Post Hematopoietic Stem Cell Transplantation Research Articles

Risk factors for positive post-transplantation measurable residual disease in patients with acute lymphoblastic leukemia.

The level of measurable residual disease (MRD) before and after transplantation is related to inferior transplant outcomes, and post-hematopoietic stem cell transplantation measurable residual disease (post-HSCT MRD) has higher prognostic value in determining risk than pre-hematopoietic stem cell transplantation measurable residual disease (pre-HSCT MRD). However, only a few work has been devoted to the risk factors for positive post-HSCT MRD in patients with acute lymphoblastic leukemia (ALL). This study evaluated the risk factors for post-HSCT MRD positivity in patients with ALL who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT). A total of 1683 ALL patients from Peking University People's Hospital between January 2009 and December 2019 were enrolled to evaluate the cumulative incidence of post-HSCT MRD. Cox proportional hazard regression models were built for time-to-event outcomes. Multivariate analysis was performed to determine independent influencing factors from the univariate analysis. Both in total patients and in T-cell ALL or B-cell ALL, pediatric or adult, human leukocyte antigen-matched sibling donor transplantation or haploidentical SCT subgroups, positive pre-HSCT MRD was a risk factor for post-HSCT MRD positivity (P<0.001 for all). Disease status (complete remission 1 [CR1] vs. ≥CR2) was also a risk factor for post-HSCT MRD positivity in all patients and in the B cell-ALL, pediatric, or haploidentical SCT subgroups (P=0.027; P=0.003; P=0.035; P=0.003, respectively). A risk score for post-HSCT MRD positivity was developed using the variables pre-HSCT MRD and disease status. The cumulative incidence of post-HSCT MRD positivity was 12.3%, 25.1%, and 38.8% for subjects with scores of 0, 1, and 2-3, respectively (P<0.001). Multivariate analysis confirmed the association of the risk score with the cumulative incidence of post-HSCT MRD positivity and relapse as well as leukemia-free survival and overall survival. Our results indicated that positive pre-MRD and disease status were two independent risk factors for post-HSCT MRD positivity in patients with ALL who underwent allo-HSCT.

Prediction of early-phase cytomegalovirus pneumonia in post-stem cell transplantation using a deep learning model.

Diagnostic challenges exist for CMV pneumonia in post-hematopoietic stem cell transplantation (post-HSCT) patients, despite early-phase radiographic changes. The study aims to employ a deep learning model distinguishing CMV pneumonia from COVID-19 pneumonia, community-acquired pneumonia, and normal lungs post-HSCT. Initially, 6 neural network models were pre-trained with COVID-19 pneumonia, community-acquired pneumonia, and normal lung CT images from Kaggle's COVID multiclass dataset (Dataset A), then Dataset A was combined with the CMV pneumonia images from our center, forming Dataset B. We use a few-shot transfer learning strategy to fine-tune the pre-trained models and evaluate model performance in Dataset B. 34 cases of CMV pneumonia were found between January 2018 and December 2022 post-HSCT. Dataset A contained 1681 images of each subgroup from Kaggle. Combined with Dataset A, Dataset B was initially formed by 98 images of CMV pneumonia and normal lung. The optimal model (Xception) achieved an accuracy of 0.9034. Precision, recall, and F1-score all reached 0.9091, with an AUC of 0.9668 in the test set of Dataset B. This framework demonstrates the deep learning model's ability to distinguish rare pneumonia types utilizing a small volume of CT images, facilitating early detection of CMV pneumonia post-HSCT.

Pulmonary pathological changes in the patient undergoing lung transplantation after chronic graft-versus-host disease complicated by pulmonary infection post-hematopoietic stem cell transplantation: report of a case

Pulmonary pathological changes in the patient undergoing lung transplantation after chronic graft-versus-host disease complicated by pulmonary infection post-hematopoietic stem cell transplantation: report of a case

Comparative Study between Cyclosporine Dynamics and Other Immunosuppressants in Patients Post Allogenic Stem Cell Transplantation

Abstract Background Bone marrow transplant has been successfully to treat diseases such as leukemia, lymphomas, aplastic anemia, immune deficiency disorders, and some solid tumor cancers. There is two types of bone marrow transplantation, one of two types of transplant may be carried out either an autograft, using the patient’s own bone marrow cells or an allograft (or allogeneic transplant), which allows the replacement of the diseased bone marrow with an healthy bone marrow taken from a compatible donor (related or unrelated) and to use the immune system of the healthy donor to fight the recipient’s illness. Aim of the Work To assess impact of cyclosporine introduction post-transplant on different organs and other immune suppressant as regards side effects and prophylactic efficacy against GVHD and good outcome of the transplantation. Patients and Methods The study enrolled two groups, 128 post-transplant patient their ages between 16 and 65, group 1 include 106 patients was taking cyclosporine for prophylaxis of GVHD, group 2 include 22 patients was taking other immunosuppressants mainly Tacrolimus and MMF. Results Incidence of GVHD occurrence was lower in group of cyclosporine as 30.2 % of them has no GVHD with statistically significant difference with P-value 0.007 and was lower in combined occurrence of acute and chronic GVHD,22.6 % in group 1 and 54.5 % of group 2 with P-value 0.006 Incidence of mild anemia was lower in group 1 with statistically significant difference with P-value 0.022 Hyponatremia was higher in group 1 (60.4 %) with statistically significant difference with P-value 0.026 AST levels elevated one fold higher in group 1 with statistically significant difference with P-value 0.009 and elevated three fold higher in group 2 with statistically significant difference with P-value &amp;lt; 0.001 ALT levels elevated one fold higher in group 1 with statistically significant difference with P-value 0.039 21 patients were presented with impairment of renal functions,12.5% with mild impairment, 3.9 % with moderate impairment, all of them from group 1 with statistically significant difference with P-value 0.023, more commonly in females and in age group from 16 to 45 years old. Conclusion Hematopoietic stem cell transplantation (HSCT) is a particularly important treatment for hematologic malignant and nonmalignant diseases. Unfortunately, following allogeneic HSCT, graft-versus-host disease, immunosuppression and susceptibility to opportunistic infections remain among the most substantial problems restricting the efficacy and use of this procedure. Cyclosporine remains the most effective prophylaxis post HSCT for prevention of GVHD, more multi centric studies are needed on wide scale to prove more relevant results that will be significant.

Prognostic value of coexisting conditions and complications in pleuroparenchymal fibroelastosis: a single-center retrospective study.

Pleuroparenchymal fibroelastosis (PPFE) is a rare idiopathic interstitial lung disease (ILD) characterized by subpleural parenchymal fibrosis and elastosis mainly in the upper lobes. PPFE occurs in a secondary form that overlaps with underlying medical conditions or complications. This study evaluated the clinical impact of coexisting factors on the survival of patients with PPFE. Fifty-five PPFE patients were retrospectively evaluated. The patients' diagnoses were categorized as "idiopathic PPFE" with no known cause or "secondary PPFE" with underlying medical conditions or complications. The clinical characteristics and survival rates of these groups were compared. Twenty-eight patients (50.9%) were diagnosed with idiopathic PPFE and 27 (49.1%) with secondary PPFE, including cases of occupational dust exposure, connective tissue disease (CTD), post-hematopoietic stem cell transplantation (HSCT), and a family history of ILD. The idiopathic and secondary PPFE groups had similar clinical features, laboratory tests, and pulmonary function profiles, including a low body mass index, normal Krebs von den Lungen-6, high surfactant protein-D, and high residual volume/total lung capacity. In the secondary PPFE group, post-HSCT was associated with a worse prognosis, and CTD was associated with better prognosis. A multivariate analysis demonstrated that post-HSCT and a reduced forced vital capacity were significantly associated with a worsened survival in patients with PPFE. The prognosis of PPFE is highly influenced by underlying medical conditions or complications. Patients with post-HSCT PPFE should be monitored particularly closely, as they are at higher risk of a poor prognosis than others.

Varicella-Zoster Virus Reactivation After Pediatric Allogeneic Hematopoietic Stem Cell Transplantation, Single-Center Experience of Acyclovir Prophylaxis.

Varicella-zoster virus (VZV) reactivation is the most common infectious complication in the late posthematopoietic stem cell transplantation (HSCT) period and is reported as 16%-41%. Acyclovir prophylaxis is recommended for at least 1 year after HSCT to prevent VZV infections. However, studies on the most appropriate prophylaxis are ongoing in pediatric patients. Patients who underwent allogeneic HSCT between January 1, 1996 and January 1, 2020 were retrospectively analyzed to outline the characteristics of VZV reactivation after allogeneic HSCT in pediatric patients using 6 months acyclovir prophylaxis. There were 260 patients and 273 HSCTs. Median age was 10.43 (0.47-18.38), and 56% was male. Median follow-up was 2325 days (18-7579 days). VZV reactivation occurred in 21.2% (n = 58) at a median of 354 (55-3433) days post-HSCT. The peak incidence was 6-12 months post-HSCT (43.1%). Older age at HSCT, female gender, history of varicella infection, lack of varicella vaccination, low lymphocyte, CD4 count, and CD4/CD8 ratio at 9 and 12 months post-HSCT was found as a significant risk for herpes zoster (HZ) in univariate analysis, whereas history of varicella infection and low CD4/CD8 ratio at 12 months post-HSCT was an independent risk factor in multivariate analysis. Tailoring acyclovir prophylaxis according to pre-HCT varicella history, posttransplant CD4 T lymphocyte counts and functions, and ongoing immunosuppression may help to reduce HZ-related morbidity and mortality.

CD56bright NK cell expansion correlated with EBV reactivation control post allogeneic hematopoietic stem cell transplantation.

Natural killer (NK) cells are equipped with anti-Epstein-Barr virus (EBV) function, however, whether EBV infection will affect NK cells reconstitution after allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains unclear. To identify the characteristics of NK cells, we prospectively enrolled 11 patients who occurred EBV reactivation post allo-HSCT and 11 patients without EBV infection as control. We found that that EBV infection induced the expansion of CD56bright and NKG2A+KIR- NK subsets,and decreased the cytotoxicity function of NK cells. The frequency of NKG2A+KIR- NK cells were higher in patients who progressed into post-transplant lymphoproliferative disorder (PTLD) than EBV viremia patients, which also correlated with decreased proliferation and cytotoxic function. By screening the activation receptors of NK cells, we found the DNAM-1+CD56bright NK cells is significantly increased after EBV stimulation, further we demonstrated that DNAM-1 is essential for EBV induced NK cells activation as the cytokine release against EBV-transformed lymphoblastoid cell lines(EBV-LCLs) of CD56bright NK cells were significantly decreased after DNAM-1 blockade. NK cells infusion suppressed the progression of EBV-related tumor mice model. A prospective cohort indicated that old donor age was an independent risk factor for EBV infection. Rapid CD56bri expansion and high expression of DNAM-1 on CD56bri NK cells in response to EBV reactivation correlated with rapid EBV clearance post allo-HSCT in patients with younger donors. In summary, our data showed that high expression of DNAM-1 receptors on NK cell may participate protective CD56bri NK cells response to EBV infection after allo-HSCT.

Association of the pre-transplant CD4/CD8 ratio with the prognosis following allogeneic hematopoietic stem cell transplantation

The tumor microenvironment’s cells can promote or inhibit tumor formation, and there are no reports on the CD4/CD8 ratio’s association with outcomes post allogeneic hematopoietic stem cell transplantation (allo-HSCT). We retrospectively evaluated the pre-transplant peripheral blood CD4/CD8 ratio in 168 patients who underwent their first allo-HSCT for hematological malignancies at our institution. When patients were divided into two groups according to the median CD4/CD8 ratio 1.35 (range, 0.09–19.89), the high CD4/CD8 ratio group had a higher incidence of relapse, equivalent non-relapse mortality and worse overall survival (OS) than the low CD4/CD8 ratio group. In a multivariate analysis, the CD4/CD8 ratio was significantly associated with an increased risk of relapse, although there was a marginally significant difference in OS. The pre-transplant peripheral blood CD4/CD8 ratio could be a novel biomarker for predicting the prognosis of allo-HSCT.

Secondary oral squamous cell carcinoma following haematopoietic stem cell transplantation.

We report the cases of 10 patients with oral squamous cell carcinoma (SCC) post-haematopoietic stem cell transplant (HSCT). Median latency from HSCT to oral SCC diagnosis was 10 years (range: 4-17 years), with 90% (9/10) reporting a history of chronic graft-versus-host disease (cGVHD) and 40% (4/10) exhibiting active severe manifestations of oral GvHD. Clinical findings at diagnosis included induration, ulceration, tenderness, bleeding, hyperkeratosis, speckling and lymphadenopathy. The tongue and buccal mucosa were the most common sites affected. The disease stage at presentation ranged from T1N0M0 to T4N2M0. Management included surgical resection in 90% (9/10) of patients with or without chemotherapy and/or radiotherapy. The median follow-up for the cohort was 1 year, with a 50% (5/10) mortality rate. SCC-specific mortality was 30% (3/10). Our data highlight the importance of regular, active oral and cutaneous surveillance of patients post-HSCT in specialized dermatology clinics, irrespective of GvHD severity and length of iatrogenic immunosuppression.

Immuno-Hematologic Complexity of ABO-Incompatible Allogeneic HSC Transplantation.

ABO incompatibility is not considered a contraindication for hematopoietic stem cell transplantation (HSCT). Approximately 30% of transplants from related donors and up to 50% of transplants from unrelated donors are ABO incompatible. Immuno-hematologic investigations allow to estimate donor/recipient ABO mismatch and anti-A/B isohemagglutinin (IHA) titration in the pre-HSCT phase. Immediate hemolysis or delayed complications (passenger lymphocyte syndrome and pure red cell aplasia) can occur post HSCT. Some preventive measures take into consideration either decision-making algorithms based on the recipient's IHA titration or clinical protocols for the removal/reduction of IHAs through plasma exchange or immunoadsorption procedures. Product manipulation through red blood cell (RBC) and/or plasma depletion can also be taken into account. Currently, the best approach in the management of ABO-incompatible transplant is not defined in expert consensus documents or with solid evidence. In addition, the methods for IHA titration are not standardized. A transfusion strategy must consider both the donor's and recipient's blood group systems until the RBC engraftment catches on and ABO conversion (forward and reverse typing) is confirmed on two consecutive and independent samples. Therefore, ABO incompatibility in HSCT represents a demanding immuno-hematologic challenge and requires all necessary preventive measures, including the appropriate selection of ABO blood components for transfusion.

A prospective study of posttransplant cyclophosphamide for unrelated donor peripheral blood stem cell transplant with special attention to graft content and the impact of a higher γδ T cell dose.

Posttransplant cyclophosphamide (PtCy) has been shown to decrease post-hematopoietic stem cell transplant acute and chronic graft-versus-host disease (GVHD). In this study, PtCy was used in 44 patients along with mycophenolate and tacrolimus with HLA matched (29) and mismatched (15) unrelated donors to determine the impact of graft content on outcome; thus, all patients had flow cytometric analysis of their graft content including the number of B cells, NK cells, and various T cell subsets. Higher γδ T cell dose was associated with the development of acute GVHD (p = .0038). For PtCy, further studies of the cell product along with further graft manipulation, such as selective γδ T cell depletion, could potentially improve outcomes.

Influence of periodontal status on patients undergoing hematopoietic stem cell transplantation: A retrospective analysis

ObjectiveThis retrospective analysis aimed to evaluate the prevalence of periodontitis in patients undergoing hematopoietic stem cell transplantation, and investigate the effects of various periodontal statuses and risk factors on oral infection incidence. Study designMedical records of patients pre– and post–hematopoietic stem cell transplantation from June 2019 to October 2021were reviewed. The study examined the effort of different periodontal statuses on oral complications and infections in patients during transplantation. ResultsOf 549 transplant patients studied, 363 had periodontitis. Patients with or without periodontitis showed significant differences in mean age, male proportion, and mucositis incidence during transplantation (P < 0.05). Bacteremia rates were slightly higher in patients with periodontitis, but not significant. Male proportion, age, and hospitalization duration significantly increased with advancing periodontitis stages. Only two patients experienced periodontal complications, that were effectively managed and did not interfere in the grafting process. ConclusionPeriodontitis is prevalent in patients with hematopoietic diseases. Despite its association with oral mucositis, the occurrence of periodontal infection remains low and controllable.

Combining serum microRNAs and machine learning algorithms for diagnosing infectious fever after HSCT.

Infection post-hematopoietic stem cell transplantation (HSCT) is one of the main causes of patient mortality. Fever is the most crucial clinical symptom indicating infection. However, current microbial detection methods are limited. Therefore, timely diagnosis of infectious fever and administration of antimicrobial drugs can effectively reduce patient mortality. In this study, serum samples were collected from 181 patients with HSCT with or without infection, as well as the clinical information. And more than 80 infectious-related microRNAs in the serum were selected according to the bulk RNA-seq result and detected in the 345 time-pointed serum samples by Q-PCR. Unsupervised clustering result indicates a close association between these microRNAs expression and infection occurrence. Compared to the uninfected cohort, more than 10 serum microRNAs were identified as the combined diagnostic markers in one formula constructed by the Random Forest (RF) algorithms, with a diagnostic accuracy more than 0.90. Furthermore, correlations of serum microRNAs to immune cells, inflammatory factors, pathgens, infection tissue, and prognosis were analyzed in the infection cohort. Overall, this study demonstrates that the combination of serum microRNAs detection and machine learning algorithms holds promising potential in diagnosing infectious fever after HSCT.

The Efficacy of Three Different Oral Hygiene Regimens in Preventing Chemotherapy-Induced Oral Mucositis in Pediatric Patients Receiving Hematopoietic Stem Cell Transplantation.

Oral mucositis is one of the side effects developed post-hematopoietic stem cell transplant. This retrospective study aimed to assess the efficacy of a mouthwash mixture (lidocaine, sodium alginate, sucralfate, pheniramine) versus hyaluronic acid and a solution of sodium bicarbonate in terms of healing time and weight gain in the treatment of oral mucositis in pediatric patients undergoing allogeneic hematopoietic stem cell transplantation with hemato-oncological malignancies. A total of 171 patients that received chemotherapy for the hematopoietic stem cell transplant were divided into three groups; group 1, treated with a mixed mouthwash of lidocaine, sodium alginate, sucralfate, and pheniramine; group 2, treated with hyaluronic acid; and group 3, treated with an aqueous solution of 5% sodium bicarbonate. Weight and mucositis scale scores derived from medical records of patients. There was a statistically significant difference in the mucositis scale scores between the groups on the transplant day and days 5, 10, 15 and 20 after the transplantation. At these measurement points, Group 2 (receiving hyaluronic acid) had a lower score, and Group 3 (who received sodium bicarbonate) had a higher score, especially on days 5 and 10 after the transplantation. The results suggest that hyaluronic acid is a more effective treatment option than the other oral care solutions that are frequently used for prophylaxis and treatment of oral mucositis.

Blinatumomab as a Curative Therapy Option for Relapsed/Refractory Infant Acute Lymphoblastic Leukemia Post-Hematopoietic Stem Cell Transplantation - Case Report

Blinatumomab as a Curative Therapy Option for Relapsed/Refractory Infant Acute Lymphoblastic Leukemia Post-Hematopoietic Stem Cell Transplantation - Case Report

Current status and new experimental diagnostic methods of invasive fungal infections after hematopoietic stem cell transplantation.

Invasive fungal infections (IFIs) are common and life-threatening complications in post-hematopoietic stem cell transplantation (post-HSCT) recipients, Severe IFIs can lead to systemic infection and organ damage, which results in high mortality in HSCT recipients. With the development of the field of fungal infection diagnosis, more and more advanced non-culture diagnostic tools have been developed, such as glip biosensors, metagenomic next-generation sequencing, Magnetic Nanoparticles and Identified Using SERS via AgNPs+ , and artificial intelligence-assisted diagnosis. The advanced diagnostic approaches contribute to the success of HSCT and improve the overall survival of post-HSCT leukemia patients by supporting therapeutical decisions. This review provides an overview of the characteristics of two high-incidence IFIs in post-HSCT recipients and discusses some of the recently developed IFI detection technologies. Additionally, it explores the potential application of cationic conjugated polymer fluorescence resonance energy transfer (CCP-FRET) technology for IFI detection. The aim is to offer insights into selecting appropriate IFI detection methods and gaining an understanding of novel fungal diagnostic approaches in laboratory settings.

An Atypical Presentation of Pulmonary Mucormycosis

Abstract Mucormycosis is a life-threatening invasive fungal infection caused by fungi belonging to mucorales order. Manifestations vary from localized disease to disseminated infection. Various types of mucormycosis are rhino-orbito-cerebral, pulmonary, cutaneous, gastrointestinal, renal, and disseminated. Pulmonary form is more common in patients with solid organ transplant and post hematopoietic stem cell transplantation. Multimodality treatment is used in the form of aggressive antifungals, surgery where possible, and control of underlying disease/factors. Here, we present an unusual presentation of pulmonary mucormycosis successfully managed with liposomal amphotericin B and surgical lobectomy.

Posaconazole in paediatric malignancy and haematopoietic stem cell transplant: dosing to achieve therapeutic concentration.

Posaconazole is increasingly used for the treatment and prophylaxis of invasive fungal infections in immunocompromised children. We aimed to review evidence for paediatric posaconazole dosing regimens focusing on attainment of target concentrations and frequency of adverse effects. In May 2023, the Cochrane, Embase, MEDLINE and PubMed databases were searched for articles reporting posaconazole dosing in children with malignancy or post-haematopoietic stem cell transplantation. Studies reporting the attainment of target serum concentrations were included. Overall, 24 studies were included. Eighteen studies of the oral suspension consistently reported poor attainment of target concentrations for prophylaxis (≥0.7 µg/mL, 12%-78%) despite high daily doses of 14-23 mg/kg/day (max. 1200 mg/day). Target attainment was significantly affected by gastric pH and food intake. Six studies of the delayed-release tablet (DRT) reported 58%-94% achieved concentrations ≥0.7 µg/mL, with the majority using lower doses of 4-12 mg/kg/day (max. 300 mg/day). Similarly, one study of powder for oral suspension found 67%-100% achieved target concentrations with a dose of 6 mg/kg/day (max. 300 mg/day). As expected, the IV formulation had high attainment of prophylaxis targets (81%-90%) with 6-10 mg/kg/day (max. 400 mg/day). All formulations were well tolerated, and no relationship between adverse effects and posaconazole concentrations was identified. The required posaconazole dose in immunocompromised children varies depending on the formulation. The IV infusion had the highest attainment of therapeutic concentration followed by the DRT and powder for suspension. By contrast, the oral suspension had low attainment of target concentrations despite higher daily doses.

Antiviral cellular therapy for enhancing T-cell reconstitution before or after hematopoietic stem cell transplantation (ACES): a two-arm, open label phase II interventional trial of pediatric patients with risk factor assessment

Viral infections remain a major risk in immunocompromised pediatric patients, and virus-specific T cell (VST) therapy has been successful for treatment of refractory viral infections in prior studies. We performed a phase II multicenter study (NCT03475212) for the treatment of pediatric patients with inborn errors of immunity and/or post allogeneic hematopoietic stem cell transplant with refractory viral infections using partially-HLA matched VSTs targeting cytomegalovirus, Epstein-Barr virus, or adenovirus. Primary endpoints were feasibility, safety, and clinical responses (>1 log reduction in viremia at 28 days). Secondary endpoints were reconstitution of antiviral immunity and persistence of the infused VSTs. Suitable VST products were identified for 75 of 77 clinical queries. Clinical responses were achieved in 29 of 47 (62%) of patients post-HSCT including 73% of patients evaluable at 1-month post-infusion, meeting the primary efficacy endpoint (>52%). Secondary graft rejection occurred in one child following VST infusion as described in a companion article. Corticosteroids, graft-versus-host disease, transplant-associated thrombotic microangiopathy, and eculizumab treatment correlated with poor response, while uptrending absolute lymphocyte and CD8 T cell counts correlated with good response. This study highlights key clinical factors that impact response to VSTs and demonstrates the feasibility and efficacy of this therapy in pediatric HSCT.

Diagnosing and Grading of Sinusoidal Obstructive Syndrome after Hematopoietic Stem Cell Transplant of Children, Adolescent and Young Adults treated in a Pediatric Institution with Pediatric Protocols

Sinusoidal obstructive syndrome (SOS), or veno-occlusive disease, of the liver has been recognized as a complex, life-threatening complication in the posthematopoietic stem cell transplant (HSCT) setting. The diagnostic criteria for SOS have evolved over the last several decades with a greater understanding of the underlying pathophysiology, with 2 recent diagnostic criteria introduced in 2018 (European Society of Bone Marrow Transplant [EBMT] criteria) and 2020 (Cairo criteria). We sought out to evaluate the performance characteristics in diagnosing and grading SOS in pediatric patients of the 4 different diagnostic criteria (Baltimore, Modified Seattle, EBMT, and Cairo) and severity grading systems (defined by the EBMT and Cairo criteria). Retrospective chart review of children, adolescent, and young adults who underwent conditioned autologous and allogeneic HSCT between 2017 and 2021 at a single pediatric institution. A total of 250 consecutive patients underwent at least 1 HSCT at UCSF Benioff Children's Hospital San Francisco for a total of 307 HSCT. The day 100 cumulative incidence of SOS was 12.1%, 21.1%, 28.4%, and 28.4% per the Baltimore, Modified Seattle, EBMT, and Cairo criteria, respectively (P < .001). We found that patients diagnosed with grade ≥4 SOS per the Cairo criteria were more likely to be admitted to the Pediatric Intensive Care Unit (92% versus 58%, P = .035) and intubated (85% versus 32%, P = .002) than those diagnosed with grade ≥4 per EBMT criteria. Age <3 years-old (HR 1.76, 95% [1.04 to 2.98], P = .036), an abnormal body mass index (HR 1.69, 95% [1.06 to 2.68], P = .027), and high-risk patients per our institutional guidelines (HR 1.68, 95% [1.02 to 2.76], P = .041) were significantly associated with SOS per the Cairo criteria. We demonstrate that age <3 years, abnormal body mass index, and other high-risk criteria associate strongly with subsequent SOS development. Patients with moderate to severe SOS based on Cairo severity grading system may correlate better with clinical course based on ICU admissions and intubations when compared to the EBMT severity grading system.