zone B Cells ◽  
Lymphoid Progenitors

Abstract Abstract 1501 Poster Board I-524 In the developing mouse embryo, hematopoietic stem cells that can reconstitute all hematopoietic lineages in irradiated adult murine recipients emerge at E10.5 in the AGM region. However, lymphoid potential has been reported in the YS and PSP region prior E10.5. Since the embryonic heartbeat starts at E8.25, the presence of circulation makes it difficult to identify the site of origin of lymphoid progenitors. Indeed, YS lymphoid progenitors have been thought to be derived from the PSP and seeded via circulation. The Ncx1 gene encodes a sodium-calcium channel and is essential for heart function. Ncx1 null embryos lack circulation due to failure to initiate a heartbeat and survive until day 11 of gestation as previously reported. Therefore, Ncx1 null embryos represent a unique model to determine the origin of lymphoid progenitors in a circulation free environment. B-1 cells are innate effectors that spontaneously secrete 'natural' antibodies independent of T cell help. These B-1 cells comprise a high proportion of the B cells in the pleural and peritoneal cavities and can be identified by their sIgMhi sIgDlo CD11b+ CD5+/− phenotype. It has been known that mid-gestation fetal liver (FL) can efficiently reconstitute B-1 cells in murine recipients, and recent studies have localized this potential to a lineage negative (Lin−) CD45Rlo-neg CD19+ AA4.1+ B-1 cell specified progenitor present in that tissue. Thus, B-1 progenitors are enriched in FL, but whether these progenitors emerge elsewhere is not fully known. The earliest B-1 cell origin has been reported in the early PSP region, and not in the YS by transplantation assay. Here we demonstrated de novo B cell emergence in the E9.0-9.5 YS as well as the PSP in the NCX1 mouse model using in vitro OP9 stromal cell co-culture. These B cells were derived from VE-cadherin+ hemogenic endothelial cells and were confirmed to show Ig rearrangement and anti-phosphorylcholine IgM secretion upon challenge. Cells directly isolated from Ncx1 null embryos did not engraft in the peritoneal cavities of recipient NOD/SCID/IL2gcnull neonate, whereas WT YS and PSP cells became B-1 cells in vivo. However, cultured B cells derived from Ncx1 null YS (>5×106 B cell produced/1YS, n=7 out of 42 null YS tested) and PSP (>5×106 B cell produced/1PSP, n=13 out of 39 null PSP tested) were transplantable and displayed a prominent B-1 phenotype in the host peritoneal cavity (85.2±5.8% compared to 48.8% control non-transplanted C57BL/6 B-1 cells), became marginal zone B cells (39.6%±18.3 of donor IgM+ cells compared to 3.6% control MZ B cells) and displayed a B-1 cell phenotype (10.4±4.6% of donor IgM+ cells compared to 4±2.3% control B-1 cells) in the spleen of transplanted mice, and failed to display a B-2 phenotype (4.6±5.2% of donor IgM+ cells compared to 31.9±4.1% control follicular B cells). Thus, we have redefined de novo B cell potential in the YS and PSP and reported that this B cells potential generates transplantable B-1 cells that may play a role in innate immunity after birth. Disclosures: No relevant conflicts of interest to declare.

scholarly journals FRI0111 TOCILIZUMAB MAY INDUCE SECONDARY HYPOGAMMAGLOBULINAEMIA. A RETROSPECTIVE CASE SERIES OF 42 PATIENTS

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 636.2-636
Author(s):  
F. Vílchez-Oya ◽  
A. Pros ◽  
I. Carrión Barberà ◽  
J. A. Meraz Ostiz ◽  
T. C. Salman Monte ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
B Cells ◽  
B Cell ◽  
Interleukin 6 ◽  
Human Monoclonal Antibody ◽  
Case Series ◽  
Infection Risk ◽  
Immunoglobulin Levels ◽  
Igg Level

Background:Tocilizumab (TCZ) is a recombinant humanized, anti-human monoclonal antibody of the immunoglobulin G1ksubclass directed against soluble and membrane-bound interleukin 6 receptors (IL-6R) [1].Interleukin-6 (IL-6) has a pleiotropic effect on inflammation, immune response, and hematopoiesis. When it was first identified, it was named as B-cell-stimulating factor 2 (BSF-2) according to its ability to induce immunoglobulin production in Epstein-Barr virus-transformed B-cell lines or in Staphylococcus aureus Cowan 1-stimulated B cells [2-4].Nowadays, it is known that IL-6 controls the survival, population expansion and maturation of B cells and plasmablasts. In that way, the regulation of Blimp-1 by STAT3 is linked to antibody secretion and is associated with long-lived plasma cells that produce large amounts of immunoglobulin. Furthermore, the ability of IL-6 to promote humoral immunity has been linked to its effects on follicular helper T cells where they promote B cell proliferation and immunoglobulin class switching [5].Objectives:Hypogammaglobulinaemia is a known complication of some immunosuppressive drugs, not previously described in patients who received therapy with monoclonal antibody against the IL-6R. We aimed to analyzed the prevalence of hypogammaglobulinaemia in our series of patients treated with tocilizumab after a carefully diagnostic workup which ruled out other causes and analyzed whether is associated with a higher risk of infection.Methods:We conducted a retrospective review from 2010 to 2019 of forty-two patients affected with a rheumatic disease and treated with TCZ at our centre. In those patients in whom we had no record of immunoglobulin levels, we determined them in the blood analysis performed by usual clinical practice.Results:42 patients were identified, from whom 38 had rheumatoid arthritis. A 31% had immunoglobulin levels prior to starting treatment with TCZ but no one had hypogammaglobulinaemia. 2 patients were excluded due to their underlying disease could justify the IgG level abnormalities. During the treatment’s follow-up, we identified that a 30% of the patients (12/40) had hypogammaglobulinaemia. Of those patients in whom immunoglobulin levels had been determined prior to starting treatment with TCZ, a 36.3% of them (4/11) developed hypogammaglobulinaemia during the follow-up. From the series, we observed a statistical significance tendency (p=0.0057) for infection risk in those patients with hypogammaglobulinaemia in contrast to those with normal IgG level (41.5% vs 14.3%, respectively).Conclusion:Secondary hypogammaglobulinaemia may occurs in patients receiving anti-IL6 agents such as tocilizumab and this could be associated with an increasing infection risk. The prevalence is not precisely known, in part because measurement of IgG prior to or during the treatment has not been a standard of care. No medical data have been previously disclosed about this possible adverse effect of anti-interleukin-6 agents. Nevertheless, ideally randomized trials are needed to assess this initial hypothesis.References:[1]Sheppard M, Laskou F, Stapleton PP, Hadavi S, Dasgupta B. Tocilizumab (Actemra). Hum Vaccin Immunother. 2017;13(9):1972–1988.[2]Tanaka T, Kishimoto T. The biology and medical implications of interleukin-6. Cancer Immunol Res. 2014;2(4):288–294.[3]Tanaka T, Narazaki M, Kishimoto T. IL-6 in inflammation, immunity, and disease. Cold Spring Harb Perspect Biol. 2014;6(10):a016295. Published 2014 Sep 4.[4]Kishimoto T. Interleukin-6: discovery of a pleiotropic cytokine. Arthritis Res Ther. 2006;8 Suppl 2(Suppl 2):S2.[5]Hunter CA, Jones SA. IL-6 as a keystone cytokine in health and disease [published correction appears in Nat Immunol. 2017 Oct 18;18(11):1271]. Nat Immunol. 2015;16(5):448–457.Disclosure of Interests:Francisco Vílchez-Oya: None declared, Ana Pros: None declared, Irene Carrión Barberà Grant/research support from: I received a grant from the Spanish Rheumatology Foundation (FER) and laboratories KERN PHARMA for a brief stay abroad., Juan Antonio Meraz Ostiz: None declared, Tarek Carlos Salman Monte: None declared, Carolina Perez-Garcia: None declared

scholarly journals CD19 Cell Count at Baseline Predicts B Cell Repopulation at 6 and 12 Months in Multiple Sclerosis Patients Treated with Ocrelizumab

2021 ◽  
Vol 18 (15) ◽  
pp. 8163
Author(s):  
Gianmarco Abbadessa ◽  
Giuseppina Miele ◽  
Paola Cavalla ◽  
Paola Valentino ◽  
Girolama Alessandra Marfia ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Count ◽  
Considerable Proportion ◽  
Cell Counts ◽  
Time Scheduling ◽  
Magnetic Resonance Imaging Mri ◽  
Multiple Sclerosis Patients ◽  
Kinetics Of ◽  
Cell Repopulation

Background: The kinetics of B cell repopulation in MS patients treated with Ocrelizumab is highly variable, suggesting that a fixed dosage and time scheduling might be not optimal. We aimed to investigate whether B cell repopulation kinetics influences clinical and radiological outcomes and whether circulating immune asset at baseline affects B cell repopulation kinetics. Methods: 218 MS patients treated with Ocrelizumab were included. Every six months we collected data on clinical and magnetic resonance imaging (MRI) activity and lymphocyte subsets at baseline. According to B cell counts at six and twelve months, we identified two groups of patients, those with fast repopulation rate (FR) and those with slow repopulation rate (SR). Results: A significant reduction in clinical and radiological activity was found. One hundred fifty-five patients had complete data and received at least three treatment cycles (twelve-month follow-up). After six months, the FR patients were 41/155 (26.45%) and 10/41 (29.27%) remained non-depleted after twelve months. FR patients showed a significantly higher percentage of active MRI scan at twelve months (17.39% vs. 2.53%; p = 0,008). Furthermore, FR patients had a higher baseline B cell count compared to patients with an SR (p = 0.02 and p = 0.002, at the six- and twelve-month follow-ups, respectively). Conclusion: A considerable proportion of MS patients did not achieve a complete CD19 cell depletion and these patients had a higher baseline CD19 cell count. These findings, together with the higher MRI activity found in FR patients, suggest that the Ocrelizumab dosage could be tailored depending on CD19 cell counts at baseline in order to achieve complete disease control in all patients.

B-Cell Acute Lymphoblastic Leukemia Arising in Patients with a Preexisting Diagnosis of Multiple Myeloma Is a Novel Cancer with High Incidence of TP53 Mutations

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 20-20
Author(s):  
Monique Chavez ◽  
Erica Barnell ◽  
Malachi Griffith ◽  
Zachary Skidmore ◽  
Obi Griffith ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Acute Lymphoblastic Leukemia ◽  
B Cells ◽  
B Cell ◽  
Mechanism Of Action ◽  
Lymphoblastic Leukemia ◽  
Treatment Options ◽  
Hematopoietic Stem ◽  
Tp53 Mutations ◽  
Cell Acute Lymphoblastic Leukemia

Multiple Myeloma (MM) is a malignancy of plasma cells that affects over 30,000 Americans every year. Despite advances in the treatment of the disease, approximately 12,000 American patients will still die of MM in 2019. One of the mainstays of treatment for MM is the immunomodulatory and antiangiogenic drug lenalidomide; which is used in induction therapy, maintenance therapy and treatment of relapsed disease. Although not fully elucidated, lenalidomide's mechanism of action in MM involves the drug binding to Cerebelon (CBN) and leads to the subsequent degradation of the Ikaros (IKZF1) and Aiolos (IKZF3) transcription factors (TF). These TFs play important regulatory roles in lymphocyte development. Despite lenalidomide's importance in MM treatment, several groups have reported that MM patients treated with lenalidomide rarely go on to develop B-cell acute lymphoblastic leukemia (B-ALL). The genetics and clonal relationship between the MM and subsequent B-ALL have not been previously defined. Importantly, it is not clear if the MM and B-ALL arise from the same founding clone that has been under selective pressure during lenalidomide treatment. As deletions in IKZF1 are common in B-ALL, one could hypothesize that lenalidomide's mechanism of action mimics this alteration and contributes to leukemogenesis. We sequenced the tumors from a cohort of seven patients with MM treated with lenalidomide who later developed B-ALL. These data did not show any mutational overlap between the MM and ALL samples-the tumors arose from different founding clones in each case. However, several genes were recurrently mutated in the B-ALL samples across the seven patients. These genes included TP53, ZFP36L2, KIR3DL2, RNASE-L, and TERT. Strikingly, five of the seven patients had a TP53 mutations in the B-ALL sample that was not present in the matched MM sample. The frequency of TP53 mutations in our cohort was much higher than that reported in adult de novo B-ALL patients which can range between 4.1-6.4% (Hernández-Rivas et al. 2017 and Foa et al. 2013). Utilizing CRISPR-Cas9 gene editing, we disrupted the Zfp36l2 or Actb in murine hematopoietic stem cells (HSCs) of mice with or without loss of Trp53. We performed our first transplantation experiment in which the cohorts of mice have loss of Trp53 alone, loss of Zfp36l2 alone, loss of both Trp53 and Zfp36l2, or a control knockout (KO) of Actb. To characterize the disruption of Zfp36l2 alone and in combination with Trp53 we analyzed the hematopoietic stem and progenitor cell compartments in the bone marrow of the above transplanted mice. In mice with a loss of Zfp36l2 there is a decrease in Lin- Sca-1+ c-Kit+ (LSK), short term-HSC (ST-HSC), and multipotent progenitors (MPP). This decrease was not observed in the mice with a loss of both Trp53 and Zfp36l2, where instead we noted an increase in monocyte progenitors (MP), granulocytes-macrophage progenitors (GMP), and common myeloid progenitors (CMP) cells. In this Trp53 Zfp36l2 double loss model we also noted a decrease in B220+ B-cells that was not seen in the Zfp36l2 alone. In this cohort of Trp53 Zfp36l2 loss, we characterized B-cell development through hardy fraction flow cytometry, and identified a decrease in fractions A and B/C (pre-pro and pro-B-cells, respectively) as compared to Zfp36l2 or Actb alone. As lenalidomide does not bind to Cbn in mice, we used the human B-ALL NALM6 cell line to test if treatment with lenalidomide will lead to a selective growth advantage of cells with the same genes knocked out versus wild-type control cells grown in the same culture. We hypothesize that lenalidomide treatment selectively enriched for pre-existing mutated cell clones that evolved into the B-ALL. Preliminary data in NALM6 cells with a loss of TP53 demonstrate a slight increase in cell number at day 7 compared to a RELA control. These experiments will be repeated with concurrent ZFP36L2 and TP53 mutations as well as ZFP36L2 alone. Treatment-related disease is a key consideration when deciding between different treatment options, and this project aims to understand the relationship between MM treatment and B-ALL occurrence. It may be possible to identify MM patients who are at-risk for B-ALL. For example, MM patients who harbor low-level TP53 mutations prior to lenalidomide treatment could be offered alternative treatment options. Disclosures Barnell: Geneoscopy Inc: Current Employment, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees. Wartman:Novartis: Consultancy; Incyte: Consultancy.

Pax5 determines B- versus T-cell fate and does not block early myeloid-lineage development

Blood ◽  
2003 ◽  
Vol 101 (11) ◽  
pp. 4342-4346 ◽  
Author(s):  
Claudiu V. Cotta ◽  
Zheng Zhang ◽  
Hyung-Gyoon Kim ◽  
Christopher A. Klug
Keyword(s):  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cell Fate ◽  
Nk Cell ◽  
Cell Lineage ◽  
Blood Analysis ◽  
Hematopoietic Stem ◽  
Peripheral Blood Analysis

Abstract Progenitor B cells deficient in Pax5 are developmentally multipotent, suggesting that Pax5 is necessary to maintain commitment to the B-cell lineage. Commitment may be mediated, in part, by Pax5 repression of myeloid-specific genes. To determine whether Pax5 expression in multipotential cells is sufficient to restrict development to the B-cell lineage in vivo, we enforced expression of Pax5 in hematopoietic stem cells using a retroviral vector. Peripheral blood analysis of all animals reconstituted with Pax5-expressing cells indicated that more than 90% of Pax5-expressing cells were B220+ mature B cells that were not malignant. Further analysis showed that Pax5 completely blocked T-lineage development in the thymus but did not inhibit myelopoiesis or natural killer (NK) cell development in bone marrow. These results implicate Pax5 as a critical regulator of B- versus T-cell developmental fate and suggest that Pax5 may promote commitment to the B-cell lineage by mechanisms that are independent of myeloid gene repression.

scholarly journals TP53INP1 deficiency maintains murine B lymphopoiesis in aged bone marrow through redox-controlled IL-7R/STAT5 signaling

2018 ◽  
Vol 116 (1) ◽  
pp. 211-216 ◽  
Author(s):  
Bochra Zidi ◽  
Christelle Vincent-Fabert ◽  
Laurent Pouyet ◽  
Marion Seillier ◽  
Amelle Vandevelde ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Bone Marrow ◽  
B Cells ◽  
B Cell ◽  
Immune Cell ◽  
B Lymphopoiesis ◽  
Hematopoietic Stem ◽  
Chronic Oxidative Stress ◽  
The Impact ◽  
Deficient Mice

Bone marrow (BM) produces all blood and immune cells deriving from hematopoietic stem cells (HSCs). The decrease of immune cell production during aging is one of the features of immunosenescence. The impact of redox dysregulation in BM aging is still poorly understood. Here we use TP53INP1-deficient (KO) mice endowed with chronic oxidative stress to assess the influence of aging-associated redox alterations in BM homeostasis. We show that TP53INP1 deletion has no impact on aging-related accumulation of HSCs. In contrast, the aging-related contraction of the lymphoid compartment is mitigated in TP53INP1 KO mice. B cells that accumulate in old KO BM are differentiating cells that can mature into functional B cells. Importantly, this phenotype results from B cell-intrinsic events associated with defective redox control. Finally, we show that oxidative stress in aged TP53INP1-deficient mice maintains STAT5 expression and activation in early B cells, driving high Pax5 expression, which provides a molecular mechanism for maintenance of B cell development upon aging.

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