Cytokine release syndrome after haploidentical hematopoietic cell transplantation: an international multicenter analysis

Itacitinib for prevention of graft-versus-host disease and cytokine release syndrome in haploidentical transplantation

ABSTRACT

Haploidentical hematopoietic cell transplantation (haplo-HCT) is an increasingly used treatment for hematologic malignancies. Although posttransplant cyclophosphamide (PtCy) has improved graft-versus-host disease (GVHD) prophylaxis in haplo-HCT, patients continue to experience life-threatening complications. Interferon gamma and interleukin-6 are central in the pathophysiology of GVHD and cytokine release syndrome (CRS), and both cytokines signal through Janus kinase 1 (JAK-1). We tested the effect of adding the JAK-1 selective inhibitor, itacitinib, to PtCy-haplo-HCT to mitigate these complications and improve overall survival (OS). This open-label, single-arm study evaluated the safety and efficacy of itacitinib combined with standard GVHD prophylaxis after haplo-HCT. A total of 42 patients were treated with itacitinib 200 mg daily from day -3 through +100 or +180, followed by a taper. Itacitinib resulted in low CRS grades, all patients had grade 0 (22%) or grade 1 (78%) CRS and there were no cases of grade 2 to 5 CRS. There were no cases of primary graft failure. No patients developed grade 3 to 4 acute GVHD (aGVHD) through day +180. The cumulative incidence of grade 2 aGVHD at day +100 was 21.9%. The 1-year cumulative incidence of moderate or severe chronic GVHD was 5%. The cumulative incidence of relapse at 2 years was 14%. OS at 1 year was 80%. The cumulative incidence of nonrelapse mortality (NRM) at day 180 was 8%. Itacitinib, when added to standard GVHD prophylaxis, was well tolerated and resulted in low rates of CRS, acute and chronic GVHD, and NRM, and encouraging rates of GVHD-free relapse-free survival and OS after haplo-HCT. This trial was registered at www.ClinicalTrials.gov as #NCT03755414.

[Clinical characteristics of cytokine release syndrome after haploidentical hematopoietic stem cell transplantation for thalassemia major]

OBJECTIVES

To investigate the clinical characteristics of cytokine release syndrome (CRS) in children with thalassemia major (TM) after haploidentical hematopoietic stem cell transplantation (haplo-HSCT) and their prognosis.

METHODS

A retrospective analysis was performed for the clinical data of 280 children with TM who underwent haplo-HSCT in the Department of Hematology and Oncology, Shenzhen Children's Hospital, from January 2019 to December 2021. According to the CRS criteria, they were divided into two groups: CRS grade <3 (260 children) and CRS grade ≥3 (20 children). The children with TM were analyzed in terms of clinical characteristics of CRS after haplo-HSCT and their prognosis.

RESULTS

There were significant differences between the two groups in neutrophil engraftment time, clinical manifestations of CRS, and the rate of use of glucocorticoids within 4 days after haplo-HSCT (P=0.012, 0.040, and <0.001 respectively). For the CRS grade <3 group, the incidence rate of acute graft-versus-host disease (aGVHD) was 9.6% within 3 months after transplantation, while no aGVHD was observed in the CRS grade ≥3 group within 3 months after transplantation, but there was no significant difference in the incidence of aGVHD between the two groups within 3 months after transplantation (P=0.146). No transplantation-related death was observed in either group within 3 months after haplo-HSCT.

CONCLUSIONS

The children with CRS grade≥3 have an early neutrophil engraftment time, severe and diverse clinical manifestations of CRS, and a high rate of use of glucocorticoids within 4 days after haplo-HSCT. For these children, early use of low-dose glucocorticoids after transplantation may alleviate CRS response and reduce the incidence of aGVHD, thereby bringing more benefits to the children. CRS after haplo-HSCT has no significant impact on the prognosis of the children.

[Medical simulation training for bone marrow harvesting from a healthy donor for an allogeneic hematopoietic cell transplant (SFGM-TC)]

This workshop presents the recommendations of the Société francophone de greffe de moelle et de thérapie cellulaire (SFGM-TC) for simulation-based training on bone marrow harvesting from healthy donors. Due to the decline in bone marrow harvests in favor of peripheral stem cells, a loss of expertise has been observed among younger hematologists. The training consists of an online theoretical component and a hands-on workshop using a mannequin at the PRESAGE simulation center at the Lille University School of Medicine. The goal is to acquire the necessary skills to safely perform bone marrow harvesting according to best practices, avoiding technical errors. Both theoretical and practical evaluations are conducted, and participants receive a training certificate upon completion.

Tislelizumab-induced cytokine release syndrome: the first case report and review of the literature

Cytokine release syndrome (CRS) is an uncommon but deadly side effect of immune checkpoint inhibitors (ICIs). ICIs are presently an increasingly important therapy option for malignant tumors, but there are limited treatments available for CRS. We present a case of a 72-year-old man who received one cycle of ICI coupled with cisplatin and albumin-binding paclitaxel therapy for a locally advanced right lung adenocarcinoma. Following an abrupt onset of dyspnea, the patient underwent a quick physical examination, blood tests and was diagnosed with CRS. After prompt initiation of glucocorticoid pulse treatment, the symptoms relieved. The case illustrates the management of severe CRS following ICI therapy while highlighting the uncommon and potentially fatal immune-related side effects.

A comparison of haploidentical versus HLA-identical sibling outpatient hematopoietic cell transplantation using reduced intensity conditioning in patients with acute leukemia

Background

Hematopoietic cell transplantation (HCT) increases survival for acute leukemia. Outpatient allogeneic HCT reduces costs and increases transplant rates in developing countries. We report outcomes of outpatient HLA-identical and haploidentical HCT in acute leukemia.

Methods

This single-center retrospective cohort study analyzed 121 adult patients with acute myeloblastic (AML) and acute lymphoblastic leukemia (ALL) receiving an outpatient allogeneic HCT with peripheral blood allografts after reduced-intensity conditioning (RIC) from 2012-2022.

Results

There were 81 (67%) haploidentical and 40 (33%) HLA-identical transplants. Complete chimerism (CC) at day +100 was not different in HLA-identical compared to haploidentical HCT (32.5% and 38.2%, P=0.054). Post-HCT complications, including neutropenic fever (59.3% vs. 40%), acute graft-versus-host-disease (aGVHD) (46.9% vs. 25%), cytokine release syndrome (CRS) (18.5% vs. 2.5%), and hospitalization (71.6% vs 42.5%) were significantly more frequent in haploidentical HCT. Two-year overall survival (OS) was 60.6% vs. 46.9%, (P=0.464) for HLA-identical and haplo-HCT, respectively. There was no difference in the 2-year disease-free-survival (DFS) (33.3% vs. 35%, P=0.924) between transplant types. In multivariate analysis, positive measurable residual disease (MRD) at 30 days (HR 8.8, P=0.018) and 100 days (HR 28.5, P=0.022) was associated with lower OS, but not with non-relapse mortality (NRM) (P=0.252 and P=0.123, univariate). In univariate analysis, both 30-day and 100-day MRD were associated with lower DFS rates (P=0.026 and P=0.006), but only day 30 MRD was significant in multivariate analysis (P=0.050). In the case of relapse, only MRD at day 100 was associated with increased risk in the univariate and multivariate analyses (HR 4.48, P=0.003 and HR 4.67, P=0.008). Chronic graft-versus-host-disease (cGVHD) was protective for NRM (HR 0.38, P=0.015). There was no difference in cumulative incidence of relapse (CIR) between transplant types (P=0.126). Forty-four (36.4%) patients died, with no difference between HCT type (P=0.307). Septic shock was the most frequent cause of death with 17 cases, with no difference between transplant types.

Conclusions

Outpatient peripheral blood allogenic HCT after RIC is a valid and effective alternative for adult patients suffering acute myeloblastic or lymphoblastic leukemia in low-income populations.

Harnessing ZIKV NS2A RNA for alleviating acute hepatitis and cytokine release storm by targeting translation machinery

BACKGROUND AND AIMS

Hyperactivated inflammatory responses induced by cytokine release syndrome are the primary causes of tissue damage and even death. The translation process is precisely regulated to control the production of proinflammatory cytokines. However, it is largely unknown whether targeting translation can effectively limit the hyperactivated inflammatory responses during acute hepatitis and graft-versus-host disease.

APPROACH AND RESULTS

By using in vitro translation and cellular overexpression systems, we have found that the nonstructural protein gene NS2A of Zika virus functions as RNA molecules to suppress the translation of both ectopic genes and endogenous proinflammatory cytokines. Mechanistically, results from RNA pulldown and co-immunoprecipitation assays have demonstrated that NS2A RNA interacts with the translation initiation factor eIF2α to disrupt the dynamic balance of the eIF2/eIF2B complex and translation initiation, which is the rate-limiting step of translation. In the acetaminophen-induced, lipopolysaccharide/D-galactosamine-induced, viral infection-induced acute hepatitis, and graft-versus-host disease mouse models, mice with myeloid cell-specific knock-in of NS2A show decreased levels of serum proinflammatory cytokines and reduced tissue damage.

CONCLUSIONS

Zika virus NS2A dampens the production of proinflammatory cytokines and alleviates inflammatory injuries by interfering translation process as RNA molecules, which suggests that NS2A RNA is potentially used to treat numerous acute inflammatory diseases characterized by cytokine release syndrome.

The degree of HLA matching determines the incidence of cytokine release syndrome and associated nonrelapse mortality in matched related and unrelated allogeneic stem cell transplantation with post-transplant cyclophosphamide

Cytokine release syndrome (CRS) occurs frequently after haplo-identical allogeneic stem cell transplantation (alloSCT) with post-transplant cyclophosphamide (PTCy), increasing nonrelapse mortality (NRM) and decreasing survival. Data on CRS in HLA-matched alloSCT are limited and effects of specific HLA-mismatches on CRS development unknown. We hypothesized that in HLA-matched alloSCT increasing degrees of HLA-mismatching influence CRS incidence, NRM and survival. Retrospective analysis of 126 HLA-matched PTCy-alloSCT patients showed that higher degrees of HLA-mismatching significantly increased CRS incidence (26%, 75% and 90% CRS with 12/12, 10/10 and 9/10 matched donors, respectively). Maximum temperature during CRS increased with higher HLA-mismatch. Specific associations between HLA-mismatches and CRS could be determined. Grade 2 CRS and CRS-induced grade 3 fever were associated with significantly increased NRM (p < 0.001 and p = 0.003, respectively) and inferior survival (p < 0.001 and p = 0.005, respectively). NRM was mainly caused by disease conditions that may be considered CRS-induced inflammatory responses (encephalopathy, cryptogenic organizing pneumonia and multi-organ failure).

Advances in ex vivo expansion of hematopoietic stem and progenitor cells for clinical applications

As caretakers of the hematopoietic system, hematopoietic stem cells assure a lifelong supply of differentiated populations that are responsible for critical bodily functions, including oxygen transport, immunological protection and coagulation. Due to the far-reaching influence of the hematopoietic system, hematological disorders typically have a significant impact on the lives of individuals, even becoming fatal. Hematopoietic cell transplantation was the first effective therapeutic avenue to treat such hematological diseases. Since then, key use and manipulation of hematopoietic stem cells for treatments has been aspired to fully take advantage of such an important cell population. Limited knowledge on hematopoietic stem cell behavior has motivated in-depth research into their biology. Efforts were able to uncover their native environment and characteristics during development and adult stages. Several signaling pathways at a cellular level have been mapped, providing insight into their machinery. Important dynamics of hematopoietic stem cell maintenance were begun to be understood with improved comprehension of their metabolism and progressive aging. These advances have provided a solid platform for the development of innovative strategies for the manipulation of hematopoietic stem cells. Specifically, expansion of the hematopoietic stem cell pool has triggered immense interest, gaining momentum. A wide range of approaches have sprouted, leading to a variety of expansion systems, from simpler small molecule-based strategies to complex biomimetic scaffolds. The recent approval of Omisirge, the first expanded hematopoietic stem and progenitor cell product, whose expansion platform is one of the earliest, is predictive of further successes that might arise soon. In order to guarantee the quality of these ex vivo manipulated cells, robust assays that measure cell function or potency need to be developed. Whether targeting hematopoietic engraftment, immunological differentiation potential or malignancy clearance, hematopoietic stem cells and their derivatives need efficient scaling of their therapeutic potency. In this review, we comprehensively view hematopoietic stem cells as therapeutic assets, going from fundamental to translational.

Opportunistic Infections in Patients Receiving Post-Transplantation Cyclophosphamide: Impact of Haploidentical versus Unrelated Donor Allograft

Post-transplantation cyclophosphamide (PTCy) is an effective strategy for graft-versus-host disease (GVHD) prophylaxis and is the standard of care for haploidentical hematopoietic cell transplantation (HCT). It is increasingly used for matched and mismatched unrelated donor (MUD/MMUD) HCT, but infections remain a concern. The objective of this study was to evaluate the characteristics and risk factors for infections in haploidentical and unrelated donor HCT recipients treated with PTCy-based GVHD prophylaxis. This single-center retrospective study examined 354 consecutive adults undergoing HCT with PTCy-based GVHD prophylaxis (161 MUD/MMUD; 193 haploidentical) between 2015 and 2022. Opportunistic infections (OIs), including cytomegalovirus (CMV), adenovirus (AdV), Epstein-Barr virus (EBV), and invasive fungal disease (IFD), were assessed from day 0 through day +365. The 1-year cumulative incidence functions of OIs and nonrelapse mortality (NRM) were calculated using dates of relapse and repeat HCT as competing risks. Secondary analysis evaluated risk factors for OIs and NRM using univariate and multivariable Cox regression models. Haploidentical HCT recipients had an increased risk of OIs compared to unrelated donor allograft recipients (39% for haploidentical versus 25% for MUD/MMUD; hazard ratio [HR], 1.70; 95% confidence interval [CI], 1.16 to 2.49; P = .006). On multivariable analysis, haploidentical donor (HR, 1.50; 95% CI, 1.01 to 2.23; P = .046), prior HCT (HR, 1.99; 95% CI, 1.29 to 3.09; P = .002), and diagnosis of aGVHD (HR, 1.47; 95% CI, 1.02 to 2.14; P = .041) were associated with increased risk of OIs. NRM within the first year was not significantly different between the 2 cohorts (HR, 1.11; 95% CI, .64 to 1.93; P = .70). Overall, haploidentical donor was a significant risk factor for OIs in patients receiving PTCy, although 1-year NRM was not different between haploidentical HCT and MUD/MMUD HCT recipients. CMV and AdV infections were significantly increased among haploidentical HCT recipients, whereas the incidences of EBV infection and IFD were similar in the 2 cohorts. Our findings may have implications for infection monitoring and prophylaxis in the setting of PTCy, particularly in haploidentical HCT recipients.

Allogeneic tumor cell-derived extracellular vesicles stimulate CD8 T cell response in colorectal cancer

Most colorectal cancer (CRC) patients present with a microsatellite-stable phenotype, rendering them resistant to immune checkpoint inhibitors (ICIs). Among the contributors to ICI resistance, tumor-derived extracellular vesicles (TEVs) have emerged as critical players. Previously we demonstrated that autologous transfer of TEVs without miR-424 can induce tumor antigen-specific immune responses in CRC models. Therefore, we postulated that allogeneic TEVs, modified to lack miR-424 and derived from an MC38 cells, could induce CD8+ T cell responses while restraining CT26 cell-based tumor. Here, we show that prophylactic administration of MC38 TEVs, without miR-424, showed a significant augmentation in CD8+ T-cells within CT26 tumors. This allogenic TEV effect was evident in CT26 tumors but not B16-F10 melanoma. Furthermore, we demonstrated the capacity of dendritic cells (DCs) to internalize TEVs, a possible mechanism to elicit immune response. Our investigation of autologously administered DCs, which had been exposed to modified TEVs, underscores their potential to dampen tumor growth while elevating CD8+ T cell levels vis-a-vis MC38 wild-type TEVs exposed to DCs. Notably, the modified TEVs were well tolerated and did not increase peripheral blood cytokine levels. Our findings underscore the potential of modified allogeneic TEVs without immune-suppressive factors to elicit robust T cell responses and limit tumor growth.

Restrictive Versus Permissive Use of Broad-spectrum Antibiotics in Patients Receiving Allogeneic Stem Cell Transplantation and With Early Fever Due to Cytokine Release Syndrome: Evidence for Beneficial Microbiota Protection Without Increase in Infectious Complications

BACKGROUND

Intestinal microbiome contributes to the pathophysiology of acute gastrointestinal (GI) graft-versus-host disease (GvHD) and loss of microbiome diversity influences the outcome of patients after allogeneic stem cell transplantation (SCT). Systemic broad-spectrum antibiotics have been identified as a major cause of early intestinal dysbiosis.

METHODS

In 2017, our transplant unit at the university hospital in Regensburg changed the antibiotic strategy from a permissive way with initiation of antibiotics in all patients with neutropenic fever independent of the underlying cause and risk to a restrictive use in cases with high likelihood of cytokine release syndrome (eg, after anti-thymocyte globulin [ATG] therapy). We analyzed clinical data and microbiome parameters obtained 7 days after allogeneic SCT from 188 patients with ATG therapy transplanted in 2015/2016 (permissive cohort, n = 101) and 2918/2019 (restrictive cohort, n = 87).

RESULTS

Restrictive antibiotic treatment postponed the beginning of antibiotic administration from 1.4 ± 7.6 days prior to 1.7 ± 5.5 days after SCT (P = .01) and significantly reduced the duration of antibiotic administration by 5.8 days (P < .001) without increase in infectious complications. Furthermore, we observed beneficial effects of the restrictive strategy compared with the permissive way on microbiome diversity (urinary 3-indoxylsulfate, P = .01; Shannon and Simpson indices, P < .001) and species abundance 7 days post-transplant as well as a positive trend toward a reduced incidence of severe GI GvHD (P = .1).

CONCLUSIONS

Our data indicate that microbiota protection can be achieved by a more careful selection of neutropenic patients qualifying for antibiotic treatment during allogeneic SCT without increased risk of infectious complications.

Combining post-transplant cyclophosphamide with antithymocyte globulin for graft-versus-host disease prophylaxis in hematological malignancies

In search of an ideal partner or alternative to conventional immunosuppressive agents, rabbit anti-thymocyte globulin (ATG) and, more recently, post-transplant cyclophosphamide (PT-Cy) have both emerged as valid and efficient options for preventing graft-versus-host disease (GvHD). To further reduce the risk of GvHD, strategies combining ATG and PT-Cy have recently been investigated. In a haploidentical setting, retrospective studies suggest that combining PT-Cy and ATG may result in a lower incidence of chronic GvHD without increasing the risks of infection or relapse, when compared to PT-Cy without ATG. In haploidentical or unrelated donor settings, adding reduced doses of PT-Cy to ATG may reduce the risk of acute and chronic GvHD and improve survival, particularly GvHD-free, relapse-free survival (GRFS), when compared to ATG without PT-Cy. Overall, the combination of PT-Cy and ATG is a safe and promising approach for patients with hematological malignancies undergoing allogeneic hematopoietic stem cell transplantation (HSCT).

Autoimmune Limbic Encephalitis in Patients with Hematologic Malignancies after Haploidentical Hematopoietic Stem Cell Transplantation with Post-Transplant Cyclophosphamide

Autoimmune limbic encephalitis (LE) is a rare, but devastating complication of allogeneic hematopoietic stem cell transplantation (HSCT). There is currently limited evidence describing the risk factors, laboratory features, and underlying mechanisms of this neurologic adverse event. We retrospectively reviewed available clinical, imaging, and laboratory data from adult patients with hematological malignancies who underwent haploidentical HSCT with post-transplant cyclophosphamide (PTCy) at Chungnam National University Hospital from June 2016 to May 2020. Patients who developed LE were compared to those who did not based on clinical assessment, serum inflammatory biomarkers, and reconstitution of various T cell populations. Of 35 patients, 4 developed LE. There were no differences in patient demographics, donor demographics, or treatment conditions between patients that did and did not develop LE. Overall, patients with LE had worse clinical outcomes and overall survival than those without. In addition, they tended to have higher markers of systemic inflammation in the early post-transplant period, including fever, C-reactive protein (CRP), and cytokines. Remarkably, baseline interleukin-6 levels before HSCT were found to be higher in patients who developed LE than those who did not. In addition, analysis of T cell subsets showed impaired expansion of CD25+FOXP3+ regulatory T (Treg) cells in LE compared to non-LE patients despite appropriate reconstitution of the total CD4+ T cell population. Patients that developed LE within the first 30 days of HSCT were likely to have high serum IL-6 among other inflammatory cytokines coupled with suppression of regulatory T cell differentiation. Further work is needed on the mechanisms underlying impaired Treg expansion following HSCT and potential therapies.

Impact of donor age and relationship on outcomes of peripheral blood haploidentical hematopoietic cell transplantation

Here we describe a retrospective analysis of outcomes in 299 patients who underwent peripheral blood haplo-HCT with PTCy from July 2009 through May 2021 and their association with donor characteristics. Patients had mostly acute leukemias and high or very high DRI. Multivariate analyses were conducted examining OS, NRM, relapse, cytokine release syndrome, acute and chronic GVHD. Donor characteristics included age, sex, relationship, ABO status, CMV status, and HLA match grade. Our analysis revealed increasing donor age was associated with higher NRM (compared to age <30; age 30-44 HR, 1.65; P = 0.110, age >44 HR, 1.80; P = 0.056) but lower relapse risk (compared to age <30; age 30-44 HR, 0.61; P = 0.034, age > 44 HR, 0.71; P = 0.132). There were no differences in CRS, aGVHD or cGVHD. We found no difference in outcomes based on the donor-recipient relationship. No differences were found based on HLA match grade or DRB1 match status. Increasing donor age was associated with lower relapse risk but higher NRM, resulting in no difference in OS based on donor age. Other donor factors including relationship (parent/sibling/child/ maternal), CMV status, donor sex, HLA match grade, and DRB1 status were not associated with outcomes.

Tocilizumab for Cytokine Release Syndrome Management After Haploidentical Hematopoietic Cell Transplantation With Post-Transplantation Cyclophosphamide-Based Graft-Versus-Host Disease Prophylaxis

Cytokine release syndrome (CRS) is a common complication after haploidentical hematopoietic cell transplantation (HaploHCT). Severe CRS after haploHCT leads to higher risk of non-relapse mortality (NRM) and worse overall survival (OS). Tocilizumab (TOCI) is an interleukin-6 receptor inhibitor and is commonly used as first-line for CRS management after chimeric antigen receptor T cell therapy, but the impact of TOCI administration for CRS management on Haplo HCT outcomes is not known. In this single center retrospective analysis, we compared HCT outcomes in patients treated with or without TOCI for CRS management after HaploHCT with post-transplantation cyclophosphamide- (PTCy-) based graft-versus-host disease (GvHD) prophylaxis. Of the 115 patients eligible patients who underwent HaploHCT at City of Hope between 2019 to 2021 and developed CRS, we identified 11 patients who received tocilizumab for CRS management (TOCI). These patients were matched with 21 patients who developed CRS but did not receive tocilizumab (NO-TOCI) based on age at the time of HCT (≤64 years or >65 years or older), conditioning intensity (myeloablative versus reduced-intensity/nonmyeloablative), and CRS grading (1, 2, versus 3-4). Instead of 22 controls, we chose 21 patients because there was only 1 control matched with 1 TOCI treatment patient in 1 stratum. With only 11 patients in receiving tocilizumab for CRS treatment, matching with 21 patients who developed CRS but did not receive tocilizumab, we had 80% power to detect big differences (hazard ratio [HR] = 3.4 or higher) in transplantation outcomes using a 2-sided 0.05 test. The power would be reduced to about 20% to 30% if the difference was moderate (HR = 2.0) using the same test. No CRS-related deaths were recorded in either group. Median time to neutrophil engraftment was 21 days (range 16-43) in TOCI and 18 days (range 14-23) in NO-TOCI group (HR = 0.55; 95% confidence interval [CI] = 0.28-1.06, P = .08). Median time to platelet engraftment was 34 days (range 20-81) in TOCI and 28 days (range 12-94) in NO-TOCI group (HR = 0.56; 95% CI = 0.25-1.22, P = .19). Cumulative incidences of day 100 acute GvHD grades II-IV (P = .97) and grades III-IV (P = .47) were similar between the 2 groups. However, cumulative incidence of chronic GvHD at 1 year was significantly higher in patients receiving TOCI (64% versus 24%; P = .05). Rates of NRM (P = .66), relapse (P = .83), disease-free survival (P = .86), and overall survival (P = .73) were similar at 1 year after HCT between the 2 groups. Tocilizumab administration for CRS management after HaploHCT appears to be safe with no short-term adverse effect and no effect on relapse rate. However, the significantly higher cumulative incidence of chronic GvHD, negates the high efficacy of PTCy on GvHD prophylaxis in this patient population. Therefore using tocilizumab for CRS management in the HaploHCT population with PTCy maybe kept only for patients with severe CRS. The impact on such approach on long term outcome in HaploHCT with PTCy will need to be evaluated in a larger retrospective study or a prospective manner.

Allogeneic Tumor Cell-Derived Extracellular Vesicles Stimulate CD8 T Cell Response in Colorectal Cancer

Colorectal Cancer (CRC) is the second leading cause of cancer-related death in the United States. Most CRC patients present with a microsatellite stable (MSS) phenotype and are highly resistant to immunotherapies. Tumor extracellular vesicles (TEVs), secreted by tumor cells, can contribute to intrinsic resistance to immunotherapy in CRC. We previously showed that autologous TEVs without functional miR-424 induce anti-tumor immune responses. We hypothesized that allogeneic modified CRC-TEVs without miR-424 (mouse homolog miR-322) derived from an MC38 background would effectively stimulate CD8+ T cell response and limit CT26 tumor growth. Here we show that prophylactic administration of MC38 TEVs without functional miR-424 significantly increased CD8+ T cells in CT26 CRC tumors and limited tumor growth, not B16-F10 melanoma tumors. We further show that the depletion of CD4+ and CD8+ T cells abolished the protective effects of MC38 TEVs without functional miR-424. We further show that TEVs can be taken up by DCs in vitro, and subsequent prophylactic administration of autologous DCs exposed to MC38 TEVs without functional miR-424 suppressed tumor growth and increased CD8+ T cells compared to MC38 wild-type TEVs exposed to DCs, in Balb/c mice bearing CT26 tumors. Notably, the modified EVs were well tolerated and did not increase cytokine expression in peripheral blood. These findings suggest that allogeneic-modified CRC-EVs without immune suppressive miR-424 can induce antitumor CD8+ T cell responses and limit tumor growth in vivo.

Mismatched donor cell infusion-related syndrome following microtransplant in patients with acute myeloid leukemia

BACKGROUND

Immunotherapies such as adoptive immune cell infusion and immune-modulating agents are widely used for cancer treatment, and the concomitant symptoms, including cytokine release syndrome (CRS) or immune-related adverse events (irAEs), are frequently reported. However, clinical manifestations induced by mismatched donor granulocyte colony-stimulating factor mobilized peripheral blood mononuclear cell (GPBMC) infusion in patients receiving microtransplant (MST) have not yet been well depicted.

METHODS

We analyzed 88 cycles of mismatched GPBMC infusion in patients with acute myeloid leukemia receiving MST and 54 cycles of chemotherapy without GPBMC infusion as a comparison. Clinical symptoms and their correlation with clinical features, laboratory findings, and clinical response were explored.

RESULTS

Fever (58.0% [51/88]) and chills (43.2% [38/88]) were the significant early-onset symptoms after GPBMC infusion. Patients possessing less human leukocyte antigen-matching loci with the donor or those with unrelated donors experienced more chills (3 [2-5] loci vs. 5 [3-5] loci, P  = 0.043 and 66.7% [12/18] vs. 37.1% [26/70], P  = 0.024). On the other hand, those with decreased CD4 + /CD8 + T-cell ratio developed more fever (0.8 [0.7-1.2] vs. 1.4 [1.1-2.2], P  = 0.007). Multivariable analysis demonstrated that younger patients experienced more fever (odds ratio [OR] = 0.963, 95% confidence interval [CI]: 0.932-0.995, P  = 0.022), while patients with younger donors experienced more chills (OR = 0.915, 95% CI: 0.859-0.975, P  = 0.006). Elevated ultra-sensitive C-reactive protein levels in the absence of cytokine storm were observed following GPBMC infusion, which indicated mild and transient inflammatory response. Although no predictive value of infusion-related syndrome to leukemia burden change was found, the proportion of host pre-treatment activated T cells was positively correlated with leukemia control.

CONCLUSIONS

Mismatched GPBMC infusion in MST induced unique infusion-related symptoms and laboratory changes, which were associated with donor- or recipient-derived risk factors, with less safety and tolerance concerns than reported CRS or irAEs.

Cytokine profiling during conditioning in haploidentical stem cell transplantation and its prognostic impact on early transplant outcomes

Cytokine storm development is a major cause of many transplant-related complications, especially during the conditioning regimen. This study aimed to characterize the cytokine profile and determine its prognostic impact during conditioning in patients undergoing subsequent haploidentical stem cell transplantation. A total of 43 patients were enrolled in this study. Sixteen cytokines associated with cytokine release syndrome (CRS) during anti-thymocyte globulin (ATG) treatment were quantified in patients undergoing haploidentical stem cell transplantation. Thirty-six (83.7%) patients developed CRS during ATG treatment; most of those cases (33/36; 91.7%) were classified as grade 1 CRS, whereas only three (7.0%) developed grade 2 CRS. CRS was observed more frequently on the first (15/43; 34.9%) and second day (30/43; 69.8%) of ATG infusion. No factors were identified that could predict the development of CRS on the first day of ATG treatment. Five of the 16 cytokines (interleukins 6, 8, and 10 (IL-6, IL-8, and IL-10), C-reactive protein (CRP), and procalcitonin (PCT)) were significantly elevated during ATG treatment, although only the level of IL-6, IL-10, and PCT were associated with the severity of CRS. However, neither CRS nor the cytokine levels significantly impacted the development of acute graft-versus-host disease (GVHD) or cytomegalovirus (CMV) infection or affected overall survival.

How I prevent GVHD in high-risk patients: posttransplant cyclophosphamide and beyond

Advances in conditioning, graft-versus-host disease (GVHD) prophylaxis and antimicrobial prophylaxis have improved the safety of allogeneic hematopoietic cell transplantation (HCT), leading to a substantial increase in the number of patients transplanted each year. This influx of patients along with progress in remission-inducing and posttransplant maintenance strategies for hematologic malignancies has led to new GVHD risk factors and high-risk groups: HLA-mismatched related (haplo) and unrelated (MMUD) donors; older recipient age; posttransplant maintenance; prior checkpoint inhibitor and autologous HCT exposure; and patients with benign hematologic disorders. Along with the changing transplant population, the field of HCT has dramatically shifted in the past decade because of the widespread adoption of posttransplantation cyclophosphamide (PTCy), which has increased the use of HLA-mismatched related donors to levels comparable to HLA-matched related donors. Its success has led investigators to explore PTCy's utility for HLA-matched HCT, where we predict it will be embraced as well. Additionally, combinations of promising new agents for GVHD prophylaxis such as abatacept and JAK inhibitors with PTCy inspire hope for an even safer transplant platform. Using 3 illustrative cases, we review our current approach to transplantation of patients at high risk of GVHD using our modern armamentarium.

The impact of tocilizumab treatment for cytokine release syndrome on the incidence of early blood stream infections after peripheral blood haploidentical hematopoietic cell transplantation

Cytokine release syndrome (CRS) is a potentially fatal systemic inflammatory response that can occur in patients undergoing peripheral blood haploidentical hematopoietic cell transplantation (haplo-HCT). Severe CRS has previously been associated with increased infection risk. IL-6 inhibitors, such as tocilizumab, are useful in moderate to severe CRS, but their effect on infection risk has not been established in this setting. We examined the effect of tocilizumab on blood stream infections (BSIs) in the early post-transplant period in 235 patients who underwent haplo-HCT from 2013 to 2020. Mild CRS was associated with a lower incidence of BSI than severe CRS (OR 0.31, 95% CI 0.13-0.74). In the tocilizumab group, 31% of patients had positive blood cultures versus 14% in the non-tocilizumab group (OR 1.61, 95% CI 0.30-8.60, p = 0.58). However, when controlling for CRS grade, tocilizumab was not independently associated with increased rates of BSIs, suggesting it does not further increase infection risk.

Cytokine Release Syndrome and Sepsis: Analogous Clinical Syndromes with Distinct Causes and Challenges in Management

Both cytokine release syndrome (CRS) and sepsis are clinical syndromes rather than distinct diseases and share considerable overlap. It can often be challenging to distinguish between the two, but it is important given the availability of targeted treatment options. In addition, several other clinical syndromes overlap with CRS and sepsis, further making it difficult to differentiate them. This has particularly been highlighted in the recent coronavirus disease-2019 pandemic. As we start to understand the differences in the inflammatory markers and presentations in these syndromes, hopefully we will be able to enhance treatment and improve outcomes.

Hematologic cytopenia post CAR T cell therapy: Etiology, potential mechanisms and perspective

Chimeric Antigen-Receptor (CAR) T-cell therapies have shown dramatic efficacy in treating relapsed and refractory cancers, especially B cell malignancies. However, these innovative therapies cause adverse toxicities that limit the broad application in clinical settings. Hematologic cytopenias, one frequently reported adverse event following CAR T cell treatment, are manifested as a disorder of hematopoiesis with decreased number of mature blood cells and subdivided into anemia, thrombocytopenia, leukopenia, and neutropenia, which increase the risk of infections, fatigue, bleeding, fever, and even fatality. Herein, we initially summarized the symptoms, etiology, risk factors and management of cytopenias. Further, we elaborated the cellular and molecular mechanisms underlying the initiation and progression of cytopenias following CAR T cell therapy based on previous studies about acquired cytopenias. Overall, this review will facilitate our understanding of the etiology of cytopenias and shed lights into developing new therapies against CAR T cell-induced cytopenias.

Invasive Yeast Infection After Haploidentical Donor Hematopoietic Cell Transplantation Associated with Cytokine Release Syndrome

BACKGROUND

Use of haploidentical donor hematopoietic cell transplantation (haploHCT) has expanded but recent reports raise concern for increased rates of infectious complications. The incidence and risk factors for invasive fungal disease (IFD) after haploHCT have not been well elucidated.

OBJECTIVE

The objective of this study is to evaluate the incidence and risk factors for IFD after haploHCT. The identification of key risk factors will permit targeted prevention measures and may explain elevated risk for other infectious complications after haploHCT.

STUDY DESIGN

We performed a single-center retrospective study of all adults undergoing haploHCT between May 2011 and May 2021 (n=205). The 30-day and one-year cumulative incidence of proven or probable IFD and one-year non-relapse mortality (NRM) were assessed. Secondary analysis evaluated risk factors for invasive yeast infection (IYI) using univariate and multivariable Cox regression models.

RESULTS

Twenty-nine patients (14%) developed IFD following haploHCT. Nineteen (9.3%) developed IYI in the first year, 13 of which occurred early with a 30-day cumulative incidence of 6.3% (95% CI 2.9 - 9.6%) and increased NRM in patients with IYI (53.9% versus 10.9%). The majority of yeast isolates (17/20; 85%) were fluconazole susceptible. The incidence of IYI in the first 30 days after haploHCT was 10% among the 110 (54%) patients who developed cytokine release syndrome (CRS) and 21% among the 29 (14%) who received tocilizumab. On multivariable analysis, AML (HR 6.24; 1.66 - 23.37; p=0.007) and CRS (HR 4.65; 1.00 - 21.58; p=0.049) were associated with an increased risk of early IYI after haploHCT.

CONCLUSION

CRS after haploHCT is common and is associated with increased risk of early IYI. The identification of CRS as a risk factor for IYI raises questions about its potential association with other infections after haploHCT. Recognition of key risk factors for infection may permit individualized strategies for prevention and intervention and minimize potential side effects.

Clinical Significance of Haplo-Fever and Cytokine Profiling After Graft Infusion in Allogeneic Stem Cell Transplantation From Haplo-Identical Donors

Allogeneic stem cell transplantation from haplo-identical donors (haplo-HSCT) has become a well-established therapeutic option for hematological malignancies. The fever of unknown origin (haplo-fever) early after the infusion of T cell repleted graft, which returned to normal right after post-transplantation cyclophosphamide (PTCy), is a unique clinical feature in patients undergoing haplo-HSCT. In the current study, the characteristics of haplo-fever and cytokine profiles during haplo-fever were retrospectively analyzed in a cohort of 37 patients undergoing T cell repleted haplo-HSCT with PTCy as graft versus host disease (GvHD) prophylaxis. In total, 33 patients (89.2%) developed haplo-fever from day 0 to day +7. Patients with high peak temperatures tended to have a lower incidence of chronic GvHD (cGvHD) (p = 0.07), moderate to severe cGvHD (p = 0.08), and superior GvHD and relapse-free survival (GRFS, p = 0.04). During the haplo-fever, there were significant increases in multiple cytokines, such as interferon gamma, interleukin (IL) 6, IL2, IL2 receptor, IL8, IL10, IL17, and tumor necrosis factor (TNF). The increases in IL2 receptor (p = 0.037) and TNF (p < 0.001) on day +4 were correlated with the lower risk of cGvHD. Increased TNF > 1.8055-fold on day +4 was the best predictive threshold for cGvHD, and was correlated with a lower incidence of cGvHD (p < 0.001), moderate to severe cGvHD (p = 0.003), and superior GRFS (p < 0.001). These observations may reflect the early reactivation of donor T cells after haplo graft infusion, which would potentially be eliminated by PTCy. Further studies with larger independent cohorts of patients are warranted, to clarify the clinical significance of haplo-fever, and day +4 TNF as a potential biomarker to predict GvHD and GRFS.

Cytokine Release Syndrome and Associated Acute Toxicities in Pediatric Patients Undergoing Immune Effector Cell Therapy or Hematopoietic Cell Transplantation

Immune effector cells (IEC) are a powerful and increasingly targeted tool, particularly for the control and eradication of malignant diseases. However, the infusion, expansion, and persistence of autologous or allogeneic IEC or engagement of endogenous immune cells can be associated with significant systemic multi-organ toxicities. Here we review the signs and symptoms, grading and pathophysiology of immune-related toxicities arising in the context of pediatric immunotherapies and haploidentical T cell replete Hematopoietic Cell Transplantation (HCT). Principles of management are discussed with particular focus on the intersection of these toxicities with the requirement for pediatric critical care level support.

Increased early mortality after fludarabine and melphalan conditioning with peripheral blood grafts in haploidentical hematopoietic cell transplantation with post-transplant cyclophosphamide

Due to the evolving use of haploidentical donor grafts in hematopoietic cell transplantation, there is increased need to better understand the risks and benefits of using bone marrow versus peripheral blood grafts, as well as how specific pre-transplantation conditioning regimens impact patient safety and treatment outcomes. We performed a retrospective analysis of 38 patients at two centers who underwent haploidentical hematopoietic cell transplantation using fludarabine plus melphalan-based conditioning regimens with post-transplant cyclophosphamide and peripheral blood donor grafts. We observed an unexpectedly high rate of early non-relapse mortality and severe cytokine release syndrome. The poor outcomes with 1-year overall survival of 34%, disease-free survival of 29%, and non-relapse mortality of 34% motivate us to reconsider the appropriateness of the combination of fludarabine and melphalan conditioning with T-cell replete peripheral blood grafts in the setting of haploidentical hematopoietic cell transplant with post-transplant cyclophosphamide.

Cytokine Release Syndrome in the Immunotherapy of Hematological Malignancies: The Biology behind and Possible Clinical Consequences

Cytokine release syndrome (CRS) is an acute systemic inflammatory syndrome characterized by fever and multiple organ dysfunction associated with (i) chimeric antigen receptor (CAR)-T cell therapy, (ii) therapeutic antibodies, and (iii) haploidentical allogeneic stem cell transplantation (haplo-allo-HSCT). Severe CRS can be life-threatening in some cases and requires prompt management of those toxicities and is still a great challenge for physicians. The pathophysiology of CRS is still not fully understood, which also applies to the identifications of predictive biomarkers that can forecast these features in advance. However, a broad range of cytokines are involved in the dynamics of CRS. Treatment approaches include both broad spectrum of immunosuppressant, such as corticosteroids, as well as more specific inhibition of cytokine release. In the present manuscript we will try to review an update regarding pathophysiology, etiology, diagnostics, and therapeutic options for this serious complication.