Kidney Injury in Murine Models of Hematopoietic Stem Cell Transplantation

Allogeneic T cells cause acute renal injury after hematopoietic cell transplantation

Acute kidney injury (AKI) is a frequent complication of allogeneic hematopoietic cell transplantation (allo-HCT). There are many causes of AKI after allo-HCT, but it is unknown whether renal acute graft-versus-host disease (aGVHD) caused by direct allogeneic donor T-cell-mediated renal damage contributes. Here, we tested whether allogeneic donor T cells attack kidneys in murine models of aGVHD. To avoid confounding effects of nephrotoxic agents, we did not administer immunosuppressants for GVHD prophylaxis. We found that urinary N-acetyl-β-D-glucosaminidase, a marker of tubular injury, was elevated in allogeneic recipients on day 14 after allogeneic bone marrow transplantation. Donor major histocompatibility complex-positive cells were present and CD3+ T cells were increased in the glomerulus, peritubular capillaries, interstitium, and perivascular areas in the kidneys of allo-HCT recipient mice. These T cells included both CD4+ and CD8+ cells with elevated activation markers, increased exhaustion markers, and greater secretion of proinflammatory cytokines and cytotoxic proteins. Consistent with allo-T-cell-mediated renal damage, expression of neutrophil gelatinase-binding lipocalin, a marker of AKI, and elafin, a marker of aGVHD, were increased in renal tissue of allogeneic recipients. Because apoptosis of target cells is observed on histopathology of aGVHD target tissues, we confirmed that alloreactive T cells increased apoptosis of renal endothelial and tubular epithelial cells in cytotoxic T-lymphocyte assays. These data suggest that immune responses induced by donor T cells contribute to renal endothelial and tubular epithelial cell injury in allo-HCT recipients and that aGVHD may contribute to AKI after allo-HCT.

Pathological evaluation of renal complications in children following allogeneic hematopoietic stem cell transplantation: a retrospective cohort study

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative therapy for hematologic malignancies and non-malignant disorders, such as aplastic anemia, fanconi anemia, and certain immune deficiencies. Post-transplantation kidney injury is a common complication and involves a wide spectrum of structural abnormalities, including glomerular (MSPGN, mesangial proliferative glomerulonephritis; FSGS, focal segmental glomerulosclerosis; MPGN, membranoproliferative glomerulonephritis; MCD, minimal change disease), vascular (TMA, thrombotic microangiopathy), and/or tubulointerstitial (TIN, tubulointerstitial nephritis; ATI, acute tubular injury). Renal biopsy is the gold-standard examination for defining multiple etiologies of kidney impairment. Although kidney injury following HSCT has been studied, little is known about the effects of allo-HSCT on renal pathology in pediatric patients.

METHODS

We retrospectively analyzed renal biopsy specimens from children with kidney injury after allo-HSCT and correlated results with clinical data in the last 10 years.

RESULTS

Among 25 children (18 males and 7 females), three patients had proteinuria indicating nephrotic syndrome (24-hour urinary total protein/weight > 50 mg/kg/d), nine patients had severely reduced estimated glomerular filtration rate (eGFR < 30 ml/min/1.73 m2) and four patients received kidney replacement therapy (KRT). The main pathologies identified from kidney biopsies were MSPGN (n = 12), FSGS (n = 12), MPGN (n = 5), TMA (n = 4), MCD (n = 3), diffuse glomerular fibrosis (DGF, n = 2), ATI and TIN, in isolation or combined with other pathologies. The median follow-up time was 16.5 (0.5 ~ 68.0) months. Three patients died of recurrent malignancy and/or severe infection, one child developed to end-stage renal disease (ESRD), six patients (24%) had elevated serum creatinine (SCr > 100µmol/l) and nine patients (36%) still had proteinuria.

CONCLUSIONS

This study evaluates histomorphologic findings from kidney biopsies of pediatric recipients following allo-HSCT. Detailed evaluation of renal biopsy samples is helpful to elucidate the nature of renal insult, and may potentially identify treatable disease processes.

Recent Advances of Acute Kidney Injury in Hematopoietic Cell Transplantation

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

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

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

Non-classical manifestations of acute GVHD

Acute graft-versus-host disease (GVHD) is a major life-threatening complication after allogeneic hematopoietic cell transplantation (allo-HCT). The classical target organs of acute GVHD include the intestines, liver, and skin. The damage of these organs is relatively easy to detect for the clinician as diarrhea, increased bilirubin, and rash. However, there is increasing evidence that also other organs, where the acute damage is less apparent or more difficult to distinguish from drug toxicity, such as the central nervous system, the lungs, the ovaries and testis, the thymus, the bone marrow and the kidney, can be target organs of acute GVHD. Here, we review current evidence for non-classical manifestations of acute GVHD in rodent models and in patients and discuss them in the context of novel emerging therapies for GVHD. A better understanding of the involvement of the non-classical GVHD target organs may help to improve patient outcomes after allo-HCT.