scholarly journals Myeloid/Lymphoid Neoplasm with Eosinophilia and a Novel RUFY1-Pdgfrb Rearrangement

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4639-4639
Author(s):  
Karly Williams Silva ◽  
Carrie L. Cummings ◽  
Nahid Rashid ◽  
Olga Sala-Torra ◽  
Xueyan Chen ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Lymph Node ◽  
T Cell ◽  
Tyrosine Kinase ◽  
Cell Population ◽  
Laboratory Evaluation ◽  
Patient Specific ◽  
High Dose ◽  
Peripheral Blood Flow ◽  
Severe Thrombocytopenia

Abstract Myeloid/lymphoid neoplasms associated with eosinophilia (MLN-Eo) and tyrosine kinase fusion genes include rearrangements of PDGFRB with over 30 different partner genes, most commonly ETV6-PDGFRB. Rearrangements are evident by cytogenetic analysis and fluorescence in situ hybridization (FISH) break-apart probes. Herein, we describe a novel rearrangement partner for PDGFRB. A 25-year-old man with a medical history significant for gout and hypertension presented to medical care after several days of progressive dyspnea, chest pain, fatigue, epistaxis, and rash. Physical exam revealed palpable cervical, axillary, and inguinal lymphadenopathy and massive splenomegaly. By CT scan the spleen measured 25 cm and diffuse lymphadenopathy was identified in the chest, abdomen and pelvis with the largest lymph node mass measuring 8.9 x 2.5 cm. Transthoracic echocardiogram showed normal heart function and no evidence of myocardial injury. The patient subsequently developed respiratory failure requiring intubation and mechanical ventilation, shock requiring vasopressors, and renal failure requiring renal replacement therapy. Initial laboratory evaluation demonstrated a leukocytosis to 83.3 x 10 9/L with neutrophilic predominance with left shift and eosinophilia (10% of WBCs, absolute eosinophil count of 8.2 x 10 9/L); hemoglobin of 8.3 g/dL and hematocrit of 25%; and thrombocytopenia to 50 x 10 9/L. Ferritin was 660 ng/mL, lactate dehydrogenase 384 U/L, and uric acid 10.4 mg/dL. Secondary causes of eosinophilia including infection, immunodeficiency, atopy, medications, and rheumatologic disease were ruled out. The patient was positive for strongyloides IgG antibodies and received ivermectin. Core biopsy of a lymph node was non-diagnostic and could not repeated safely due to progressive severe thrombocytopenia. Skin biopsy demonstrated a perivascular leukocytoclasis, but no abnormal B or T cell population. Bone marrow aspirate and biopsy revealed a hypercellular marrow (90%) with mild trilineage dysplasia, granulocytic hyperplasia, moderate reticulin fibrosis, and slightly increased mast cells. Blasts were not increased and no hemophagocytic histiocytes were identified. Eosinophils accounted for 6.9% of myeloid cells. Flow cytometry did not reveal an abnormal B or T lymphoid, blast or myeloid population. Peripheral blood flow cytometry did not reveal an abnormal B or T-cell population and T-cell rearrangement studies showed an oligoclonal population. No clonal B cell population was identified. FISH, which identified a rearrangement of PDGFRB in 28% of cells, confirmed the diagnosis. Karyotype analysis revealed an abnormal male karyotype with a paracentric inversion of 5q with breakpoints at 5q32 and 5q35. FusionPlex® Solid Tumor Panel (Clinical Genomics Laboratory, University of Washington SOM) identified a novel fusion between RUFY1 and PDGFRB. RUFY1 is expressed in most tissues and encodes a protein that contains a RUN domain and a FYVE-type zinc finger domain and plays a role in early endosomal trafficking (Figure). We are currently demonstrating the fusion is oncogenic and sensitive to tyrosine kinase inhibition in Ba/F3 cells. The patient's remarkable clinical response, however, supports imatinib sensitivity and is in keeping with other published reports of MLN-Eo with PDGFRB rearrangements. Initial treatment included high dose steroids for 7 days and hydroxyurea briefly. Imatinib 400 mg daily was started, then decreased to 200 mg daily due to gastrointestinal toxicity. Follow-up is limited (8 weeks). However, the patient has recovered clinically. Six weeks after starting imatinib he had renal recovery and has achieved a complete hematologic response except for mild anemia due to resolving acute kidney injury. Splenomegaly and peripheral lymphadenopathy have resolved. PDGFRB FISH has declined to 9%. Inversions of chromosome 5 have very rarely been described in association with eosinophilia, but only one report has specifically identified a rearrangement of PDGFRB. This report described a novel rearrangement involving exons 12 to 23 of PDGFRB at 5q32 and the 5′ (UTR) of G3BP1 at 5q33.1. Notably, this specific rearrangement was undetectable by PDGFRB break-apart FISH. These reports and ours highlight the clinical relevance of NGS in identifying novel rearrangement partners. Furthermore, patient-specific ddPCR assays can be designed for sensitive monitoring. Figure 1 Figure 1. Disclosures Oehler: BMS: Consultancy; OncLive: Honoraria; Pfizer: Research Funding; Takeda: Consultancy; Blueprint Medicines: Consultancy.

scholarly journals Normative data for flow cytometry immunophenotyping of benign lymph nodes sampled by surgical biopsy

2017 ◽  
Vol 71 (2) ◽  
pp. 174-179 ◽  
Author(s):  
Gregory David Scott ◽  
Susan K Atwater ◽  
Dita A Gratzinger
Keyword(s):  
Flow Cytometry ◽  
Lymph Node ◽  
T Cell ◽  
Lymph Nodes ◽  
Inflammatory Disease ◽  
Clinical History ◽  
Surgical Biopsy ◽  
Data Set ◽  
Flow Cytometry Data ◽  
Benign Lymph Node

AimsTo create clinically relevant normative flow cytometry data for understudied benign lymph nodes and characterise outliers.MethodsClinical, histological and flow cytometry data were collected and distributions summarised for 380 benign lymph node excisional biopsies. Outliers for kappa:lambda light chain ratio, CD10:CD19 coexpression, CD5:CD19 coexpression, CD4:CD8 ratios and CD7 loss were summarised for histological pattern, concomitant diseases and follow-up course.ResultsWe generated the largest data set of benign lymph node immunophenotypes by an order of magnitude. B and T cell antigen outliers often had background immunosuppression or inflammatory disease but did not subsequently develop lymphoma.ConclusionsDiagnostic immunophenotyping data from benign lymph nodes provide normative ranges for clinical use. Outliers raising suspicion for B or T cell lymphoma are not infrequent (26% of benign lymph nodes). Caution is indicated when interpreting outliers in the absence of excisional biopsy or clinical history, particularly in patients with concomitant immunosuppression or inflammatory disease.

A Phase I Study of Immunization of Indolent Non Hodgkin’s Lymphoma Patients with Autologous Monocyte-Derived Dendritic Cells Loaded with Heat Shocked and Killed Autologous Tumor Cells.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2437-2437
Author(s):  
Massimo Di Nicola ◽  
Carmelo Carlo-Stella ◽  
Maddalena Marchesi ◽  
Gianluca Del Conte ◽  
Liliana Devizzi ◽  
...  
Keyword(s):  
T Cells ◽  
Lymph Node ◽  
T Cell ◽  
Lymph Nodes ◽  
Phase I ◽  
Tumor Cells ◽  
Phase I Study ◽  
The Other ◽  
High Dose ◽  
Autologous Tumor

Abstract B-cell malignancies represent a potential target for anti-cancer vaccination programs due to the expression of tumor-specific antigens. Although immunization with tumor-derived idiotype protein is a frequently used procedure, vaccination with DCs loaded with killed tumor cells may activate response to a much wider range of antigens, without requiring prior molecular identification of such determinants. Furthermore, such DC-based vaccines could be available to all patients, irrespective of the HLA type. To evaluate the safety and tolerability of this approach, 18 patients with measurable relapse/refractory follicular (FCL; n= 12) and lymphoplasmocytoid (n= 6) lymphoma have been enrolled in a phase I study. Median prior number of treatment regimens was 2 (range 1–5) comprising 4 patients treated with high-dose chemotherapy supported by autologous stem cell transplantation. The vaccination was started after at least 6-months from the last chemotherapy treatment. All patients were evaluable for toxicity and 16/18 patients for efficacy with a median follow-up of 12.5 months (range 3–29 months). Each patient received 4 intradermal/subcutaneous injections at 2-weekly intervals of 50x10e6 tumor-loaded DCs. Immature DCs were generated by 5-days culture of autologous monocytes in the presence of IL-4 and GM-CSF. After selection by immunomagnetic technique, autologous CD19+ tumor cells, harvested from lymph nodes (n= 12) and/or peripheral blood (n= 6), were heat shocked and then irradiated by UVC. DCs were loaded for 48 hrs with killed tumor cells and then, to induce their maturation, were cultured for 12 hrs in the presence of TNF-alfa. Overall, vaccinations were well tolerated and no autoimmune reactions were observed. Mild erythema in the site of injection developed in the majority of patients (12/18), but only in 2 cases induration and extended erythema was observed. Six of 16 (37.5%) evaluable patients had objective responses. Two patients had partial responses (PR). One is still in PR and the other had a PR lasting 7 months. Four patients had complete remission (CR). Two patients are still in CR and the other 2 patients had a mean CR duration of 14.5 months. The remaining 10 patients had stable disease (n=5) or progressive disease (n=5). The overall monitoring of immune responses is ongoing. However, in one patient in PR, we evaluated the frequency of anti autologous tumor-specific T cells, by ELISPOT assay for IFN-gamma, on pathologic lymph nodes harvested before and after 2 months from the last vaccination. A significant increase of specific T-cell frequency was observed in the post-vaccination lymph node, compared to the tissue sample taken before vaccination. Moreover, evaluation of CD8+ T cell maturation markers, by analysis for CCR7 and CD45RA expression, indicated a shift of tumor-infiltrating T cells towards memory and effector stages in the lymph-node isolated after vaccination. In conclusion, injection of DCs loaded with killed tumor cells is a well-tolerated procedure achieving clinical and immunological responses also in the presence of significant tumor burden. However, further strategies, following DC-vaccination, are needed to ensure durable immune and clinical responses.

High Expression of Human Leukocyte Formin Protein in T Non-Hodgkin’s Lymphomas and in CD19− Cell Population of Normal Tonsils.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4662-4662
Author(s):  
Patricia M.B. Favaro ◽  
Fabiola Traina ◽  
Marta Crespo ◽  
Francesc Bosch ◽  
Pierre Brousset ◽  
...  
Keyword(s):  
Lymph Node ◽  
T Cell ◽  
Lymph Nodes ◽  
B Cell ◽  
Cell Population ◽  
Western Blotting ◽  
Human Leukocyte ◽  
Hematologic Malignancies ◽  
Hodgkin's Lymphomas ◽  
Large B Cell

Abstract We recently described a new gene, denominated human leukocyte formin (hlf), which was overexpressed in lymphoid malignancies and cancer cell lines. In contrast, a low expression of the hlf protein was observed in lymph node and peripheral blood leukocytes in normal tissues. Interestingly, the hlf protein associates with Akt, a protein kinase of an important pathway for cell survival. In order to better characterize the expression of the hlf protein we performed Western blotting in the lymphocytes isolated from 4 tonsils from adult patients obtained during routine tonsillectomy, at the Department of Hematology, Clinic Hospital, Barcelona. Results demonstrated that the CD19− cell population of the tonsil displayed a higher expression of this protein when compared with CD19+ cells. In addition, CD19+ cells were separated into two subpopulations: CD27+ (memory cells) and CD27− (naïve cells), and the CD19+/CD27+ cell presented a higher expression when compared with naïve B cells. Furthermore, we performed Western blotting analysis in frozen biopsies of non-Hodgkin’s lymphoma (NHL) patients obtained from the Department of Pathology, Purpan Hospital (Toulouse, France). The lymph node biopsies were performed at the time of clinical diagnosis and the initial diagnosis was confirmed by immunohistochemical analysis and classified according to REAL classification. Fifty-four patients were studied with ages ranging between 28 and 93 years (median 57 years). The histologic types were: 22 follicular NHL, 15 diffuse large B-cell NHL, 17 T cell NHL (non-otherwise specified). Five reactive lymph nodes were also studied. The expression of the hlf protein was detected in all lymphoma samples studied and also in the 5 reactive lymph nodes. The hlf expression, however, was higher in T cell NHL when compared with the others NHL and reactive lymph nodes (T cell NHL vs reactive lymph node, p=0.002; T cell NHL vs follicular NHL, p=0.0001; T cell NHL vs diffuse large B-cell, p=0.012; Mann Whitney test). The hlf protein may be involved in the anti-apoptosis mechanisms, as it is expressed in all types of lymphoproliferative samples and it is associated with Akt, a pathway that is constitutively activated in some hematologic malignancies. Indeed, the ortholog protein described in mice, presents a role in the protection of the cells from apoptosis, but the pathway is unknown. This report provides a more detailed description of the expression of hlf protein in normal lymphocytes and supports the hypothesis that the hlf protein has a role in the cancer molecular pathology of hematologic malignancies.

The Absence of Vasoactive Intestinal Peptide Augments Allo-Reactivity and the Anti-Viral Response in Bone Marrow Transplantation.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3267-3267
Author(s):  
Lauren T. Southerland ◽  
Jian-Ming Li ◽  
Sohrab Hossain ◽  
Cynthia Giver ◽  
Wayne Harris ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Cd8 T Cells ◽  
Cell Response ◽  
Low Dose ◽  
T Cell Response ◽  
High Dose ◽  
Mcmv Infection

Abstract Background: The severe morbidity and mortality associated with bone marrow transplantation (BMT) is caused by uninhibited immune responses to alloantigen and suppressed immune responses to pathogens. Vasoactive Intestinal Peptide (VIP) is an immunomodulatory neuropeptide produced by T-cells and nerve fibers in peripheral lymphoid organs that suppresses immune responses by induction of tolerogenic dendritic cells. In order to determine the immunoregulatory effects of VIP, we examined T-cell immune responses to allo- and viral-antigens in VIP knockout (KO) mice and mouse BMT recipients of hematopoietic cells from VIP KO donors. Methods: VIP KO mice and VIP WT littermates were infected with lethal or sub-lethal doses (5 × 104− 5 × 105 PFU) of murine cytomegalovirus (mCMV) and the T-cell response to viral antigen was measured by flow cytometry for mCMV peptide-MHC class 1-tetramer+ CD8+ T-cells. We transplanted 5 × 106 BM plus 1 × 106 splenocytes (SP) either from VIP KO or VIP WT donors in an C57BL/6 to F1(BL/6 × Balb/c) allo-BMT model and assessed survival, GvHD, donor T-cell expansion, chimerism, and response to mCMV vaccination and mCMV infection. Results: B-cell, αβ and γδ T-cell, CD8+ T-cell, CD11b+ myeloid cell, and dendritic cell numbers were equivalent between VIP KO and WT mice, while VIP KO mice had higher number of CD4+ and CD4+CD62L+CD25+ T-cells. Non-transplanted VIP KO mice survived mCMV infection better compared to VIP WT, with a brisker anti-viral T-cell response in the blood. In the allogeneic BMT setting, recipients of VIP KO BM plus VIP KO SP had more weight loss and lower (40%) 100 day post-transplant survival compared to the recipients of VIP KO BM plus WT SP (80% survival), recipients of WT BM plus KO SP (100% survival), and recipients of WT BM plus WT SP (80% survival). Recipients of VIP KO grafts had a significantly greater anti-mCMV response that peaked four days earlier than the tetramer response of mice transplanted with WT cells. This increased anti-viral response to vaccination correlated with a greater and more rapid T-cell response to secondary viral challenge. Conclusions: These experiments suggest that the absence of all VIP in the body, or the absence of VIP in a transplanted immune system, enhances anti-viral immunity and allo-immune responses. Modulation of the VIP pathway is a novel method to regulate post-transplant immunity. Figure 1: VIP knockout(KO) mice have an increased CMV tetramer response. VIP KO and VIP WT mice were infected (day 0) with either a sub-lethal low dose (5 × 10^4 PFU) or a lethal high dose (5 × 10^5 PFU) of CMV. Peripheral blood was stained for T cell markers and tetramer and analyzed by flow cytometry. On day 3, high dosed VIP KO mice had a higher number of tetramer positive CD8 T cells and better survival than WT mice (all high dose VIP WT died prior to day 10). VIP KO mice had a significant increase in tetramer positive CD8 T cells between days 3 and 10. *** p<0.01, difference between VIP KO and VIP WT littermate at designated dose level and day. Figure 1:. VIP knockout(KO) mice have an increased CMV tetramer response. VIP KO and VIP WT mice were infected (day 0) with either a sub-lethal low dose (5 × 10^4 PFU) or a lethal high dose (5 × 10^5 PFU) of CMV. Peripheral blood was stained for T cell markers and tetramer and analyzed by flow cytometry. On day 3, high dosed VIP KO mice had a higher number of tetramer positive CD8 T cells and better survival than WT mice (all high dose VIP WT died prior to day 10). VIP KO mice had a significant increase in tetramer positive CD8 T cells between days 3 and 10. *** p<0.01, difference between VIP KO and VIP WT littermate at designated dose level and day.

Isolation and Characterization of CD4+ T Cells Specific for the HPA 1a Epitope Associated with Neonatal Alloimmune Thrombocytopenia.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2091-2091
Author(s):  
Maria T. Ahlen ◽  
Mette K. Killie ◽  
Bjorn Skogen ◽  
Anne Husebekk ◽  
Tor B. Stuge
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
T Cell ◽  
Cell Lines ◽  
Cell Detection ◽  
Severe Thrombocytopenia ◽  
Isolation And Characterization ◽  
T Cell Lines ◽  
Alloimmune Thrombocytopenia

Abstract Neonatal alloimmune thrombocytopenia (NAIT) can cause severe complications such as intrauterine death or intracranial hemorrhage (ICH) in the newborn, and is caused by the transfer of platelet-depleting antibodies from the mother to the fetus during pregnancy. These antibodies react with allogeneic epitopes, most commonly human platelet antigen (HPA) 1a, when present on fetal platelets. Although these responses are thought to be a result of a T cell-dependent immune response, HPA 1a specific T cells have not yet been isolated. To examine whether HPA 1a specific T cells could be detected and isolated, we collected PBMC post delivery from an HPA 1a negative mother who gave birth to an HPA 1a positive neonate suffering from severe thrombocytopenia (platelet count &lt;50×109/L). The cells were stimulated with HPA 1a peptides (20aa) in long term cultures supplemented with IL-7 and IL-2, and subsequently, IL-15. After 4 weeks in culture these cells were labeled with CFSE dye and restimulated with HPA 1a or control peptides. After additional 2 weeks in culture supplemented with IL-2 and IL-15, specific proliferative responses were detectable by CFSE dye dilution by flow cytometry. The cells were cloned by fluorescent-activated cell sorting (FACS) and expanded in numbers with anti-CD3 stimulation in the presence of irradiated allogeneic PBMC and IL-2. The resulting clonal T cell lines were characterized in proliferation assays, ELISPOT assays and phenotyped by flow cytometry. All clones were CD3+, CD4+ and CD19−, and the majority of the clones proliferated and secreted cytokines in response to stimulation with HPA 1a peptides, but not control peptides. In ELISPOT assays, peptide-pulsed antigen-presenting cells were required for T cell detection. These clonal HPA 1a specific CD4+ T cell lines represent formal evidence of the existence of HPA 1a specific T cell responses related to NAIT and will serve as important tools for further characterization of maternal immune responses associated with NAIT.

Hepatosplenic T Cell Lymphoma Mimicking Hemophagocytic Lymphomhistiocytosis: A Case Report

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 4864-4864
Author(s):  
Inhye E Ahn ◽  
Lawrence Rice
Keyword(s):  
Bone Marrow ◽  
T Cell ◽  
Cell Lymphoma ◽  
T Cell Lymphoma ◽  
Cell Phenotype ◽  
High Dose ◽  
Severe Thrombocytopenia ◽  
Gamma Delta ◽  
Bone Marrow Biopsies ◽  
Hepatosplenic T Cell Lymphoma

Abstract Abstract 4864 Background. Hepatosplenic T cell lymphoma (HSTCL) is rare and aggressive extranodal lymphoma characteristically involves young males in third or fourth decade of life. It frequently manifests as pancytopenia with severe thrombocytopenia, hepatosplenomegaly, and much rarely, hemophagocytic lymphohistiocytosis (HLH). Methods. Medical records of a patient who presented with HLH as a presenting signs of HSTCL were reviewed. Literature search was performed to identify characteristic demographics and natural course of HSTCL reported to date. Results. A 30-year-old male presented after 6 months of constitutional symptoms. Remarkable findings were pancytopenia, mildly elevated LFT, and high ferritin level (89,000). Extensive work up for autoimmune and infectious etiology was negative. Worsening anemia and thrombocytopenia prompted the third bone marrow biopsy, which revealed the first evidence of hemophagocytosis. Despite of Cyclosporine A and Etoposide, pancytopenia worsened which prompted splenectomy and core needle liver biopsy. Sinusoids of spleen and liver were densely infiltrated with atypical lymphocytes consistent with T cell phenotype. Diagnosis of HSTCL was confirmed after PCR detection of gamma delta T cell receptor rearrangement. Previous bone marrow biopsies were retrospectively reviewed, which revealed small clusters of cells staining positive for CD3. The patient underwent three courses of chemotherapy that included high-dose Cytarabine, Etoposide and adriamycin. Post-chemotherapy course was complicated with disseminated Candidiasis complicated with mycortic aneurysm and worsening pancytopenia. The patient expired due to overwhelming septic shock 6 months after the pathologic diagnoses of HSTCL. Conclusion. HSTCL causes aberrant expansion of gamma delta T cells and defective innate immunity, and is an important secondary etiology for HLH. Splenectomy has diagnostic significance but little therapeutic benefit. Longer survival was reported in patients who underwent cytarabine-based chemotherapy; however median survivals in anecdotal case series all fall within 2 years regardless of regimen. Disclosures: No relevant conflicts of interest to declare.

Immunopathology of ATG Prior to Bone Marrow Transplantation in Mouse Model

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4603-4603
Author(s):  
Behnam Sadeghi ◽  
Sulaiman Al Hashmi ◽  
Zuzana Hassan ◽  
Bjorn Rozell ◽  
Manuchehr Abedi-Valugerdi ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Lymph Node ◽  
Bone Marrow Transplantation ◽  
T Cell ◽  
Mouse Model ◽  
Lymph Nodes ◽  
Cell Population ◽  
Marrow Transplantation ◽  
Cell Phenotype ◽  
Administration Time

Abstract Introduction: Polyclonal anti-thymocyte globulin (ATG) is mainly used in hematopoietic stem cell transplantation, as a prevention for graft rejection as well as for GVHD. Immunosuppressive properties of ATG have been considered primarily from the depletion of peripheral lymphocytes. However direct or indirect effects of ATG on other immune components still is controversial. In the present study we evaluated the immunopathologic effects of ATG on immune system in a mouse model. Methods Ten to fourteen weeks old BALB/c and C57BL/6 mice, were injected intra- peritoneally or intravenously with different doses of ATG (0.2mg/kg -25mg/kg) at three dosage schedules. Considering bone marrow transplantation as day 0, ATG were given at days -10, -7 and -5 or -7, -5 and -1 or -5, -3 and -1. At day 0, mice were killed; spleen (SP), bone marrow (BM), lymph nodes (LN) and thymus were removed and analyzed for T-, B-, DC, NK-, T-reg and myeloid cells. To evaluate the efficacy of immunosuppressive effect of ATG, a group of BALB/c mice were conditioned using busulfan (Bu) and ATG and compared to a control group of BALB/c conditioned with Bu (80mg/kg) followed by cyclophosphamide (200mg/kg). Both groups transplanted with BM and spleen cells from C57BL/6 and followed for engraftment and/or GVHD. Results The administration of ATG (0.2- 4.5mg/kg) has resulted in an increase in spleen cellularity while in lymph node and thymus a decreased cellularity was observed. We have found that injecting 4.5mg/kg of ATG at day -7, -5 and -3 significantly decreased T-cell population in spleen and LN compare to Bu-Cy conditioning. The ratio CD4/CD8 increased after ATG treatment showing that CD8 cells are six-fold more sensitive to ATG treatment compared to CD4 lymphocyte. Interestingly T-reg cell population increase after ATG at day 0, however, the increment was negatively correlated with the administration time and positively correlated with the dose. ATG treatment has resulted in an increase in B-cell population by two- and three- fold in spleen and lymph nodes, respectively. Moreover, 1.2- to 3.5-fold increase in DCs, NK and myeloid cells was observed in SP and LN. Thymus cellularity and cell phenotype was less affected while BM cellularity was not affected by ATG treatment. No differences in the ATG effect on cellularity or cell phenotype between IP and IV route was observed. Despite the high immunosuppressive effect observed in T-cell population compared to that seen in Bu-Cy conditioning, no chimerism was observed when Cy was substituted with ATG (4.5 – 10 mg/kg). Conclusion No donor chimerism could be obtained using ATG as a single agent up to 25mg/kg. ATG dose and the administration time are important factors affecting the repopulation of residual T-cells in spleen and lymph node that have to be considered in bone marrow transplantation setting.

Sign in / Sign up

Export Citation Format

Share Document