Diagnostic criteria for hematopoietic stem cell transplant-associated microangiopathy: results of a consensus process by an International Working Group

Use of Eculizumab in Pediatric Patients with High-Risk Transplantation-Associated Thrombotic Microangiopathy: Outcomes and Risk Factors Associated with Response and Survival. A Retrospective Study on Behalf of the Spanish Group for Hematopoietic Transplantation and Cellular Therapy (GETH-TC)

Transplantation-associated thrombotic microangiopathy (TA-TMA) is associated with high morbidity and mortality. Although survival has improved significantly with the introduction of eculizumab, the need for improvement remains, especially in high-risk patients. This study aimed to describe the results obtained with eculizumab in a pediatric cohort with the attempt to define which risk factors could determine the response to treatment. We designed a national multicenter retrospective study of children treated with eculizumab for high-risk TA-TMA. The study cohort comprised 29 patients who had undergone a first (n = 28) or second (n = 1) allogeneic hematopoietic stem cell transplantation (HSCT) for malignant (n = 17) or nonmalignant (n = 12) disease. The median time from HSCT to TA-TMA diagnosis was 154 days (interquartile range [IQR], 103 to 263 days). Eleven patients (38%) who were initially diagnosed with low- to intermediate-risk TA-TMA progressed to high-risk TA-TMA (hrTA-TMA), within a median time of 4 days (IQR, 1 to 33 days). SC5b-9 was increased in 90% of 20 patients in whom it was measured. Renal (n = 12), pulmonary (n = 1), and intestinal (n = 1) biopsy confirmed the diagnosis in 12 of 14 patients (85%). Seventeen patients (58%) had extrarenal involvement with serositis (n = 13; 44,8%), pulmonary (n = 12; 41,4%), gastrointestinal (n = 8; 27.6%), cardiovascular (n = 7; 24.1%), or central nervous system (CNS) (n = 2; 6.9%) involvement. The median time from hrTA-TMA diagnosis to the initiation of eculizumab was 7 days (IQR, 1 to 8 days). Overall, 19 patients (65.5%) responded to eculizumab, of whom 17 (58.6%) achieved a complete response and 2 (6.9%) achieved a partial response. The remaining 10 patients (34.5%) did not show any of response. The overall response rate to eculizumab for TA-TMA was 27.59% (95% confidence interval [CI], 14.87% to 47.66%) at 1 month, 55.17% (95% CI, 38.43% to 73.48%) at 3 months, and 62.07% (95% CI, 45.10% to 79.13%) at 6 months after eculizumab initiation. In multivariate analysis, the pulmonary involvement decreased the probability of response (hazard ratio [HR], .18; P = .0298). The 1-year overall survival (OS) was 55.2% (95% CI, 35.6% to 71.0%) for the whole cohort and 83.3% (95% CI, 56.7% to 94.3%) for patients who responded to eculizumab. Pulmonary involvement (HR, 14.93; P = .0043) and CNS involvement (HR, 8.63; P = .0497) were associated with a statistically significant decrease in survival. We found that patients diagnosed with hrTA-TMA with pulmonary involvement had a poor response to eculizumab, and that patients with pulmonary and CNS involvement had significantly decreased survival. Given these results, we hypothesize that providing eculizumab therapy at an early stage of the disease before organ damage is established might significantly improve the response and, consequently, survival.

Safety and efficacy of narsoplimab in pediatric and adult patients with transplant-associated thrombotic microangiopathy: a real-world experience

Transplant-associated thrombotic microangiopathy (TA-TMA) is a severe complication following hematopoietic stem cell transplantation (HSCT). No approved treatments are currently available. This study presents real-world data obtained with narsoplimab, a human immunoglobulin G4 monoclonal antibody that inhibits MASP-2, the effector enzyme of the lectin pathway of the complement system. Between January 2018 and August 2023, 20 (13 adult and 7 pediatric) patients diagnosed with TA-TMA received narsoplimab under an ongoing compassionate use program. The diagnosis was based on internationally defined criteria for pediatric and adult patients. Fifteen patients fulfilled the criteria recently established by an international consensus on TA-TMA. Nineteen patients exhibited high-risk characteristics. Thirteen patients (65%) responded to narsoplimab, achieving transfusion independence and significant clinical improvement. The one-hundred-day Overall Survival (OS) post-TA-TMA diagnosis was 70%, and 100% for responders. Narsoplimab proved to be effective and safe in the treatment of high-risk TA-TMA, with no increased infectious complications or other safety signals of concern across all age groups. The high response rates and the encouraging survival outcomes underscore the potential of narsoplimab as a valuable therapeutic option, particularly for high-risk cases.

Late transplant-associated thrombotic microangiopathy verified in bone marrow biopsy specimens is associated with chronic GVHD and viral infections

OBJECTIVES

To describe late transplant-associated thrombotic microangiopathy (TA-TMA) as chronic endothelial complication in bone marrow (BM) after allogeneic hematopoietic stem cell transplantation (HSCT).

METHODS

BM specimens along with conventional diagnostic parameters were assessed in 14 single-institutional patients with late TA-TMA (more than 100 days after HCST), including 11 late with history of early TA-TMA, 10 with early TA-TMA (within 100 days), and 12 non TA-TMA patients. Three non-HSCT patients served as control. The time points of BM biopsy were +1086, +798, +396, and +363 days after HSCT, respectively.

RESULTS

Late TA-TMA patients showed an increase of CD34+ and von Willebrand Factor (VWF)+ microvascular endothelial cells with atypical VWF+ conglomerates forming thickened VWF+ plaque sinus in the BM compared to patients without late TA-TMA and non-HSCT. Severe chronic (p = .002), steroid-refractory GVHD (p = .007) and reactivation of HHV6 (p = .002), EBV (p = .003), and adenovirus (p = .005) were pronounced in late TA-TMA. Overall and relapse-free survival were shorter in late TA-TMA than in patients without late TA-TMA (5-year OS and RFS: 78.6% vs. 90.2%, 71.4% vs. 86.4%, respectively).

CONCLUSION

Chronic allo-immune microangiopathy in BM associated with chronic, steroid-refractory GVHD and/or viral infections are key findings of late, high-risk TA-TMA, which deserves clinical attention.

Thrombotic Microangiopathy After Hematopoietic Stem Cell and Solid Organ Transplantation: A Review for Intensive Care Physicians

Intensive care physicians may assume the primary care of patients with transplant-associated thrombotic microangiopathy (TA-TMA), an uncommon but potentially critical complication of hematopoietic stem cell transplants (HSCTs) and solid organ transplants. TA-TMA can have a dramatic presentation with multiple organ dysfunction syndrome (MODS) associated with high morbidity and mortality. The typical presenting clinical features are hemolytic anemia, thrombocytopenia, refractory hypertension, proteinuria and worsening renal failure. Intestinal involvement, with abdominal pain, nausea and vomiting, gastrointestinal bleeding, and ascites are also common. Cardiopulmonary involvement may develop from various causes including pulmonary arteriolar hypertension, pleural and pericardial effusions, and diffuse alveolar hemorrhage. Due to other often concurrent complications after HSCT, early diagnosis and effective management of TA-TMA may be challenging. Close collaboration between ICU and transplant physicians, along with other relevant specialists, is needed to best manage these patients. There are currently no approved therapies for the treatment of TA-TMA. Plasma exchange and rituximab are not recommended unless circulating factor H (CFH) antibodies or thrombotic thrombocytopenic purpura (TTP; ADAMTS activity < 10%) are diagnosed or highly suspected. The role of the complement pathway activation in the pathophysiology of TA-TMA has led to the successful use of targeted complement inhibitors, such as eculizumab. However, the relatively larger studies using eculizumab have been mostly conducted in the pediatric population with limited data on the adult population. This review is focused on the role of intensive care physicians to emphasize the clinical approach to patients with suspected TA-TMA and to discuss diagnosis and treatment strategies.

Endoscopic manifestation of intestinal transplant-associated microangiopathy after stem cell transplantation

BACKGROUND

Endoscopic features of intestinal transplant-associated microangiopathy (iTAM) have not been comprehensively investigated. This study aimed to examine the endoscopic characteristics of patients diagnosed with iTAM.

METHODS

This retrospective analysis included 14 patients pathologically diagnosed with iTAM after stem cell transplantation for hematolymphoid neoplasms (n = 13) or thalassemia (n = 1). The sex, age at diagnosis, endoscopic features, and prognosis of each patient were assessed. Serological markers for diagnosing transplant-associated thrombotic microangiopathy were also evaluated.

RESULTS

The mean age at the time of iTAM diagnosis was 40.2 years. Patients diagnosed based on the pathognomonic pathological changes of iTAM presented with diverse symptoms at the times of endoscopic examinations, including diarrhea (n = 10), abdominal pain (n = 5), nausea (n = 4), appetite loss (n = 2), bloody stools (n = 2), abdominal discomfort (n = 1), and vomiting (n = 1). At the final follow-up, six patients survived, while eight patients succumbed, with a median time of 100.5 days (range: 52-247) post-diagnosis. Endoscopic manifestations included erythematous mucosa (n = 14), erosions (n = 13), ulcers (n = 9), mucosal edema (n = 9), granular mucosa (n = 9), and villous atrophy (n = 4). Erosions and/or ulcers were primarily observed in the colon (10/14, 71%), followed by the ileum (9/13, 69%), stomach (4/10, 40%), cecum (5/14, 36%), duodenum (3/10, 30%), rectum (4/14, 29%), and esophagus (1/10, 10%). Cytomegalovirus infection (n = 4) and graft-versus-host disease (n = 2) coexisted within the gastrointestinal tract. Patients had de novo prolonged or progressive thrombocytopenia (6/14, 43%), decreased hemoglobin concentration (4/14, 29%), reduced serum haptoglobin level (3/14, 21%), and a sudden and persistent increase in lactate dehydrogenase level (2/14, 14%). Peripheral blood samples from 12 patients were evaluated for schistocytes, with none exceeding 4%.

CONCLUSIONS

This study provides a comprehensive exploration of the endoscopic characteristics of iTAM. Notably, all patients exhibited erythematous mucosa throughout the gastrointestinal tract, accompanied by prevalent manifestations, such as erosions (93%), ulcers (64%), mucosal edema (64%), granular mucosa (64%), and villous atrophy (29%). Because of the low positivity for serological markers of transplant-associated thrombotic microangiopathy in patients with iTAM, endoscopic evaluation and biopsy of these lesions are crucial, even in the absence of these serological features.

Eculizumab treatment in paediatric patients diagnosed with aHUS after haematopoietic stem cell transplantation: a HSCT-TMA case series from Japanese aHUS post-marketing surveillance

Haematopoietic stem-cell transplantation (HSCT)-associated thrombotic microangiopathy (HSCT-TMA) is a serious complication with high mortality. Accumulating evidence suggests that complement dysregulation is potentially involved in the development of HSCT-TMA. We retrospectively analysed the clinical characteristics and outcomes of thirteen paediatric patients who were diagnosed with atypical haemolytic uremic syndrome and treated with eculizumab to manage HSCT-TMA during post-marketing surveillance in Japan. The median time from HSCT to TMA was 31 days (Interquartile range, IQR;21-58) and the median doses of eculizumab was three (IQR;2-5). Seven patients (54%) were alive at the last follow-up while six died due to complications related to HSCT. Six of seven survivors initiated eculizumab after insufficient response to plasma therapy. Following eculizumab treatment, median platelet counts and LDH levels in all survivors significantly improved and renal function improved in 4/7 patients. All survivors possessed potential risk factors of complement overactivation. During the follow-up period after eculizumab discontinuation (median;111.5 days, IQR;95-555), no TMA recurrence was observed. In this analysis, eculizumab showed benefit in over half of this paediatric patient population. Ongoing clinical studies are expected to optimize the treatment regimen of terminal complement pathway inhibitor, and it may become a therapeutic option for paediatric HSCT-TMA in the future.

The effect of danger-associated molecular patterns on survival in acute graft versus host disease

Danger-associated molecular patterns (DAMPs) are molecules that can initiate and maintain robust inflammatory responses and were investigated in the pathogenesis of graft versus host disease (GvHD). Uric acid (UA) and fibrinogen (Fib) are DAMPs released from damaged tissue during allogeneic hematopoietic stem cell transplantation (allo-HCT) and GvHD. We aimed to evaluate the effects of UA and Fib levels on survival in GvHD. One hundred seventy-four patients with grade 2-4 acute GvHD were included. UA and Fib levels were evaluated on allo-HCT day 0 and GvHD on days 0, 7, 14, and 28. Fib GvHD day 0 was the independent predictor for overall survival (OS), non-relapse mortality (NRM), and progression-free survival in multivariable models (HR 0.98, p < 0.001; HR 0.98, p = 0.001, HR 0.98, p = 0.006, respectively). Also UA GvHD day 28 was the independent predictor for OS and NRM (HR 0.77, p = 0.004; HR 0.76, p = 0.011, respectively). Our results indicated that hypouricemia and hypofibrinogenemia were associated with a significantly shorter OS and higher NRM. UA and Fib are remarkable molecules in GvHD because they are routinely utilized, readily available, can be therapeutic targets, and have DAMPs and antioxidant features.

Endothelial Activation and Stress Index (EASIX) to predict mortality after allogeneic stem cell transplantation: a prospective study

BACKGROUND

We previously reported that the "Endothelial Activation and Stress Index" (EASIX; ((creatinine×lactate dehydrogenase)÷thrombocytes)) measured before start of conditioning predicts mortality after allogeneic hematopoietic stem cell transplantation (alloSCT) when used as continuous score. For broad clinical implementation, a prospectively validated EASIX-pre cut-off is needed that defines a high-risk cohort and is easy to use.

METHOD

In the current study, we first performed a retrospective cohort analysis in n=2022 alloSCT recipients and identified an optimal cut-off for predicting non-relapse mortality (NRM) as EASIX-pre=3. For cut-off validation, we conducted a multicenter prospective study with inclusion of n=317 first alloSCTs from peripheral blood stem cell in adult patients with acute leukemia, lymphoma or myelodysplastic syndrome/myeloproliferative neoplasms in the European Society for Blood and Marrow Transplantation network.

RESULTS

Twenty-three % (n=74) of alloSCT recipients had EASIX-pre ≥3 taken before conditioning. NRM at 2 years was 31.1% in the high EASIX group versus 11.5% in the low EASIX group (p<0.001). Patients with high EASIX-pre also had worse 2 years overall survival (51.6% vs 70.9%; p=0.002). We were able to validate the cut-off and found that EASIX ≥3 was associated with more than twofold increased risk for NRM in multivariate analysis (HR=2.18, 95% CI 1.2 to 3.94; p=0.01). No statistically significant difference could be observed for the incidence of relapse.

CONCLUSIONS

The results of this study provide a prospectively validated standard laboratory biomarker index to estimate the transplant-related mortality risk after alloSCT. EASIX ≥3 taken before conditioning identifies a population of alloSCT recipients who have a more than twofold increased risk of treatment-related mortality.

Soluble Urokinase-Type Plasminogen Activator Receptor (suPAR) and Growth Differentiation Factor-15 (GDF-15) Levels Are Significantly Associated with Endothelial Injury Indices in Adult Allogeneic Hematopoietic Cell Transplantation Recipients

Hematopoietic stem cell transplantation-associated thrombotic microangiopathy (HSCT-TMA) and graft-versus-host disease (GvHD) represent life-threatening syndromes after allogeneic hematopoietic stem cell transplantation (allo-HSCT). In both conditions, endothelial dysfunction is a common denominator, and development of relevant biomarkers is of high importance for both diagnosis and prognosis. Despite the fact that soluble urokinase plasminogen activator receptor (suPAR) and growth differentiation factor-15 (GDF-15) have been determined as endothelial injury indices in various clinical settings, their role in HSCT-related complications remains unexplored. In this context, we used immunoenzymatic methods to measure suPAR and GDF-15 levels in HSCT-TMA, acute and/or chronic GVHD, control HSCT recipients, and apparently healthy individuals of similar age and gender. We found considerably greater SuPAR and GDF-15 levels in HSCT-TMA and GVHD patients compared to allo-HSCT and healthy patients. Both GDF-15 and suPAR concentrations were linked to EASIX at day 100 and last follow-up. SuPAR was associated with creatinine and platelets at day 100 and last follow-up, while GDF-15 was associated only with platelets, suggesting that laboratory values do not drive EASIX. SuPAR, but not GDF-15, was related to soluble C5b-9 levels, a sign of increased HSCT-TMA risk. Our study shows for the first time that suPAR and GDF-15 indicate endothelial damage in allo-HSCT recipients. Rigorous validation of these biomarkers in many cohorts may provide utility for their usefulness in identifying and stratifying allo-HSCT recipients with endothelial cell impairment.

IL-10 plus the EASIX score predict bleeding events after anti-CD19 CAR T-cell therapy

Chimeric antigen receptor (CAR) T-cell-associated coagulopathy can cause bleeding events. To explore risk factors for hemorrhage after CAR T-cell therapy, we retrospectively analyzed routine indicators in 56 patients with non-Hodgkin lymphoma and B-cell acute lymphoblastic leukemia who received anti-CD19 CAR T-cell therapy. Disturbance of coagulation occurred mainly within one month post infusion, especially on day 7 and 14. The cumulative incidence of bleeding events within one month was 32.8%, with the median onset of 7 (range, 0-28) days. All bleeding events were grade 1-3. Patients who experienced bleeding events within one month had longer prothrombin time, higher IL-6, higher IL-10, and lower platelets before lymphodepletion. There were also correlations among coagulation-, inflammatory-, and tumor burden-related markers. Multi-variate analysis showed IL-10 (> 7.98 pg/mL; adjusted odds ratio [OR], 13.84; 95% confidence interval [CI], 2.03-94.36; P = 0.007) and the endothelial activation and stress index (EASIX, defined as dehydrogenase [U/L] × creatinine [mg/dL] / platelets [×109 cells/L]; >7.65; adjusted OR, 7.06; 95% CI, 1.03-48.23; P = 0.046) were significant risk factors for bleeding events. IL-10 plus the EASIX defined three risk groups for bleeding events with cumulative incidence of 100% (hazard ratio [HR], 14.47; 95% CI, 2.78-75.29; P < 0.0001), 38.5% (HR, 3.68; 95% CI, 0.82-16.67; P = 0.089), and 11.8% (reference), respectively. Future studies are needed to verify the risk assessment models for bleeding events after CAR T-cell treatment in larger cohorts.

Diagnosis and management of endothelial disorders following haematopoietic stem cell transplantation

Haematopoietic stem cell transplantation is a mainstay of therapy for numerous malignant and nonmalignant diseases. Endothelial activation and dysfunction occur after stem cell transplantation, driven by various patient- and transplant-specific factors. This can manifest as one of the relatively uncommon endothelial injury syndromes, such as sinusoidal obstruction syndrome, transplant-associated thrombotic microangiopathy, idiopathic pneumonia syndrome, capillary leak syndrome, engraftment syndrome or posterior reversible encephalopathy syndrome. This review focuses on the pathogenesis, classification and diagnosis of these disorders, as well as provides guidance on risk mitigation and treatment.

Beyond Immunosuppression: The Intricate Relationship Between Tacrolimus and Microangiopathy

Tacrolimus, widely known as Prograf, has become the preferred immunosuppressant for preventing graft rejection in solid organ transplant recipients, particularly in steroid-sparing regimens. Its efficacy and reduced risk of acute and chronic rejection compared to cyclosporine have made it the preferred treatment option for transplant patients. However, tacrolimus has drawbacks as it is associated with adverse effects, such as renal tubular necrosis, kidney failure, hypertension, metabolic acidosis, and new-onset diabetes mellitus. Among the less common but potentially severe complications is thrombotic microangiopathy linked to tacrolimus usage. Identifying and addressing this condition early on is crucial given its severity and potential complications. Manifestations of this microangiopathy can vary, encompassing renal, neurological, cardiac, and respiratory symptoms, and, in some cases, presenting as pancreatitis, intestinal ischemia, or skin abnormalities. Although conventional management often involves plasma exchange as the primary therapeutic option, recent insights into the pathophysiology have led to newer drugs, such as eculizumab and belatacept, offering promising outcomes. In this narrative review, we delve deeper into the underlying pathophysiological mechanisms of tacrolimus-induced thrombotic microangiopathy and aim to provide clinicians with valuable recommendations for efficient and timely treatment strategies. By understanding the complexities of this condition and staying abreast of the latest advancements in therapeutic options, healthcare providers can optimize patient outcomes and ensure safer tacrolimus administration in solid organ transplant recipients.

Prospective Clinical and Biomarker Validation of the American Society for Transplantation and Cellular Therapy Consensus Definition for Transplantation-Associated Thrombotic Microangiopathy

Transplantation-associated thrombotic microangiography (TA-TMA) is a disorder that causes severe complications after allogeneic hematopoietic cell transplantation (allo-HCT). Diagnosing TA-TMA is challenging because of the lack of standardized criteria. In this study, we aimed to evaluate the new TA-TMA consensus definition from the American Society for Transplantation and Cellular Therapy (ASTCT) panel as part of an ongoing prospective pediatric cohort study, and also to compare the impact and outcomes of using the current definition of clinical TMA (cTMA) versus the new consensus definition. We included patients age 0 to 18 years who underwent their first allo-HCT between May 2021 and January 2023 at Texas Children's Hospital. We compared the incidence, biomarkers, and outcomes of TA-TMA applying the previous and recently proposed screening algorithms and definitions. Whereas use of the classic microangiopathic hemolytic anemia (MAHA)-based cTMA definition led to an incidence of 12.7% by day 100 post-transplantation, the ASTCT-HR definition doubled the incidence to 28.5% by day 100. In contrast to patients with a concordant diagnosis (+/+), who had significantly worse post-transplantation survival, those reclassified as TA-TMA only by the new definition (-/+) had a significantly different prognosis (100% survival at day 100) despite the lack of TMA-directed therapy. Furthermore, biomarkers of the terminal and alternative complement pathways (sC5b9 and Ba, respectively) were significantly elevated compared with non-TMA patients around day 15 in the concordant group (+/+) but not in the discordant group (-/+). The recently proposed ASTCT consensus TA-TMA diagnosis is more sensitive and allows earlier recognition of manifestation that requires closer clinical monitoring but risks overdiagnosis and overtreatment. We recommend additional prospective validation.

Systemic complement activation influences outcomes after allogeneic hematopoietic cell transplantation: A prospective French multicenter trial

Complement activation has shown a role in murine models of graft-versus-host disease (GVHD) and in endothelial complications after allogeneic hematopoietic cell transplantation (allo-HSCT). However, its impact on post-transplant outcomes has not been so far fully elucidated. Here, we conducted a prospective multicentric trial (NCT01520623) performing serial measurements of complement proteins, regulators, and CH50 activity for 12 weeks after allo-HSCT in 85 patients receiving a myeloablative conditioning (MAC) regimen for various hematological malignancies. Twenty-six out of 85 patients showed an "activated" complement profile through the classical/lectin pathway, defined as a post-transplant decline of C3/C4 and CH50 activity. Time-dependent Cox regression models demonstrated that complement activation within the first weeks after allo-HSCT was associated with increased non-relapse mortality (hazard ratio [HR]: 3.69, 95% confident interval [CI]: 1.55-8.78, p = .003) and poorer overall survival (HR: 2.72, 95% CI: 1.37-5.39, p = .004) due to increased incidence of grade II-IV acute GVHD and in particular gastrointestinal (GI) GVHD (HR: 36.8, 95% CI: 12.4-109.1, p < .001), higher incidences of thrombotic microangiopathy (HR: 8.58, 95% CI: 2.16-34.08, p = .0022), capillary leak syndrome (HR: 7.36, 95% CI: 2.51-21.66, p = .00028), post-engraftment bacterial infections (HR: 2.37, 95% CI: 1.22-4.63, p = .0108), and EBV reactivation (HR: 3.33, 95% CI: 1.31-8.45, p = .0112). Through specific immune staining, we showed the correlation of deposition of C1q, C3d, C4d, and of C5b9 components on endothelial cells in GI GVHD lesions with the histological grade of GVHD. Altogether these findings define the epidemiology and the clinical impact of complement classical/lectin pathway activation after MAC regimens and provide a rational for the use of complement inhibitory therapeutics in a post-allo-HSCT setting.

Triple-Drug Graft-versus-Host Disease Prophylaxis after HLA-Matched Unrelated Donor Nonmyeloablative Allogenic Hematopoietic Stem Cell Transplantation

Adding sirolimus to graft-versus-host disease (GVHD) prophylaxis with cyclosporin and mycophenolate mofetil (MMF) reduced the risk of grade II-IV acute GVHD after nonmyeloablative (NMA) allogenic hematopoietic stem cell transplantation (HSCT) with an HLA-matched unrelated donor in a randomized clinical trial. We analyzed real-life data to investigate the impact of implementing the triple-drug regimen with cyclosporin, MMF and sirolimus as standard GVHD prophylaxis after NMA HSCT with an HLA-matched unrelated donor at our institution. We studied all adult patients (age ≥18 years) who underwent NMA HSCT with an HLA-matched unrelated donor at Rigshospitalet, Copenhagen University Hospital, Denmark between 2018 and 2021 and received GVHD prophylaxis with cyclosporin, MMF and sirolimus (triple-drug group [TDG]). Comparisons were made with a historical cohort who received tacrolimus and MMF as GVHD prophylaxis after HLA-matched unrelated donor NMA HSCT between 2014 and 2017 (control group [CG]). Outcomes were grade II-IV and grade III-IV acute GVHD, chronic GVHD, relapse, nonrelapse mortality (NRM) and overall survival (OS). A total of 264 patients were included (TDG, n = 137; CG, n = 127). Median age was 66 years (interquartile range [IQR], 58 to 69 years) in the TDG and 63 years (IQR, 57 to 68 years) in the CG. Acute myeloid leukemia and myelodysplastic syndrome were the most frequent indications for HSCT in both groups (TDG, 33% and 23%, respectively; CG, 36% and 22%, respectively). The cumulative incidence at day +110 of grade II-IV GVHD was 17% (95% confidence interval [CI] 11% to 23%) in the TDG versus 29% (95% CI, 21% to 37%) in the CG (P = .02, Gray's test) and that of grade III-IV acute GVHD was 3% (95% CI, 0 to 6%) versus 5% (95% CI, 1% to 8%), respectively (P = .4, Gray's test). In a Cox regression model adjusted for age, donor age and female donor to male recipient the risk of grade II-IV acute GVHD was lower in the TDG compared to the CG (hazard ratio [HR], .51; 95% CI .30 to .86; P = .01). The 2-year OS was 77% (95% CI, 70% to 84%) in the TDG and 69% (95% CI, 61% to 77%) in the CG (P = .04), and this difference remained significant after adjustment for age and Karnofsky Performance Status (HR, .65; 95% CI, .42 to .99; P = .04). The 2-year cumulative incidences of chronic GVHD, relapse and NRM were 60% (95% CI, 51% to 69%), 21% (95% CI, 13% to 28%), and 12% (95% CI, 6% to 17%), respectively, in the TDG and 62% (95% CI, 54% to 71%), 27% (95% CI, 19% to 35%) and 14% (95% CI, 8% to 20%), respectively, in the CG. Multivariable analyses revealed no difference in the risk of chronic GVHD (HR, .91; 95% CI, .65 to 1.26; P = .56), relapse (HR, .70; 95% CI, .42 to 1.15; P = .16) or NRM (HR, .56; 95% CI, .31 to 1.05; P = .07). After changing the standard GVHD prophylaxis in patients undergoing NMA HSCT with an HLA-matched unrelated donor from tacrolimus and MMF to cyclosporin, MMF and sirolimus, we observed a reduction in the incidence of grade II-IV acute GVHD and improved 2-year OS.

Potential factors for and the prognostic impact of ascites after allogeneic hematopoietic stem cell transplantation

Ascites is sometimes detected after allogeneic hematopoietic stem cell transplantation (allo-HSCT); however, since limited information is currently available, its clinical meaning remains unclear. Therefore, we herein examined potential factors for and the impact of ascites on the prognosis of patients after allo-HSCT at our institutes. Fifty-eight patients developed ascites within 90 days of allo-HSCT (small in 34 (16%), moderate-large in 24 (11%)). A multivariate analysis identified veno-occlusive disease/sinusoidal obstruction syndrome (p = 0.01) and myeloablative conditioning (p = 0.01) as significant potential factors for the development of small ascites. Thrombotic microangiopathy (TMA) (p < 0.01) was a significant potential factor for moderate-large ascites. The incidence of both small and moderate-large ascites correlated with lower overall survival (p = 0.03 for small ascites and p < 0.01 for moderate-large ascites) and higher non-relapse mortality rates (p = 0.03 for small ascites and p < 0.01 for moderate-large ascites). Lower OS and higher NRM rates correlated with the incidence of both small and moderate-large ascites. Further investigation is warranted to establish whether the clinical sign of ascites improves the diagnostic quality of TMA in a large-scale study.

Pathway-driven rare germline variants associated with transplant-associated thrombotic microangiopathy (TA-TMA)

The significance of rare germline mutations in transplant-associated thrombotic microangiopathy (TA-TMA) is not well studied. We performed a genetic association study in 100 adult TA-TMA patients vs. 98 post-transplant controls after matching by race, sex, and year. We focused on 5 pathways in complement, von Willebrand factor (VWF) function and related proteins, VWF clearance, ADAMTS13 function and related proteins, and endothelial activation (3641variants in 52 genes). In the primary analysis focused on 189 functional rare variants, no differential variant enrichment was observed in any of the pathways; specifically, 29 % TA-TMA and 33 % controls had at least 1 rare complement mutation. In the secondary analysis focused on 37 rare variants predicted to be pathogenic or likely pathogenic by ClinVar, Complement Database, or REVEL in-silico prediction tool, rare variants in the VWF clearance pathway were found to be significantly associated with TA-TMA (p = 0.008). On the gene level, LRP1 was the only one with significantly increased variants in TA-TMA in both analyses (p = 0.025 and 0.015). In conclusion, we did not find a significant association between rare variants in the complement pathway and TA-TMA; however, we discovered a new signal in the VWF clearance pathway driven by the gene LRP1 among likely pathogenic variants.

EASIX score predicts inferior survival after allogeneic hematopoietic cell transplantation

The Endothelial Activation and Stress Index (EASIX) is a prognostic tool that uses common clinical laboratory values and has been shown to predict non-relapse mortality (NRM) and overall survival (OS) at the onset of acute graft-versus-host disease (GVHD) after allogeneic hematopoietic cell transplantation (HCT). We hypothesized that EASIX calculated at different time points pre- and post- HCT may predict NRM and OS, and that EASIX calculated at onset of GVHD may predict response to steroids. We evaluated the EASIX score pre- and post-HCT in 152 patients with lymphoid malignancies undergoing unmodified reduced intensity conditioning (RIC) alloHCT with uniform GVHD prophylaxis. In multivariate analysis, EASIX calculated pre-HCT was significantly associated with higher NRM (HR = 1.64, p = 0.009) and lower OS (HR = 1.33, p = 0.046). Furthermore, EASIX calculated at day 30 and at day 100 was associated with increased NRM (HR = 1.65, p < 0.001; and HR = 1.65, p < 0.001) and decreased OS (HR = 1.27, p = 0.018; and HR = 1.49, p < 0.001), independent of HCT-CI, disease and conditioning regimen. Our study shows that high EASIX scores at various time points pre- and post-HCT are significantly associated with poorer overall outcomes. EASIX provides an independent and easily accessible tool to predict outcomes that can be complementary to other measures of risk stratification for patients undergoing HCT.

Hematopoietic stem cell transplantation-associated thrombotic microangiopathy and the role of advanced practice providers and pharmacists

Hematopoietic stem cell transplantation-associated thrombotic microangiopathy (HSCT-TMA) is a severe and potentially life-threatening complication. HSCT-TMA is often underdiagnosed due to multifactorial pathophysiology and a historic lack of standard diagnostic criteria. Identification of the multi-hit hypothesis and the key role of the complement system, particularly the lectin pathway of complement, has led to development of treatments targeting the underlying pathogenesis of HSCT-TMA. Additional research is ongoing to investigate the efficacy and safety of these targeted therapies in patients with HSCT-TMA. Advanced practice providers (APPs; nurse practitioners and physician assistants) and pharmacists are critical members of the multidisciplinary HSCT team and ensure management of patients throughout the continuum of care. Additionally, pharmacists and APPs can improve patient care through medication management of complex regimens; transplant education for patients, staff, and trainees; evidence-based protocol and clinical guideline development; assessment and reporting of transplant-related outcomes; and quality improvement initiatives to improve outcomes. Understanding the presentation, prognosis, pathophysiology, and treatment options for HSCT-TMA can improve each of these efforts. Collaborative practice model for monitoring and care of HSCT-TMA. Advanced practice providers and pharmacists contribute to many aspects of patient care in transplant centers, including medication management for complex regimens; transplant education for patients, staff, and trainees; evidence-based protocol and clinical guideline development; assessment and reporting of transplant-related outcomes; and quality improvement initiatives. HSCT-TMA is a severe and potentially life-threatening complication that is often underdiagnosed. The collaboration of a multidisciplinary team of advanced practice providers, pharmacists, and physicians can optimize recognition, diagnosis, management, and monitoring of patients with HSCT-TMA, thereby improving outcomes for these patients.

Systematic Review of Signs and Symptoms Associated with Hematopoietic Stem Cell Transplantation-Associated Thrombotic Microangiopathy

Hematopoietic stem cell transplantation-associated thrombotic microangiopathy (HSCT-TMA) is a serious complication of the transplantation process that has been consistently associated with substantially greater morbidity and mortality compared with HSCT recipients who do not develop TMA. This study aimed to systematically review published signs and symptoms of HSCT-TMA and compare patients with HSCT-TMA and HSCT recipients who do not develop TMA. Publications were identified using multiple search term variations for stem cell transplantation that were entered into the PubMed, Embase, and CINAHL databases. Two reviewers screened references at the abstract level before reviewing full texts against inclusion and exclusion criteria using a PICOS-T framework. Complication proportions were grouped by organ class and then by complication type. Meta-analyses were conducted using a random-effects model in RevMan 5.4. After 2338 references were screened, a total of 30 studies were included in our analyses. The majority of studies (n = 23; 14 adult, 5 pediatric, 4 both) examined allogeneic transplantations only. Four studies examined autologous transplantation only (all pediatric), and 3 studies included both transplantation types (all pediatric). HSCT-TMA was associated with renal dysfunction (odds ratio [OR], 11.04 for adult, allogeneic and 7.35 for pediatric, all transplantations), renal failure (OR, 2.41 for adult and pediatric, allogeneic), renal replacement therapy (OR, 6.99 for pediatric, all transplantations and 60.85 for adult, allogeneic), and hypertension (OR, 5.44 for adult, allogeneic). HSCT-TMA was associated with respiratory failure (OR, 8.00 for adult and pediatric, allogeneic), pulmonary hypertension (OR, 9.86 for adult and pediatric, allogeneic), need for pleurocentesis (OR, 5.45 for pediatric, all transplantations), noninvasive ventilation (OR, 6.15 for pediatric, all transplantations), and invasive mechanical ventilation (OR, 5.18 for pediatric, all transplantations). Additionally, HSCT-TMA was associated with neurologic symptoms (OR, 2.28 for adult and pediatric, allogeneic), pericardial effusion (OR, 2.56 for adult and pediatric, allogeneic and 8.76 for pediatric, all transplantations), liver injury (OR, 3.87 for adult, allogeneic), infection (OR, 9.25 for adult, allogeneic; 2.06 for pediatric, all transplantations), gastrointestinal (GI) bleeding (OR, 7.78 for adult and pediatric, allogeneic), and acute graft-versus-host disease grade III-IV (OR, 3.29 for adult and pediatric, allogeneic). This study represents the first systematic review of HSCT-TMA signs and symptoms. Current diagnostic criteria systems involve laboratory markers for multiorgan dysfunction, including renal dysfunction, liver injury, and general tissue damage. Diagnostic criteria include neurologic symptoms, increased need for transfusions, and hypertension. This study identified additional associations with HSCT-TMA, including increased pulmonary hypertension, respiratory failure, fever, GI bleeding, and pericardial effusion. These symptoms might be included for evaluation in future diagnostic criteria and current practice.

Clinical characteristics of pediatric allogeneic hematopoietic stem cell transplantation-associated thrombotic microangiopathy (TA-TMA): a retrospective single-center analysis

OBJECTIVES

To investigate the clinical features of thrombotic microangiopathy associated with allogeneic hematopoietic stem cell transplantation in children.

METHODS

A retrospective analysis of continuous clinical data from HSCT received in the Department of Hematology and Oncology of Wuhan Children's Hospital from August 1, 2016 to December 31, 2021.

RESULTS

During this period, 209 patients received allo-HSCT in our department, 20 (9.6%) of whom developed TA-TMA. TA-TMA was diagnosed at a median of 94 (7-289) days post-HSCT. Eleven (55%) patients had early TA-TMA within 100 days post-HSCT, while the other 9 (45%) patients had TA-TMA thereafter. The most common symptom of TA-TMA was ecchymosis (55%), while the main signs were refractory hypertension (90%) and multi-cavity effusion (35%). Five (25%) patients had central nervous system symptoms (convulsions and lethargy). All 20 patients had progressive thrombocytopenia, with 16 patients receiving transfusion of platelets that was ineffective. Ruptured red blood cells were visible in only two patients with peripheral blood smears. Cyclosporine A or Tacrolimus (CNI) dose was reduced once TA-TMA was diagnosed. Nineteen cases were treated with low-molecular-weight heparin, 17 patients received plasma exchange, and 12 patients were treated with rituximab. TA-TMA-related mortality percentage in this study was 45% (9/20).

CONCLUSION

Platelet decline and/or ineffective transfusion post-HSCT should be considered an early indicator of TA-TMA in pediatric patients. TA-TMA in pediatric patients may occur without evidence of peripheral blood schistocytes. Aggressive treatment is required once diagnosis is confirmed, but the long-term prognosis is poor.

A Fatal Case of Neuroblastoma Complicated by Posterior Reversible Encephalopathy with Rapidly Evolving Transplantation-Associated Thrombotic Microangiopathy

Background: Transplantation-associated thrombotic microangiopathy (TA-TMA) is a severe complication of hematopoietic stem cell transplantation and is sometimes fatal. Observations: A 4-year-old, male patient with stage M neuroblastoma (NBL) who had received an allogeneic bone marrow transplantation (BMT) from his sibling five months previously presented with rapidly progressive posterior reversible encephalopathy (PRES) complicated with TA-TMA. Although the patient was transferred to the pediatric intensive care unit, he died within one week after the onset of the latest symptoms. Conclusions: This is the first description of a fatal case of NBL complicated by PRES with rapidly evolving TA-TMA after an allogenic BMT.

Harmonizing Definitions for Diagnostic Criteria and Prognostic Assessment of Transplantation-Associated Thrombotic Microangiopathy: A Report on Behalf of the European Society for Blood and Marrow Transplantation, American Society for Transplantation and Cellular Therapy, Asia-Pacific Blood and Marrow Transplantation Group, and Center for International Blood and Marrow Transplant Research

Transplantation-associated thrombotic microangiopathy (TA-TMA) is an increasingly recognized complication of hematopoietic cell transplantation (HCT) associated with significant morbidity and mortality. However, TA-TMA is a clinical diagnosis, and multiple criteria have been proposed without universal application. Although some patients have a self-resolving disease, others progress to multiorgan failure and/or death. Poor prognostic features also are not uniformly accepted. The lack of harmonization of diagnostic and prognostic markers has precluded multi-institutional studies to better understand incidence and outcomes. Even current interventional trials use different criteria, making it challenging to interpret the data. To address this urgent need, the American Society for Transplantation and Cellular Therapy, Center for International Bone Marrow Transplant Research, Asia-Pacific Blood and Marrow Transplantation, and European Society for Blood and Marrow Transplantation nominated representatives for an expert panel tasked with reaching consensus on diagnostic and prognostic criteria. The panel reviewed literature, generated consensus statements regarding diagnostic and prognostic features of TA-TMA using the Delphi method, and identified future directions of investigation. Consensus was reached on 4 key concepts: (1) TA-TMA can be diagnosed using clinical and laboratory criteria or tissue biopsy of kidney or gastrointestinal tissue; however, biopsy is not required; (2) consensus diagnostic criteria are proposed using the modified Jodele criteria with additional definitions of anemia and thrombocytopenia. TA-TMA is diagnosed when ≥4 of the following 7 features occur twice within 14 days: anemia, defined as failure to achieve transfusion independence despite neutrophil engraftment; hemoglobin decline by ≥1 g/dL or new-onset transfusion dependence; thrombocytopenia, defined as failure to achieve platelet engraftment, higher-than-expected transfusion needs, refractory to platelet transfusions, or ≥50% reduction in baseline platelet count after full platelet engraftment; lactate dehydrogenase (LDH) exceeding the upper limit of normal (ULN); schistocytes; hypertension; soluble C5b-9 (sC5b-9) exceeding the ULN; and proteinuria (≥1 mg/mg random urine protein-to-creatinine ratio [rUPCR]); (3) patients with any of the following features are at increased risk of nonrelapse mortality and should be stratified as high-risk TA-TMA: elevated sC5b-9, LDH ≥2 times the ULN, rUPCR ≥1 mg/mg, multiorgan dysfunction, concurrent grade II-IV acute graft-versus-host disease (GVHD), or infection (bacterial or viral); and (4) all allogeneic and pediatric autologous HCT recipients with neuroblastoma should be screened weekly for TA-TMA during the first 100 days post-HCT. Patients diagnosed with TA-TMA should be risk-stratified, and those with high-risk disease should be offered participation in a clinical trial for TA-TMA-directed therapy if available. We propose that these criteria and risk stratification features be used in data registries, prospective studies, and clinical practice across international settings. This harmonization will facilitate the investigation of TA-TMA across populations diverse in race, ethnicity, age, disease indications, and transplantation characteristics. As these criteria are widely used, we expect continued refinement as necessary. Efforts to identify more specific diagnostic and prognostic biomarkers are a top priority of the field. Finally, an investigation of the impact of TA-TMA-directed treatment, particularly in the setting of concurrent highly morbid complications, such as steroid-refractory GVHD and infection, is critically needed.

Statin-based endothelial prophylaxis and outcome after allogeneic stem cell transplantation

BACKGROUND

Allogeneic haematopoietic stem cell transplantation (alloSCT) often remains the only curative therapy for hematologic malignancies. Although the management of transplant-associated adverse events considerably improved over the last decades, nonrelapse mortality (NRM) remains a challenge, and endothelial dysfunction was identified as a major contributor to NRM.

METHODS

Statin-based endothelial prophylaxis (SEP) has been implemented in the standard of care in our transplant centre to reduce NRM caused by endothelial injury. Here, we retrospectively analysed the impact of SEP on clinical outcome in a cohort of 347 alloSCT patients.

RESULTS

SEP (n = 209) was associated with significantly reduced NRM (hazard ratio 0.61, 95% CI 0.38-0.96) and better overall survival (OS) after acute graft-versus-host disease (HR 0.59, 95% CI 0.37-0.93). Subgroup analyses showed that the NRM benefit was mainly found in patients with an intermediate endothelial activation and stress index (EASIX), while relapse risk was not affected. On day 100 post-alloSCT, patients receiving SEP had significantly higher levels of the rate-limiting enzyme of tryptophan metabolism, indoleamine 2,3-dioxygenase (IDO), higher kynurenine to tryptophan ratios as a proxy of IDO activity and tended to have lower levels of the endothelial injury marker ST2 (p = .055). No significant differences in interferon-gamma or IL18 levels were observed. These biomarker signatures suggest that the beneficial effects of SEP might be mediated by both endothelial protection and immunomodulation.

CONCLUSIONS

Together, these data suggest that SEP improves NRM and OS post-alloSCT in particular in patients with intermediate endothelial risk and provide first mechanistic clues about its potential mode of action.

Use of eculizumab in children with allogeneic haematopoietic stem cell transplantation associated thrombotic microangiopathy - a multicentre retrospective PDWP and IEWP EBMT study

Terminal complement blockade by humanised monoclonal antibody eculizumab has been used to treat transplantation-associated thrombotic microangiopathy (TA-TMA) in recent years. This retrospective international study conducted by the Paediatric Diseases (PDWP) and Inborn Error Working Party (IEWP) of the European Society for Blood and Marrow Transplantation (EBMT) describes outcome and response of 82 paediatric patients from 29 centres who developed TA-TMA and were treated with eculizumab between January 2014 and May 2019. The median time from hematopoietic stem cell transplantation (HSCT) to TA-TMA manifestation was 92 days (range: 7-606) and from TA-TMA diagnosis to the start of eculizumab treatment 6 days (range: 0-135). Most patients received eculizumab weekly (72%, n = 55) with a standard weight (kg)-based dose (78%, n = 64). Six months from beginning of eculizumab therapy, the cumulative incidence of TA-TMA resolution was 36.6% (95% CI: 26.2-47) and the overall survival (OS) was 47.1% (95% CI: 35.9-57.5). All 43 patients with unresolved TA-TMA died. The cause of death was HSCT-related in 41 patients. This study also documents poor outcome of patients without aGvHD and their frequent concomitant viral infections. Considering recent publications, intensified eculizumab dosing and complement monitoring could potentially improve upon outcomes observed in this study.

Endothelial Dysfunction Syndromes after Allogeneic Stem Cell Transplantation

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the only therapy with a curative potential for a variety of malignant and non-malignant diseases. The major limitation of the procedure is the significant morbidity and mortality mainly associated with the development of graft versus host disease (GVHD) as well as with a series of complications related to endothelial injury, such as sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD), transplant-associated thrombotic microangiopathy (TA-TMA), etc. Endothelial cells (ECs) are key players in the maintenance of vascular homeostasis and during allo-HSCT are confronted by multiple challenges, such as the toxicity from conditioning, the administration of calcineurin inhibitors, the immunosuppression associated infections, and the donor alloreactivity against host tissues. The early diagnosis of endothelial dysfunction syndromes is of paramount importance for the development of effective prophylactic and therapeutic strategies. There is an urgent need for the better understanding of the pathogenetic mechanisms as well as for the identification of novel biomarkers for the early diagnosis of endothelial damage. This review summarizes the current knowledge on the biology of the endothelial dysfunction syndromes after allo-HSCT, along with the respective therapeutic approaches, and discusses the strengths and weaknesses of possible biomarkers of endothelial damage and dysfunction.

Transplant-Associated Thrombotic Microangiopathy in the Context of Allogenic Hematopoietic Stem Cell Transplantation: Where We Stand

Transplant-associated thrombotic microangiopathy (TA-TMA) constitutes a significant contributor to the increased morbidity and mortality after allogenic hematopoietic stem cell transplantation (allo-HSCT). TA-TMA is a heterogenous disease, characterized by the triad of endothelial cell activation, complement dysregulation and microvascular hemolytic anemia, which may affect all organs. The lack of consensus diagnostic criteria, along with the common clinical features mimicking other diseases that complicate allo-HSCT, make the diagnosis of TA-TMA particularly challenging. Significant effort has been made to recognize specific risk factors predisposing to the development of TA-TMA and to identify serum biomarkers predicting the development of the disease. With regard to treatment, therapeutic plasma exchange (TPE) has been traditionally used, although with doubtful efficacy. On the other hand, the pivotal role of complement activation in the pathophysiology of TA-TMA has led to the exploration of the therapeutic potential of complement inhibitors in this setting. Eculizumab has been proposed as a first-line therapeutic agent in TA-TMA, owing to the very promising results in both pediatric and adult clinical trials. Pharmacokinetic and pharmacodynamic studies and CH50 levels are of paramount importance in the allo-HSCT setting, as a different dosing schedule (more intensive-in dose and frequency-at the beginning) seems to be required for successful outcomes. Furthermore, Narsoplimab, a MASP-2 inhibitor, recently received a Breakthrough Therapy Designation from the FDA for the treatment of TA-TMA after allo-HSCT. Finally, the decision to withdraw the CNIs, although initially advised by the Bone and Marrow Transplant Clinical Trials Network Committee, remains debatable owing to the controversial results of recent clinical trials. This review summarizes the current updates on pathophysiology, diagnosis and therapeutic approaches and emphasizes future goals and perspectives.

Haemolytic uraemic syndrome

Haemolytic uraemic syndrome (HUS) is a heterogeneous group of diseases that result in a common pathology, thrombotic microangiopathy, which is classically characterised by the triad of non-immune microangiopathic haemolytic anaemia, thrombocytopenia, and acute kidney injury. In this Seminar, different causes of HUS are discussed, the most common being Shiga toxin-producing Escherichia coli HUS. Identifying the underlying thrombotic microangiopathy trigger can be challenging but is imperative if patients are to receive personalised disease-specific treatment. The quintessential example is complement-mediated HUS, which once carried an extremely high mortality but is now treated with anti-complement therapies with excellent long-term outcomes. Unfortunately, the high cost of anti-complement therapies all but precludes their use in low-income countries. For many other forms of HUS, targeted therapies are yet to be identified.

The Endothelial Activation and Stress Index (EASIX) score is an independent prognostic factor in patients with diffuse large B-cell lymphoma

BACKGROUND

The endothelial activation and stress index (EASIX) score has been reported to predict overall survival (OS) in hematological cancers. However, it has not been validated as a prognostic marker for diffuse large B-cell lymphoma (DLBCL) to date.

METHODS

The records of 265 patients who presented with DLBCL in the Republic of Korea between January 07, 2004, and March 05, 2020 were retrospectively reviewed. For all included patients, EASIX scores were calculated using serum lactate dehydrogenase (LDH) and creatinine levels and the platelet count measured at diagnosis as follows: LDH (U/L) × creatinine (mg/dL)/platelet count (10⁹/L).

RESULTS

The median age of the patients was 64 years. The optimal cutoff value of EASIX according to the receiver operating characteristic analysis for OS was 1.33. All the patients were treated with cyclophosphamide, doxorubicin, vincristine, and prednisone combined with rituximab. The 1-year OS and progression-free survival (PFS) rates were lower in the high-EASIX group than in the low EASIX group (63.8% vs. 84.4%, p < 0.001 and 54.0% vs. 79.6%, p < 0.001, respectively). A high EASIX was an independent poor prognostic factor for OS and PFS (hazard ratio, 1.606; 95% CI, 1.077-2.395; p = 0.020 and hazard ratio, 1.621; 95% CI, 1.066-2.464; p = 0.024, respectively).

CONCLUSIONS

EASIX is a readily available and cheaply obtainable parameter in clinical studies and shows considerable potential as a new prognostic marker for patients with newly diagnosed DLBCL.

Complement System as a New Target for Hematopoietic Stem Cell Transplantation-Related Thrombotic Microangiopathy

Thrombotic microangiopathy (TMA) is a complication that may occur after autologous or allogeneic hematopoietic stem cell transplantation (HSCT) and is conventionally called transplant-associated thrombotic microangiopathy (TA-TMA). Despite the many efforts made to understand the mechanisms of TA-TMA, its pathogenesis is largely unknown, its diagnosis is challenging and the case-fatality rate remains high. The hallmarks of TA-TMA, as for any TMA, are platelet consumption, hemolysis, and organ dysfunction, particularly the kidney, leading also to hypertension. However, coexisting complications, such as infections and/or immune-mediated injury and/or drug toxicity, together with the heterogeneity of diagnostic criteria, render the diagnosis difficult. During the last 10 years, evidence has been provided on the involvement of the complement system in the pathophysiology of TA-TMA, supported by functional, genetic, and therapeutic data. Complement dysregulation is believed to collaborate with other proinflammatory and procoagulant factors to cause endothelial injury and consequent microvascular thrombosis and tissue damage. However, data on complement activation in TA-TMA are not sufficient to support a systematic use of complement inhibition therapy in all patients. Thus, it seems reasonable to propose complement inhibition therapy only to those patients exhibiting a clear complement activation according to the available biomarkers. Several agents are now available to inhibit complement activity: two drugs have been successfully used in TA-TMA, particularly in pediatric cases (eculizumab and narsoplimab) and others are at different stages of development (ravulizumab, coversin, pegcetacoplan, crovalimab, avacopan, iptacopan, danicopan, BCX9930, and AMY-101).

Acute kidney injury in pediatric hematopoietic cell transplantation: critical appraisal and consensus

Hematopoietic cell transplantation (HCT) is a common therapy for the treatment of neoplastic and metabolic disorders, hematological diseases, and fatal immunological deficiencies. HCT can be subcategorized as autologous or allogeneic, with each modality being associated with their own benefits, risks, and post-transplant complications. One of the most common complications includes acute kidney injury (AKI). However, diagnosing HCT patients with AKI early on remains quite difficult. Therefore, this evidence-based guideline, compiled by the Pediatric Continuous Renal Replacement Therapy (PCRRT) working group, presents the various factors that contribute to AKI and recommendations regarding optimization of therapy with minimal complications in HCT patients.

Neurological complications in adult allogeneic hematopoietic stem cell transplant patients: Incidence, characteristics and long-term follow-up in a multicenter series

Neurological complications (NCs) represent a diagnostic and clinical challenge in allogeneic hematopoietic stem cell transplant (alloHSCT) patients. We retrospectively analyzed NC incidence, etiology, timing, characteristics, outcome, and long-term effects in 2384 adult patients transplanted in seven Italian institutions between January 2007 and December 2019. Ninety-three (3.9%) patients were affected by 96 NCs that were infectious (29.2%), immune/inflammatory (26%), drug-related (12.5%), cerebrovascular (5.2%), metabolic (3.1%), related to central nervous system disease relapse (11.5%) and malignancy (3.1%), or undefined (9.4%). Six patients (6.4%) had neurological manifestations of chronic graft-versus-host disease (GVHD). NCs occurred on average at day +128 (from -5 to +4063). Early (< day +120) and late NCs had similar frequencies (46.9% vs 53.1%, p = 0.39). Thirty-one patients (33.3%) were affected by acute or chronic GVHD at the NC onset. With a median follow-up of 25.4 (0.4-163) months, the overall mortality due to NCs was 22.6%. The median time between NC onset and death was 36 (1-269) days. Infectious NCs were the main cause (61.9%) of NC-related mortality. A persistent neurological impairment occurred in 20.4% patients, 57.9% of whom being affected by immune/inflammatory NCs. This study highlights the rare, yet severe impact of alloHSCT-associated NCs on patient survival and long-term functional ability.

EASIX and Severe Endothelial Complications After CD19-Directed CAR-T Cell Therapy—A Cohort Study

Background

Endothelial dysfunction is associated with two main complications of chimeric antigen receptor T (CAR-T) cell therapy, cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). This study evaluates the Endothelial Activation and Stress Index (EASIX) as a prognostic marker for high-grade CRS and ICANS in patients treated with CD19-directed CAR-T cells.

Methods

In this retrospective study, a training cohort of 93 patients from the ZUMA-1 trial and a validation cohort of 121 patients from two independent centers (University Hospital Heidelberg, Charité University Medicine Berlin) were investigated. The primary objective was to assess the predictive capacity of EASIX measured immediately before the start of lymphodepletion (EASIX-pre) for the occurrence of grade ≥3 CRS and/or ICANS. To explore a possible endothelial link, serum levels of endothelial stress markers (angiopoietin-2, suppressor of tumorigenicity-2, soluble thrombomodulin, and interleukin-8) were determined before lymphodepletion and on day 7 after CART infusion in the validation cohort (n = 47).

Results

The prognostic effect of EASIX-pre on grade ≥3 CRS and/or ICANS was significant in the training cohort [OR 2-fold increase 1.72 (1.26–2.46)] and validated in the independent cohort. An EASIX-pre cutoff >4.67 derived from the training cohort associated with a 4.3-fold increased odds ratio of severe CRS/ICANS in the independent cohort. Serum endothelial distress markers measured on day+7 correlated with EASIX-pre and associated with severe complications.

Conclusions

EASIX-pre is a powerful predictor of severe CRS/ICANS after CD19-directed CART therapy and might be used as a basis for risk-adapted prevention strategies.

Acute graft-versus-host disease increase risk and accuracy in prediction model of transplantation-associated thrombotic microangiopathy in patients with myelodysplastic syndrome

Allogeneic hematopoietic stem cell transplantation is the only curative therapy for patients with myelodysplastic syndrome. Transplantation-associated thrombotic microangiopathy (TA-TMA) remains a cause of death after transplantation. This study assessed the risk factors of TA-TMA and established a prediction model for this complication. We launched a real-world study from 303 MDS patients after allo-HSCT from Dec 1, 2007, to Jun 1, 2018. Logistic regression was used to analyze risk factors and to establish a nomogram. The accuracy of the model was assessed by C-index and calibration curve. TA-TMA class was associated with an over twofold increase in the risk of death (HR 2.66, 95% CI 1.39-5.09, p = 0.003). Stage III or IV acute graft-versus-host disease (aGVHD) (OR: 6.17, 95% CI: 2.19-17.18, p < 0.001) and occurrence time of aGVHD were the risk factors for TA-TMA. Next, we put these two variants and the other three variants into the prediction model via multivariate Lasso regression. In order to quantify the contribution of each factor, a nomogram was generated and displayed (C index of 0.783). TA-TMA predicts worsened outcomes of overall survival. A cross-validated multivariate score including aGVHD occurrence showed excellent concordance and efficacy of predicting TA-TMA in HSCT patients.

Recent Advances of Acute Kidney Injury in Hematopoietic Cell Transplantation

Acute kidney injury (AKI) is a common complication of allogeneic hematopoietic cell transplantation (allo-HCT) and is associated with non-relapse mortality (NRM) and quality of life (QOL). Multiple factors may contribute to AKI during allo-HCT and are often present at the same time making it difficult to determine the cause of AKI in each patient. Nephrotoxic drugs, infections, thrombotic microangiopathy (TMA), and sinusoidal obstruction syndrome (SOS) are well described causes of AKI during allo-HCT. Acute graft-versus-host disease (aGVHD) is a major complication of allo-HCT that mainly targets the intestines, liver, and skin. However, recent studies suggest aGVHD may also attack the kidney and contribute to AKI following allo-HCT. For example, severe aGVHD is associated with AKI, suggesting a link between the two. In addition, animal models have shown donor immune cell infiltration and increased expression of inflammatory cytokines in recipient kidneys after allo-HCT. Therefore, aGVHD may also target the kidney and contribute to AKI following allo-HCT. Herein, we describe the etiology, diagnosis, risk factors, pathophysiology, prevention, and treatment of renal injury after allo-HCT. In addition, we highlight emerging evidence that aGVHD may contribute to the development of AKI after allo-HCT.

Kidney Disease Following Hematopoietic Stem Cell Transplantation

Hematopoietic stem cell transplantation (SCT) provides a curative option for the treatment of several malignancies. Its growing use is associated with an increased burden of kidney disease. Acute kidney injury is usually seen within the first 100 days of transplantation and has an incidence ranging between 12 and 73%, with the highest rate in myeloablative allogeneic SCT. A large subset of patients after SCT develop chronic kidney disease. They can be broadly classified into thrombotic microangiopathy, nephrotic syndrome, and calcineurin toxicity. Dialysis requirement after SCT is associated with mortality exceeding 80%. Given the higher morbidity and mortality related to development kidney disease, nephrologists need to be aware of the various causes and best treatment options.

Endothelial Dysfunction after Hematopoietic Stem Cell Transplantation: A Review Based on Physiopathology

Endothelial dysfunction (ED) is frequently encountered in transplant medicine. ED is an argument of high complexity, and its understanding requires a wide spectrum of knowledge based on many fields of basic sciences such as molecular biology, immunology, and pathology. After hematopoietic stem cell transplantation (HSCT), ED participates in the pathogenesis of various complications such as sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD), graft-versus-host disease (GVHD), transplant-associated thrombotic microangiopathy (TA-TMA), idiopathic pneumonia syndrome (IPS), capillary leak syndrome (CLS), and engraftment syndrome (ES). In the first part of the present manuscript, we briefly review some biological aspects of factors involved in ED: adhesion molecules, cytokines, Toll-like receptors, complement, angiopoietin-1, angiopoietin-2, thrombomodulin, high-mobility group B-1 protein, nitric oxide, glycocalyx, coagulation cascade. In the second part, we review the abnormalities of these factors found in the ED complications associated with HSCT. In the third part, a review of agents used in the treatment of ED after HSCT is presented.

Incidence and Risk Factors for Acute Kidney Injury after Allogeneic Stem Cell Transplantation: A Prospective Study

(1) Background: Acute kidney injury (AKI) is a serious complication of hematopoietic stem cell transplantation (HSCT). (2) Methods: The aim was to identify the incidence, severity, and risk factors for AKI during the first 100 days after allo-HSCT; we performed a prospective observational study on 135 consecutive patients. (3) Results: The mean age was 38.3 ± 11.9 years (50.6% females), AKI developed in 93 patients (68.9%), the median time of appearance was 28 days, and the mean serum creatinine at the time of AKI was 1.8 ± 0.8 mg/dL. A total of 36 (38.7%) patients developed stage 1 AKI, 33 (35.5%) patients developed stage 2, and 24 (25.8%) patients developed stage 3; eight (8.6%) patients required temporary hemodialysis, and the mortality rate in these patients was 87.5%. Death was twice as frequent in the AKI subgroup, without statistical significance. Cyclosporine overdose (HR = 2.36, 95% CI: 1.45-3.85, p = 0.001), tacrolimus overdose (HR = 4.72, 95% CI: 2.22-10.01, p < 0.001), acute graft-versus-host disease (aGVHD) (HR = 1.96, 95% CI: 1.13-3.40, p = 0.01), and CRP level (HR = 1.009, 95% CI: 1.007-1.10, p < 0.001) were independent risk factors for AKI. Sepsis (HR = 5.37, 95% CI: 1.75-16.48, p = 0.003) and sinusoidal obstruction syndrome (HR = 5.10, 95% CI: 2.02-12.85, p = 0.001) were found as independent risk factors for AKI stage 3. (4) Conclusions: AKI occurs with high incidence and increased severity after allo-HSCT. Careful monitoring of calcineurin inhibitors and proper management of sepsis may reduce this risk.

Incidence and risk factors of transplant-associated thrombotic microangiopathy (TA-TMA): a systematic review and meta-analysis

BACKGROUND

Transplant-associated thrombotic microangiopathy (TA-TMA) is an increasingly recognized post-transplant complication, yet the overall incidence of the disease remains debated.

OBJECTIVES

To determine the pooled incidence of TA-TMA in a systematic review of literature and to identify consistent risk factors.

STUDY DESIGN

We performed a systematic review using Medline, Embase, and CENTRAL databases to identify cohort studies that reported incidence of and risk factors for TA-TMA from 2004 to 2020. We conducted a meta-analysis of proportion to estimate the pooled incidence of TA-TMA using a random-effects model. We assessed moderators of heterogeneity through subgroup analysis, risk of bias through ROBINS-I, and publication bias through funnel plot.

RESULTS

Among 21 cohort studies with 36,163 adult and pediatric patients that underwent allogeneic transplant, the pooled incidence of TA-TMA was 12% (95% CI 9-16). The diagnostic criteria used to define the disease was the most significant contributor identified to the high inter-study heterogeneity (I² 98%). Studies using provider/clinician diagnosis instead of laboratory diagnosis reported the lowest incidence at 3%. The most salient risk factor for TA-TMA reported in 14 studies was preceding acute graft-versus-host disease (GVHD). Other risk predictors described in 5 or more studies included preceding infection, prior transplant, mismatched donor, and myeloablative conditioning.

CONCLUSION

With a pooled incidence at 12% among a significantly heterogeneous population, TA-TMA is an important but relatively uncommon post-transplant complication. Given the divergence between laboratory-based and provider-based incidence, as well as the multitude of risk factors beyond acute GVHD, future studies should focus on risk stratifying the subset of TA-TMA patients who would benefit from therapeutic intervention.

A systematic review of diagnostic, prognostic, and risk blood and urine biomarkers of transplant-associated thrombotic microangiopathy

Transplant-associated thrombotic microangiopathy (TA-TMA) is an increasingly recognized complication of allogeneic and autologous hematopoietic cellular therapy (HCT), associated with significant morbidity and mortality. Although the central drivers of the disease are thought to be endothelial damage and complement activation, no specific diagnostic biomarkers have been identified. TA-TMA is typically diagnosed using criteria comprised of non-specific clinical and laboratory features. Some patients will have a self-remitting course, but more than half develop multi-organ dysfunction or die, making prognostic biomarkers critical. Prevention of TA-TMA, an approach central to other HCT complications such as graft-versus-host disease, is largely untested in part due to a lack of identified early high-risk biomarkers. We conducted a systematic review to summarize the diagnostic, early risk, and prognostic biomarkers of TA-TMA. We screened the titles and abstracts of 1524 citations. After screening out duplications, we read the abstracts of 979 papers and fully reviewed 132 full-text publications. Thirty-one publications fulfilled the inclusion criteria of more than five patients with TA-TMA and a reported measure of association with diagnosis, prognosis, or risk of later development of the disease. Fourteen studies (45%) were with adults, 12 (39%) were with children <18 years old, three included both children and adults, and two did not report age. There were 53 biomarker or biomarker signature entries, and a total of 27 unique biomarkers. Only four biomarkers reported sensitivity and specificity. The single biomarker with the most robust data was sC5b-9, which conferred diagnostic, prognostic, and risk implications. Studies of combinations of biomarkers were rare. No meta-analyses were performed because of significant heterogeneity between studies. The limitations of studies included small sample size, study designs with a high risk of bias (i.e., case-control), the timing of sample collection, and the selection of controls. Furthermore, only two (6%) studies included a training and validation cohort. Cut-off points are needed to stratify groups, as most biomarkers do not have normal values, or normal values cannot be assumed in the HCT setting. In the future, multi-institutional, collaborative efforts are needed to perform rigorously designed, prospective studies with serially enrolled patients, with samples collected at the time of TA-TMA diagnosis, careful selection of controls, and validation of selected biomarkers and cut-off points in a separate cohort.

Early vascular endothelial complications after hematopoietic cell transplantation: Role of the endotheliopathy in biomarkers and target therapies development

This work aims to review the role of endothelial dysfunction underlying the main complications appearing early after autologous and allogeneic hematopoietic cell transplantation (HCT). The endothelial damage as the pathophysiological substrate of sinusoidal obstruction syndrome (SOS) is well established. However, there is growing evidence of the involvement of endothelial dysfunction in other complications, such as acute graft-versus-host disease (aGVHD) and transplant-associated thrombotic microangiopathy (TA-TMAs). Moreover, HCT-related endotheliopathy is not only limited to the HCT setting, as there is increasing evidence of its implication in complications derived from other cellular therapies. We also review the incidence and the risk factors of the main HCT complications and the biological evidence of the endothelial involvement and other linked pathways in their development. In addition, we cover the state of the art regarding the potential use of the biomarkers of endotheliopathy in the prediction, the early diagnosis, and the follow-up of the HCT complications and summarize current knowledge points to the endothelium and the other linked pathways described as potential targets for the prevention and treatment of HCT-complications. Lastly, the endothelium-focused therapeutic strategies that are emerging and might have a potential impact on the survival and quality of life of post-HCT-patients are additionally reviewed.

Acute GVHD, BK hemorrhagic cystitis and age are risk factors for transplant-associated thrombotic microangiopathy in adults

Clinically actionable thrombotic microangiopathy (CA-TMA) occurring in the absence of aGVHD occurs earlier than day 100.

aGVHD is a key and consistent risk factor for late-onset CA-TMA.

Hematopoietic cell transplantation–associated thrombotic microangiopathy (TMA) is a complication associated with higher nonrelapse mortality (NRM) in patients who undergo allogeneic transplant (HCT). Current classification criteria are not generally agreed on or validated, and the presence of confounding factors after transplant contribute to underdiagnosis or delayed diagnosis of TMA. We studied risk factors, incidence, and biomarkers of TMA in 119 adult allogeneic HCT recipients. Twenty-seven patients developed a clinically actionable phenotype of TMA (CA-TMA) and the incidence of CA-TMA was 22% by day 180. Among the 27 patients who developed CA-TMA, 10 developed it before the onset of acute graft-versus-host disease (aGVHD), and 17 patients developed it after the onset of aGVHD. We report for the first time that age >50 years, BK hemorrhagic cystitis, and other viral infections (CMV, HHV-6, or adenovirus) are risk factors for adult CA-TMA. Even after adjustment for aGVHD, CA-TMA was independently associated with significantly higher NRM. These data illustrate relationships between CA-TMA and aGVHD, describe new risk factors for CA-TMA and emphasizes the need to develop validated set of criteria for timely diagnosis.

Role of the lectin pathway of complement in hematopoietic stem cell transplantation-associated endothelial injury and thrombotic microangiopathy

Hematopoietic stem cell transplantation-associated thrombotic microangiopathy (HSCT-TMA) is a life-threatening syndrome that occurs in adult and pediatric patients after hematopoietic stem cell transplantation. Nonspecific symptoms, heterogeneity within study populations, and variability among current diagnostic criteria contribute to misdiagnosis and underdiagnosis of this syndrome. Hematopoietic stem cell transplantation and associated risk factors precipitate endothelial injury, leading to HSCT-TMA and other endothelial injury syndromes such as hepatic veno-occlusive disease/sinusoidal obstruction syndrome, idiopathic pneumonia syndrome, diffuse alveolar hemorrhage, capillary leak syndrome, and graft-versus-host disease. Endothelial injury can trigger activation of the complement system, promoting inflammation and the development of endothelial injury syndromes, ultimately leading to organ damage and failure. In particular, the lectin pathway of complement is activated by damage-associated molecular patterns (DAMPs) on the surface of injured endothelial cells. Pattern-recognition molecules such as mannose-binding lectin (MBL), collectins, and ficolins—collectively termed lectins—bind to DAMPs on injured host cells, forming activation complexes with MBL-associated serine proteases 1, 2, and 3 (MASP-1, MASP-2, and MASP-3). Activation of the lectin pathway may also trigger the coagulation cascade via MASP-2 cleavage of prothrombin to thrombin. Together, activation of complement and the coagulation cascade lead to a procoagulant state that may result in development of HSCT-TMA. Several complement inhibitors targeting various complement pathways are in clinical trials for the treatment of HSCT-TMA. In this article, we review the role of the complement system in HSCT-TMA pathogenesis, with a focus on the lectin pathway.

Management of thrombotic microangiopathy after hematopoietic cell transplantation: A position statement of ThREG (Turkish Hematology Research and Education Group)

Hematopoietic stem cell transplantation associated-thrombotic microangiopathy (TA-HCT) is one of the early complications of endothelial origin in the course of HCT. Endothelial damage to the microvascular structure and the platelet-rich microthrombi, which are formed as a result of accompanying complement activation, constitute the main pathological conditions resulting TA-TMA. Early diagnosis and management are of utmost importance to prevent multi-organ failure and death. This review summarizes the current understanding of TA-TMA regarding pathogenesis, definition, differential diagnosis, risk factors, surveillance for early diagnosis and management.

Endothelial cell dysfunction: a key determinant for the outcome of allogeneic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (alloSCT) carries the promise of cure for many malignant and non-malignant diseases of the lympho-hematopoietic system. Although outcome has improved considerably since the pioneering Seattle achievements more than 5 decades ago, non-relapse mortality (NRM) remains a major burden of alloSCT. There is increasing evidence that endothelial dysfunction is involved in many of the life-threatening complications of alloSCT, such as sinusoidal obstruction syndrome/venoocclusive disease, transplant-associated thrombotic microangiopathy, and refractory acute graft-versus host disease. This review delineates the role of the endothelium in severe complications after alloSCT and describes the current status of search for biomarkers predicting endothelial complications, including markers of endothelial vulnerability and markers of endothelial injury. Finally, implications of our current understanding of transplant-associated endothelial pathology for prevention and management of complications after alloSCT are discussed.

A prognostic model (BATAP) with external validation for patients with transplant-associated thrombotic microangiopathy

Transplant-associated thrombotic microangiopathy (TA-TMA) is a potentially life-threatening complication following allogeneic hematopoietic stem cell transplantation (allo-HSCT). Information on markers for early prognostication remains limited, and no predictive tools for TA-TMA are available. We attempt to develop and validate a prognostic model for TA-TMA. A total of 507 patients who developed TA-TMA following allo-HSCT were retrospectively identified and separated into a derivation cohort and a validation cohort according to the time of transplantation to perform external temporal validation. Patient age (OR 2.371, 95% CI 1.264-4.445), anemia (OR 2.836, 95% CI 1.566-5.138), severe thrombocytopenia (OR 3.871, 95% CI 2.156-6.950), elevated total bilirubin (OR 2.716, 95% CI 1.489-4.955) and proteinuria (OR 2.289, 95% CI 1.257-4.168) were identified as independent prognostic factors for the 6-month outcome of TA-TMA. A risk score model termed BATAP (Bilirubin, Age, Thrombocytopenia, Anemia, Proteinuria) was then constructed according to the regression coefficients. The validated c-statistics were 0.816 (95% CI 0.766-0.867) and 0.756 (95% CI 0.696-0.817) in the internal and external validation, respectively. Calibration plots indicated that the model-predicted probabilities correlated well with the actual observed frequencies. This predictive model may facilitate the prognostication of TA-TMA and contribute to the early identification of high-risk patients.

2021 update of the 2012 ICSH Recommendations for identification, diagnostic value, and quantitation of schistocytes: Impact and revisions

In 2012, the International Council for Standardization in Hematology (ICSH) published recommendations for the identification, quantitation, and diagnostic value of schistocytes. In the present review, the impact of these recommendations is evaluated. This work is based on citations in peer-reviewed papers published since 2012. The first 2012 ICSH Recommendations have also been revised to incorporate newly published data in the literature and current best laboratory practice. Recommended reference ranges have been proposed for healthy adults and full-term neonates of 1% or less schistocytes. More than 1% of morphologically identified schistocytes on the blood film are considered suspicious for thrombotic microangiopathy. For preterm infants, a normal level of 5% or less is recommended. The fragment red cell count (FRC) generated by some automated hematological analyzers provides a valuable screening tool for the presence of schistocytes. Specifically, the absence of FRCs can be used as a valuable parameter to exclude the presence of schistocytes on the blood film. The validity and usefulness of microscope schistocytes and automated FRCs, respectively, are discussed in the context of the laboratory diagnostic tests used for thrombotic microangiopathies.

Predictors of Transplant-Associated Thrombotic Microangiopathy in Patients With Overlap or Chronic Graft-vs-Host-Disease

BACKGROUND

Recent data suggest that novel biologic agents are associated with increased risk of thrombotic microangiopathy (TMA). Ruxolitinib, an approved treatment for graft-vs-host-disease (GVHD), has been associated with thrombocytopenia of unclear etiology.

METHODS

We investigated factors and outcomes associated with transplant-associated thrombotic microangiopathy (TA-TMA) in patients with GVHD. We retrospectively enrolled consecutive allogeneic hematopoietic cell transplantation recipients with overlap or chronic GVHD at our Joint Accreditation Committee ISCT-Europe & EBMT-accredited unit (January 2016-June 2019). Ruxolitinib has been administered off-label since 2016.

RESULTS

Among 160 patients with GVHD, 18 were diagnosed with TA-TMA. TA-TMA developed at a median of 150 posttransplant days (range, 98-3013). Among pre- and posttransplant factors, TA-TMA was associated only with ruxolitinib administration and severe GVHD. Interestingly, these 2 variables did not correlate with each other. In the multivariate analysis, both were independent predictors of TA-TMA. Time-dependent analysis confirmed ruxolitinib's association with TA-TMA. With a follow-up of 38.4 months (4.6-83.9) in surviving patients, 5-year overall survival was 52.9%, independently predicted by TA-TMA, severe acute GVHD, and CD34+ cells infused. Ruxolitinib was not associated with survival outcomes.

CONCLUSIONS

Our data suggest that ruxolitinib and GVHD severity are associated with TA-TMA. Given the expanding use of ruxolitinib in GVHD and ongoing trials on chronic GVHD, further studies are warranted to confirm these findings.