Transplant-associated microangiopathy (TAM) in recipients of allogeneic hematopoietic stem cell transplants

Neurological involvement in hematopoietic stem cell transplantation-associated thrombotic microangiopathy

Transplantation-associated thrombotic microangiopathy (TA-TMA) is a well-recognized serious complication of hematopoietic stem cell transplantation (HSCT). The understanding of TA-TMA pathophysiology has expanded in recent years. Dysregulation of the complement system is thought to cause endothelial injury and, consequently, microvascular thrombosis and tissue damage. TA-TMA can affect multiple organs, and each organ exhibits specific features of injury. Central nervous system (CNS) manifestations of TA-TMA include posterior reversible encephalopathy syndrome, seizures, and encephalopathy. The development of neurological dysfunction is associated with a significantly lower overall survival in patients with TA-TMA. However, there are currently no established histopathological or radiological criteria for the diagnosis of CNS TMA. Patients who receive total body irradiation (TBI), calcineurin inhibitors (CNI), and severe acute and chronic graft-versus-host disease (GVHD) are at a high risk of experiencing neurological complications related to TA-TMA and should be considered for directed TA-TMA therapy. However, the incidence and clinical manifestations of TA-TMA neurotoxicity remain unclear. Studies specifically examining the involvement of CNS in TMA syndromes are limited. In this review, we discuss clinical manifestations and imaging abnormalities in patients with nervous system involvement in TA-TMA. We summarize the mechanisms underlying TA-TMA and its neurological complications, including endothelial injury, evidence of complement activation, and treatment options for TA-TMA.

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.

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

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

Corticosteroids as graft-versus-host disease prophylaxis for allogeneic hematopoietic cell transplant recipients with calcineurin inhibitor intolerance

BACKGROUND AIMS

Although calcineurin inhibitors (CNIs) have a well-established role in the prevention of graft-versus-host disease (GVHD) after allogeneic hematopoietic cell transplantation (HCT), their use can be limited by significant toxicities, which may result in premature treatment discontinuation. The optimal management of patients with CNI intolerance is unknown. The objective of this study was to determine the effectiveness of corticosteroids as GVHD prophylaxis for patients with CNI intolerance.

METHODS

This retrospective single-center study included consecutive adult patients with hematologic malignancies who underwent myeloablative peripheral blood allogeneic HCT with anti-thymocyte globulin, CNI, and methotrexate GVHD prophylaxis in Alberta, Canada. Multivariable competing-risks regression was used to compare cumulative incidences of GVHD, relapse, and non-relapse mortality between recipients of corticosteroid versus continuous CNI prophylaxis, and multivariable Cox proportional hazards regression was applied to compare overall survival, relapse-free survival (RFS) and moderate-to-severe chronic GVHD and RFS.

RESULTS

Among 509 allogeneic HCT recipients, 58 (11%) patients developed CNI intolerance and were switched to corticosteroid prophylaxis at median 28 days (range 1-53) after HCT. Compared with patients who received continuous CNI prophylaxis, recipients of corticosteroid prophylaxis had significantly greater cumulative incidences of grade 2-4 acute GVHD (subhazard ratio [SHR] 1.74, 95% confidence interval [CI] 1.08-2.80, P = 0.024), grade 3-4 acute GVHD (SHR 3.22, 95% CI 1.55-6.72, P = 0.002), and GVHD-related non-relapse mortality (SHR 3.07, 95% CI 1.54-6.12, P = 0.001). There were no significant differences in moderate-to-severe chronic GVHD (SHR 0.84, 95% CI 0.43-1.63, P = 0.60) or relapse (SHR 0.92, 95% CI 0.53-1.62, P = 0.78), but corticosteroid prophylaxis was associated with significantly inferior overall survival (hazard ratio [HR] 1.77, 95% CI 1.20-2.61, P = 0.004), RFS (HR 1.54, 95% CI 1.06-2.25, P = 0.024), and chronic GVHD and RFS (HR 1.46, 95% CI 1.04-2.05, P = 0.029).

CONCLUSIONS

Allogeneic HCT recipients with CNI intolerance are at increased risks of acute GVHD and poor outcomes despite institution of corticosteroid prophylaxis following premature CNI discontinuation. Alternative GVHD prophylaxis strategies are needed for this high-risk population.

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.

Risk factors for transplant-associated thrombotic microangiopathy (TA-TMA): a systematic review and meta-analysis

INTRODUCTION

Transplant-associated thrombotic microangiopathy (TA-TMA) is a severe hematopoietic stem cell transplantation complication with high mortality and a poor patient prognosis. The pathogenesis of TA-TMA is not yet clear. In previous studies, the conclusions of different centers remain controversial. We conducted a systematic review and meta-analysis of nine selected risk factors that might be associated with the onset of TA-TMA.

MATERIALS AND METHODS

PubMed databases were searched from their inception up to 15 September 2021, for relevant studies. The articles included unprocessed data related to one or more of the risk factors discussed in this meta-analysis, including recipient gender, donor type, graft source, pretreatment, infection, aGVHD, diagnosis, total body irradiation (TBI), and CMV infection. The outcome is the incidence rate (IR) of TA-TMA.

RESULTS AND CONCLUSIONS

According to the sixteen articles included, risk factors included in this Meta-analysis included gender, unrelated donor source (95% CI: 1.29-2.01), graft source from peripheral blood stem cell (PBSC)(95% CI: 0.48-0.97), RIC/NMA, class II-IV aGVHD (95% CI: 2.22-4.78), nonmalignant disease, TBI. However, inconsistent diagnostic criteria for TA-TMA and the limited number of studies have an impact on the results of the study. More prospective cohort studies and More accurate diagnostic criteria are needed.

Epidemiology and outcomes of pediatric transplant-associated thrombotic microangiopathy in Hong Kong

BACKGROUND

Transplant-associated thrombotic microangiopathy (TA-TMA) is an under-recognized yet potentially devastating complication of hematopoietic stem cell transplantation (HSCT) which had increased awareness in recent years. This report summarizes the demographics and outcomes of pediatric TA-TMA in Hong Kong.

METHODS

All patients aged below 18 years who underwent HSCT in the Hong Kong Children's Hospital and were diagnosed to have TA-TMA during the 2-year period from April 1, 2019 to March 31, 2021 were included.

RESULTS

A total of 73 transplants (51 allogeneic and 22 autologous) in 63 patients had been performed. Six patients (four males and two females) developed TA-TMA at a median duration of 2.5 months post-HSCT. The incidence rate was 9.52%. Of the six TA-TMA patients, five underwent allogenic one underwent autologous HSCT, respectively. Three of them were histologically proven. All four patients with cyclosporine had stopped the drug once TA-TMA was suspected. Median six doses of eculizumab were administered to five out of six patients. Three patients died (two due to fungal infection and one due to acute-on-chronic renal failure) within 3 months upon diagnosis of TA-TMA. Among three survivors, two stabilized with mild stage 2 chronic kidney disease (CKD) while the other suffered from stage 5 end-stage CKD requiring lifelong dialysis.

CONCLUSION

In conclusion, recognition and diagnosis of TA-TMA are challenging. Early recognition and prompt administration of complement blockage with eculizumab may be beneficial in selected cases. Further prospective research studies are recommended to improve the management and outcomes of TA-TMA.

Cerebral vascular injury in transplant-associated thrombotic microangiopathy

Transplant-associated thrombotic microangiopathy (TA-TMA) and atypical hemolytic uremic syndrome (aHUS) are complement-mediated TMAs. The central nervous system (CNS) is the most common extrarenal organ affected by aHUS, and, despite mechanistic overlap between aHUS and TA-TMA, CNS involvement is rarely reported in TA-TMA, suggesting that CNS involvement in TA-TMA may be underdiagnosed and that these patients may benefit from complement blockers. In addition, there are no widely used histologic or radiologic criteria for the diagnosis of TMA in the brain. Thirteen recipients of pediatric hematopoietic cell transplants (HCTs) who had TA-TMA and who underwent autopsy were studied. Seven of 13 brains had vascular injury, and 2 had severe vascular injury. Neurologic symptoms correlated with severe vascular injury. Classic TMA histology was present and most often observed in the cerebellum, brainstem, and cerebral white matter. Abnormalities in similar anatomic regions were seen on imaging. Brain imaging findings related to TMA included hemorrhages, siderosis, and posterior reversible encephalopathy syndrome. We then studied 100 consecutive HCT recipients to identify differences in neurologic complications between patients with and those without TA-TMA. Patients with TA-TMA were significantly more likely to have a clinical concern for seizure, have an electroencephalogram performed, and develop altered mental status. In summary, our study confirms that TA-TMA involves the brains of recipients of HCT and is associated with an increased incidence of neurologic symptoms. Based on these findings, we propose that patients with low- or moderate-risk TA-TMA who develop neurologic complications should be considered for TA-TMA-directed therapy.

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.

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.

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.

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.

Conversion from calcineurin inhibitors to sirolimus in transplant-associated thrombotic microangiopathy

Transplant-associated thrombotic microangiopathy (TA-TMA) is a specific complication of allogeneic hematopoietic cell transplantation with a multifactorial etiology. There is little evidence published regarding the efficacy and factors influencing the outcome of substitution of calcineurin inhibitors (CNIs) with other agentsas a widely accepted practice in this disorder; however, there are limited data on the options for immunosuppression manipulation (ISM). In our study, we retrospectively analyzed outcomes of 45 patients with TA-TMA with ISM and substitution either with steroids (steroid group) or anmTOR inhibitor sirolimus (sirolimus group). In our study, sirolimus was associated with significantly better 1-year overall survival (HR 0.3, 95% CI 0.13-0.7, p = .004) and faster time to normalization of LDH (HR 2.2, 95% CI 0.99-4.99, p = .044). Replacing CNIs with sirolimus could be an effective option in patients with TA-TMA. A multicenter confirmatory study of CNIs replacement with sirolimus is justified.

Incidence, Risk Factors for and Outcomes of Transplant-Associated Thrombotic Microangiopathy

Transplant-associated thrombotic microangiopathy (TA-TMA) is a complication of allogeneic transplantation (allo-HCT). The incidence and risk factors associated with TA-TMA are not well known. A retrospective analysis from the Center for International Blood and Marrow Transplant Research (CIBMTR) was conducted including patients receiving allo-HCT between 2008 and 2016, with the primary objective of evaluating the incidence of TA-TMA. Secondary objectives included identification of risk factors associated with TA-TMA, and the impact of TA-TMA on overall survival and the need for renal replacement therapy (RRT). Among 23,665 allo-HCT recipients, the 3-year cumulative incidence of TA-TMA was 3%. Variables independently-associated with increased incidence of TA-TMA included female sex, prior autologous transplant, primary disease (acute lymphoblastic leukaemia and severe aplastic anaemia), donor type (mismatched or unrelated donor), conditioning intensity (myeloablative), GVHD prophylaxis (sirolimus + calcineurin inhibitor), pre-transplant kidney dysfunction and acute GVHD (time-varying effect). TA-TMA was associated with higher mortality (HR = 3·1, 95% Confidence Interval [CI] = 2·8-16·3) and RRT requirement (HR = 7·1, 95% CI = 5·7-311·6). This study provides epidemiologic data on TA-TMA and its impact on transplant outcomes. Increased awareness of the risk factors will enable providers to be vigilant of this uncommon but serious transplant complication. The results will also provide benchmarking for future study designs and comparisons.

Distribution of Transplantation-Associated Thrombotic Microangiopathy (TA-TMA) and Comparison between Renal TA-TMA and Intestinal TA-TMA: Autopsy Study

Transplantation-associated thrombotic microangiopathy (TA-TMA) is an important complication of hematopoietic stem cell transplantation. To date, information regarding the organs that are affected by TA-TMA as confirmed histologically remains limited; the clinicopathologic differences between renal TA-TMA and intestinal TA-TMA have not been examined despite being the well-known and commonly affected sites of TA-TMA. We therefore examined 165 autopsied patients after hematopoietic stem cell transplantation and compared the clinicopathologic factors of renal and intestinal TA-TMA. It was clear that 38 (23%) of our patients had TA-TMA. In the TA-TMA cases, the kidney (61%) and intestine (53%) were commonly affected, and the ileum and right colon were vulnerable. Other organs that we found to be affected by TA-TMA included the stomach (8%), gallbladder (5%), and oral cavity, pharynx, esophagus, liver, heart, urinary bladder, and ureter (all at 3%), and symptoms thought to be caused by TA-TMA of these organs were not observed in any patient. Histologically, TA-TMA only affected the arteriole, or small arteries, regardless of the organ, and the veins or larger arteries were not affected at all. In the kidney, the glomerular capillary was also affected, and mesangiolysis and double contours of the basement membranes were often in evidence. The histologic overlap of renal and intestinal TA-TMA was rare (13%), and the patients in the intestinal TA-TMA group exhibited more frequency of a history of intestinal acute graft-versus-host disease (GVHD) during the clinical course compared with that of the renal TA-TMA group (80% versus 22%, P = .0016). Although TA-TMA can affect many other organs, the frequency of these ancillary events was low, and the clinical effect may have been small. Our results suggest that in comparison to renal TA-TMA, intestinal GVHD could be more closely associated with intestinal TA-TMA as a risk factor.

Severe, persistent neurotoxicity after transplant-associated thrombotic microangiopathy in a pediatric patient despite treatment with eculizumab

BACKGROUND

TA-TMA is a described complication of aHCT in children with neuroblastoma. Outcomes are poor with mortality rates approaching 60%. Described late effects in survivors include chronic kidney disease and persistent pulmonary hypertension.

CASE

We report a case of a 2-year-old with neuroblastoma who developed severe TA-TMA 35 days after high dose chemotherapy and autologous stem cell rescue. He presented with respiratory failure, pericardial and pleural effusions, hemolysis, hypertension, and mild altered mental status. He was mechanically ventilated for 3 weeks and after sedation was lifted, he was minimally responsive. He was treated with eculizumab with resolution of hemolysis, kidney injury and polyserositis. Initially he was more responsive; however, after almost a year of intensive therapy he remained nonverbal and had persistent irritability and behavioral changes. He had an extensive negative evaluation. On day +345, he presented with severe, refractory epilepsy. Three years after TA-TMA, he continues to have severe neurologic disabilities.

CONCLUSIONS

To our knowledge, persistent neurologic toxicity has not been reported in TA-TMA. However, deficits and seizures are reported in other TMAs, particularly in children with atypical HUS who present with significant neurologic changes at diagnosis. Our patient's persistent neurologic disability despite eculizumab response in all other involved organs may reflect irreversible damage. This case describes a new long-term sequela of TA-TMA and highlights the need for further studies to understand both acute and long-term neurologic complications of this disease.

Transplant-Associated Thrombotic Microangiopathy Is a Multifactorial Disease Unresponsive to Immunosuppressant Withdrawal

Transplant-associated thrombotic microangiopathy (TA-TMA) after allogeneic hematopoietic cell transplantation (HCT) has not been well characterized in large population studies with clinically adjudicated cases. We performed a retrospective cohort study of adults who underwent allogeneic HCT between 2006 and 2015 to determine the incidence of and risk factors for TA-TMA and to describe its natural history and response to immunosuppressant withdrawal management. Among 2145 patients in this study, 192 developed TA-TMA with a cumulative incidence of 7.6% by 100days post-transplant. Independent pretransplant risk factors included the receipt of a second (or third) allogeneic HCT, HLA-mismatched donor, and myeloablative conditioning with or without total body irradiation; post-transplant risk factors included the antecedent development of acute graft-versus-host disease, diffuse alveolar hemorrhage, bacteremia, invasive aspergillosis, BK viremia, and higher sirolimus trough level. Among TA-TMA patients 27% achieved hematologic resolution and 57% remained alive as of 90days after diagnosis. Antecedent risk factors stratified patients into different survival groups, and immunosuppressant withdrawal alone did not improve patient outcomes. In conclusion, TA-TMA is a heterogenous disease that occurs after allogeneic transplantation. Management with immunosuppressant withdrawal does not impact patient outcomes. Until further evidence becomes available, the management of TA-TMA should focus on the treatment of underlying diseases.

Eculizumab for transplant-associated thrombotic microangiopathy in adult allogeneic stem cell transplant recipients

OBJECTIVE

To evaluate response rates and survival in adults with transplant-associated thrombotic microangiopathy (TA-TMA) after allogeneic hematopoietic stem cell transplantation (HSCT) who were treated with eculizumab (ECU).

METHODS

Patients were identified retrospectively and data collected through HSCT and pharmacy databases.

RESULTS

Ten patients with TA-TMA after allogeneic HSCT were treated with ECU between 2013 and 2016. TA-TMA was diagnosed at a median of 93 days post-HSCT. Organ-specific injury was documented in all ten patients at time of TA-TMA diagnosis, the most common being renal dysfunction (90%). Acute GVHD (70%) and active infection (80%) were common at time of diagnosis. The median time to ECU initiation from TA-TMA diagnosis was 4 days. Seven patients received ECU as first-line therapy in combination with other treatment modalities, while three patients were treated with ECU as second-line therapy. ECU was well tolerated with the exception of one case of severe skin rash leading to discontinuation. ECU achieved an overall hematologic response rate of 70% and an overall survival rate of 60%. One patient achieved a complete response with corresponding organ recovery.

CONCLUSION

Early initiation of ECU may not alter the disease process enough to restore organ function, but it may prolong survival.

Thrombotic microangiopathy following haematopoietic stem cell transplant

Thrombotic microangiopathy is a potentially lethal complication of haematopoietic stem cell (bone marrow) transplantation. The pathophysiology is incompletely understood, although endothelial damage appears to be central. Platelet activation, neutrophil extracellular traps and complement activation appear to play key roles. Diagnosis may be difficult and universally accepted diagnostic criteria are not available. Treatment remains controversial. In some cases, withdrawal of calcineurin inhibitors is adequate. Rituximab and defibrotide also appear to have been used successfully. In severe cases, complement inhibitors such as eculizumab may play a valuable role. Further research is required to define the pathophysiology and determine both robust diagnostic criteria and the optimal treatment.

Thrombotic microangiopathy with concomitant GI aGVHD after allogeneic hematopoietic stem cell transplantation: Risk factors and outcome

OBJECTIVES

To explore the possible risk factors for the occurrence and mortality of thrombotic microangiopathy (TMA) with concomitant acute graft-vs-host disease (aGVHD) and to investigate outcomes and treatments of this disorder after allo-HSCT.

METHODS

Fifty cases diagnosed with TMA with concomitant aGVHD and 150 controls were identified from a cohort composed of 3992 patients who underwent allo-HSCT from 2008 to 2016.

RESULTS

Grade III-IV aGVHD (P = .000), acute kidney injury (AKI) (P = .033), and hypertension (P = .028) were significant independent risk factors associated with the occurrence of TMA with concomitant aGVHD. A haptoglobin level below normal (P = .013), a maximum volume of diarrhea >2500 mL/d (P = .015), and bloody diarrhea (P = .049) were significant markers for death in both univariate and multivariate analyses. Patients diagnosed with TMA with concomitant aGVHD had a lower overall survival (OS), a higher non-relapse mortality (NRM), but a lower risk of relapse.

CONCLUSIONS

Thrombotic microangiopathy with concomitant aGVHD is a significant complication after allo-HSCT, with a worse outcome, including significantly lower OS and higher NRM. There are specific risk factors associated with occurrence and mortality of this complication.

Central nervous system complications after allogeneic hematopoietic stem cell transplantation

Allogenic hematopoietic stem cell transplant (alloSCT) is a potentially curative modality of treatment for patients with hematological malignancies. However, CNS complications following transplant pose a risk to survival of the patients. Early recognition and management of these complications are crucial to reduce morbidity and mortality of patients following transplant. Early CNS complications associated with alloSCT are infection, cerebrovascular events, chemotherapy and radiation-induced toxicities while late complications include post-transplant lymphoproliferative disorder, CNS relapse of underlying malignancy and viral and fungal infections. Development of graft-versus-host disease can further increase the risk of CNS complications and outcomes after alloSCT. Strategies aimed to reduce the risk of CNS complications and early management may ameliorate the morbidity and mortality in transplant recipients.

[Thrombotic microangiopathy and cancer]

Thrombotic microangiopathy (TMA) is a group of disorders characterized by mechanical hemolytic anemia with thrombocytopenia and an ischemic organic lesion of variable and potentially fatal importance affecting mostly the kidneys and the brain with histologically a disseminated and occlusive microvasculopathy. The incidence of TMA represents 15% of acute kidney failure in oncological setting, largely due to the introduction of anti-angiogenic agents over the past decade. It may be more rarely related to cancer itself. The iatrogenic TMA can be classified into 2 types: The type I, secondary to chemotherapy (mitomycinC, gemcitabine), exposes to a chronic dose-dependent renal injury as well as an increase in morbidity and mortality; iatrogenic type II, secondary to anti-angiogenic agents', results in a dose-independent renal involvement and renal functional recovery is usual when the drug is discontinued. There is no randomized controlled trial to establish EBM-type management in TMA support. However, complement activation pathways and regulatory factors analyses allowed us to understand the mechanisms of endothelial lesions. As a result, the current trend includes the use of immunosuppressive agents in recurrent or plasmapheresis-refractory MAT.

Clinical dissection of thrombotic microangiopathy

Differential treatment strategies are applied in thrombotic microangiopathy (TMA) according to the sub-classifications. Hence, it is worthwhile to overview clinical manifestations and outcomes of overall TMA patients according to sub-classifications. We analyzed TMA patients whose serum lactate dehydrogenase levels >250 IU/L, with the presence of schistocytes in their peripheral blood smear, or with typical vascular pathologic abnormalities in their renal biopsy. We compared clinical manifestations including overall survival (OS) and renal survival according to TMA causes. A total of 117 TMA patients (57 primary and 60 secondary TMA) were analyzed. Renal symptom was the most common manifestation in whole patients, while renal function at diagnosis was worst in pregnancy-related TMA group. Primary TMA patients had more frequent CNS symptom and hematologic manifestation compared to secondary TMAs. Among secondary TMAs, pregnancy- and HSCT-related TMA patients showed prevalent hemolytic features. During 150.2 months of follow-up, 5-year OS rate was 64.8%. Poor prognostic factors included older age, combined hematologic and solid organ malignancies, lower hemoglobin levels, and lower serum albumin levels. There was no significant difference in OS between primary and secondary TMAs. Seventy-eight percent of patients experienced AKI during TMA. Five-year death-censored renal survival rate was poor with only 69.2%. However, excellent renal outcome was observed in pregnancy-associated TMA. TMA showed various clinical manifestations according to their etiology. Notably, both OS and renal survival were poor regardless of their etiologies except pregnancy-associated TMA. Physicians should differentiate a variety of TMA categories and properly manage this complex disease entity.

Transplant-associated thrombotic microangiopathy: opening Pandora's box

Transplant-associated thrombotic microangiopathy (TA-TMA) is an early complication of hematopoietic cell transplantation (HCT). A high mortality rate is documented in patients who are refractory to calcineurin inhibitor cessation. Estimates of TA-TMA prevalence vary significantly and are higher in allogeneic compared with autologous HCT. Furthermore, our understanding of the pathophysiology that is strongly related to diagnosis and treatment options is limited. Recent evidence has linked TA-TMA with atypical hemolytic uremic syndrome, a disease of excessive activation of the alternative pathway of complement, opening the Pandora's box in treatment options. As conventional treatment management is highly inefficient, detection of complement activation may allow for early recognition of patients who will benefit from complement inhibition. Preliminary clinical results showing successful eculizumab administration in children and adults with TA-TMA need to be carefully evaluated. Therefore, realizing the unmet needs of better understanding TA-TMA in this complex setting, we aimed to summarize current knowledge focusing on (1) critical evaluation of diagnostic criteria, (2) epidemiology and prognosis, (3) recent evidence of complement activation and endothelial damage and (4) treatment options.

Is complement blockade an acceptable therapeutic strategy for hematopoietic cell transplant-associated thrombotic microangiopathy?

Diagnosis and management of hematopoietic cell transplant-associated thrombotic microangiopathy (TA-TMA) are very complex and controversial, given multiple ongoing issues and comorbidities in sick transplant recipients. Complement activation via classic and alternative pathways is emerging as a potential pathogenetic mechanism in the development of TA-TMA. Complement-centric diagnostic strategy using functional and genetic tests may possibly support diagnosis, enhance molecular understanding and direct drug development. Complement blockade using eculizumab has shown some promising rates of hematologic responses, however, survival may still be poor. Early discontinuation of calcineurin inhibitor where feasible, use of eculizumab, aggressive infection prophylaxis, close monitoring and early treatment of potential complications including GvHD and organ failure may improve outcomes. A number of complement inhibitors are in the development and may change treatment paradigm. Future studies are important to better understand TA-TMA as a disease process and may aim to confirm the role of complement activation in TA-TMA, enhance diagnostic strategy, determine therapeutic approaches and strategies to reduce the risk of other complications particularly infection and GvHD.

Clinical evaluation of thrombotic microangiopathy: identification of patients with suspected atypical hemolytic uremic syndrome

Atypical hemolytic uremic syndrome (aHUS) is a rare genetic disorder caused by defective complement regulation resulting in thrombotic microangiopathy (TMA). Patients can present as children or adults. The syndrome consists of hemolytic anemia with schistocytosis, thrombocytopenia, significant renal damage, and/or other organ system dysfunction(s). Patients with aHUS may succumb to the complications of the disease with the very first manifestation; surviving patients often suffer from progressive organ dysfunction with significant morbidity and mortality despite plasma infusion or plasma exchange. Eculizumab, a humanized monoclonal antibody to C5, was approved for treatment of aHUS in 2011. This is an expensive but highly effective therapy changing the lives and improving the outcome of patients with aHUS. Making timely and accurate diagnosis of aHUS can be life-saving if eculizumab treatment is begun promptly. Finding a genetic mutation in a complement regulatory protein is diagnostic with the appropriate clinical syndrome, but at least 30 % of patients do not have defined or reported mutations. Thus the diagnosis rests on the clinical acumen of the physician. However, the clinical manifestations of aHUS are shared by other etiologies of thrombotic microangiopathy. While laboratory finding of undetectable ADAMTS13 activity defines TTP, distinguishing aHUS from the other causes of TMA remains an art. In addition, aHUS can be unmasked by conditions with enhanced complement activation, such as systemic lupus erythematosus, pregnancy, malignant hypertension, and hematopoietic stem cell transplantation. Thus if TMA occurs in the setting of enhanced complement activation, one must consider aHUS as an underlying etiology, especially if treatment of the condition does not resolve the TMA.

Eculizumab in Transplant-Associated Thrombotic Microangiopathy

Introduction:

Transplant-associated thrombotic microangiopathy (TA-TMA) is a rare entity with no standard of care and high mortality, despite the use of plasma exchange.

Methods:

Using specific search terms, all cases having TA-TMA treated with eculizumab and indexed in MEDLINE (English language only) by November 2014 were reviewed.

Results:

A total of 26 cases, 53% men, had a median age of 33 years (range 2-61). Transplant-associated thrombotic microangiopathy occurred after stem-cell transplant (35%) or solid-organ transplant (65%), frequently associated with the use of cyclosporine or tacrolimus (96%). A disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS 13) level was always >10%. After TA-TMA diagnosis, the following drug adjustments were made: discontinuation of cyclosporine or tacrolimus in 45%, dose reduction in another 27%, continuation of the drugs in 23%, and switch from cyclosporine to tacrolimus in remaining 5%. Plasma exchange was performed in ∼43%. The median interval between transplant and initiation of eculizumab was 63 days (range 11-512). A median of 5.5 doses (range 2-21) of eculizumab was utilized with 92% response occurring after a median of 2 doses (range 1-18). At a median follow-up of 52 weeks (range 3-113), the survivors (92%) were doing well.

Conclusion:

Within the limits of this retrospective analysis, our study demonstrates that eculizumab use may result in high response rate and 1-year survival in patients with TA-TMA refractory to discontinuation of calcineurin inhibitor and plasma exchange.

Cancer-associated thrombotic microangiopathy

Cancer-associated thrombotic microangiopathy refers to a group of disorders characterised by microvascular thrombosis, thrombocytopenia, and ischaemic end-organ damage. Haemolytic uraemic syndrome and thrombotic thrombocytopenic purpura are the two major subtypes. It can be a manifestation of the malignancy itself or a complication of its therapy. The addition of several new drugs to the therapeutic armamentarium of cancer has brought to light several novel causative factors of this hitherto uncommon complication. This review covers the aetiology, pathogenesis, clinical manifestations, complications, and the management of cancer-associated thrombotic microangiopathy. Careful review of the patient’s medical records coupled with the correlation of clinical findings and laboratory reports can help clinch the diagnosis and institute appropriate treatment on time.

Treatment of thrombotic microangiopathy after hematopoietic stem cell transplantation with recombinant human soluble thrombomodulin

BACKGROUND

Transplant-associated thrombotic microangiopathy (TA-TMA) after hematopoietic stem cell transplantation (HSCT) remains a severe complication associated with underlying endothelial damage. TMA has a high mortality rate with no definite treatments and effective treatments are needed.

STUDY DESIGN AND METHODS

The study objective was to retrospectively analyze the outcome of patients receiving recombinant human soluble thrombomodulin (rTM), which has cytoprotective effects against calcineurin inhibitor-induced endothelial cell damage, or other therapeutics for TA-TMA from 254 consecutive HSCT recipients between 2009 to 2014 at a single institution. We hypothesized that patients receiving rTM as a first-line treatment would receive a benefit.

RESULTS

Sixteen patients were diagnosed as TA-TMA. Of these 16 patients, nine were treated with rTM (rTM group), and seven received treatment other than rTM (control group) as a first-line therapy. Seven of the nine patients in the rTM group recovered from TA-TMA without complications, but none in the control group recovered. The rTM group showed a significantly better overall survival after TA-TMA onset than did the control group (median, 123.0 days vs. 45.5 days, respectively; p = 0.045). The cumulative incidence of acute graft-versus-host disease was the same in both groups (56% vs. 57%, respectively; p = 0.52) on Day 100 after TA-TMA onset.

CONCLUSION

This is the first report evaluating rTM administration for TA-TMA compared with previous treatments. Our data suggests that rTM might offer a better clinical outcome in patients with TA-TMA.

Prognosis of Allogeneic Haematopoietic Stem Cell Recipients Admitted to the Intensive Care Unit: A Retrospective, Single-Centre Study

BACKGROUND

Allogeneic haematopoietic stem cell transplantation (HSCT) is a procedure with inherent complications and intensive care may be necessary. We evaluated the short- and long-term outcomes of the HSCT recipients requiring admission to the intensive care unit (ICU).

METHODS

We retrospectively examined the outcome of 54 adult haematological HSCT recipients admitted to the ICU at the University Hospital Rigshospitalet between January 2007 and March 2012.

RESULTS

The overall in-ICU, in-hospital, 6-month and 1-year mortality rates were 46.3, 75.9, 79.6 and 86.5%, respectively. Mechanical ventilation had a statistically significant effect on in-ICU (p = 0.02), 6-month (p = 0.049) and 1-year (p = 0.014) mortality. Renal replacement therapy also had a statistically significant effect on in-hospital (p = 0.038) and 6-month (p = 0.026) mortality. Short ICU admissions, i.e. <10 days, had a statistically significant positive effect on in-hospital, 6-month and 1-year mortality (all p < 0.001). The SAPS II, APACHE II and SOFA scoring systems grossly underestimated the actual in-hospital mortality observed for these patients.

CONCLUSION

The poor prognosis of critically ill HSCT recipients admitted to the ICU was confirmed in our study. Mechanical ventilation, renal replacement therapy and an ICU admission of ≥10 days were each risk factors for mortality in the first year after ICU admission.

Hematopoietic Stem Cell Transplant-Associated Thrombotic Microangiopathy

Hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA) is a fatal, multifactorial disorder, which may present with thrombocytopenia, hemolysis, acute renal failure, mental status changes and involvement of other organs. The pathogenesis of TA-TMA is complex and includes multiple risk factors such as certain conditioning regimens, calcineurin inhibitors (CNIs), graft-versus-host disease (GVHD), human leukocyte antigen mismatch, and opportunistic infections. The end result of these insults is endothelial injury in the kidney and other organs. Recent studies also indicate a role of complement activation in tissue damage. The lack of sensitive and specific diagnostic tests for TA-TMA often results in delayed diagnosis. Biopsy is not always possible for diagnosis because of the risk of complications such as bleeding. Recently, an emerging role of renal-centered screening approach has been demonstrated, which utilize the monitoring of blood pressure, urine protein, serum lactate dehydrogenase and hemogram for early detection. Therapeutic options are limited, and plasma exchange plays a minor role. Withdrawal of offending agent such as CNIs and the use of rituximab can be effective in some patients. However, the current treatment strategy is suboptimal and associated with high mortality rate. Recently, eculizumab has been utilized in a few patients with good outcomes. Patients, who develop TA-TMA, are also at an increased risk of GVHD, infection, renal, cardiovascular, and other complications, which can contribute to high mortality. Better understanding of molecular pathogenesis, improvement in posttransplant management, leading to early diagnosis, and management of TA-TMA are required to improve outcomes of this fatal entity.

Renal and neurological response with eculizumab in a patient with transplant associated thrombotic microangiopathy after allogeneic hematopoietic progenitor cell transplantation

Transplantation-associated thrombotic microangiopathy (TA-TMA) is a challenge after allogeneic hematopoietic progenitor cell transplantation, considering the diagnostic uncertainties and lack of established treatment. We report a 43-year-old male patient who was diagnosed as TA-TMA after allogeneic progenitor cell transplantation for a progressive ALK negative anaplastic large cell lymphoma and responded to eculizumab with dramatically improving neurological status and renal function. Rapid neurological and renal recovery achieved after eculizumab could support a possible relationship between complement activation and TA-TMA. Eculizumab should be a reasonable treatment approach in patients with TA-TMA after allogeneic hematopoietic progenitor cell transplantation.

Management of hemolytic anemia following allogeneic stem cell transplantation

Hemolytic anemia (HA) is a frequent condition with variable pathophysiology. Hematopoietic stem cell transplantation (HSCT) is unique because it is performed across the ABO blood group barrier. Thereby, there is a transfer of plasma, red blood cells, and immunocompetent cells from the donor to the recipient, possibly leading to HA, due to red blood cell incompatibility. The underlying disease, drugs (particularly those used for conditioning and immunosuppressants), infections, graft-versus-host disease, and autoimmune diseases may all contribute to the clinical and laboratory picture of HA. Additionally, transplantation-associated thrombotic microangiopathy (TA-TMA) may occur and is associated with significant morbidity and mortality. This review highlights the current knowledge on HA after allogeneic HSCT, particularly due to ABO incompatibility. We follow the timeline of the transplantation process and discuss investigations, differential diagnosis, and prophylactic measures including graft processing to avoid hemolysis in case of ABO incompatibility. Finally, current therapeutic approaches for both TA-TMA and post-HSCT autoimmune HA, which are associated with high morbidity and mortality, are discussed.

Impact of recipient ABH secretor status on outcome in minor ABO-incompatible hematopoietic stem cell transplantation

BACKGROUND

The impact of ABO incompatibility on hematopoietic stem cell transplantation (HSCT) outcome is controversial. As ABH substances are expressed on tissues and secreted in body fluids, they could drive an immune response in minor ABO-incompatible HSCT. The aim of the study was to investigate the prognostic role of the recipients' ABH secretor status.

STUDY DESIGN AND METHODS

Patients who underwent minor ABO-incompatible HSCT were included. Secretor status was determined either serologically or by molecular genetics.

RESULTS

Between March 1996 and June 2012, a total of 176 patients received minor ABO-incompatible HSCT and 150 (85%) were secretors. Incidence and severity of acute graft-versus-host disease (GVHD) and chronic GVHD did not differ between secretors and nonsecretors (cumulative incidences ± standard errors: acute GVHD on Day 100, 41 ± 11 and 46 ± 5%, p = 0.59; chronic GVHD at 2 years, 52 ± 13 and 56 ± 5%, p = 0.62, for secretors and nonsecretors, respectively). Additionally, nonrelapse mortality (NRM) and overall survival (OS) were similar in the two groups (2-year NRM, 27 ± 9 and 23 ± 3%, p = 0.45; 4-year OS, 64 ± 10 and 55 ± 4%, p = 0.28, for secretors and nonsecretors, respectively).

CONCLUSION

The recipients' ABH secretor status in minor ABO-incompatible HSCT has no prognostic impact on major transplant outcomes.

A new paradigm: Diagnosis and management of HSCT-associated thrombotic microangiopathy as multi-system endothelial injury

Hematopoietic stem cell transplantation (HSCT)-associated thrombotic microangiopathy (TA-TMA) is now a well-recognized and potentially severe complication of HSCT that carries a high risk of death. In those who survive, TA-TMA may be associated with long-term morbidity and chronic organ injury. Recently, there have been new insights into the incidence, pathophysiology, and management of TA-TMA. Specifically, TA-TMA can manifest as a multi-system disease occurring after various triggers of small vessel endothelial injury, leading to subsequent tissue damage in different organs. While the kidney is most commonly affected, TA-TMA involving organs such as the lung, bowel, heart, and brain is now known to have specific clinical presentations. We now review the most up-to-date research on TA-TMA, focusing on the pathogenesis of endothelial injury, the diagnosis of TA-TMA affecting the kidney and other organs, and new clinical approaches to the management of this complication after HSCT.

The Use of Hyperbaric Oxygen Therapy in the Treatment of Non-healing Ulcers Secondary to Graft-versus-host Disease

We present the case of a 69 year-old gentleman with non-healing ulcers of the bilateral medial malleoli as a result of graft-versus-host disease (GvHD). The patient discussed was diagnosed with stage IV mantle cell lymphoma. Over the course of 4 years the patient was treated with autologous stem cell transplant, later reduced-intensity allogeneic stem cell transplant, and finally donor lymphocyte infusion due to recurrence. Following these therapies, the patient developed extensive GvHD that resulted in bilateral non-healing ulcers of the medial malleoli. The patient was seen in the wound care center, and his ulcers were treated with standard care that included off-loading, minor outpatient debridement, macrovascular assessment, and local moist wound healing. Despite this care, the ulcers failed to heal over a 6 month period. The patient underwent adjunctive hyperbaric oxygen therapy (HBO). He healed both ulcers within a month of completing HBO. It is our goal to discuss the pathophysiologic mechanism of non-healing wounds in the setting of GvHD and discuss the potential role of HBO in their treatment.

Third-party mesenchymal stromal cell infusion is associated with a decrease in thrombotic microangiopathy symptoms observed post-hematopoietic stem cell transplantation

TA-TMA is a pathology that occurs after allogenic HSC transplantation with an incidence of 4-13%, and represents one of the most severe vascular damage related with this therapy. We report here the case of a nine-yr-old girl suffering from a severe refractory aplastic anemia who received an unrelated, 9/10 HLA-matched HSC. Soon after transplantation, the patient developed a graft-versus-host disease (GvHD), a TA-TMA, and renal insufficiency. These pathologies remained refractory to the various treatments undertaken and required several hospitalizations in the intensive care unit. On day 106 post-HSC transfusion, after several episodes of intensive care, the patient was infused with mismatched, third-party MSCs. Schizocyte levels rapidly decreased after MSC infusion, and two wk later, most biological parameters returned to normal. Erythrocyte and thrombocyte transfusions were discontinued, and the patient remained stable for 10 wk. Thereafter, TA-TMA symptoms, viral reactivation, pleural and cardiac effusions reappeared and lead to the death of the patient. Our observations suggest that allogenic MSC infusion may decrease the symptoms of TA-TMA, but further investigation is required to determine how and when MSC should be infused to develop a long-lasting protective effect.

Late effects on haemostasis after haematopoietic stem cell transplantation

Allogeneic and autologous hematopoietic stem cell transplantations are important therapeutic options for patients with hematologic disorders. Hemostatic complications are frequent after hematopoietic stem cell transplantation with a considerable morbidity and mortality. The incidence of bleedings and thrombosis is highest in the first few weeks after transplantation, but may also occur later. However, beyond the first year of transplantation only limited data are available. In long-term survivors the risk for premature atherosclerosis increases over time after allogeneic hematopoietic stem cell transplantation and it is higher than in the age-adjusted general population and in recipients of autologous transplantation.

ICSH recommendations for identification, diagnostic value, and quantitation of schistocytes

Schistocytes are fragments of red blood cells (RBCs) produced by extrinsic mechanical damage within the circulation. The detection of schistocytes is an important morphological clue to the diagnosis of thrombotic microangiopathic anemia (TMA). Reporting criteria between different laboratories, however, are not uniform, owing to variability of shape and nature of fragments, as well as subjectivity and heterogeneity in their morphological assessment. Lack of standardization may lead to inconsistency or misdiagnosis, thereby affecting treatment and clinical outcome. The Schistocyte Working Group of the International Council for Standardization in Haematology (ICSH) has prepared specific recommendations to standardize schistocyte identification, enumeration, and reporting. They deal with the type of smear, method of counting, morphological description based on positive criteria (helmet cells, small, irregular triangular, or crescent-shaped cells, pointed projections, and lack of central pallor). A schistocyte count has a definite clinical value for the diagnosis of TMA in the absence of additional severe red cell shape abnormalities, with a confident threshold value of 1%. Automated counting of RBC fragments is also recommended by the ICSH Working Group as a useful complement to the microscope, according to the high predictive value of negative results, but worthy of further research and with limits in quantitation.

Vascular endothelium changes after conditioning in hematopoietic stem cell transplantation: role of cyclophosphamide and busulfan

Vascular endothelial injury, a feature of some complications of hematopoietic stem cell transplantation (HSCT), is characterized by increased endothelial cells. We investigated that classical pretreatment drugs in HSCT could result in vascular endothelial injury in mice. Six-to eight-week-old female BALB/c mice were divided into a control group, a cyclophosphamide group (60 mg/kg per day for 2 days) and a busulfan group (4 mg/kg per day for 4 days). We observed the general state of health and regularly counted the number of white blood cells. Circulating endothelial cells and their progenitors were estimated by flow cytometry. Morphologic endothelial changes were analyzed with optical and transmission electron microscopy. After conditioning with cyclophosphamide or busulfan, white blood cells fell to a low number with injuries noted on hematoxylin and eosin-stained pathology sections. Circulating endothelial cells and their progenitors peaked significantly higher than in the control group. Vascular endothelial injuries were observed in the 2 experimental groups by transmission electron microscopy. These data support the hypothesis the vascular endothelial injury occurs during conditioning with cyclophosphamide or busulfan for HSCT, with simultaneous mobilization of endothelial progenitor cells.