Renal dysfunction following bone marrow transplantation

Impact of BK polyomavirus viremia on the outcomes of allogeneic hematopoietic stem cell transplantation

Although it is known that BK polyomavirus (BKPyV) causes hemorrhagic cystitis (HC) after allogeneic hematopoietic stem cell transplantation (HSCT), the clinical significance of BKPyV viremia has not been fully evaluated. We retrospectively analyzed the results of quantitative polymerase chain reaction (PCR) evaluations for detecting BKPyV in the whole blood samples of patients undergoing allogeneic HSCT during the period from January 2010 to June 2020 at a single institute, Tokyo Medical and Dental University. BKPyV was detected in the blood of 28 of the 107 evaluated patients, and the cumulative incidence of was 27.9% (95%CI: 20.2-37.9%). HC due to BKPyV developed in four of the 28 patients with BKPyV viremia (14.3%) and in two of the 79 patients without it (2.5%; P < 0.05). BKPyV viremia itself did not affect the patients' post-transplant estimated glomerular filtration rate (eGFR), but BKPyV viremia with a high viral load was significantly associated with decreased eGFR values (P < 0.05). BKPyV viremia was also associated with significantly lower progression-free survival at 3 years (35.1% [95%CI: 17.8-53.1%] vs. 60.4% [95%CI: 48.4-70.5], P < 0.05). Our findings demonstrated that BKPyV viremia was associated with onset of HC, an early decline of renal function, and poorer survival after allogeneic HSCT. Further studies are needed to test these results and elucidate the mechanisms of renal dysfunction associated with BKPyV viremia.

Autophagy differentially regulates tissue tolerance of distinct target organs in graft-versus-host disease models

Tissue-intrinsic mechanisms that regulate severity of systemic pathogenic immune-mediated diseases, such as acute graft-versus-host disease (GVHD), remain poorly understood. Following allogeneic hematopoietic stem cell transplantation, autophagy, a cellular stress protective response, is induced in host nonhematopoietic cells. To systematically address the role of autophagy in various host nonhematopoietic tissues, both specific classical target organs of acute GVHD (intestines, liver, and skin) and organs conventionally not known to be targets of GVHD (kidneys and heart), we generated mice with organ-specific knockout of autophagy related 5 (ATG5) to specifically and exclusively inhibit autophagy in the specific organs. When compared with wild-type recipients, animals that lacked ATG5 in the gastrointestinal tract or liver showed significantly greater tissue injury and mortality, while autophagy deficiency in the skin, kidneys, or heart did not affect mortality. Treatment with the systemic autophagy inducer sirolimus only partially mitigated GVHD mortality in intestine-specific autophagy-deficient hosts. Deficiency of autophagy increased MHC class I on the target intestinal epithelial cells, resulting in greater susceptibility to damage by alloreactive T cells. Thus, autophagy is a critical cell-intrinsic protective response that promotes tissue tolerance and regulates GVHD severity.

Immunotherapy in hematologic malignancies: achievements, challenges and future prospects

The immune-cell origin of hematologic malignancies provides a unique avenue for the understanding of both the mechanisms of immune responsiveness and immune escape, which has accelerated the progress of immunotherapy. Several categories of immunotherapies have been developed and are being further evaluated in clinical trials for the treatment of blood cancers, including stem cell transplantation, immune checkpoint inhibitors, antigen-targeted antibodies, antibody-drug conjugates, tumor vaccines, and adoptive cell therapies. These immunotherapies have shown the potential to induce long-term remission in refractory or relapsed patients and have led to a paradigm shift in cancer treatment with great clinical success. Different immunotherapeutic approaches have their advantages but also shortcomings that need to be addressed. To provide clinicians with timely information on these revolutionary therapeutic approaches, the comprehensive review provides historical perspectives on the applications and clinical considerations of the immunotherapy. Here, we first outline the recent advances that have been made in the understanding of the various categories of immunotherapies in the treatment of hematologic malignancies. We further discuss the specific mechanisms of action, summarize the clinical trials and outcomes of immunotherapies in hematologic malignancies, as well as the adverse effects and toxicity management and then provide novel insights into challenges and future directions.

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%.

Association of β₂ microglobulin level and glomerular filtration rate in patients with acute leukemia after hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation is a life-saving therapy in patients suffering from acute leukemia. However, kidney complications developed after performing hematopoietic stem cell transplantation can affect the course and prognosis of the disease in patients with acute leukemia. This study is aimed at assessing the functional status of the kidneys in patients with acute leukemia who have undergone hematopoietic stem cell transplantation. The study has observed a group of patients with acute lymphoblastic leukemia and acute myeloid leukemia who have undergone hematopoietic stem cell transplantation. It has been discovered that β2 microglobulin is a sensitive method of analyzing renal function, with the β2 microglobulin threshold urine level not exceeding 0.3 mg/L. The complex diagnostics of kidney function in hematopoietic stem cell transplantation recipients has given the opportunity to identify the relationship between increased β2 microglobulin levels and decreased glomerular filtration rate. It has been determined that β2 microglobulin is a biomarker of renal disorders. The obtained data have showed that β2 microglobulin can be used as a diagnostic marker of reduced kidney function.

Delayed renal injury in survivors of hematologic acute radiation syndrome

PURPOSE

A mass casualty disaster involving radiological or nuclear agents continues to be a public health concern which requires consideration of both acute and late tissue toxicities in exposed victims. With the advent of advanced treatment options for the mitigation of hematological injuries, there are likely to be survivors of total body irradiation (TBI) exposures as high as 8-10 Gy. These survivors are at risk for a range of delayed multi-organ morbidities including progressive renal failure.

MATERIAL AND METHODS

Here, we established the WAG/RijCmcr rat as an effective model for the evaluation of medical countermeasures (MCM) for acute hematologic radiation syndrome (H-ARS). The LD50/30 dose for adult and pediatric WAG/RijCmcr rats was determined for both sexes. We then confirmed the FDA-approved MCM pegfilgrastim (peg-GCSF, Neulasta®) mitigates H-ARS in adult male and female rats. Finally, we evaluated survival and renal dysfunction up to 300 d post-TBI in male and female adult rats.

RESULTS

In the WAG/RijCmcr rat model, 87.5% and 100% of adult rats succumb to lethal hematopoietic acute radiation syndrome (H-ARS) at TBI doses of 8 and 8.5 Gy, respectively. A single dose of the hematopoietic growth factor peg-GCSF administered at 24 h post-TBI improved survival during H-ARS. Peg-GCSF treatment improved 30 d survival from 12.5% to 83% at 8 Gy and from 0% to 63% at 8.5 Gy. We then followed survivors of H-ARS through day 300. Rats exposed to TBI doses greater than 8 Gy had a 26% reduction in survival over days 30-300 compared to rats exposed to 7.75 Gy TBI. Concurrent with the reduction in long-term survival, a dose-dependent impairment of renal function as assessed by blood urea nitrogen (BUN) and urine protein to urine creatinine ratio (UP:UC) was observed.

CONCLUSION

Together, these data show survivors of H-ARS are at risk for the development of delayed renal toxicity and emphasize the need for the development of medical countermeasures for delayed renal injury.

Predicting the risk of acute kidney injury after hematopoietic stem cell transplantation: development of a new predictive nomogram

The purpose was to predict the risk of acute kidney injury (AKI) within 100 days after hematopoietic stem cell transplantation (HSCT) in patients with hematologic disease by using a new predictive nomogram. Collect clinical data of patients with hematologic disease undergoing HSCT in our hospital from August 2012 to March 2018. Parameters with non-zero coefficients were selected by the Least Absolute Selection Operator (LASSO). Then these parameters were selected to build a new predictive nomogram model. Receiver operating characteristic (ROC) curve, calibration curve, C-index, and decision curve analysis (DCA) were used for the validation of the evaluation model. Finally, the nomogram was further evaluated by internal verification. According to 2012 Kidney Disease Improving Global Guidelines (KDIGO) diagnostic criteria, among 144 patients, the occurrence of AKI within 100 days after HSCT The rate was 29.2% (42/144). The C-index of the nomogram was 0.842. The C-value calculated by the internal verification was 0.809. The AUC was 0.842, and The DCA range of the predicted nomogram was from 0.01 to 0.71. This article established a high-precision nomogram for the first time for predicting the risk of AKI within 100 days after HSCT in patients with hematologic diseases. The nomogram had good clinical validity and reliability. For clinicians, it was very important to prevent AKI after HSCT.

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.

KIDNEY DAMAGE IN PATIENTS AFTER ALLOGENEIC STEM CELL TRANSPLANTATION

The aim of the review is to present the most common renal complications after HSCT such as acute kidney injury, chronic kidney disease glomerulopathies. HSCT is a critical therapy for many cancer patients with cancer, as well as patients with some other nonmalignant hematologic disorders and certain congenital immune deficiencies. Kidney complications after HSCT in a form of acute kidney injury is associated with significant morbidity and worse patient outcome. In addition, risk of chronic kidney disease is also increased following HSCT. It is very important to be aware, prevent, early recognize and treat renal damage to improve kidney and patient survival.

Day100 Score predicts moderate-severe cGVHD, transplant mortality, and survival after hematopoietic cell transplantation

We report a simple 4 variables-based laboratory score taken on day +100 to predict transplant outcomes.

The Day100 score stratifies patients into 3 groups for moderate-severe GVHD and TRM.

The aim of this study was to develop a predictive score for moderate-severe chronic graft-versus-host disease (cGVHD) on day +100 after allogeneic stem cell transplantation (HSCT). We studied 1292 patients allografted between 1990 and 2016, alive on day +100 after transplant, without cGVHD, and with full biochemistry laboratory values available. Patients were randomly assigned to a training and a validation cohort (ratio 1:1). In the training cohort, a multivariate analysis identified 4 independent predictors of moderate-severe cGVHD: gamma-glutamyl transferase ≥75 UI/l, creatinine ≥1 mg/dl, cholinesterase ≤4576 UI/l, and albumin ≤4 g/dl. A score of 1 was assigned to each variable, producing a low (0 to 1), intermediate (2 to 3), and high (4) score. The cumulative incidence of moderate-severe cGVHD was 12%, 20%, and 52% (P < .0001) in the training cohort, and 13%, 24%, and 33% (P = .002) in the validation cohort, respectively. The 5-year cumulative incidence of transplant-related mortality (TRM) was 5%, 14%, 27% (P < .0001) and 5%, 16%, 31% (P < .0001), respectively. The 5-year survival was 64%, 57%, 54% (P = .009) and 70%, 59%, 42% (P = .0008) in the 2 cohorts, respectively. In conclusion, Day100 score predicts cGVHD, TRM, and survival and, if validated in a separate group of patients, could be considered for trials of preemptive therapy.

Ruxolitinib exposure in patients with acute and chronic graft versus host disease in routine clinical practice-a prospective single-center trial

Purpose

Knowledge on Ruxolitinib exposure in patients with graft versus host disease (GvHD) is scarce. The purpose of this prospective study was to analyze Ruxolitinib concentrations of GvHD patients and to investigate effects of CYP3A4 and CYP2C9 inhibitors and other covariates as well as concentration-dependent effects.

Methods

262 blood samples of 29 patients with acute or chronic GvHD who were administered Ruxolitinib during clinical routine were analyzed. A population pharmacokinetic model obtained from myelofibrosis patients was adapted to our population and was used to identify relevant pharmacokinetic properties and covariates on drug exposure. Relationships between Ruxolitinib exposure and adverse events were assessed.

Results

Median of individual mean trough serum concentrations was 39.9 ng/mL at 10 mg twice daily (IQR 27.1 ng/mL, range 5.6–99.8 ng/mL). Applying a population pharmacokinetic model revealed that concentrations in our cohort were significantly higher compared to myelofibrosis patients receiving the same daily dose (p < 0.001). Increased Ruxolitinib exposure was caused by a significant reduction in Ruxolitinib clearance by approximately 50%. Additional comedication with at least one strong CYP3A4 or CYP2C9 inhibitor led to a further reduction by 15% (p < 0.05). No other covariate affected pharmacokinetics significantly. Mean trough concentrations of patients requiring dose reduction related to adverse events were significantly elevated (p < 0.05).

Conclusion

Ruxolitinib exposure is increased in GvHD patients in comparison to myelofibrosis patients due to reduced clearance and comedication with CYP3A4 or CYP2C9 inhibitors. Elevated Ruxolitinib trough concentrations might be a surrogate for toxicity.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00280-021-04351-w.

Harnessing the Physiological Functions of Cellular Prion Protein in the Kidneys: Applications for Treating Renal Diseases

A cellular prion protein (PrP^C) is a ubiquitous cell surface glycoprotein, and its physiological functions have been receiving increased attention. Endogenous PrP^C is present in various kidney tissues and undergoes glomerular filtration. In prion diseases, abnormal prion proteins are found to accumulate in renal tissues and filtered into urine. Urinary prion protein could serve as a diagnostic biomarker. PrP^C plays a role in cellular signaling pathways, reno-protective effects, and kidney iron uptake. PrP^C signaling affects mitochondrial function via the ERK pathway and is affected by the regulatory influence of microRNAs, small molecules, and signaling proteins. Targeting PrP^C in acute and chronic kidney disease could help improve iron homeostasis, ameliorate damage from ischemia/reperfusion injury, and enhance the efficacy of mesenchymal stem/stromal cell or extracellular vesicle-based therapeutic strategies. PrP^C may also be under the influence of BMP/Smad signaling and affect the progression of TGF-β-related renal fibrosis. PrP^C conveys TNF-α resistance in some renal cancers, and therefore, the coadministration of anti-PrP^C antibodies improves chemotherapy. PrP^C can be used to design antibody-drug conjugates, aptamer-drug conjugates, and customized tissue inhibitors of metalloproteinases to suppress cancer. With preclinical studies demonstrating promising results, further research on PrP^C in the kidney may lead to innovative PrP^C-based therapeutic strategies for renal disease.

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.

Hyponatremia in Patients with Hematologic Diseases

Hyponatremia is the most common electrolyte disorder in clinical practice and is associated with increased morbidity and mortality. It is frequently encountered in hematologic patients with either benign or malignant diseases. Several underlying mechanisms, such as hypovolemia, infections, toxins, renal, endocrine, cardiac, and liver disorders, as well as the use of certain drugs appear to be involved in the development or the persistence of hyponatremia. This review describes the pathophysiology of hyponatremia and discusses thoroughly the contributing factors and mechanisms that may be encountered specifically in patients with hematologic disorders. The involvement of the syndrome of inappropriate antidiuretic hormone (SIADH) secretion and renal salt wasting syndrome (RSWS) in the development of hyponatremia in such patients, as well as their differential diagnosis and management, are also presented. Furthermore, the distinction between true hyponatremia and pseudohyponatremia is explained. Finally, a practical algorithm for the evaluation of hyponatremia in hematologic patients, as well as the principles of hyponatremia management, are included in this review.

Incidence and mortality of acute kidney injury in patients undergoing hematopoietic stem cell transplantation: a systematic review and meta-analysis

BACKGROUND

While acute kidney injury (AKI) is commonly reported following hematopoietic stem cell transplant (HCT), the incidence and impact of AKI on mortality among patients undergoing HCT are not well described. We conducted this systematic review to assess the incidence and impact of AKI on mortality risk among patients undergoing HCT.

METHODS

Ovid MEDLINE, EMBASE and the Cochrane Databases were searched from database inceptions through August 2019 to identify studies assessing the incidence of AKI and mortality risk among adult patients who developed AKI following HCT. Random-effects and generic inverse variance method of DerSimonian-Laird were used to combine the effect estimates obtained from individual studies.

RESULTS

We included 36 cohort studies with a total of 5144 patients undergoing HCT. Overall, the pooled estimated incidence of AKI and severe AKI (AKI Stage III) were 55.1% (95% confidence interval (CI) 46.6-63.3%) and 8.3% (95% CI 6.0-11.4%), respectively. The pooled estimated incidence of AKI using contemporary AKI definitions (RIFLE, AKIN and KDIGO criteria) was 49.8% (95% CI 41.6-58.1%). There was no significant correlation between study year and the incidence of AKI (P = 0.12) or severe AKI (P = 0.97). The pooled odds ratios of 3-month mortality and 3-year mortality among patients undergoing HCT with AKI were 3.05 (95% CI 2.07-4.49) and 2.23 (95% CI 1.06-4.73), respectively.

CONCLUSION

The incidence of AKI among patients who undergo HCT remains high, and it has not changed over the years despite advances in medicine. AKI after HCT is associated with increased short- and long-term mortality.

Efficacy, Safety, and Practicality of Tacrolimus Monitoring after Bone Marrow Transplant: Assessment of a Change in Practice

BACKGROUND

Currently, there is no standardized approach to the frequency of monitoring tacrolimus levels in patients who have undergone hematopoietic stem cell transplant (HSCT). Previously, the practice at the study hospital was to monitor tacrolimus levels daily throughout a patient's admission. A recent institutional study suggested that measurement of tacrolimus level is more frequent than needed to achieve consistent time in the therapeutic range (TTR), particularly after the first 7 days. As a result, tacrolimus monitoring was changed to daily measurement for the initial week of therapy, followed by measurements on Monday, Wednesday, and Friday in subsequent weeks.

OBJECTIVE

To confirm the safety and efficacy of the recent practice change.

METHODS

This retrospective chart review of HSCT patients admitted to The Ottawa Hospital involved 68 patients in the pre-practice change group and 43 patients in the post-practice change group. Data on tacrolimus measurement were collected for up to 21 days after initiation of this medication. The proportion of TTR was compared between the 2 groups. Differences in the incidence and severity of renal dysfunction and the incidence of acute graft versus host disease (GVHD) were determined and described.

RESULTS

In the pre-practice change cohort, the median proportion of TTR for tacrolimus was 40.5% for days 1-7, 65.1% for days 8-14, and 78.9% for days 15-21, similar to the values for the post-practice change group (46.6% [p = 0.09], 62.9% [p = 0.93], and 70.0% [p = 0.22], respectively, for the same periods). The incidence of acute GVHD within 100 days after HSCT was 24% and 33% for the pre- and post-practice change cohorts, respectively. The incidence and severity of renal dysfunction were similar between the 2 groups.

CONCLUSION

The proportion of TTR for tacrolimus was not significantly affected by the recent practice change. Similarly, the incidence and severity of renal dysfunction and the incidence of acute GVHD did not appear to differ between the pre- and post-practice change groups.

Complement in Pathophysiology and Treatment of Transplant-Associated Thrombotic Microangiopathies

Transplant-associated thrombotic microangiopathy (TA-TMA) is a form of microangiopathy specifically occurring in the context of hematopoietic stem cell transplantation. Similarly, to other microangiopathies, TA-TMA is characterized by hemolytic anemia, thrombocytopenia, and organ failure due to endothelial injury. Although its clinical association with medications (eg, calcineurin inhibitors), immune reactions (eg, graft vs host disease) or infectious complications is well established, the pathophysiology remains largely unknown. Recent data have highlighted the role of complement in the pathophysiology of TA-TMA, which are frequently associated with a functional impairment (either inherited or acquired) of the endogenous regulation of the complement classic and alternative pathway. This manuscript will review the data supporting the involvement of complement in the pathophysiology of TA-TMA, as well as the clinical data supporting the use of anticomplement agents in this rare condition.

Kidney Pathology after Hematologic Cell Transplantation-A Single-Center Observation Study of Indication Biopsies and Autopsies

Hematopoietic cell transplantation (HCT) is an increasingly used treatment for hematologic malignancies as well as for nonmalignant diseases. Kidney impairment remains an important early and late post-transplantation complication. Although numerous histopathological changes have been reported, the pathophysiology remains incompletely understood. Furthermore, correlations between clinical findings and morphological changes have not been well studied. Between 2000 and 2016, 17 recipients of allogeneic (n = 12) or autologous (n = 5) HCT underwent kidney biopsy for either proteinuria or deterioration of kidney function at our center. The most common biopsy findings were therapy-related changes with thrombotic microangiopathy (n = 5), calcineurin inhibitor toxicity (n = 4), and membranous glomerulonephritis (n = 3), representing the majority of cases in this category. In addition, kidney findings from 137 autopsies performed between 1995 and March 2017 were analyzed. The most common changes were acute kidney injury (n = 55), most likely due to the patients' premortal deteriorated state, and thrombotic microangiopathy (n = 14). Several cases demonstrated involvement by either infectious agents (n = 6) or tumors (n = 9). Distinct kidney diseases, such as glomerulonephritis, were rare (3% of cases). Uncommon and yet rarely described diagnoses for this patient cohort were IgG4-related tubulointerstitial nephritis and fibrillary nephritis. This study provides a comprehensive overview of the histomorphological findings in kidney biopsy specimens from HCT recipients. Along with treatment-related complications, one putative correlate of chronic GVHD of the kidney could be documented: membranous glomerulonephritis. In contrast, no morphological correlate of acute GVHD of the kidney was identified. Findings at the time of autopsy varied greatly, spanning a wider range than those of indication biopsies.

Thrombotic Microangiopathy With Granulomatosis Interstitial Nephritis in an Allogenic Bone Marrow Transplant Patient: A Case Report and Review of the Literature

Transplant-associated thrombotic microangiopathy (TA-TMA) is a rare complication of hematopoietic stem cell transplantation (HSCT) with variable presentations. TA-TMA has often been described as a diagnosis of exclusion but a renal biopsy is rarely pursued to confirm the diagnosis, an essential step for our patient with renally limited TMA. We report a case report from the onconephrology clinic and review the literature associated with TA-TMA as it relates to diagnosis and treatment. A 45-year-old woman with acute myeloid leukemia and stage 3 chronic kidney disease underwent a matched unrelated donor allogenic HSCT. Postoperatively, she developed gastrointestinal graft versus host disease (GvHD) and was treated with tacrolimus, sirolimus, budesonide, and beclomethasone. Following discharge, she developed uncontrolled hypertension and required losartan, amlodipine, carvedilol, clonidine patch, and hydralazine as needed. On day 180 post-transplant, she developed lower extremity edema and acute kidney injury (AKI) with creatinine increasing to 2 mg/dL. On day 480 post-transplant, she developed worsening thrombocytopenia, anemia, new hematuria, left flank pain, and worsening renal function with creatinine peaking to 6 mg/dL. Peripheral smear revealed no schistocytes, lactate dehydrogenase of 265 mg/dL, and urinalysis with 100 mg/dL protein. ADAMTS 13 activity was normal (92%) and no inhibitor was detected. She became anuric and was started on hemodialysis. Renal biopsy revealed glomerular changes consistent with TA-TMA. During HSCT, systemic vascular endothelial injury triggers microangiopathic hemolytic anemia, platelet consumption, injury of glomerular endothelial cells and fibrin occluded renal capillaries. Thus, TA-TMA should be considered in HSCT patients with elevated LDH, proteinuria, hypertension, and AKI. However, a diagnosis is difficult to confirm without a renal biopsy. Treatment involves discontinuing potentially toxic agents such as calcineurin inhibitors and sirolimus, prescribing adequate antimicrobial treatment, and using renal replacement therapy if needed. A renal biopsy early in the course of disease not only confirms the diagnosis, but may limit the extent of disease.