Safety and infectious outcomes in pediatric kidney transplant recipients after COVID-19 vaccination: A pediatric nephrology research consortium study

BACKGROUND

Adult kidney transplant recipients (KTRs) fully vaccinated against COVID-19 have substantial morbidity and mortality related to SARS-CoV-2 infection compared with the general population. However, little is known regarding the safety and efficacy of the COVID-19 vaccination series in pediatric KTRs.

METHODS

A multicenter, retrospective observational study was performed across nine pediatric transplantation centers. Eligible KTRs fully vaccinated against COVID-19 were enrolled and data were collected pertaining to SARS-CoV-2 infection incidence and severity, graft outcomes and post-vaccination safety profile, as well as overall patient survival.

RESULTS

A total of 247 patients were included in this investigation with a median age at transplantation of 11 years (IQR 5-15). SARS-CoV-2 infection was observed in 30/110 (27.27%) of fully vaccinated patients, tested post-transplant, within the defined follow-up period. Of these patients, 6/30 (18.18%) required hospitalization and 3/30 (12.12%) required reduction in immunosuppression, with no reported deaths. De novo donor-specific antibodies (DSAs) were found in 8/86 (9.30%) of DSA-tested patients with two experiencing rejection and subsequent graft loss. The overall incidence of rejection and graft loss among the total cohort was 11/247 (4.45%) and 6/247 (3.64%), respectively. A 100% patient survival was observed.

CONCLUSIONS

Observationally, infectious outcomes of SARS-CoV-2 in fully vaccinated pediatric KTRs are excellent, with a low incidence of infection requiring hospitalization and no associated deaths. Though de novo DSAs were observed, there was minimal graft rejection and graft loss reported in the total cohort.

Outcomes of granulocyte colony-stimulating factor use in pediatric kidney transplant recipients: A Pediatric Nephrology Research Consortium study

BACKGROUND

Neutropenia is common in the first year after pediatric kidney transplant and is associated with an increased risk of infection, allograft loss, and death. Granulocyte colony-stimulating factor (G-CSF) increases neutrophil production, but its use in pediatric solid organ transplant recipients remains largely undescribed.

METHODS

We performed a multicenter retrospective cohort study of children with neutropenia within the first 180 days after kidney transplant. Multivariable linear regression and Poisson regression were used to assess duration of neutropenia and incidence of hospitalization, infection, and rejection.

RESULTS

Of 341 neutropenic patients, 83 received G-CSF during their first episode of neutropenia. Median dose of G-CSF was 5 mcg/kg for 3 (IQR 2-7) doses. G-CSF use was associated with transplant center, induction immunosuppression, steroid-free maintenance immunosuppression, hospitalization, and decreases in mycophenolate mofetil, valganciclovir, and trimethoprim-sulfamethoxazole dosing. Absolute neutrophil count nadir was also significantly lower among those treated with G-CSF. G-CSF use was not associated with a shorter duration of neutropenia (p = .313) and was associated with a higher rate of neutropenia relapse (p = .002) in adjusted analysis. G-CSF use was associated with a decreased risk of hospitalization (aIRR 0.25 (95%CI 0.12-0.53) p < .001) but there was no association with incidence of bacterial infection or rejection within 90 days of neutropenic episode.

CONCLUSION

G-CSF use for neutropenia in pediatric kidney transplant recipients did not shorten the overall duration of neutropenia but was associated with lower risk of hospitalization. Prospective studies are needed to determine which patients may benefit from G-CSF treatment.

Persistent Disease Activity in Patients With Long-Standing Glomerular Disease

Introduction

Methods

Results

Conclusion

One Health operations: a critical component in the International Health Regulations Monitoring and Evaluation Framework

Under the International Health Regulations (IHR, 2005), a legally binding document adopted by 196 States Parties, countries are required to develop their capacity to rapidly detect, assess, notify and respond to unusual health events of potential international concern. To support countries in monitoring and enhancing their capacities and complying with the IHR (2005), the World Health Organization (WHO) developed the IHR Monitoring and Evaluation Framework (IHR MEF). This framework comprises four complementary components: the State Party Annual Report, the Joint External Evaluation, after-action reviews and simulation exercises. The first two are used to review capacities and the second two to help to explore their functionality. The contribution of different disciplines, sectors, and areas of work, joining forces through a One Health approach, is essential for the implementation of the IHR (2005). Therefore, WHO, in partnership with the Food and Agriculture Organization of the United Nations (FAO), the World Organisation for Animal Health (OIE), and other international and national partners, has actively worked on facilitating the inclusion of the relevant sectors, in particular the animal health sector, in each of the four components of the IHR MEF. Other tools complement the IHR MEF, such as the WHO/OIE IHR-PVS [Performance of Veterinary Services] National Bridging Workshops, which facilitate the optimal use of the results of the IHR MEF and the OIE Performance of Veterinary Services Pathway and create an opportunity for stakeholders from animal health and human health services to work on the coordination of their efforts. The results of these various tools are used in countries' planning processes and are incorporated in their National Action Plan for Health Security to accelerate the implementation of IHR core capacities. The present article describes how One Health is incorporated in all components of the IHR MEF.

Kidney biopsy findings in children with sickle cell disease: a Midwest Pediatric Nephrology Consortium study

BACKGROUND

Renal damage is a progressive complication of sickle cell disease (SCD). Microalbuminuria is common in children with SCD, while a smaller number of children have more severe renal manifestations necessitating kidney biopsy. There is limited information on renal biopsy findings in children with SCD and subsequent management and outcome.

METHODS

This is a multicenter retrospective analysis of renal biopsy findings and clinical outcomes in children and adolescents with SCD. We included children and adolescents (age ≤ 20 years) with SCD who had a kidney biopsy performed at a pediatric nephrology unit. The clinical indication for biopsy, biopsy findings, subsequent treatments, and outcomes were analyzed.

RESULTS

Thirty-six SCD patients (ages 4-19 years) were identified from 14 centers with a median follow-up of 2.6 years (0.4-10.4 years). The indications for biopsy were proteinuria (92%) and elevated creatinine (30%). All biopsies had abnormal findings, including mesangial hypercellularity (75%), focal segmental glomerulosclerosis (30%), membranoproliferative glomerulonephritis (16%), and thrombotic microangiopathy (2%). There was increased use of hydroxyurea, angiotensin-converting-enzyme inhibitors, and angiotensin receptor blockers following renal biopsy. At last follow-up, 3 patients were deceased, 2 developed insulin-dependent diabetes mellitus, 6 initiated chronic hemodialysis, 1 received a bone marrow transplant, and 1 received a kidney transplant.

CONCLUSIONS

Renal biopsies, while not commonly performed in children with SCD, were universally abnormal. Outcomes were poor in this cohort of patients despite a variety of post-biopsy interventions. Effective early intervention to prevent chronic kidney disease (CKD) is needed to reduce morbidity and mortality in children with SCD.

Clinical Characteristics and Treatment Patterns of Children and Adults With IgA Nephropathy or IgA Vasculitis: Findings From the CureGN Study

Introduction

The Cure Glomerulonephropathy Network (CureGN) is a 66-center longitudinal observational study of patients with biopsy-confirmed minimal change disease, focal segmental glomerulosclerosis, membranous nephropathy, or IgA nephropathy (IgAN), including IgA vasculitis (IgAV). This study describes the clinical characteristics and treatment patterns in the IgA cohort, including comparisons between IgAN versus IgAV and adult versus pediatric patients.

Methods

Patients with a diagnostic kidney biopsy within 5 years of screening were eligible to join CureGN. This is a descriptive analysis of clinical and treatment data collected at the time of enrollment.

Results

A total of 667 patients (506 IgAN, 161 IgAV) constitute the IgAN/IgAV cohort (382 adults, 285 children). At biopsy, those with IgAV were younger (13.0 years vs. 29.6 years, P < 0.001), more frequently white (89.7% vs. 78.9%, P = 0.003), had a higher estimated glomerular filtration rate (103.5 vs. 70.6 ml/min per 1.73 m², P < 0.001), and lower serum albumin (3.4 vs. 3.8 g/dl, P < 0.001) than those with IgAN. Adult and pediatric individuals with IgAV were more likely than those with IgAN to have been treated with immunosuppressive therapy at or prior to enrollment (79.5% vs. 54.0%, P < 0.001).

Conclusion

This report highlights clinical differences between IgAV and IgAN and between children and adults with these diagnoses. We identified differences in treatment with immunosuppressive therapies by disease type. This description of baseline characteristics will serve as a foundation for future CureGN studies.

Heat shock proteins in the kidney

Heat shock proteins (Hsps) are essential to cell survival through their function as protein chaperones. The role they play in kidney health and disease is varied. Hsp induction may be either beneficial or detrimental to the kidney, depending on the specific Hsp, type of cell, and context. This review addresses the role of Hsps in the kidney, including during development, as osmoprotectants, and in various kidney disease models. Heat shock transcription factor, activated by a stress on renal cells, induces Hsp elaboration and separately regulates immune responses that can contribute to renal injury. Induced Hsps in the intracellular compartment are mostly beneficial in the kidney by stabilizing and restoring cell architecture and function through acting as protein chaperones. Intracellular Hsps also inhibit apoptosis and facilitate cell proliferation, preserving renal tubule viability after acute injury, but enhancing progression of cystic kidney disease and malignancy. Induced Hsps in the extracellular compartment, either circulating or located on outer cell membranes, are mainly detrimental through enhancing inflammation pathways to injury. Correctly harnessing these stress proteins promises the opportunity to alter the course of acute and chronic kidney disease.

Mice with an absent stress response are protected against ischemic renal injury

Inducible heat shock proteins (HSP), regulated by heat shock factor-1 (HSF-1), protect against renal cell injury in vitro. To determine whether HSPs ameliorate ischemic renal injury in vivo, HSF-1functional knock-out mice (HSF-KO) were compared with wild-type mice following bilateral ischemic renal injury. Following injury, the kidneys of wild-type mice had the expected induction of HSP70 and HSP25; a response absent in the kidneys of HSF-KO mice. Baseline serum creatinine was equivalent between strains. Serum creatinines at 24 hours reflow in HSF-KO mice were significantly lower than in the wild-type. Histology showed similar tubule injury in both strains after ischemic renal injury but increased medullary vascular congestion in wild-type compared with HSF-KO mice. Flow-cytometry of mononuclear cells isolated from kidneys showed no difference between strains in the number of CD4⁺ and CD8⁺ T cells in sham operated animals. At 1 hour of reflow, CD4⁺ and CD8⁺ cells were doubled in the kidneys of wild type but not HSF-KO mice. Foxp3⁺ T regulatory cells were significantly more abundant in the kidneys of sham-operated HSF-KO than wild-type mice. Suppression of CD25⁺Foxp3⁺ cells in HSF-KO kidneys with the anti-CD25 antibody PC61 reversed the protection against ischemic renal injury. Thus, HSF-KO mice are protected from ischemic renal injury by a mechanism that depends on an increase in the T regulatory cells in the kidney associated with altered T cell infiltration early in reflow. Hence, stress response activation may contribute to early injury by facilitating T cell infiltration into ischemic kidney.

Chromosome substitution modulates resistance to ischemia reperfusion injury in Brown Norway rats

Brown Norway rats (BN, BN/NHsdMcwi) are profoundly resistant to developing acute kidney injury (AKI) following ischemia reperfusion. To help define the genetic basis for this resistance, we used consomic rats, in which individual chromosomes from BN rats were placed into the genetic background of Dahl SS rats (SS, SS/JrHsdMcwi) to determine which chromosomes contain alleles contributing to protection from AKI. The parental strains had dramatically different sensitivity to ischemia reperfusion with plasma creatinine levels following 45 minutes of ischemia and 24 hours reperfusion of 4.1 and 1.3 mg/dl in SS and in BN, respectively. No consomic strain showed protection similar to the parental BN strain. Nine consomic strains (SS-7BN, SS-XBN, SS-8BN, SS-4BN, SS-15BN, SS-3BN, SS-10BN, SS-6BN, and SS-5BN) showed partial protection (plasma creatinine about 2.5-3.0 mg/dl), suggesting that multiple alleles contribute to the severity of AKI. In silico analysis was performed using disease ontology database terms and renal function quantitative trait loci from the rat genome database on the BN chromosomes giving partial protection from AKI. This tactic identified at least 36 candidate genes, with several previously linked to the pathophysiology of AKI. Thus, natural variants of these alleles or yet to be identified alleles on these chromosomes provide protection against AKI. These alleles may be potential modulators of AKI in susceptible patient populations.

The maximal cytoprotective function of the heat shock protein 27 is dependent on heat shock protein 70

Endogenous heat shock proteins (HSPs) 70 and 25/27 are induced in renal cells by injury from energy depletion. Transfected over-expression of HSPs 70 or 27 (human analogue of HSP25), provide protection against renal cell injury from ATP deprivation. This study examines whether over-expressed HSP27 depends on induction of endogenous HSPs, in particular HSP70, to afford protection against cell injury. LLC-PK1 cells transfected with HSP27 (27OE cells) were injured by ATP depletion for 2h and recovered for 4h in the presence of HSF decoy, HSP70 specific siRNA (siRNA-70) and their respective controls. Injury in the presence of HSF decoy, a synthetic oligonucleotide identical to the heat shock element, the nuclear binding site of HSF, decreased HSP70 induction by 80% without affecting the over-expression of transfected HSP27. The HSP70 stress response was completely ablated in the presence of siRNA-70. Protection against injury, provided by over-expression of HSP27, was reduced by treatment with HSF decoy and abolished by treatment with siRNA-70. Immunoprecipitation studies demonstrated association of HSP27 with actin that was not affected by either treatment with HSF decoy or siRNA. Therefore, HSP27 is dependent on HSP70 to provide its maximal cytoprotective effect, but not for its interaction with actin. This study suggests that, while it has specific action on the cytoskeleton, HSP 25/27 must have coordinated activity with other HSP classes, especially HSP70, to provide the full extent of resistance to injury from energy depletion.

Modulation of renal cell injury by heat shock proteins: lessons learned from the immature kidney

The mechanisms that underlie tolerance to injury in immature animals and tissues have been a subject of interest since 1670. Observations in neonatal units that premature infants are less prone to develop acute renal failure than adults in critical care units have prompted a series of investigations. Although initially attributed to metabolic adaptation such as increased glycolytic capacity and preservation of high energy phosphate, more recent studies have indicated a prominent role for the heat shock response. Observed modulations of injury by heat shock proteins in the immature kidney have significant implications for advancement of our understanding of renal cell injury in both adults and children.

Congenital nephrotic syndrome responsive to angiotensin-converting enzyme inhibition

Congenital nephrotic syndrome is a severe disorder caused by increased permeability of the glomerular capillary leading to massive proteinuria. Typically, this disorder presents in the first three months and is caused by inherited mutations in genes encoding structural proteins of the podocyte slit membrane and, as such, is usually irreversible. Medical management is often insufficient to stem the enormous losses of protein, and the patients require nephrectomies. Here, we present results for a patient with congenital nephrotic syndrome of unknown etiology which responded to treatment with an angiotensin-converting enzyme inhibitor alone. The patient's proteinuria relapsed when the medication was stopped, but went into complete remission after restarting treatment. This remarkable response is discussed in the light of recent investigations into the effect of angiotensin II on podocyte integrity.

HSP70 binding modulates detachment of Na-K-ATPase following energy deprivation in renal epithelial cells

The molecular mechanisms associated with reestablishment of renal epithelial polarity after injury remain incompletely delineated. Stress proteins may act as molecular chaperones, potentially modulating injury or enhancing recovery. We tested whether overexpression of heat shock protein 70 (HSP70) would stabilize Na-K-ATPase attachment to the cytoskeleton, under conditions of ATP depletion, and whether a direct association existed between Na-K-ATPase and HSP70 in cultured renal epithelial cells. LLC-PK1 cells were transfected with a tagged HSP70 (70FLAG) or vector alone (VA). Detachment of Na-K-ATPase was detected in Triton soluble lysate after ATP depletion. 70FLAG cells demonstrated a significant (P < 0.01) decrease in detachment of Na-K-ATPase after either 2 or 4 h of ATP depletion. Interactions between HSP70 and Na-K-ATPase were determined by coimmunoprecipitation of 70FLAG and Na-K-ATPase, by direct and competitive binding assays and by immunocytochemical localization. Binding of HSP70 and Na-K-ATPase increased dramatically following injury. Interactions were: 1) reversible; 2) reciprocal to changes in the HSP70 binding protein clathrin; and 3) present only when ATP turnover was inhibited in cell lysate, an established characteristic of HSP binding. These studies indicate that 1) overexpression of HSP70 is associated with decreased detachment of Na-K-ATPase from the cytoskeleton following injury; 2) HSP70 binds to Na-K-ATPase; and 3) binding of HSP70 to Na-K-ATPase is dynamic and specific, increasing in response to injury and decreasing during recovery. Interaction between the molecular chaperone HSP70 and damaged or displaced Na-K-ATPase may represent a fundamental cellular mechanism underlying maintenance and recovery of renal tubule polarity following energy deprivation.

Reduced tolerance of immature renal tubules to anoxia by HSF-1 decoy

Immature animals demonstrate an amplified heat shock response following a variety of insults compared with that seen in mature animals (M). The potential role of the heat shock response in modulating immature tolerance to injury was compared between rat pups, 10 postnatal days of age (P10), and M. Baseline levels of the heat shock transcription factor (HSF-1) were substantially elevated in P10 compared with M animals. In uninjured P10 pups, HSF-1 level was comparable to that of M animals subjected to 45 min of ischemia. As anticipated, the integrity of suspensions of tubules exposed to anoxia was preserved in P10 animals (23% LDH release) compared with M (40%), P < 0.01. The effect of targeted inhibition of HSF-1 on tubular integrity was studied using a cyclic oligonucleotide decoy. The HSF-1 decoy increased the severity of anoxic injury in P10 pups to a level comparable with M animals. LDH release was 33% in decoy-treated P10 tubules compared with 40% in M. When P10 tubules were treated with scrambled decoy, resistance to anoxia remained intact (24%). The increased vulnerability of the tubular suspension to injury was specific to the HSF-1 decoy and proportional to the dose of decoy applied. This study demonstrates maturation in the abundance of HSF-1 in the immature rat kidney. The loss of resistance of immature tubules to anoxia with specific inhibition of HSF-1 may be due to its effect on the heat shock response or other signaling pathways of critical pathobiological importance in renal cell injury.

An ethnopharmacological survey for potential angiotensin converting enzyme inhibitors from Indian medicinal plants

Plants used in different traditional systems of Indian medicine and some relatives/substitutes have been investigated for their angiotensin converting enzyme (ACE) inhibitory activity. They were selected on the basis of their usage as cardiotonics, diuretics and other uses related to the symptoms of hypertension. Out of the 73 species investigated, 22 showed more than 50% ACE inhibitory activity.

Liver abscess and disseminated intravascular coagulation in tuberculosis

We report the case of a 55-year-old man with chronic renal failure, and a history of prolonged fever and jaundice. Radiological studies revealed a multiloculated irregular liver abscess. Mycobacterium tuberculosis was isolated from the abscess on smear and culture of aspirated pus. Haematological studies revealed the presence of disseminated intravascular coagulation. A detailed search failed to identify any reason for this other than the tuberculous infection. The treatment of tuberculous liver abscess and pathogenesis of disseminated intravascular coagulation in tuberculosis are discussed.