The Application of Umbilical Cord Blood-derived Platelet Gel for Skin Ulcers Associated With Chronic Graft-Versus-Host Disease in Pediatrics: A Randomized Trial.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative strategy against a variety of malignant and nonmalignant disorders. However, acute and chronic graft-versus-host disease (aGVHD and cGVHD, respectively) commonly complicate this approach, culminating in substantial morbidities and mortalities. The integumentary system is the preponderant organ involved in cGVHD, and its response to existing treatments, including well-versed immunosuppressants and novel targeted therapies, is not desirable. Despite the rarity, ulcers of sclerotic skin cGVHD are treatment-refractory and associated with significant morbidities and an exaggerated risk of infectious complications. Platelet-rich plasma (PRP) and its derivatives are endowed with growth factors and proangiogenic molecules and hold regenerative potential. This study aimed to assess the safety and efficacy of the application of platelet gel-containing dressing against ulcerative skin cGVHD in pediatric patients. This randomized trial is conducted at the hematopoietic stem cell transplantation unit of the Children's Medical Center Hospital in Tehran, Iran. Twenty-one pediatric patients (aged between 5 and 15 years) were initially enrolled, and 16 met the inclusion criteria. All cases (4 females) were recipients of allo-HSCT who had been complicated with symmetrically or near-symmetrically ulcerative sclerotic skin cGVHD. Fresh umbilical cord blood (UCB) was obtained from healthy donors and underwent centrifugation using a novel PRP preparation kit in a single-step process. Platelet gel was produced by adding thrombin to the isolated buffy coat layer. Two similar ulcers of each patient were randomized to receive either conventional dressing or platelet gels up to 6 times. At each time point evaluation, ulcer size and its relative reduction compared to the basal size were recorded. Included patients received a total of 80 platelet gel-containing dressings. While the mean sizes of randomized ulcers at the beginning of the study were similar, their differences became significant 15 days after the initiation of intervention (P = .019). In addition, the mean reduction in the ulcers' surface area (in comparison to their baseline values) was significantly higher for the intervention arm at all evaluation points (P = .001 for day 5 and P < .001 for subsequent time points). At the end of the trial, the number of ulcers with a more than 50% reduction in size was 14 (87.5%) in the intervention arm (including 6 completely healed ulcers) versus 1 (6.25%, which was not completely healed) in the control arm (P < .001). None of the patients exhibited any localized or systemic treatment-related adverse events. In this study, using a relatively large number of cases, we showed that UCB-derived platelet gel is a safe, feasible, and effective curative approach for skin ulcers of sclerotic skin cGVHD in pediatric patients. Designing upcoming trials on the efficacy of this therapeutic approach for ocular, mucosal, and acute skin GVHD is prudent. Retrospectively registered at the Iranian Registry of Clinical Trials (registration number IRCT20190101042197N1) on August 24, 2020.

Posterior Reversible Encephalopathy Syndrome in Pediatric Hematopoietic Stem Cell Transplantation with Beta Major Thalassemia: The Association between the PRES Occurrence and Class of Beta Major Thalassemia.

INTRODUCTION: Allogeneic hematopoietic stem cell transplantation (HSCT) is the only definitive curative option for ß-major thalassemia patients (ß-MT). Posterior reversible encephalopathy syndrome (PRES) is a pervasive neurological complication which typically occurs following HSCT. ß-MT patients are prone to a higher PRES incidence due to long-term immunosuppression; thus, it is imperative that these patients are closely monitored for PRES after HSCT. PATIENTS AND METHODS: We included 148 pediatric patients with ß-MT who underwent HSCT between March 2015 and August 2022 in Children's Medical Center. Patients in this study were divided into two groups. The association between PRES and class of ß-MT and other risk factors were assessed and the overall survival rate was determined. RESULTS: Fourteen out of 112 patients (12%) with class I and II ß-MT developed PRES. However, PRES occurred in 11 out of 36 patients (30.5%) with ß-MT-III. Our results indicated that there was a significant association between class III ß-MT and the occurrence of (P = .004). Additionally, acute graft-versus-host disease (aGVHD) occurred in 80% and 44.7% of patients in the PRES and non-PRES groups, respectively (P = .001). The results of the Kaplan-Meier analysis revealed that the 5-year overall survival (OS) was 75.6% in the PRES group versus 95% in the non-PRES group, which was statistically significant (P = .001). CONCLUSION: Based on our results, pediatric ß-MT III patients are at a higher risk of developing PRES. Additionally, pediatric ß-MT patients with a history of aGVHD, regardless of disease class, are more likely to develop PRES. Considering these results, PRES has a higher chance of being the etiology of symptoms and should be considered more often in these patients.

The Reconstitution of T-cells after Allogeneic Hematopoietic Stem Cell Transplant in a Pediatric Patient with Congenital Amegakaryocytic Thrombocytopenia (CAMT).

BACKGROUND: Congenital amegakaryocytic thrombocytopenia (CAMT) is a bone marrow failure syndrome with autosomal recessive inheritance characterized by the lack of megakaryocytes and thrombocytopenia. The cause of the disease is a mutation in the c-Mpl gene, which encodes the thrombopoietin (TPO) receptor. The main treatment for this genetic disorder is an allogeneic hematopoietic stem cell transplant (allo-HSCT). However, transplant-related mortality, development of acute and chronic graft-versushost disease (GvHD), and susceptibility to opportunistic infections are major barriers to transplantation. Delay in the reconstitution of T cells and imbalance in the regeneration of distinct functional CD4 and CD8 T-cell subsets mainly affect post-transplant complications. We report a case of CAMT, who developed acute GvHD but had no signs and symptoms of chronic GvHD following allo-HSCT. CASE PRESENTATION: At the age of four, she presented with petechiae and purpura. In laboratory investigations, pancytopenia without organomegaly, and cellularity less than 5% in bone marrow biopsy, were observed. A primary diagnosis of idiopathic aplastic anemia was made, and she was treated with prednisolone, cyclosporine, and anti-thymocyte globulin (ATG), which did not respond. Genetic analysis revealed the mutation c.1481T>G (p. L494W) in exon 10 of the c-Mpl gene, and the diagnosis of CAMT was confirmed. The patient underwent allo-HSCT from a healthy sibling donor. Alloimmunization reactions and immune disorders were present due to long-term treatment with immunosuppressive medications and repeated blood and platelet transfusions. Hence, the regeneration of T-lymphocytes after allo-HSCT was evaluated. CONCLUSION: Successful treatment of acute GvHD prevented advancing the condition to chronic GvHD, and this was accompanied by delayed T-cell reconstitution through an increase in Treg:Tcons ratio.

Report on hematopoietic cell transplantations performed in 2018/2019 focusing on the trends of selection of stem cell sources in the Asia-Pacific region: APBMT Activity Survey.

The number of hematopoietic stem cell transplantations (HCTs) is increasing annually worldwide, and the Asia-Pacific (AP) region is no exception. We report on the absolute number of HCTs in 2018 and 2019 and the trends in graft selection and disease indication in the past few decades. In 2018, 24,292 HCTs were performed in the AP region, of which 8,754 (36.0%) were autologous and 15,538 (64.0%) were allogeneic. Among the allogeneic HCTs, 10,552 (67.9%) of the recipients were related to their donors, whereas 4,986 (32.1%) were unrelated. In 2019, 27,583 HCTs were reported, of which 17,613 (63.9%) were allogeneic and 9,970 (36.1%) were autologous. Although, in 2010, there was a nearly equal number of related and unrelated HCTs, the difference has shown an annual increase, with more than double (2.05) the number of related than unrelated HCTs in 2019. Recent trends in the AP region show that peripheral blood has overwhelmingly surpassed the bone marrow as a graft source for both related and unrelated HCTs, with the haploidentical donor type being preferred; however, their trends in each country/region were quite different among countries/regions. In 2019, the main conditions requiring HCT were acute myelogenous leukemia (n=6,629 [24.0%]), plasma cell disorders (PCD) (n=4,935 [17.9%]), malignant lymphoma (ML) (n=4,106 [14.9%]), acute lymphoblastic leukemia (AML) (n=3,777 [13.7%]), myelodysplastic syndrome or myelodysplastic/myeloproliferative neoplasm (n=1,913 [6.9%]), severe aplastic anemia (n=1,671 [6.1%]), and hemoglobinopathy (n=910 [3.3%]). PCD and ML were the main indications for autologous HCT, and the number of PCD cases has grown more prominent than the corresponding of ML. The increased number of allogeneic transplants for hemoglobinopathy remains prominent, as well as that of AML and acute lymphocytic leukemia for the past 5 years. There was a significant regional variation in the number of facilities performing HCTs, ranging from one in Mongolia and Nepal to 313 in Japan, and differing regional densities varying from 0.1 in Indonesia and Pakistan to 24.7 in Japan. The total transplant density per 10 million population in each country/region also differed (0.2 in Indonesia and 627 in New Zealand). This annual Activity Survey aims to help all participating countries/regions understand the changes in HCT, serve as an asset in promoting HCT activities in the AP region, and be used as a reference for comparison with other registries from Europe and the United States.

A comprehensive comparison between TBI vs non-TBI-based conditioning regimen in pediatric patients with acute lymphoblastic leukemia: A systematic review and meta-analysis.

INTRODUCTION: We aimed to evaluate the efficacy, safety, and latent toxicity of total body irradiation (TBI)-based conditioning regimens compared to non-TBI regimens for pediatric patients (under 18 years old) with acute lymphoblastic leukemia (ALL) undergoing allogeneic hematopoietic stem cell transplantation (HSCT). METHODS: A systematic search was performed on MEDLINE, Scopus, WOS, and PMC. Also, a search for grey literature was performed on Google Scholar and relevant articles' references were included. Relevant articles which met the inclusion criteria were retrieved up to October 31th, 2022. CMA version 2 was used for the quantitative synthesis of the data. RESULTS: Eight studies on efficacy and safety of TBI and non-TBI as a conditioning regimen were analyzed and six comparative studies on late toxicity were investigated. The meta-analysis revealed a hazard ratio (HR) of 1.508 (95% CI 0.96-2.35) for overall survival (OS) in instances of non-TBI conditioning. Also, an HR of 1.503 (95% CI 1.006-2.25) for disease-free- survival (DFS) favoring TBI-based conditioning. Late complications were reported to be significantly higher in the TBI conditioning regimen group than in the non-TBI group. CONCLUSION: It appears that non-TBI regimens are as effective as TBI regimens in pediatrics with ALL regarding OS. Occurrence of latent toxicity is higher with TBI conditioning regimen. Conversely, TBI-based regimens are superior to non-TBI conditioning regimens regarding DFS. Considering all aspects, non-TBI conditioning regimens can be an alternative treatment option for pediatric ALL undergoing HSCT.

Evaluation of safety and efficacy of allogeneic adipose tissue-derived mesenchymal stem cells in pediatric bronchiolitis obliterans syndrome (BoS) after allogeneic hematopoietic stem cell transplantation (allo-HSCT).

BACKGROUND: Allo-HSCT is a definite approach for the management of a wide variety of lethal and debilitating malignant and non-malignant disorders. However, its two main complications, acute and chronic graft-versus-host disease (GVHD), exert significant morbidities and mortalities. BoS, as a manifestation of chronic lung GVHD, is a gruesome complication of allo-HSCT, and for those with steroid-refractory disease, no approved second-line therapies exist. Mesenchymal stem cells (MSCs) exert anti-inflammatory and growth-promoting effects, and their administration against a wide range of inflammatory and neurologic disorders, as well as GVHD, has been associated with promising outcomes. However, literature on the safety and effectiveness of MSC therapy for BoS and pediatric cGVHD is scarce. METHODS: We designed a single-arm trial to administer adipose tissue (AT)-derived MSCs to pediatric patients with refractory BoS after allo-HSCT. AT-MSCs from obese, otherwise healthy donors were cultured in an ISO class 1 clean room and injected into the antecubital vein of eligible patients with a dose of 1 × 106/kg. The primary endpoints included a complete or partial response to therapy [in terms of increased forced expiratory volume in one second (FEV1) values and steroid dose reduction] and its safety profile. RESULTS: Four eligible patients with a median age of 6.5 years were enrolled in the study. Steroid-induced osteoporosis and myopathy were present in three cases. A partial response was evident in three cases after a single injection of AT-MSCs. The treatment was safe and tolerable, and no treatment-related adverse events were noted. Two patients developed manageable COVID-19 infections one and 4 months after AT-MSC injection. After a median follow-up duration of 19 months, all cases are still alive and have had no indications for lung transplantation. CONCLUSIONS: AT-MSCs could be safely administered to our pediatric cases with BoS post-allo-HSCT. Considering their advanced stage of disease, their sub-optimal functional capacity due to steroid-induced complications, and COVID-19 infection post-treatment, we believe that AT-MSC therapy can have possible efficacy in the management of pediatric BoS. The conduction of further studies with larger sample sizes and more frequent injections is prudent for further optimization of AT-MSC therapy against BoS. Trial registration Iranian Registry of Clinical Trials (IRCT), IRCT20201202049568N2. Registered 22 February 2021, https://en.irct.ir/trial/53143 .

Clinical, Immunological, and Genetic Findings in Iranian Patients with MHC-II Deficiency: Confirmation of c.162delG RFXANK Founder Mutation in the Iranian Population.

PURPOSE: Major histocompatibility complex class II (MHC-II) deficiency is a rare inborn error of immunity (IEI). Impaired antigen presentation to CD4 + T cells results in combined immunodeficiency (CID). Patients typically present with severe respiratory and gastrointestinal tract infections at early ages. Hematopoietic stem cell transplantation (HSCT) is the only curative therapy. METHODS: We describe the clinical, immunologic, and genetic features of eighteen unrelated Iranian patients with MHC-II deficiency. RESULTS: Consanguinity was present in all affected families. The median age at the initial presentation was 5.5 months (range 7 days to 18 years). The main symptoms included failure to thrive, persistent diarrhea, and pneumonia. Autoimmune and neurologic features were also documented in about one-third of the patients, respectively. Thirteen patients carried RFXANK gene mutations, two carried RFX5 gene mutations, and three carried a RFXAP gene mutation. Six patients shared the same RFXANK founder mutation (c.162delG); limited to the Iranian population and dated to approximately 1296 years ago. Four of the patients underwent HSCT; three of them are alive. On the other hand, nine of the fourteen patients who did not undergo HSCT had a poor prognosis and died. CONCLUSION: MHC-II deficiency is not rare in Iran, with a high rate of consanguinity. It should be considered in the differential diagnosis of CID at any age. With the limited access to HSCT and its variable results in MHC-II deficiency, implementing genetic counseling and family planning for the affected families are mandatory. We are better determined to study the c.162delG RFXANK heterozygous mutation frequency in the Iranian population.

Disturbance in the reconstitution of distinct T-cell subsets and the incidence of GvHD following allo-HSCT in pediatric patients with non-malignant hematological disorders.

BACKGROUND: The reconstitution of different T-cell subsets following allogeneic hematopoietic stem cell transplantation (allo-HSCT) is critical for efficient pathogen protection and the prevention of graft-versus-host disease (GvHD). In particular, studies have highlighted the importance of balanced ratios of regulatory T-cells (Tregs) and distinct functionally T-cells in preventing acute and chronic GvHD. METHODS: We evaluated the regeneration of CD4 and CD8 T-cell subpopulations in nine pediatric patients with non-malignant disorders following allo-HSCT from a fully HLA-identical donor. RESULTS: CD4 and CD8 T-cells were higher 12 months after the transplant but still lower than in healthy controls and pre-transplant. However, we found after allo-HSCT, central memory and effector memory cell subsets were the predominant phenotypes in the CD4 and CD8 T-cell populations, respectively. In patients who had developed acute GvHD, there was an increase in the frequency of TEMRA (effector memory T cells that re-express CD45RA) cells within the CD4 T-cell population. Meanwhile, in patients with chronic GvHD, we observed a decrease in Th1 cells in CD4 T-cells and effector memory cells within the CD8 T-cell population. In addition, we found decreased TEMRA cell subsets in CD4 and CD8 T-cell populations in chronic GvHD. CONCLUSION: Our findings suggest a possible relationship between the influence of acute GvHD and its prevention on delayed CD4 T-cell reconstitution and, reciprocally, unbalanced regeneration of CD4 and CD8 T-cell subsets in the development of chronic GvHD.

Clinical and immunological characteristics of 69 leukocyte adhesion deficiency-I patients.

BACKGROUND: In order to support the comprehensive classification of Leukocyte Adhesion Deficiency-I (LAD-I) severity by simultaneous screening of CD11a/CD18, this study assessed clinical, laboratory, and genetic findings along with outcomes of 69 LAD-I patients during the last 15 years. METHODS: Sixty-nine patients (40 females and 29 males) with a clinical phenotype suspected of LAD-I were referred to Immunology, Asthma, and Allergy research institute, Tehran, Iran between 2007 and 2022 for further advanced immunological screening and genetic evaluations as well as treatment, were enrolled in this study. RESULTS: The diagnosis median age of the patients was 6 months. Delayed umbilical cord separation was found in 25 patients (36.2%). The median diagnostic delay time was 4 months (min-max: 0-82 months). Forty-six patients (66.7%) were categorized as severe (CD18 and/or CD11a: below 2%); while 23 children (33.3%) were in moderate category (CD18 and/or CD11a: 2%-30%). During the follow-ups, 55.1% of children were alive with a mortality rate of 44.9%. Skin ulcers (75.4%), omphalitis (65.2%), and gingivitis (37.7%) were the most frequent complaints. Genetic analysis of the patients revealed 14 previously reported and three novel pathogenic mutations in the ITGB2 gene. The overall survival of patients with and without hematopoietic stem cell transplantation was 79.3% and 55.6%, respectively. CONCLUSION: Physicians' awareness of LAD-I considering delayed separation of umbilical cord marked neutrophilic leukocytosis, and variability in CD11 and CD18 expression levels, and genetic analysis leads to early diagnosis and defining disease severity. Moreover, the prenatal diagnosis would benefit families with a history of LAD-I.

Intra-lesion injection of activated Natural Killer (NK) cells in recurrent malignant brain tumors.

Despite multi-modal therapies for patients with malignant brain tumors, their median survival is < 2 years. Recently, NK cells have provided cancer immune surveillance through their direct natural cytotoxicity and by modulating dendritic cells to enhance the presentation of tumor antigens and regulate T-cell-mediated antitumor responses. However, the success of this treatment modality in brain tumors is unclear. The main reasons are; the brain tumor microenvironment, the NK cell preparations and administration, and the donor selection. Our previous study showed that intracranial injection of activated haploidentical NK cells resulted in the eradication of glioblastoma tumor mass in the animal model without any evidence of tumor recurrence. Therefore, in the present study, we evaluated the safety of intra-surgical cavity or intra cerebrospinal fluid (CSF) Injectionofex vivoactivated haploidentical NK cells in six patients with recurrent glioblastoma multiform (GBM) and malignant brain tumors resistance to chemo/radiotherapy. Our results indicated that activated haploidentical NK cells express activator and inhibitor markers and can kill the tumor cells. However, their cytotoxic potential on patient-derived GBM (PD-GBM) was more than that of its cell line. Also, their infusion increased the overall disease control rate by about 33.3%, with a mean survival of 400 days. Moreover, we showed that local administration of the activated haploidentical NK cells in malignant brain tumors is safe, feasible, tolerated at higher doses, and cost-effective.

Fanconi anemia phenotypic and transplant outcomes' associations in Iranian patients.

Objectives: Fanconi anemia (FA) is a rare, heterogeneous, inherited disorder. Allogeneic hematopoietic stem cell transplantation (HSCT) represents the only therapeutic option to restore normal hematopoiesis. This study reports the outcomes of FA-HSCT patients and identifies factors, including clinical phenotype. Our team examined more than 95% of Iranian FA patients during the last decade. Study Design: One hundred and six FA patients (age range: 2-41) who underwent HSCT from March 2007 to February 2018 were enrolled. Clinical characteristics of genetic disease, pre-HSCT findings, HSCT indication, and long-term follow-up evaluated and recorded. Data were analyzed using SPSS 19.0. Results: The mean follow-up period for survivors was 36 months (range, 1-101). The 3-year overall survival (OS) and disease-free survival were 72.2% and 71.2%, respectively. The 3-year OS rate for patients with limited and extensive malformations was 78.8% and 56.6%, respectively (p = 0.025). Acute graft versus host disease incidence was 60.52% for patients with limited malformations versus 70% for patients with extensive ones (p = 0.49). Chronic graft versus host disease incidence for these two groups was 9.21% and 10%, respectively (p = 0.91). Conclusions: OS was not associated with each of the malformations singly; however, it was lower in the extensive group. The younger age of patients at the HSCT time leads to a higher OS. The differences in FA patients' outcomes and the various genotypes were probably related. These data provide a powerful tool for further studies on genotype-phenotype association with HSCT results.

Total body irradiation-free haploidentical peripheral blood stem cell transplantation compared to related and unrelated donor transplantation in pediatrics with acute lymphoblastic leukemia.

BACKGROUND: Acute lymphoblastic leukemia (ALL) is the most prevalent childhood cancer under the age of 15 years. Despite the recent advances in therapeutic regimens, relapse occurs in 15%-20% of pediatric patients after chemotherapy, and hematopoietic stem cell transplantation (HSCT) is the best treatment option. However, donor availability is one of the major challenges. Over the last decade, haploidentical donor (HID) transplantation has evolved as an alternative option. Herein, we aimed to compare the transplant outcomes in pediatric patients receiving total body irradiation (TBI)-free myeloablative regimens, between non-HID and HID transplant. PATIENTS AND METHODS: The study included 60 pediatric ALL patients who had undergone HSCT from October 2016 until September 2020. Forty-three patients received non-HID HSCT, while 17 patients received HID. The sources of stem cells (SC) were peripheral blood stem cells (PBSC) for all the patients. The conditioning regimen was based on busulfan and cyclophosphamide. For graft-versus-host disease (GvHD) prophylaxis, patients received cyclosporine and methotrexate in the setting of non-HID transplantation, where HIDs received post-transplant cyclosporine and cyclophosphamide. RESULTS: The cumulative incidences of 3-year overall survival (OS) were 73.1%, 66.6%, and 69.5%, for matched sibling donor-matched related donor (MSD-MRD), matched unrelated donor-mismatched unrelated donor (MUD-MMUD), and HID groups, respectively (p = .85). The cumulative incidences of grade II-IV acute GvHD for the MRD, MUD-MMUD, and HID groups were 29%, 41%, and 49%, respectively (p = .47). Furthermore, the 3-year cumulative incidence of chronic GvHD was MSD-MRD: 70% versus MUD-MMUD: 42% versus HID: 45% (p = .64). The 3-year cumulative incidence of relapse post transplantation was 45%, 18%, and 45%, respectively, for the MSD-MRD, MUD-MMUD, and HID groups, and the differences were not statistically significant (p = .55). There was a higher risk for cytomegalovirus (CMV) infection in patients receiving HID transplants compared to those of non-HIDs (p < .01). CONCLUSION: Our results indicate that PBSC-HID transplant outcomes in the setting of non-TBI conditioning are comparable to those of non-HIDs in pediatric ALL patients.

T helper 17 and regulatory T-cell profile and graft-versus-host disease after allogeneic hematopoietic stem cell transplantation in pediatric patients with beta-thalassemia.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an effective treatment option for hereditary hemoglobin disorders, such as beta-thalassemia; However, this procedure is not without constraints, mainly engendering complications such as acute graft-versus-host disease (aGvHD), chronic GvHD (cGvHD), and susceptibility to infections. The clinical outcomes of allo-HSCT are highly dependant on the quality and quantity of T-cell subsets reconstitution. Following the allo-HSCT of six pediatric patients afflicted with beta-thalassemia, their mononuclear cells were isolated, and then cultured with a combination of phorbol myristate acetate (PMA)/ionomycin and Brefeldin A. The content of CD4 T-cell subsets, including T helper 17 (Th17) cells and regulatory T cells (Tregs), were determined by specific conjugated-monoclonal antibodies three and six months post-HSCT. An increased frequency of total CD4 T-cells, Tregs and Th17 cells was observed at day 90 and 180 after allo-HSCT, albeit the numbers were still lower than that of our healthy controls. In patients who developed cGvHD, a lower Th17/Treg ratio was observed, owing it to a decreased proportion of Th17 cells. In conclusion, creating balance between Th17 and Treg subsets may prevent acute and chronic GvHD in patients after allo-HSCT.

Effect of Early Bacillus Calmette-Guerin Vaccination of Pediatric Severe Combined Immunodeficiency Patients on the Outcome of Hematopoietic Stem Cell Transplantation Using a Reduced-Intensity Conditioning Regimen.

The eminence of Bacillus Calmette-Guerin (BCG) vaccine in newborn vaccination programs has been conspicuous throughout the years, especially in low-income developing countries where tuberculosis is prevalent; however, application of the BCG vaccine is not without constraints, especially in patients afflicted with immunodeficiency diseases, such as severe combined immunodeficiency (SCID). The present study aimed to evaluate whether the administration of BCG vaccine at birth could improve the outcomes of hematopoietic stem cell transplantation (HSCT) in pediatric patients with SCID. In this study, 30 SCID patients who underwent HSCT using a reduced-intensity conditioning regimen (RIC) were followed-up for 2 years post-HSCT. The outcomes of HSCT were evaluated in both non-BCG-vaccinated patients (n = 12) and BCG-vaccinated patients (n = 18). Our results show a higher incidence of acute graft-versus-host disease (aGVHD), but not of chronic GVHD, in the BCG-vaccinated patients, and a similar overall survival (OS) rate in the 2 groups. We speculate that the similar OS rate in the 2 groups, despite the risk of BGC vaccination, was because this group received an RIC conditioning regimen. There was no other difference between the 2 groups. Considering the effect of the BCG vaccine on HSCT outcome, we suggest that the administration of BCG vaccine be deferred until age 3 months so that APT testing without the interference of maternal antibodies can be performed. However, this study could benefit from a larger cohort to further validate our findings, as the possible reason for some factors not being statistically significant was our small sample size.

Spontaneous xenogeneic GvHD in Wilms' tumor Patient-Derived xenograft models and potential solutions.

Severely immunocompromised NOD.Cg-Prkdcscid Il2rgtm1Sug (NOG) mice are among the ideal animal recipients for generation of human cancer models. Transplantation of human solid tumors having abundant tumor-infiltrating lymphocytes (TILs) can induce xenogeneic graft-versus-host disease (xGvHD) following engraftment and expansion of the TILs inside the animal body. Wilms' tumor (WT) has not been recognized as a lymphocyte-predominant tumor. However, 3 consecutive generations of NOG mice bearing WT patient-derived xenografts (PDX) xenotransplanted from a single donor showed different degrees of inflammatory symptoms after transplantation before any therapeutic intervention. In the initial generation, dermatitis, auto-amputation of digits, weight loss, lymphadenopathy, hepatitis, and interstitial pneumonitis were observed. Despite antibiotic treatment, no response was noticed, and thus the animals were prematurely euthanized (day 47 posttransplantation). Laboratory and histopathologic evaluations revealed lymphoid infiltrates positively immunostained with anti-human CD3 and CD8 antibodies in the xenografts and primary tumor, whereas no microbial infection or lymphoproliferative disorder was found. Mice of the next generation that lived longer (91 days) developed sclerotic skin changes and more severe pneumonitis. Cutaneous symptoms were milder in the last generation. The xenografts of the last 2 generations also contained TILs, and lacked lymphoproliferative transformation. The systemic immunoinflammatory syndrome in the absence of microbial infection and posttransplant lymphoproliferative disorder was suggestive of xGvHD. While there are few reports of xGvHD in severely immunodeficient mice xenotransplanted from lymphodominant tumor xenografts, this report for the first time documented serial xGvHD in consecutive passages of WT PDX-bearing models and discussed potential solutions to prevent such an undesired complication.

Adoptive NK-cell transfer as a potential treatment paradigm for Wilms tumor: A preclinical study.

BACKGROUND: Natural killer (NK) cell therapy has been shown to be effective in the treatment of some cancers. However, the effects of this adoptive immunotherapy have not been investigated for Wilms tumor (WT). In this study, the effects of adoptive NK-cell transfer on a patient-derived xenograft (PDX) model of anaplastic WT were evaluated, and the impacts of cell source and ex vivo activation strategy on the therapeutic efficacy of NK-cell product were appraised. METHODS: NK cells were isolated from human peripheral blood mononuclear cells (NKPB ) and human cord blood (NKCB ), and were expanded and activated using a cytokine cocktail. Another group of NK cells (NKET ) was produced through activation with the exosomes extracted from previously challenged NKPB cells with WT. PDX-bearing mice were treated with clinically relevant doses of NKPB , NKCB , NKET , standard chemotherapy, and placebo (phosphate-buffered saline). RESULTS: PDX models treated with NKCB showed a better survival rate, though the difference among the study groups was not significant. Compared with the placebo control group, NKCB significantly improved the histopathologic response, NKPB significantly inhibited the proliferation of neoplastic cells, and NKET led to a significant decrease in the metastasis score (all p-values <.05). Standard chemotherapy provided the greatest tumor growth inhibition and the lowest mitotic count, though it did not show any significant advantage over NK-cell therapies in any of the outcome parameters in two-by-two comparisons. CONCLUSIONS: This study spotlights the efficacy of adoptive NK-cell transfer as a potential treatment candidate for high-risk WT.

Escalated Dose Donor Lymphocyte Infusion Treatment in Patients with Primary Immune Deficiencies After HSCT with Reduced-Intensity Conditioning Regimen.

OBJECTIVE/BACKGROUND: Mixed chimerism is a major concern after allogenic hematopoietic stem cell transplantation (HSCT) using a reduced-intensity conditioning (RIC) regimen in primary immunodeficiencies (PIDs). A donor lymphocyte infusion (DLI) escalating dose regimen has been developed with the aim of reducing toxicity while preserving efficacy. However, the graft-versus-host disease (GvHD) development remains the most common and adverse effect of DLI and continues to be a limiting factor in its application, especially nonmalignant diseases such as PIDs. We prospectively evaluated PID patients after HSCT using RIC in Childrens Medical Center, who were candidates for an escalating dose of DLI for MC from 2016 to 2018. METHODS: With the median follow-up of 16.4 months, 12 patients (nine males and three females) with a median age of 3.72 years received DLI. The median number of DLI was 3.2 (range, 1-5), the maximum and total dose of DLIs administered per patient were 3.6 × 107 (range, 1-5) cells/kg CD3+ and 9.3 × 107 (range, 1-15) cells/kg CD3+ cells, respectively. RESULTS: Median donor chimerism at baseline before the DLIs was 41% (range, 11-73%), patients received DLIs at a median of 105 (range, 37-230) days and 52 (range, 3-168) days after the HSCT and onset of the MC, respectively. At the final assessment, six (54.5%) patients improved after DLIs at a median of 47.3 days. CONCLUSION: PID patients may benefit from DLI with an escalating dose regimen, but the GvHD development remains a concern during the DLI, and the optimum dose and frequency must be standardized.

Fludarabine-based Reduced Intensity Conditioning for Allogeneic Hematopoietic Stem Cell Transplantation in a Pediatric Patient With Bone Marrow Failure Syndrome Type 3.

Bone marrow failure syndrome (BMFS) type 3 is a rare genetic heterogeneous disorder, considered to be one of Inherited BMFSs related to ribosomopathies. It caused by a novel Homozygous variant in DNAJC21 gene, which affects cytoplasmic maturation of 60S ribosomal, leading to increase cell death, and inhibits cellular proliferation causing shwachman-diamond Syndrome-like syndrome. Only 15 cases of BMFS type 3 have been published in the literature. Therefore, the full phenotypic spectrum and the experience of hematopoietic stem cell transplantation (HSCT) are limited. Herein, we report an uncomplicated HSCT from human leukocyte antigen-identical sibling for a BMFS-3 patient at 22 months of age, who suffered from chronic diarrhea, severe failure to thrive and cytopenia required transfusions. We used a reduced intensity conditioning regimen including fludarabine, low-dose cyclophosphamide, and antithymocyte globulin with cyclosporine for prevent graft versus host disease. This regimen was safe and sufficient to achieve rapid engraftment without significant toxicity. Although, Mixed chimerism between 80% and 90% was observed since day +30, she gained 2 kg during 12 months post-transplant and no need for transfusions has been reported any more. Thus, we recommend HSCT with fludarabine-based reduced intensity conditioning regimen in this syndrome as progressive cytopenia occurs and an human leukocyte antigen-matched family donor is available.