The role of autologous bone marrow transplantation in primary effusion lymphoma: a case report and literature review.

Primary effusion lymphoma (PEL) is an aggressive and rare type of diffuse large B-cell lymphoma (DLBL) that commonly presents itself as pleural, pericardial or peritoneal effusion without lymph node or extranodal involvement in immunosuppressed patients, such as HIV-positive or transplanted receptors. On rare occasions, it may be found in solid sites without effusion, in an immunophenotypically and morphologically similar neoplasm well-known as extracavitary PEL (EC-PEL). Both PEL and EC-PEL are associated with extremely poor prognosis. Due to the rarity of these entities, ther e are no gold standard treatments . Here we discuss the role of autologous bone marrow transplant (auto-BMT) in the treatment of these patients as well as report the case of a young HIV-positive male diagnosed with both PEL and EC-PEL, who underwent a salvage therapy with auto-BMT and achieved complete and sustained remission eight years after the diagnosis.

Successful bone marrow transplantation in a patient with Omenn syndrome, a rare variant of severe combined immunodeficiency syndrome: A case report.

Key Clinical Message: Bone marrow transplantation (BMT) saves lives in Omenn syndrome, a severe immunodeficiency disorder. Timely genetic diagnosis and matched donor BMT are crucial. Emphasis on newborn screening and multidisciplinary care improves outcomes for infants with inherited disorders. Prompt intervention and comprehensive management are vital for a successful transplant outcome. Abstract: Omenn syndrome represents a severe variant of combined immunodeficiency characterized by disregulated immune responses and susceptibility to recurrent infections. We present the case of a 3-month-old female infant initially presenting with upper respiratory infection symptoms and a diffuse rash, unresponsive to local treatment. At 4 months of age, the patient underwent allogeneic bone marrow transplantation (BMT) utilizing stem cells from a fully matched sibling donor. Pre-transplant conditioning included antimicrobial prophylaxis and supportive therapies. Following BMT, the patient received immunosuppressive medications to prevent graft rejection and graft-versus-host disease. Clinical monitoring post-transplant showed timely neutrophil and platelet engraftment, with subsequent follow-up demonstrating stable clinical parameters and negative cytomegalovirus status. The case highlights the importance of timely diagnosis and treatment in managing severe immunodeficiency disorders, demonstrating the potential for successful outcomes with appropriate timely interventions. Regular monitoring and follow-up appointments were crucial in ensuring the success of the treatment. This case also emphasizes the significance of multidisciplinary care and genetic testing in identifying and managing rare immunodeficiency disorders. The successful outcome in this case provides hope for improved treatment options and better patient outcomes in the future.

Identification of the novel HLA-DRB3*03:69 allele by next-generation sequencing.

The new HLA-DRB3*03:69 allele differs from DRB3*03:01:01:03 by change of C → G in exon 3.

Fanconi Anaemia associated with café au lait spots: A rare case report.

Fanconi Anaemia is an autosomal recessive disorder, which is characterised by progressive pancytopenia, café au lait spots (>50%), bruising, petechie, recurrent infections, short height (50%), and thumb and radial bone anomalies (40%). Herein, is presented a case of a lean emaciated female child, who presented with the chief complaints of fever, loose stools and decreased appetite for one month reported at Sindh Government General Hospital, Karachi, on February, 1, 2023. She had cutaneous findings of hyperpigmentation and café au lait spots and a tri-phalangeal thumb. On investigation, pancytopenia and a low reticulocyte count of 0.7% was also observed. Karyotype and chromosomal breakage test induced by Diepoxybutane confirmed her as a case of Fanconi Anaemia.

An update on pharmacotherapy for fungal infections in allogeneic stem cell transplant recipients.

INTRODUCTION: Invasive fungal diseases (IFD) constitute a major cause of morbidity and mortality in hematopoietic stem cell transplantation (HSCT) recipients. AREAS COVERED: We describe epidemiology, causes and risk factors of IFD in allogeneic HSCT discussing prophylaxis and treatment in various HSCT phases. We present the most recent studies on this thematic area, including novel data on currently available antifungals, i.e. formulations, dosing, safety, efficacy and therapeutic drug monitoring. Finally, we present the most recent relevant recommendations published. Literature search included PubMed, Scopus, and clinicaltrials.gov between January 2014 and April 2024. EXPERT OPINION: The antifungal agents employed for prophylaxis and therapy should be predicated on local epidemiology of IFD. Fluconazole prophylaxis remains a first-line choice before engraftment when the main pathogen is Candida spp. After engraftment, prophylaxis should be with mold-active agents (i.e. triazoles). For candidiasis, echinocandins are suggested as first-line treatment, whereas aspergillosis responds well to mold-active azoles and liposomal amphotericin B (L-AmB). For mucormycosis, treatment of choice includes L-AmB and isavuconazole. Choice between fever-driven and diagnostics-driven strategies remains equivocal. Open research topics remain: 1) optimization of tools to ensure prompt and accurate IFD diagnosis to avoid unnecessary exposure to antifungals, drug interactions and cost; 2) refinement of treatment for resistant/refractory strains.

Cxcl10 and Cxcr3 regulate self-renewal and differentiation of hematopoietic stem cells.

BACKGROUND: The function of hematopoietic stem cells (HSC) is regulated by HSC internal signaling pathways and their microenvironment. Chemokines and chemokine ligands play important roles in the regulation of HSC function. Yet, their functions in HSC are not fully understood. METHODS: We established Cxcr3 and Cxcl10 knockout mouse models (Cxcr3-/- and Cxcl10-/-) to analyze the roles of Cxcr3 or Cxcl10 in regulating HSC function. The cell cycle distribution of LT-HSC was assessed via flow cytometry. Cxcr3-/- and Cxcl10-/- stem/progenitor cells showed reduced self-renewal capacity as measured in serial transplantation assays. To study the effects of Cxcr3 or Cxcl10 deficient bone marrow microenvironment, we transplanted CD45.1 donor cells into Cxcr3-/-or Cxcl10-/- recipient mice (CD45.2) and examined donor-contributed hematopoiesis. RESULTS: Deficiency of Cxcl10 and its receptor Cxcr3 led to decreased BM cellularity in mice, with a significantly increased proportion of LT-HSC. Cxcl10-/- stem/progenitor cells showed reduced self-renewal capacity in the secondary transplantation assay. Notably, Cxcl10-/- donor-derived cells preferentially differentiated into B lymphocytes, with skewed myeloid differentiation ability. Meanwhile, Cxcr3-deficient HSCs demonstrated a reconstitution disadvantage in secondary transplantation, but the lineage bias was not significant. Interestingly, the absence of Cxcl10 or Cxcr3 in bone marrow microenvironment did not affect HSC function. CONCLUSIONS: The Cxcl10 and Cxcr3 regulate the function of HSC, including self-renewal and differentiation, adding to the understanding of the roles of chemokines in the regulation of HSC function.

The preclinical data and immunologic rationale for hematopoietic stem cell transplantation in autoimmunity.

The development of autoimmune diseases (ADs) is thought to be caused by a dysfunction of the intrinsic ability of our immune system for "self-nonself" discrimination. Following the breakdown of "self-tolerance," an orchestrated immune cascade develops, involving B- and T-lymphocytes and autoantibodies that target self-antigens. An imbalance of the regulatory immune network and a suitable genetic background, along with external (infectious and environmental) triggers, are all important contributors to the outbreak of clinical autoimmunity. Immunotherapies for ADs can be classified into treatments that are given continuously (chronic treatments) and therapies that are applied only once or intermittently, aiming to induce partial or complete reconstitution of the immune system [immune reconstitution therapies (IRTs)]. The principle underlying IRTs is based on the depletion of mature immune cells and the rebuilding of the immune system. During this process of immune reconstitution, a substantial change in the lymphocyte repertoire occurs, which may explain the impressive and long-term beneficial effects of IRTs, including the possibility of induction of tolerance to self-antigens. Hematopoietic (or bone marrow) stem cell transplantation (HSCT or BMT) represents the prototype-and the most radical type-of IRT therapy. The rationale for HSCT or BMT for the treatment of severe ADs is based on convincing proof in preclinical studies, utilizing various animal models of autoimmunity. More than 30 years' worth of pioneering experiments in various models of ADs have shown that HSCT can lead to substantial improvement or even cure of the autoimmune syndromes and induction of long-term tolerance to autoantigens. The success of treatment depends on how completely the autoantigen-reactive lymphocytes and memory cells are eradicated by the conditioning chemotherapy, which is administered in a single dose before the transplantation. The most successful conditioning methods in animal models of ADs are total body irradiation (TBI) and high-dose cyclophosphamide (CY). These preclinical studies, summarized in this review, have provided important data about the therapeutic potential of HSCT in human ADs and the associated mechanisms of action and have contributed to the formulation of guidelines for clinical applications of autologous or allogeneic HSCT/BMT in refractory autoimmunity.

MASCC/ISOO Clinical Practice Statement: Management of oral manifestations of chronic graft-versus-host-disease.

PURPOSE: A MASCC/ISOO Clinical Practice Statement (CPS) is aimed at generating a concise tool for clinicians, which concentrates practical information needed for the management of oral complications of cancer patients. This CPS is focused on the management of oral manifestations of chronic graft-versus-host-disease (cGVHD). METHODS: This CPS was developed based on critical evaluation of the literature followed by a structured discussion of a group of leading experts, members of the Oral Care Study Group of MASCC/ISOO. The information is presented in the form of succinct bullets and table to generate a short manual about the best standard of care. RESULTS: The treatment goals in oral cGVHD are to relieve pain and xerostomia, improve oral function, prevent secondary infection, prevent deterioration of the dentition, and detect malignant transformation as early as possible. The prevention and treatment measures for oral mucosal lesions, hypofunction of the salivary glands, and sclerodermatous changes in the oral and perioral tissues are detailed, as well as the possible complications and side effects of these interventions. CONCLUSIONS: Patients post allogeneic hematopoietic cell transplantations, with cGVHD manifest in the oral and perioral tissues, should be regularly monitored and treated as needed by an oral care practitioner. This CPS provides the clinician with practical tools for examining, preventing, and treating the various sequalae that may affect the oral cavity in these patients.

Cardiovascular and Metabolic Risk Incidence Among Adult Allogeneic Stem Cell Transplant Recipients: A Narrative Review.

Advances in allogeneic hematopoietic stem cell transplantation (alloHSCT) and supportive care over the past decade have reduced transplant and relapse-related mortality, leading to a greater number of long-term survivors. However, transplant-related late effects, such as cardiovascular disease (CVD) and metabolic diseases, are becoming significant concerns for this group. This review aims to address several key questions regarding cardiovascular late effects in alloHSCT recipients, including the long-term incidence of CVD-related events, the prevalence of risk factors, screening and management recommendations, and evidence for screening and prevention strategies. A literature search was conducted in PubMed Central using the National Library of Medicine search engine, covering all relevant research from inception to 2023. The initial search identified 751 research records, of which 41 were shortlisted based on specific criteria (≥18 years of age at the time of transplant, allogeneic transplant, and inclusion of more than 30 patients). Our review highlights published evidence confirming the increased CVD risk among alloHSCT recipients. This risk is especially pronounced among individuals who have developed traditional and modifiable risk factors or have been exposed to transplant-specific risk factors. Evidence of the use of traditional cardiac risk factor calculators in the alloHSCT population is limited, in addition, there is emerging evidence that general population calculators potentially underestimate CVD risk given the increased risk of CVD in the allogeneic group as a whole. Studies that develop and validate transplant recipient-specific CVD risk stratification tools appear to be severely lacking and the field's focus needs to be shifted here in the coming years. To improve patient engagement and adherence to CVD risk factor measures, we recommend that a multidisciplinary model involving both specialists and primary care physicians is crucial in ensuring regular follow-up in the community and to potentially improve adherence.

Comparison of atrial fibrillation prevalence and in-hospital cardiovascular outcomes between patients undergoing allogeneic versus autologous hematopoietic stem cell transplantation: insights from the national inpatient sample.

Hematopoietic stem cell transplantation (HSCT) is a potentially curative therapy for several malignant and non-malignant hematologic conditions. However, patients undergoing HSCT are at increased risk of developing serious cardiovascular events. Whether cardiovascular risks differ by the type of transplantation strategy used, allogeneic versus autologous HSCT, is unknown. Leveraging the National Inpatient Sample (2016-2019), we assessed the incidence of early cardiovascular events by HSCT mode (allogeneic vs autologous). The primary outcome was the incidence of atrial fibrillation (AF). The secondary outcome was the occurrence of any major adverse cardiac events (MACE), defined as acute heart failure, myocardial infarction (MI), symptomatic atrial or ventricular arrhythmia or heart block, and cardiovascular death. Outcomes were compared between those undergoing allogeneic versus autologous HSCT. Multivariable regression, adjusting for cardiovascular and cancer-related factors, was used to define the association between pre-HSCT factors and MACE. We further assessed the effect of acute cardiovascular events on in-patient mortality by calculating adjusted odds ratio (aOR) with corresponding 95% confidence intervals (CI) and p-values. Overall, 64,705 weighted hospitalizations for HSCT were identified, of which 22,655 (35.0%) were allogeneic HSCT and 42,050 (65.0%) were autologous HSCT. The prevalence of AF was 9.1%, and 12.1% for any arrhythmia. In multivariable regression, allogeneic HSCT was associated with higher adjusted odds of peri-HSCT acute heart failure (aOR 2.64; 1.86-3.76; p < 0.0001), QT prolongation (aOR 1.40; 1.04-1.88; p = 0.025), MI (aOR 2.87; 1.16-7.11; p = 0.023), any major cardiovascular complication (aOR 1.16; 1.03-1.32; p = 0.016), and inpatient mortality (aOR 4.87; 3.60-6.58; p < 0.0001). Following cerebrovascular events, AF was the strongest predictor of mortality. Allogeneic HSCT was associated with higher odds of in-hospital cardiovascular complications among patients undergoing HSCT.

Donor lymphocyte infusions: An experience from a tertiary care center of North India.

Donor lymphocyte infusions (DLIs) are often recommended products after allogeneic hematopoietic stem cell transplant to increase graft - versus - leukemia effect. More success rate of DLI has been reported in relapsed posttransplant chronic myeloid leukemia. Whatever the indication for DLI, mortality related to post-DLI infusion is 5%-20%, and more than one-third of patients will develop acute and/or chronic graft versus host disease (GVHD) after DLI. We report two cases where DLIs were used for residual disease after posttransplant. Both of DLI went uneventful. None of the patient's developed signs of GVHD postinfusion. Although both patients expired with different causes, none were related to DLI infusion. Information from published literature suggests that DLI should be administered early after relapse or as a prophylactic strategy in patients receiving T-cell-depleted grafts, and patients with aggressive diseases may benefit from disease reduction before DLI. However, further evidence is required to evaluate its efficacy, especially in relapsed or residual hematological malignancies.

Myelofibrosis and allogeneic transplantation: critical points and challenges.

New available drugs allow better control of systemic symptoms associated with myelofibrosis (MF) and splenomegaly but they do not modify the natural history of progressive and poor prognosis disease. Thus, hematopoietic stem cell transplantation (HSCT) is still considered the only available curative treatment for patients with MF. Despite the increasing number of procedures worldwide in recent years, HSCT for MF patients remains challenging. An increasingly complex network of the patient, disease, and transplant-related factors should be considered to understand the need for and the benefits of the procedure. Unfortunately, prospective trials are often lacking in this setting, making an evidence-based decision process particularly arduous. In the present review, we will analyze the main controversial points of allogeneic transplantation in MF, that is, the development of more sophisticated models for the identification of eligible patients; the need for tools offering a more precise definition of expected outcomes combining comorbidity assessment and factors related to the procedure; the decision-making process about the best transplantation time; the evaluation of the most appropriate platform for curative treatment; the impact of splenomegaly; and splenectomy on outcomes.

Follow-Up of Patients Diagnosed With Germinal Testicular Tumors (Seminomas and Non-seminomatous) Treated With a Bone Marrow Transplant and a High Dose of Chemotherapy.

INTRODUCTION: Germinal testicular tumors are the most common malignant neoplasm in men around 20 to 34 years. Even though they are unusual, they have increased incidence in the last decade; they have an excellent prognosis and overall survival at five years, approximately 95%. Divergent data exists regarding treatment options in patients with first, second, and third relapses with conventional therapy. Some studies describe the possible benefit of using high-dose chemotherapy associated with a bone marrow transplant with variable results. METHODS:  The present study describes clinical outcomes, clinical response, mortality, overall survival, and progression-free survival to two years in a group of patients with germinal malignant tumors, seminoma versus non-seminomatous with evidence of progression of the disease at first, second, or third conventional chemotherapy regimens, and who received high dose chemotherapy and bone marrow transplantation at the National Cancer Institute between 2010 and 2021. RESULTS: A retrospective observational study of case series showed that 57% of patients in third-line therapy received high-dose chemotherapy and bone marrow transplantation, with progression disease median time from diagnosis more than two years. Patients in the post-graft period presented infectious complications (71%). The most common were febrile neutropenia (29%) with a mortality rate of 71% (n=5), progression-free survival of 2.3 months, and overall survival of 7.4 months. CONCLUSIONS:  These results show that in this group of patients, regimens with high-dose chemotherapy associated with bone marrow transplants, have a worse prognosis compared to other cohorts of patients, and may not be the best candidates for this rescue therapy.

Retrospective analysis of the incidence and outcome of late acute and chronic graft-versus-host disease-an analysis from transplant centers across Europe.

Introduction: Chronic graft-versus-host disease (cGvHD) is a serious late complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Methods: This multicenter analysis determined the cumulative incidence (CI) of cGvHD and late acute GvHD (laGvHD) and its impact on transplantation-related mortality (TRM), relapse (R), and overall survival (OS) in 317 patients [296 adults, 21 pediatrics (<12 years of age)] who underwent their first allo-HSCT in 2017. Results: The CI of laGvHD was 10.5% in adults and 4.8% in pediatrics, and the CI of cGvHD was 43.0% in all adult transplant patients and 50.2% in the adult at-risk cohort at the study end. The onset of cGvHD was de novo in 42.0% of patients, quiescent in 52.1%, and progressive in 5.9%. In adults, prophylactic use of antithymocyte globulin or posttransplant cyclophosphamide was associated with a significantly lower incidence of cGvHD (28.7%) vs. standard prophylaxis with calcineurin inhibitors (30.6%) and methotrexate/mycophenolate mofetil (58.4%) (all p < 0.01). TRM was significantly higher in patients with aGvHD (31.8%) vs. cGvHD (12.6%) and no GvHD (6.3%) (all p = 0.0001). OS in the adult at-risk cohort was significantly higher in patients with cGvHD (78.9%) vs. without (66.2%; p = 0.0022; HR 0.48) due to a significantly lower relapse rate (cGvHD: 14.5%; without cGvHD: 27.2%; p = 0.00016, HR 0.41). OS was also significantly higher in patients with mild (80.0%) and moderate (79.2%) cGvHD vs. without cGvHD (66.2%), excluding severe cGvHD (72.7%) (all p = 0.0214). Discussion: The negative impact of severe cGvHD on OS suggests a focus on prevention of severe forms is warranted to improve survival and quality of life.

Systemic knockout of Tmem175 results in aberrant differentiation but no effect on hematopoietic reconstitution.

Lysosomes play crucial roles in regulating cell metabolism, and K+ channels are critical for controlling various aspects of lysosomal function. Additionally, lysosomal activity is essential for maintaining the quiescence of hematopoietic stem cells (HSCs) under both steady-state and stress conditions. Tmem175 is a lysosomal potassium channel protein. To further investigate the role of K+ channels in HSCs, our study employed knockout mice to examine the function of Tmem175. Our research findings demonstrate that the deletion of Tmem175 does not disrupt the functionality of HSCs in both stable and stressed conditions, including irradiation and intraperitoneal 5-FU injections. However, we did observe that the absence of Tmem175 impairs the long-term differentiation capacity of HSCs into myeloid differentiated subpopulation cells（In this paper, it is referred to simply as M cells）in HSC transplantation test, while promoting their differentiation into T cells. This suggests that Tmem175 plays a role in the lineage differentiation of HSCs without being essential for their self-renewal or long-term regenerative capabilities.

Oncogene-induced TIM-3 ligand expression dictates susceptibility to anti-TIM-3 therapy in mice.

Leukemia relapse is a major cause of death after allogeneic hematopoietic cell transplantation (allo-HCT). We tested the potential of targeting T cell (Tc) immunoglobulin and mucin-containing molecule 3 (TIM-3) for improving graft-versus-leukemia (GVL) effects. We observed differential expression of TIM-3 ligands when hematopoietic stem cells overexpressed certain oncogenic-driver mutations. Anti-TIM-3 Ab treatment improved survival of mice bearing leukemia with oncogene-induced TIM-3 ligand expression. Conversely, leukemia cells with low ligand expression were anti-TIM-3 treatment resistant. In vitro, TIM-3 blockade or genetic deletion in CD8+ Tc enhanced Tc activation, proliferation, and IFN-γ production while enhancing GVL effects, preventing Tc exhaustion, and improving Tc cytotoxicity and glycolysis in vivo. Conversely, TIM-3 deletion in myeloid cells did not affect allogeneic Tc proliferation and activation in vitro, suggesting that anti-TIM-3 treatment-mediated GVL effects are Tc induced. In contrast to anti-programmed cell death protein 1 (anti-PD-1) and anti-cytotoxic T lymphocyte-associated protein 4 (anti-CTLA-4) treatment, anti-TIM-3-treatment did not enhance acute graft-versus-host disease (aGVHD). TIM-3 and its ligands were frequently expressed in acute myeloid leukemia (AML) cells of patients with post-allo-HCT relapse. We decipher the connections between oncogenic mutations found in AML and TIM-3 ligand expression and identify anti-TIM-3 treatment as a strategy for enhancing GVL effects via metabolic and transcriptional Tc reprogramming without exacerbation of aGVHD. Our findings support clinical testing of anti-TIM-3 Ab in patients with AML relapse after allo-HCT.

Restoration of thymic T-cell development by bone marrow transplantation in mouse radiation lymphomagenesis.

Fractionated total body irradiation (TBI) with X-rays induces thymic lymphoma/leukemia (TL) in C57BL/6 mice. Radiation-induced mouse TL (RITL) can be prevented by bone marrow transplantation (BMT) of unirradiated BM cells. However, the mechanisms underlying the prevention of RITL with BMT remain unclear. Here, we show that BMT restores thymic T-cell differentiation in mice subjected to TBI. TBI (four times of 1.8 Gy X-rays weekly) was conducted with C57BL/6 mice. BMT was performed immediately after the last irradiation of TBI in mice by transplantation of BM cells isolated from enhanced green fluorescence protein (eGFP) transgenic mice. Thymic cell numbers were drastically decreased in TBI and TBI + BMT mice compared to those in non-irradiated mice. Flow cytometry showed a dramatic decrease in double negative (DN, CD4-CD8-) thymocytes, especially DN2 (CD25+CD44+) and DN3 (CD25+CD44-) subpopulations, in the TBI mice on Day 10 after the last irradiation. In contrast, the DN2 and DN3 populations were recovered in TBI + BMT mice. Interestingly, these restored DN2 and DN3 cells mainly differentiated from eGFP-negative recipient cells but not from eGFP-positive donor cells, suggesting that transplanted BM cells may interact with recipient cells to restore thymic T-cell development in the RITL model. Taken together, our findings highlight the significance of restoring thymic T-cell differentiation by BMT in RITL prevention.

Calcineurin inhibition rescues alloantigen-specific central memory T cell subsets that promote chronic GVHD.

Calcineurin inhibitors (CNIs) constitute the backbone of modern acute graft-versus-host disease (aGVHD) prophylaxis regimens but have limited efficacy in the prevention and treatment of chronic GVHD (cGVHD). We investigated the effect of CNIs on immune tolerance after stem cell transplantation with discovery-based single-cell gene expression and T cell receptor (TCR) assays of clonal immunity in tandem with traditional protein-based approaches and preclinical modeling. While cyclosporin and tacrolimus suppressed the clonal expansion of CD8+ T cells during GVHD, alloreactive CD4+ T cell clusters were preferentially expanded. Moreover, CNIs mediated reversible dose-dependent suppression of T cell activation and all stages of donor T cell exhaustion. Critically, CNIs promoted the expansion of both polyclonal and TCR-specific alloreactive central memory CD4+ T cells (TCM) with high self-renewal capacity that mediated cGVHD following drug withdrawal. In contrast to posttransplant cyclophosphamide (PT-Cy), CSA was ineffective in eliminating IL-17A-secreting alloreactive T cell clones that play an important role in the pathogenesis of cGVHD. Collectively, we have shown that, although CNIs attenuate aGVHD, they paradoxically rescue alloantigen-specific TCM, especially within the CD4+ compartment in lymphoid and GVHD target tissues, thus predisposing patients to cGVHD. These data provide further evidence to caution against CNI-based immune suppression without concurrent approaches that eliminate alloreactive T cell clones.

Effect of Transplanted Bone Marrow on Spleen of Irradiated Pregnant Rats and Their Fetuses.

<b>Background and Objective:</b> Prenatal ionizing radiation exposure may hinder fetal and embryonic growth depending on the dose and gestational age. The current study's objective was to discover how bone marrow transplants affected the spleens of pregnant rats that had been subjected to γ (Gamma) radiation. <b>Materials and Methods:</b> Sixty rats that were pregnant were separated into five different groups, each with 6 females. The pregnant rats in the second Group were exposed to 2Gy of γ-rays. Group III; pregnant rats subjected to 2Gy of γ-rays, followed by an intraperitoneal injection of newly prepared bone marrow transplantation (BMT). The fifth Group were exposed to 2Gy γ-rays and received 1 dosage of BMT an hour later. Spleen samples from the pregnant rats as well as their fetuses were taken for histological and histochemical analyses. <b>Results:</b> Gamma rays damaged the splenic tissue of women and their fetuses on days 7 or 14 of pregnancy in a variety of histological and histochemical ways, although bone marrow transplantation significantly reduced the damage. Treated mothers with bone marrow post-radiation showed a noticeable recovery in spleen of their fetuses. Improved spleen architecture was accompanied by appearance of normal content of collagen, polysaccharides and total protein in the fetal spleen tissue especially on day 7 of gestation. <b>Conclusion:</b> Bone marrow transplantation can lessen the damage caused by gamma radiation.

Transplantation of Donor-Recipient Chimeric Cells Restores Peripheral Blood Cell Populations and Increases Survival after Total Body Irradiation-Induced Injury in a Rat Experimental Model.

Current therapies for acute radiation syndrome (ARS) involve bone marrow transplantation (BMT), leading to graft-versus-host disease (GvHD). To address this challenge, we have developed a novel donor-recipient chimeric cell (DRCC) therapy to increase survival and prevent GvHD following total body irradiation (TBI)-induced hematopoietic injury without the need for immunosuppression. In this study, 20 Lewis rats were exposed to 7 Gy TBI to induce ARS, and we assessed the efficacy of various cellular therapies following systemic intraosseous administration. Twenty Lewis rats were randomly divided into four experimental groups (n = 5/group): saline control, allogeneic bone marrow transplantation (alloBMT), DRCC, and alloBMT + DRCC. DRCC were created by polyethylene glycol-mediated fusion of bone marrow cells from 24 ACI (RT1a) and 24 Lewis (RT11) rat donors. Fusion feasibility was confirmed by flow cytometry and confocal microscopy. The impact of different therapies on post-irradiation peripheral blood cell recovery was evaluated through complete blood count, while GvHD signs were monitored clinically and histopathologically. The chimeric state of DRCC was confirmed. Post-alloBMT mortality was 60%, whereas DRCC and alloBMT + DRCC therapies achieved 100% survival. DRCC therapy also led to the highest white blood cell counts and minimal GvHD changes in kidney and skin samples, in contrast to alloBMT treatment. In this study, transplantation of DRCC promoted the recovery of peripheral blood cell populations after TBI without the development of GVHD. This study introduces a novel and promising DRCC-based bridging therapy for treating ARS and extending survival without GvHD.