Acute Kidney Injury in Hematopoietic Stem Cell Transplantation: A Review

Acute kidney injury and risk factors in pediatric patients undergoing hematopoietic stem cell transplantation

BACKGROUND

Acute kidney injury (AKI) is a common complication of hematopoietic stem cell transplantation (HSCT) with increased mortality and morbidity. Understanding the risk factors for AKI is essential. This study aimed to identify AKI incidence, risk factors, and prognosis in pediatric patients post-HSCT.

METHODS

We conducted a retrospective case-control study of 278 patients who were divided into two groups: those with AKI and those without AKI (non-AKI). The groups were compared based on the characteristics and clinical symptoms of patients, as well as post-HSCT complications and the use of nephrotoxic drugs. Logistic regression analysis was employed to identify the risk factors for AKI.

RESULTS

A total of 16.9% of patients had AKI, with 8.5% requiring kidney replacement therapy. Older age (OR 1.129, 95% CI 1.061-1.200, p < 0.001), sinusoidal obstruction syndrome (OR 2.562, 95% CI 1.216-5.398, p = 0.011), hemorrhagic cystitis (OR 2.703, 95% CI 1.178-6.199, p = 0.016), and nephrotoxic drugs, including calcineurin inhibitors, amikacin, and vancomycin (OR 17.250, 95% CI 2.329-127.742, p < 0.001), were identified as significant independent risk factors for AKI following HSCT. Mortality rate and mortality due to AKI were higher in stage 3 patients than those in stage 1 and 2 AKI (p = 0.019, p = 0.007, respectively). Chronic kidney disease developed in 1 patient (0.4%), who was in stage 1 AKI (2.1%).

CONCLUSIONS

AKI poses a serious threat to children post-HSCT, leading to alarming rates of mortality and morbidity. To enhance outcomes and mitigate these risks, it is vital to identify AKI risk factors, adopt early preventive strategies, and closely monitor this patient group.

One Novel Urinary Biomarkers of Acute Kidney Injury in Patients After Allogeneic Hematopoetic Stem Cell Transplantation

Hematopoietic stem cell transplantation could be complicated by acute kidney injury and chronic kidney disease. It may be due to either previous chemotherapy or exposure to a variety of nephrotoxic drug or other causes. The aim of the study was to assess biomarkers of kidney injury in patients at least 3 months after hematopoetic stem cell transplantation (HSCT) under ambulatory care of the Hematology, Transplantation and Internal Medicine Department. We studied 80 prevalent patients after allogeneic HSCT and 32 healthy volunteers to obtain normal ranges of biomarkers. In this cross-sectional study we assessed retinol-binding protein 4 (RBP4), a biomarker of kidney injury in urine using commercially available assays. It was significantly higher in patients after HSCT when compared to healthy volunteers. When we divided patients according to kidney function (below and over 60 mL/min/1.72 m2), we found that the concentration of RBP4 was significantly higher in 23 patients with chronic kidney disease stage 3 compared to patients with estimated glomerular filtration (eGFR) over 60 mL/min/1.72 m2. In univariate correlations RBP4 was positively related to serum creatinine (r = 0.34, P < .01) and inversely to eGFR (r = -0.20, P < .05). Patients after allogeneic HSCT despite normal or near normal kidney function show evidence of kidney injury.

Assessment of Risk Factors for Acute Kidney Injury with Machine Learning Tools in Children Undergoing Hematopoietic Stem Cell Transplantation

Background: Although acute kidney injury (AKI) is a common complication in patients undergoing hematopoietic stem cell transplantation (HSCT), its prophylaxis remains a clinical challenge. Attempts at prevention or early diagnosis focus on various methods for the identification of factors influencing the incidence of AKI. Our aim was to test the artificial intelligence (AI) potential in the construction of a model defining parameters predicting AKI development. Methods: The analysis covered the clinical data of children followed up for 6 months after HSCT. Kidney function was assessed before conditioning therapy, 24 h after HSCT, 1, 2, 3, 4, and 8 weeks after transplantation, and, finally, 3 and 6 months post-transplant. The type of donor, conditioning protocol, and complications were incorporated into the model. Results: A random forest classifier (RFC) labeled the 93 patients according to presence or absence of AKI. The RFC model revealed that the values of the estimated glomerular filtration rate (eGFR) before and just after HSCT, as well as methotrexate use, acute graft versus host disease (GvHD), and viral infection occurrence, were the major determinants of AKI incidence within the 6-month post-transplant observation period. Conclusions: Artificial intelligence seems a promising tool in predicting the potential risk of developing AKI, even before HSCT or just after the procedure.

Nephrons and non-relapse mortality: simplified comorbidity index and acute kidney injury are associated with NRM in adults undergoing allogeneic hematopoietic cell transplant

The Simplified Comorbidity Index (SCI) is a recently published 5-component, pre-transplant tool to predict non-relapse mortality (NRM) in allogeneic hematopoietic cell transplantation (alloHCT) patients. The SCI captures chronic kidney disease (CKD) using estimated glomerular filtration rate (eGFR) based on the CKD-EPI equation (KDIGO 2021 CKD-EPI), which may be more sensitive to predict risk of NRM than the creatinine cut-off in the 16-component, Hematopoietic Cell Transplant-Comorbidity Index (HCT-CI). We retrospectively assessed the ability of the SCI to risk-stratify patients and the impact of acute kidney injury (AKI) to NRM in adults who underwent alloHCT at the University of Minnesota. We included 373 patients who underwent their first alloHCT between 2015 and 2019. Through multivariate analysis, we found that patients with an SCI of greater than 4 had a higher risk of NRM. Additionally, we noted that AKIs stages 2-3 prior to day +100 was independently associated with a 3-fold greater NRM than patients who did not experience clinically significant AKI.

Incidence of acute kidney injury after hematopoietic stem cell transplantation in children: a systematic review and meta-analysis

While acute kidney injury (AKI) has been reported after hematopoietic stem cell transplantation (HCT) in children, the incidence of this condition in the pediatric population has not been fully addressed. To assess the incidence of pediatric AKI after HCT treatment,we conducted a systematic literature review. Databases PubMed, Embase, Cochrane Library, and WOS were searched as of June 2022 to identify studies on the incidence and the risk of death in AKI children undergoing HCT. Random effects and generic inverse variance methods were used, and effect estimates were subsequently derived from individual studies. Twelve cohort studies with 2 159 HCT cases were included in this analysis. The combined estimated incidence of AKI and severe AKI (stage AKI III) was 51% (95% confidence interval (CI) 39-64%) and 12% (95%CI 4-24%), respectively. The estimated incidence of AKI based on RIFLE (pRIFLE), AKIN, and KDIGO criteria was 61% (95%CI 40-82% score I 95.1%), 64% (95%CI 49-79% score I 90.4%), and 51% (95%CI 2-100% score 99.0%), respectively. However, we found no significant correlation between the years of publication of the included studies and the incidence of AKI.  Conclusions: AKI affects approximately half of the children after HCT. With the advancements in medical techniques, it is expected that AKI in this population will decrease gradually. What is Known: • Hematopoietic stem cell transplantation is recognized as a treatment for malignant and non-malignant diseases in children. • Hematopoietic stem cell transplantation causes acute kidney injury in children. What is New: • This metanalysis showed that the overall frequency of post-HCT AKI in children is 51%. • The frequency of severe AKI after HCT was found to be 12%.

Clinical Features of Acute Kidney Injury in the Early Post-Transplantation Period Following Reduced-Intensity Conditioning Allogeneic Hematopoietic Stem Cell Transplantation

Allogeneic hematopoietic stem cell transplantation (HCT) is a potentially curative therapy for patients with hematologic malignancies but is associated with acute kidney injury (AKI). To date, few studies have examined risk factors for AKI at engraftment, or the relationship between AKI and clinical outcomes. This study examined the incidence and risk factors for periengraftment AKI, as well as the association between AKI and overall survival (OS) and nonrelapse mortality (NRM). We conducted a retrospective analysis of adult patients undergoing reduced-intensity conditioning (RIC) allogeneic HCT at the Dana-Farber Cancer Institute between 2012 and 2019. Periengraftment (day 0 to day 30) AKI incidence and severity were defined using modified KDIGO (Kidney Disease: Improving Global Outcomes) criteria. Factors associated with periengraftment AKI risk were examined using Cox regression analysis. The impact of periengraftment AKI on OS and NRM (defined as death without recurrent disease after HCT), was evaluated using Cox regression and the Fine and Gray competing risks model, respectively. Kidney recovery, defined as a return of serum creatinine (SCr) to within 25% of baseline or liberation from kidney replacement therapy (KRT), was examined at day 90 post-HCT. Periengraftment AKI occurred in 330 of 987 patients (33.4%) at a median of 13 days (interquartile range, 4 to 30 days) post-transplantation. Factors associated with a higher multivariable-adjusted risk of AKI were supratherapeutic rapamycin (hazard ratio [HR], 1.56; 95% confidence interval [CI], 1.20 to 2.03; P < .001), fludarabine/melphalan conditioning (HR, 1.35, 95% CI, 1.01 to 1.81; P = .05, compared to fludarabine/busulfan and fludarabine, cyclophosphamide, and total body irradiation), HCT Comorbidity Index ≥4 (HR, 1.43; 95% CI, 1.14 to 1.79; P = .002), albumin <3.4 g/dL (HR, 2.04; 95% CI, 1.33 to 3.12; P = .001), hemoglobin ≤12 (HR, 1.96; 95% CI, 1.38 to 2.78; P < .001), supratherapeutic tacrolimus (HR, 1.45; 95% CI, 1.07 to 1.95; P = .02), and baseline SCr >1.1 mg/dL (HR, 1.87; 95% CI, 1.48 to 2.35; P < .001). Periengraftment AKI was associated with worse OS (HR, 1.40; 95% CI, 1.16 to 1.71; P < .001) and NRM (subdistribution HR, 2.10; 95% CI, 1.52 to 2.89; P < .001). Kidney recovery occurred in 18%, 15%, and 30% of patients with stage 1, stage 2, and stage 3 AKI without KRT, respectively, and 4 of 16 patients (25%) were liberated from KRT. Periengraftment AKI is common among RIC allogeneic HCT recipients. We identified several important risk factors for periengraftment AKI. Its association with worse OS and NRM underscores the importance of timely recognition and management.

Acute kidney injury and chronic kidney disease in umbilical cord blood transplant recipients

Introduction

Acute kidney injury (AKI) is a frequent early complication post hematopoietic stem cell transplant (HSCT), associated with high morbidity and mortality. Cord blood transplant (CBT) recipients are potentially exposed to more nephrotoxic insults, compared to patients undergoing HSCT from other donor sources. We aimed to identify risk factors for AKI in patients undergoing CBT. We also aimed to identify the impact of AKI on chronic kidney disease (CKD) and survival outcomes by one-year post-CBT.

Methods

Adults and children who underwent a first CBT at our Institution were retrospectively evaluated. AKI was staged according to Kidney Disease Improving Global Outcomes (KDIGO) definitions. Cox regression models were used to estimate the association of demographic factors and post-CBT parameters with the cause-specific hazard of AKI.

Results

We identified 276 patients. Median age was 32 years, 28% (77/276) were children (<18 years) and 129 (47%) were white. A myeloablative conditioning regimen was administered to 243 patients (88%) and 248 (90%) received cyclosporine for GVHD prophylaxis. One-hundred and eighty-six patients (67%) developed AKI by day 60 post-transplant, with 72 (26%) developing severe AKI (stage 2 and 3). In a multivariable analysis, each increase in bilirubin level of 1 mg/dL was associated with a 23% increase in the risk of severe AKI (adjusted HR 1.23, 95% CI 1.13 - 1.34, p<.0001). Conversely, systemic steroid administration appeared to be protective of severe AKI (unadjusted HR 0.36, 95% CI 0.18 - 0.72, p=.004) in a univariate model . Two-hundred-forty-seven patients were evaluable at the one-year time point. Among those, 100 patients (40%) developed CKD one-year post-CBT. Severe AKI was associated with a higher hazard of non-relapse mortality (adjusted HR=3.26, 95% CI 1.65-6.45, p=.001) and overall mortality (adjusted HR=2.28, 95% CI 1.22-4.27, p=.01).

Discussion

AKI is a frequent complication after CBT and is associated with worse outcomes. Questions remain as to the mechanism of the protective role of steroids on kidney function in the setting of CBT.

Therapeutic Potency of Ginger, Garlic, and Pomegranate Extracts Against Cryptosporidium parvum-Mediated Gastro-Splenic Damage in Mice

PURPOSE

Cryptosporidium parvum is a protozoan parasite infecting most mammalian hosts and causing major health issues. The present study investigated the efficacy of ginger (Zingiber officinale), garlic (Allium sativum), and pomegranate (Punica granatum) peel extracts on the development and progression of experimental cryptosporidiosis in mice.

METHODS

Eighty-two mice were assigned to 6 groups: control, infected non-treated, metronidazole (MTZ), ginger, garlic, and pomegranate. The control group topically received no treatments. The infected non-treated group was experimentally infected by 104 C. parvum oocysts per mouse using a stomach tube. The MTZ group was infected with C. parvum oocysts combined with MTZ (50 mg/kg b.w./day). The ginger, garlic, and pomegranate groups daily received different plant extracts at doses of 100 mg/kg BW, 50 mg/kg BW, and 3 gm/kg BW, respectively, followed by infection with C. parvum oocysts. All treatments were applied orally one day after the infection for continuous 30 days.

RESULTS

Histopathological and immunohistochemical examinations for P53 and caspase-3 expressions in stomach and spleen tissues showed that MTZ and garlic-treated mice had a more significant effect on infected mice.

CONCLUSION

The garlic extract was found to exert a more pronounced effect on infected mice compared with the other treatments as well as to improve health. Garlic extracts, therefore, represent an effective and natural therapeutic alternative for the treatment of cryptosporidiosis with low side effects and without drug resistance.

Advantageous tactics with certain probiotics for the treatment of graft-versus-host-disease after hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation (HSCT) becomes a standard form of cellular therapy for patients with malignant diseases. HSCT is the first-choice of immunotherapy, although HSCT can be associated with many complications such as graft-versus-host disease (GVHD) which is a major cause of morbidity and mortality after allogeneic HSCT. It has been shown that certain gut microbiota could exert protective and/or regenerative immunomodulatory effects by the production of short-chain fatty acids (SCFAs) such as butyrate in the experimental models of GVHD after allogeneic HSCT. Loss of gut commensal bacteria which can produce SCFAs may worsen dysbiosis, increasing the risk of GVHD. Expression of G-protein coupled receptors such as GPR41 seems to be upre-gulated in the presence of commensal bacteria, which might be associated with the biology of regulatory T cells (Tregs). Treg cells are a suppressive subset of CD4 positive T lymphocytes implicated in the prevention of GVHD after allogeneic HSCT. Here, we discuss the current findings of the relationship between the modification of gut microbiota and the GVHD-related immunity, which suggested that tactics with certain probiotics for the beneficial symbiosis in gut-immune axis might lead to the elevation of safety in the allogeneic HSCT.

Endocrine sequelae of hematopoietic stem cell transplantation: Effects on mineral homeostasis and bone metabolism

Hematopoietic stem cell transplantation (HSCT) is an established therapeutic strategy for the treatment of malignant (leukemia and lymphoma) and non-malignant (thalassemia, anemia, and immunodeficiency) hematopoietic diseases. Thanks to the improvement in patient care and the development of more tolerable conditioning treatments, which has extended the applicability of therapy to the elderly, a growing number of patients have successfully benefited from HSCT therapy and, more importantly, HSCT transplant-related mortality has consistently reduced in recent years. However, concomitantly to long term patient survival, a growing incidence of late HSCT-related sequelae has been reported, being variably associated with negative effects on quality of life of patients and having a non-negligible impact on healthcare systems. The most predominantly observed HSCT-caused complications are chronic alterations of the endocrine system and metabolism, which endanger post-operative quality of life and increase morbidity and mortality of transplanted patients. Here, we specifically review the current knowledge on HSCT-derived side-effects on the perturbation of mineral metabolism; in particular, the homeostasis of calcium, focusing on current reports regarding osteoporosis and recurrent renal dysfunctions that have been observed in a percentage of HSC-transplanted patients. Possible secondary implications of conditioning treatments for HSCT on the physiology of the parathyroid glands and calcium homeostasis, alone or in association with HSCT-caused renal and bone defects, are critically discussed as well.

Acute kidney injury after allogeneic hematopoietic stem cell transplantation - Predictors and survival impact: A single center retrospective study

INTRODUCTION AND OBJECTIVES

Acute kidney injury (AKI) is a frequent complication of hematopoietic stem cell transplantation (HSCT) and appears to be linked to increased morbidity and mortality. The aim of this study was to evaluate the incidence, etiology, predictors and survival impact of early AKI in the post-allogeneic HSCT setting.

PATIENTS AND METHODS

We performed a retrospective single center study that included 155 allogeneic transplant procedures from June 2017 through September 2019.

RESULTS

AKI was observed in 50 patients (32%). In multivariate analysis, age (OR 31.55, 95% CI [3.42; 290.80], p=0.002), evidence of disease at the time of transplant (OR 2.54, 95% CI [1.12; 5.75], p=0.025), cytomegalovirus reactivation (OR 5.77, 95% CI [2.43; 13.72], p<0.001) and hospital stay >35 days (OR 2.66, 95% CI [1.08; 6.52], p=0.033) were independent predictors for AKI. Increasing age (HR 1.02, 95% CI [1.00; 1.04], p=0.029), increasing length of hospital stay (HR 1.02, 95% CI [1.01; 1.03], p=0.002), matched unrelated reduced intensity conditioning HSCT (HR 1.91, 95% CI [1.10; 3.33], p=0.022), occurrence of grade III/IV acute graft-versus-host disease (HR 2.41, 95% CI [1.15; 5.03], p=0.019) and need for mechanical ventilation (HR 3.49, 95% CI [1.54; 7.92], p=0.003) predicted an inferior survival in multivariate analysis. Early AKI from any etiology was not related to worse survival.

CONCLUSION

Patients submitted to HSCT are at an increased risk for AKI, which etiology is often multifactorial. Due to AKI incidence, specialized nephrologist consultation as part of the multidisciplinary team might be of benefit.

[Risk factors for acute kidney injury after hematopoietic stem cell transplantation in children: a retrospective study]

OBJECTIVES

To investigate the risk factors for acute kidney injury (AKI) after hematopoietic stem cell transplantation (HSCT) in children.

METHODS

A retrospective analysis was performed on the medical data of 111 children who underwent HSCT from January 2018 to January 2020. A multivariate logistic regression analysis was used to identify the risk factors for AKI. The Kaplan-Meier survival analysis was used to compare the prognosis in children with different grades of AKI.

RESULTS

Graft-versus-host disease (grade Ⅱ-Ⅳ) (OR=4.406, 95%CI: 1.501-12.933, P=0.007), hepatic veno-occlusive disease (OR=4.190, 95%CI: 1.191-14.740, P=0.026), and thrombotic microangiopathy (OR=10.441, 95%CI: 1.148-94.995, P=0.037) were closely associated with the development of AKI after HSCT. The children with stage Ⅲ AKI had a lower 1-year survival rate than those without AKI or with stage Ⅰ AKI or stage Ⅱ AKI (28.6%±12.1% vs 82.8%±5.2%/81.7%±7.4%/68.8%±11.6%; P<0.05).

CONCLUSIONS

Children with stage Ⅲ AKI after HSCT have a higher mortality rate. Graft-versus-host disease, hepatic veno-occlusive disease, and thrombotic microangiopathy are closely associated with the development of AKI after HSCT.

Impact of decreasing vancomycin exposure on acute kidney injury in stem cell transplant recipients

OBJECTIVE

To evaluate the change in vancomycin days of therapy (DOT) and vancomycin-associated acute kidney injury (AKI) after an antimicrobial stewardship program (ASP) intervention to decrease vancomycin use in stable patients after hematopoietic stem cell transplantation (HSCT).

DESIGN

Retrospective cohort study and quasi-experimental interrupted time series analysis. Change in unit-level vancomycin DOT per 1,000 inpatient days after the intervention was assessed using segmented Poisson regression. Subject-specific risk of vancomycin-associated AKI was evaluated using a random intercept logistic regression model with mediation analysis.

SETTING

HSCT unit at a single quaternary-care pediatric hospital.

PARTICIPANTS

Inpatients aged 3 months and older who underwent HSCT between January 1, 2015, and March 31, 2019 (27 months before and after the intervention) who received any dose of vancomycin.

INTERVENTION

An ASP intervention in April 2017 creating a new practice guideline to decrease prolonged (>72 hours) vancomycin courses for stable HSCT patients with febrile neutropenia.

RESULTS

Overall, 439 vancomycin exposures (234 before the intervention and 205 after the intervention) occurring across 300 transplants and 259 subjects were included. The mean vancomycin DOT was 307 per 1,000 inpatient days (95% confidence interval [CI], 272-342) and decreased after the intervention to 207 per 1,000 inpatient days (95% CI, 173-240). In multivariable analyses, the odds of AKI in the postintervention period were 37% lower than in the preintervention period (adjusted OR, 0.63; 95% CI, 0.42-0.95; P = .0268); 56% of the excess risk was mediated by vancomycin DOT.

CONCLUSIONS

An ASP intervention successfully decreased vancomycin use after HSCT and resulted in a decrease in AKI. Reducing empiric antibiotic exposure for stable patients after HSCT can improve clinical outcomes.

Acute kidney injury within 100 days post allogeneic hematopoietic cell transplantation is associated with increased risk of post-transplant complications and poor transplant outcomes

Allogeneic hematopoietic cell transplantation (HCT) offers cure for some patients with hematological diseases but is associated with significant risk of morbidity and mortality. We investigated the incidence of AKI and its impact on transplant outcomes among 408 patients transplanted at Princess Margaret Hospital Cancer Centre, Toronto, Canada. The overall incidence of AKI at 100 days was 64.2%. Compared to those with no AKI, patients who developed AKI had inferior 2-y overall survival (OS), 44.7% vs. 62.4% (P = 0.0004), higher 2-y transplant related mortality (TRM) 36.8% vs. 18.7% (P = 0.0003), lower 2-y graft-vs-host disease (GVHD)- and relapse-free survival (GRFS), 21.0% vs. 39.8% (P = 0.0002), and higher 100-day grade 3-4 acute GVHD (aGVHD), 12.4% vs. 6.3% (P = 0.01). There was no difference in 2-y incidence of relapse between the AKI and non-AKI groups, 24.2% vs. 24.3% (P = 0.84), 100-day grade 2-4 aGVHD, 27.7% vs. 25.7 (P = 0.41) or 2-y moderate-severe chronic GVHD, 24.0% vs. 21.6% (P = 0.79). Patients who develop AKI within 100 days of HCT have inferior OS and GRFS with higher rates of TRM and grade 3-4 aGVHD. These results highlight the importance of close monitoring of renal function, multidisciplinary collaboration, and implementation of protective strategies throughout HCT to optimize transplant and kidney outcomes.

Predictive Value of 3 Clinical Criteria for Sepsis (Quick Sequential Organ Failure Assessment, Systemic Inflammatory Response Syndrome, and National Early Warning Score) With Respect to Short-term Mortality in Allogeneic Hematopoietic Cell Transplant Recipients With Suspected Infections

BACKGROUND

Sepsis disproportionately affects allogeneic hematopoietic cell transplant (HCT) recipients and is challenging to define. Clinical criteria that predict mortality and intensive care unit end-points in patients with suspected infections (SIs) are used in sepsis definitions, but their predictive value among immunocompromised populations is largely unknown. Here, we evaluate 3 criteria among allogeneic HCT recipients with SIs.

METHODS

We evaluated Systemic Inflammatory Response Syndrome (SIRS), quick Sequential Organ Failure Assessment (qSOFA), and National Early Warning Score (NEWS) in relation to short-term mortality among recipients transplanted between September 2010 and July 2017. We used cut-points of ≥ 2 for qSOFA/SIRS and ≥ 7 for NEWS and restricted to first SI per hospital encounter during patients' first 100 days posttransplant.

RESULTS

Of the 880 recipients who experienced ≥ 1 SI, 58 (6.6%) died within 28 days and 22 (2.5%) within 10 days of an SI. In relation to 10-day mortality, SIRS was the most sensitive (91.3% [95% confidence interval {CI}, 72.0%-98.9%]) but least specific (35.0% [95% CI, 32.6%-37.5%]), whereas qSOFA was the most specific (90.5% [95% CI, 88.9%-91.9%]) but least sensitive (47.8% [95% CI, 26.8%-69.4%]). NEWS was moderately sensitive (78.3% [95% CI, 56.3%-92.5%]) and specific (70.2% [95% CI, 67.8%-72.4%]).

CONCLUSIONS

NEWS outperformed qSOFA and SIRS, but each criterion had low to moderate predictive accuracy, and the magnitude of the known limitations of qSOFA and SIRS was at least as large as in the general population. Our data suggest that population-specific criteria are needed for immunocompromised patients.

Correlates and Outcomes of Early Acute Kidney Injury after Hematopoietic Cell Transplantation

BACKGROUND

Patients undergoing hematopoietic cell transplantation (HCT) are at high risk for acute kidney injury (AKI). The etiology of AKI is often multifactorial and includes exposure to antibiotics and calcineurin inhibitors (CNI) for prevention of graft versus host disease.

METHODS

This is a retrospective, single center study which evaluated patients undergoing inpatient HCT at Froedtert Memorial Hospital, Milwaukee, Wisconsin from Jan 1 to Dec 31, 2016. AKI was defined as an increase in serum creatinine > 0.3 mg/dL from baseline value.

RESULTS

The total number of patients included in the study was 280, 64 had AKI and 216 were in the non-AKI group. AKI was noted in 23% patients. Exposure to CNI or vancomycin accounted for the majority of the cases (82%). The median pre-AKI vancomycin trough was elevated in the AKI group at 21.3 mcg/mL (range: 17.4-24.4 mcg/mL) while the pre-AKI CNI trough was lower in the AKI group at 12.3 ng/mL (range: 8.7-14.7 ng/mL).There were also a higher number of ICU transfers (19%) and higher 100 day mortality (15.6%) in the AKI group.

CONCLUSION

AKI is a frequent complication following HCT and is associated with a higher risk of ICU transfer and higher mortality post HCT. While a higher vancomycin trough level may be indicative of a higher risk of AKI, the risk following CNI exposure may not be related to trough levels alone. There may be underlying pharmacogenetic factors which may alter the risk of AKI with CNI use.

The Impact of Allogeneic Hematopoietic Stem Cell Transplantation on Kidney Function in Children-A Single Center Experience

Background: Knowledge about the impact of allogeneic hematopoietic stem cell transplantation (alloHSCT) on renal function in children is still limited. Objectives: The aim of the study was to evaluate kidney function in children undergoing alloHSCT, with special focus on differences between patients transplanted due to oncological and non-oncological indications. Materials and Methods: The data of 135 children undergoing alloHSCT were analyzed retrospectively. The serum creatinine and estimated glomerular filtration rate (eGFR) values were estimated before transplantation at 24 h; 1, 2, 3, 4 and 8 weeks; and 3 and 6 months after alloHSCT. Then, acute kidney injury (AKI) incidence was assessed. Results: Oncological children presented with higher eGFR values and more frequent hyperfiltration rates than non-oncological children before alloHSCT and until the 4th week after transplantation. The eGFR levels rose significantly after alloHSCT, returned to pre-transplant records after 2–3 weeks, and decreased gradually until the 6th month. AKI incidence was comparable in oncological and non-oncological patients. Conclusions: Children undergoing alloHSCT due to oncological and non-oncological reasons demonstrate the same risk of AKI, but oncological patients may be more prone to sustained renal injury. Serum creatinine and eGFR seem to be insufficient tools to assess kidney function in the early post-alloHSCT period, when hyperfiltration prevails, yet they reveal significant differences in long-term observation.

Risk factors for chronic kidney disease following acute kidney injury in pediatric allogeneic hematopoietic cell transplantation

Risk factors associated with the progression of acute kidney injury to chronic kidney disease in pediatric allogeneic hematopoietic cell transplantation (AlloHCT) recipients are not well described. We retrospectively investigated the risk factors for the progression to CKD in 275 AlloHCT recipients. AKI and CKD grading was defined according to the Kidney Disease Improving Global Outcomes classification. PRI90 was defined as persistent renal insufficiency (estimated GFR < 90 ml/min/1.73 m²) 90 days after the first episode of AKI. The median age was 9.1 years. Incidence of stages 1, 2, and 3 AKI were 43%, 41%, and 15%, respectively. 86.1% met our study criteria for PRI90. Of the 236 PRI90 patients, 213 and 152 patients were evaluable for CKD at 1 and 3 years, respectively. The incidence of CKD at 1 and 3 years was 63.1% and 62.9%, respectively. On multivariable analysis, estimated GFR at initial episode of AKI (<80 ml/min/1.73 m²) and estimated GFR (<70 ml/min/1.73 m²) at PRI90 was a risk factor associated with CKD development and both risk factors were associated with significantly lower overall survival. To conclude, eGFR at the time of AKI and PRI90 may be considered for screening pediatric AlloHCT recipients at risk for the progression to CKD.

Acute Kidney Injury in Children after Hematopoietic Cell Transplantation Is Associated with Elevated Urine CXCL10 and CXCL9

Acute kidney injury (AKI) is nearly universally associated with worse outcomes, especially among children after hematopoietic stem cell transplant (HCT). Our objective was to examine urinary immune biomarkers of AKI after HCT to provide insights into novel mechanisms of kidney injury in this population. Studying patients undergoing allogeneic HCT provides a unique opportunity to examine immune markers of AKI because the risk of AKI is high and the immune system newly develops after transplant. Children (>2 years old) and young adults undergoing their first allogeneic HCT and enrolled in a prospective, observational cohort study at 2 large children's hospitals had urine collected pre-HCT and monthly for the first 4 months after HCT. Urine samples at each monthly time point were assayed for 8 immune-related biomarkers. AKI was defined as a 1.5-fold increase in the monthly serum creatinine value, which was recorded ±1 day from when the research urine sample was obtained, as compared with the pre-HCT baseline. Generalized estimating equation regression analysis evaluated the association between the monthly repeated measures (urinary biomarkers and AKI). A total of 176 patients were included from 2 pediatric centers. Thirty-six patients from 1 center were analyzed as a discovery cohort and the remaining 140 patients from the second center were analyzed as a validation cohort. AKI rates were 18% to 35% depending on the monthly time point after HCT. Urine CXCL10 and CXCL9 concentrations were significantly higher among children who developed AKI compared with children who did not (P < .01) in both cohorts. In order to gain a better understanding of the cellular source for these biomarkers in the urine, we also analyzed in vitro expression of CXCL10 and CXCL9 in kidney cell lines after stimulation with interferon-γ and interferon-α. HEK293-epithelial kidney cells demonstrated interferon-induced expression of CXCL10 and CXCL9, suggesting a potential mechanism driving the key finding. CXCL10 and CXCL9 are associated with AKI after HCT and are therefore promising biomarkers to guide improved diagnostic and treatment strategies for AKI in this high-risk population.

Permanent Impairment-Free, Relapse-Free Survival: A Novel Composite Endpoint to Evaluate Long-Term Success in Allogeneic Transplantation

Permanent impairment (PI) of vital organs is one of the transplantation-related health problems affecting the quality of life and morbidity even in patients who do not develop graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (allo-HCT), but no data are available on PI of multiple organs. This retrospective study aimed to estimate a novel composite endpoint of PI-free, relapse-free survival (PIRFS) in 164 allo-HCT recipients. We defined PI as >26% to 30% impairment of the whole person in 6 vital organs using the whole person impairment rating. Conventional GVHD-free/relapse-free survival (GRFS) and PIRFS at 5 years were 33.8% (95% confidence interval [CI], 26.5% to 41.3%) and 40.6% (95% CI, 32.6% to 48.4%), respectively. In the whole cohort, PIRFS was higher than GRFS at any time after allo-HCT. However, PIRFS was lower than GRFS after day 397 post-transplantation in patients who underwent umbilical cord blood transplantation (UCBT). In UCBT recipients, 5-year GRFS and PIRFS were 47.6% (95% CI, 34.3% to 59.7%) and 39.2% (95% CI, 26.6% to 51.5%), respectively. The cumulative incidence of PI after 5 years was 20.9% (95% CI, 13.7% to 29.0%) in patients surviving for ≥6 months without relapse. The multivariate analysis revealed that high disease risk (hazard ratio [HR], 1.91; 95% CI, 1.26 to 2.88; P < .01) and Karnofsky Performance Status score ≤90% at transplantation (HR, 1.73; 95% CI, 1.14 to 2.63; P = .01) were correlated with the lower PIRFS, whereas UCBT (HR, 2.35; 95% CI, 1.11 to 4.99; P = .03), grade III-IV acute GVHD by day 180 (HR, 3.59; 95% CI, 1.04 to 12.4; P = .04), and thrombotic microangiopathy by day 180 (HR, 2.74; 95% CI, 1.10 to 6.87; P = .03) were significantly correlated with a higher incidence of PI. More than 20% of long-term survivors had PI. Our data suggest that PIRFS is a useful endpoint for assessing long-term transplantation success from a different perspective than has been established previously.

Incidence and Risk Factors for Acute and Chronic Kidney Injury after Adult Cord Blood Transplantation

Although cord blood transplantation (CBT) extends allograft access, patient comorbidities, chemoradiation, and nephrotoxic medications all contribute to acute kidney injury (AKI) risk. We analyzed AKI in adult myeloablative CBT recipients who underwent transplantation from 2006 to 2017 for hematologic malignancies using cyclosporine A (CSA)/mycophenolate mofetil immunosuppression. Maximum grades of AKI were calculated using Kidney Disease: Improving Global Outcomes (grade 1, 1.5 to <2-fold; grade 2, 2 to <3-fold; or grade 3, ≥3-fold over baseline) definitions. In total, 153 patients (median 51 years [range, 23-65], 114/153 [75%] acute leukemia, 27/153 [18%] African, 88/153 [58%] cytomegalovirus seropositive, median age-adjusted hematopoietic cell comorbidity index 3 [range, 0-9], median pretransplant albumin 4.0 g/dL [range, 2.6-5.2]) underwent transplantation. The day 100 cumulative incidence of grade 1-3 AKI was 83% (95% confidence interval [CI], 77%-89%) (predominantly grade 2, median onset 40 days, range 0 to 96), and grade 2-3 AKI incidence was 54% (95% CI, 46%-62%) (median onset 43 days, range 0 to 96). Mean CSA level preceding AKI onset was high (360 ng/mL, target range 300-350). In multivariate analysis, African ancestry, addition of haploidentical CD34⁺ cells, low day -7 albumin, critical illness/intensive care admission, and nephrotoxic drug exposure (predominantly CSA and/or foscarnet) were associated with AKI. In a day 100 landmark analysis, 6% of patients with no prior AKI had chronic kidney disease (CKD) at 2 years versus 43% with prior grade 1 and 38% with prior grade 2-3 AKI (overall P= .02). Adult CBT recipients are at significant AKI risk, and AKI is associated with increased risk of CKD. Prevention strategies, early recognition, and prompt intervention are critical to mitigate kidney injury.

Kidney Injury in Murine Models of Hematopoietic Stem Cell Transplantation

Acute graft-versus-host disease (GVHD) affects different organs, including the skin, liver, and gastrointestinal tract. Although kidneys are not among the organs commonly known to be the target of acute GVHD, kidney damage is frequently reported after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We have studied the effect of bone marrow transplantation (BMT) on the kidneys in different murine models of GVHD. We found that glomerular damage in the kidneys is a common pathological finding in mice after BMT. The histopathological features of glomeruli damage included mesengiolysis, mesangial proliferation and edema, subendothelial and endothelial thickening, splitting of capillary walls in glomeruli, narrowing and collapsing of capillary lumens, fibrinoid necrosis of afferent arterioles, intimal hyperplasia, and microthrombi. These pathological features are similar to those detected in kidneys of patients with thrombotic microangiopathy (TMA) after allo-HSCT. We previously showed that activation of the complement system plays a role in GVHD-induced tissue injury in mice. Here we report the presence of complement activation products in the kidney specimens of mice after BMT. We also report that complement deficiency reduced the extent and severity of post-BMT glomerular damage in mice. We conclude that BMT in mice is associated with glomerular injury and tubulointerstitial nephritis, and that kidney damage is at least partially mediated by activation of the complement system.

Sequential transplantation and implications for clinical management: OLT followed by HCT and consequent RT in a pediatric patient

We report a case of a pediatric patient who required three separate transplants: OLT at the age 5, HCT at age 13 (8 years post-OLT), and cadaveric RT at age 15 (10 years post-OLT). The child initially presented with fulminant liver failure without known cause, ultimately undergoing OLT from his mother. He then developed SAA, for which he required HCT. Unfortunately, he developed ESRD secondary to prolonged CNI exposure, for which he underwent cadaveric RT. These processes then resulted in 7 years largely free from complications, during which a multi-disciplinary team monitored the patient for complications. Regrettably, at the age of 21 he developed poorly differentiated mucinous adenocarcinoma of the colon which ultimately led to his demise. While there are case reports of patients requiring two sequential transplants, there is a paucity of reports of successfully completing three separate organ transplants in the same patient. Our case demonstrates progression of a pediatric patient through OLT, HCT, and RT with discussion of notable clinical implications. Secondarily, this case highlights the importance of coordination of care amongst various subspecialties to facilitate tandem transplantations and manage the complications of these processes. As pediatric patients have improved survival rates and may require multiple transplants, it remains important to highlight the feasibility as well as the complications of the tandem transplant process.

Pathophysiology and Management of Hyperammonemia in Organ Transplant Patients

Neurologic complications are common after solid-organ transplantation, occurring in one-third of patients. Immunosuppression-related neurotoxicity (involving calcineurin inhibitors and corticosteroids), opportunistic central nervous system infections, seizures, and delirium are some of the causes of neurologic symptoms following solid-organ transplantation. An uncommon often missed complication posttransplantation involves buildup of ammonia levels that can lead to rapid clinical deterioration even when treated. Ammonia levels are not routinely checked due to the myriad of other explanations for encephalopathy in a transplant recipient. A treatment of choice for severe hyperammonemia involves renal replacement therapy (RRT), but there are no guidelines on the mode or parameters of RRT for reducing ammonia levels. Hyperammonemia in a transplant recipient poses specific challenges beyond the actual condition because the treatment (RRT) involves significant hemodynamic fluctuations that may affect the graft. In this review, we describe a patient with posttransplantation hyperammonemia and discuss the pathways of ammonia metabolism, potential factors underlying the development of hyperammonemia posttransplantation, and choice of appropriate therapeutic options in these patients.

Incidence of acute kidney disease after receiving hematopoietic stem cell transplantation: a single-center retrospective study

Background

Previous reports have shown that acute kidney injury (AKI) is common after hematopoietic stem cell transplantation (HSCT), which is a crucial treatment for patients with hematological disorders. AKI could increase mortality and induce adverse effects including the development of chronic kidney disease. The incidence of AKI in association with HSCT reportedly varies significantly because several definitions of AKI have been adopted. Acute kidney disease (AKD) is a new concept that can clinically define both AKI and persistent decreases in glomerular filtration rate (GFR) state. We conducted a retrospective cohort study to determine the incidence of AKD after HSCT.

Methods

This study included 108 patients aged between 16 and 70 years undergoing HSCT. In this study, AKD included clinical condition of AKI or subacute decreases in GFR. AKI was defined according to the Kidney Disease: Improving Global Outcomes guidelines based on serum creatinine. However, urine output data were not included to define AKI because the database lacked some of these data. Comparisons were made between groups using the Mann–Whitney U test.

Results

Acute kidney disease occurred in 17 patients (15.7%). There were significant differences between the AKD and non-AKD with respect to ABO-incompatible HSCT (p = 0.001) and incidence of acute graft versus host disease (GVHD) after HSCT (p < 0.001). The 100-day overall survival of patients with AKD and without AKD after HSCT was 70.6% and 79.8%, respectively (p = 0.409).

Discussion

ABO-incompatible HSCT and acute GVHD after HSCT were risk factors for the incidence of AKD. However, we could not find a significant association between AKD after HSCT and mortality.

Acute Kidney Injury in Pediatric Patients Receiving Allogeneic Hematopoietic Cell Transplantation: Incidence, Risk Factors, and Outcomes

Acute kidney injury (AKI) is a common adverse event after hematopoietic cell transplantation (HCT). AKI is associated with early death or chronic kidney disease among transplant survivors. However, large-scale pediatric studies based on standardized criteria are lacking. We performed a retrospective analysis of 1057 pediatric patients who received allogeneic HCT to evaluate the incidence and risk factors of AKI according to AKI Network criteria within the first 100 days of HCT. We also determined the effect of AKI on patient survival. The 100-day cumulative incidences of all stages of AKI, stage 3 AKI, and AKI requiring renal replacement therapy (RRT) were 68.2% ± 1.4%, 25.0% ± 1.3%, and 7.6% ± .8%, respectively. Overall survival at 1 year was not different between patients without AKI and those with stage 1 or 2 AKI (66.1% versus 73.4% versus 63.9%, respectively) but was significantly different between patients without AKI and patients with stage 3 AKI with or without RRT requirement (66.1% versus 47.3% versus 7.5%, respectively; P < .001). Age, year of transplantation, donor type, sinusoidal obstruction syndrome (SOS), and acute graft-versus-host disease (GVHD) were independent risk factors for stages 1 through 3 AKI. Age, donor, conditioning regimen, number of HCTs, SOS, and acute GVHD were independent risk factors for AKI requiring RRT. Our study revealed that AKI was a prevalent adverse event, and severe stage 3 AKI, which was associated with reduced survival, was common after pediatric allogeneic HCT. All patients receiving allogeneic HCT, especially those with multiple risk factors, require careful renal monitoring according to standardized criteria to minimize nephrotoxic insults.