The Kelch13 compartment contains highly divergent vesicle trafficking proteins in malaria parasites.

Single amino acid changes in the parasite protein Kelch13 (K13) result in reduced susceptibility of P. falciparum parasites to artemisinin and its derivatives (ART). Recent work indicated that K13 and other proteins co-localising with K13 (K13 compartment proteins) are involved in the endocytic uptake of host cell cytosol (HCCU) and that a reduction in HCCU results in reduced susceptibility to ART. HCCU is critical for parasite survival but is poorly understood, with the K13 compartment proteins among the few proteins so far functionally linked to this process. Here we further defined the composition of the K13 compartment by analysing more hits from a previous BioID, showing that MyoF and MCA2 as well as Kelch13 interaction candidate (KIC) 11 and 12 are found at this site. Functional analyses, tests for ART susceptibility as well as comparisons of structural similarities using AlphaFold2 predictions of these and previously identified proteins showed that vesicle trafficking and endocytosis domains were frequent in proteins involved in resistance or endocytosis (or both), comprising one group of K13 compartment proteins. While this strengthened the link of the K13 compartment to endocytosis, many proteins of this group showed unusual domain combinations and large parasite-specific regions, indicating a high level of taxon-specific adaptation of this process. Another group of K13 compartment proteins did not influence endocytosis or ART susceptibility and lacked detectable vesicle trafficking domains. We here identified the first protein of this group that is important for asexual blood stage development and showed that it likely is involved in invasion. Overall, this work identified novel proteins functioning in endocytosis and at the K13 compartment. Together with comparisons of structural predictions it provides a repertoire of functional domains at the K13 compartment that indicate a high level of adaption of endocytosis in malaria parasites.

The exception that proves the rule: Virulence gene expression at the onset of Plasmodium falciparum blood stage infections.

Controlled human malaria infections (CHMI) are a valuable tool to study parasite gene expression in vivo under defined conditions. In previous studies, virulence gene expression was analyzed in samples from volunteers infected with the Plasmodium falciparum (Pf) NF54 isolate, which is of African origin. Here, we provide an in-depth investigation of parasite virulence gene expression in malaria-naïve European volunteers undergoing CHMI with the genetically distinct Pf 7G8 clone, originating in Brazil. Differential expression of var genes, encoding major virulence factors of Pf, PfEMP1s, was assessed in ex vivo parasite samples as well as in parasites from the in vitro cell bank culture that was used to generate the sporozoites (SPZ) for CHMI (Sanaria PfSPZ Challenge (7G8)). We report broad activation of mainly B-type subtelomeric located var genes at the onset of a 7G8 blood stage infection in naïve volunteers, mirroring the NF54 expression study and suggesting that the expression of virulence-associated genes is generally reset during transmission from the mosquito to the human host. However, in 7G8 parasites, we additionally detected a continuously expressed single C-type variant, Pf7G8_040025600, that was most highly expressed in both pre-mosquito cell bank and volunteer samples, suggesting that 7G8, unlike NF54, maintains expression of some previously expressed var variants during transmission. This suggests that in a new host, the parasite may preferentially express the variants that previously allowed successful infection and transmission. Trial registration: ClinicalTrials.gov - NCT02704533; 2018-004523-36.

Executive summary of the KDIGO 2024 Clinical Practice Guideline for the Management of ANCA-Associated Vasculitis.

In 2021, the Kidney Disease: Improving Global Outcomes (KDIGO) Guideline for the Management of Glomerular Diseases was published. KDIGO is committed to providing the nephrology community with periodic updates, based on new developments for each disease. For patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), avacopan received regulatory approval in late 2021, leading to this KDIGO guideline update. In addition, the evidence supporting a lower-dose glucocorticoid induction regimen or even complete replacement of glucocorticoids has become stronger. Herein, an executive summary of the most important guideline changes from the AAV chapter is provided as a quick reference.

The role of neutrophil extracellular trap formation in kidney transplantation: Implications from donors to the recipient.

Kidney transplantation remains the gold standard for patients with end-stage renal disease, but severe donor organ shortage has led to long waiting lists. The utilization of expanded criteria donor kidneys within the category of deceased donors has enlarged the pool of available kidneys for transplantation; however, these grafts often have an increased risk for delayed graft function or reduced graft survival following transplantation. During brain or circulatory death, neutrophils are recruited to the vascular beds of kidneys where a proinflammatory microenvironment might prime the formation of neutrophil extracellular traps (NETs), web-like structures, containing proteolytic enzymes, DNA, and histones. NETs are known to cause tissue damage and specifically endothelial damage while activating other systems such as coagulation and complement, contributing to tissue injury and an unfavorable prognosis in various diseases. In lung transplantation and kidney transplantation studies, NETs have also been associated with primary graft dysfunction or rejection. In this review, the role that NETs might play across the different phases of transplantation, already initiated in the donor, during preservation, and in the recipient, will be discussed. Based on current knowledge, NETs might be a promising therapeutic target to improve graft outcomes.

Targeting NF-κB signaling in B cells as a potential new treatment modality for ANCA-associated vasculitis.

B lineage cells are critically involved in ANCA-associated vasculitis (AAV), evidenced by alterations in circulating B cell subsets and beneficial clinical effects of rituximab (anti-CD20) therapy. This treatment renders a long-term, peripheral B cell depletion, but allows for the survival of long-lived plasma cells. Therefore, there is an unmet need for more reversible and full B lineage cell targeting approaches. To find potential novel therapeutic targets, RNA sequencing of CD27+ memory B cells of patients with active AAV was performed, revealing an upregulated NF-κB-associated gene signature. NF-κB signaling pathways act downstream of various B cell surface receptors, including the BCR, CD40, BAFFR and TLRs, and are essential for B cell responses. Here we demonstrate that novel pharmacological inhibitors of NF-κB inducing kinase (NIK, non-canonical NF-κB signaling) and inhibitor-of-κB-kinase-ß (IKKß, canonical NF-κB signaling) can effectively inhibit NF-κB signaling in B cells, whereas T cell responses were largely unaffected. Moreover, both inhibitors significantly reduced B cell proliferation, differentiation and production of antibodies, including proteinase-3 (PR3) autoantibodies, in B lineage cells of AAV patients. These findings indicate that targeting NF-κB, particularly NIK, may be an effective, novel B lineage cell targeted therapy for AAV and other autoimmune diseases with prominent B cell involvement.

Pre-donation Assessment of Cystatin C to Improve Prediction of Pre- and Post-Donation GFR in Potential Living Kidney Donors.

BACKGROUND AND HYPOTHESIS: Accurate estimation of glomerular filtration rate (GFR) is crucial in living kidney donation. While most eGFR equations are based on plasma creatinine, its levels are strongly influenced by muscle mass. Application of cystatin C (CysC)-based estimates before donation may improve both estimation of current GFR and prediction of post-donation GFR. METHODS: We assessed the performance of CKD-EPI equations based on creatinine (eGFRcreat-2009, eGFRcreat-2021), cystatin C (eGFRCysC-2012), or both (eGFRcombined-2012, eGFRcombined-2021) for estimating pre- and post-donation measured GFR in 486 living kidney donors. We subsequently focused on a subgroup of individuals with high/low muscle mass (25% highest/lowest 24-hour urinary creatinine excretion, sex-stratified and height-indexed). RESULTS: Pre-donation eGFRcombined 2012 and eGFRcombined 2021 showed the strongest associations with pre- and post-donation mGFR. Pre-donation eGFRcombined 2021 was most accurate for estimating both pre-donation (bias 0.01±11.9 mL/min/1.73m2) and post-donation mGFR (bias 1.3±8.5 mL/min/1.73 m2). In donors with high/low muscle mass, CysC-based equations (with or without creatinine) performed better compared to equations based on only creatinine. CONCLUSIONS: In conclusion, combined eGFR equations yielded a better estimate of pre- and post-donation mGFR, compared to estimates based on creatinine or CysC only. The added value of CysC seems particularly pronounced in donors with high or low muscle mass.

Kidney Transplantation Improves Health-Related Quality of Life in Older Recipients.

Kidney transplantation is the best treatment for kidney failure in older patients. However, little is known regarding changes in health-related quality of life (HRQoL) from before to after transplantation and determinants of HRQoL in older kidney transplant recipients (KTR). We studied both, using data of older (≥65 years) patients waitlisted for kidney transplantation and older KTR 1 year after transplantation from the TransplantLines Biobank and Cohort Study. HRQoL was assessed using the SF-36 questionnaire. We included 145 older waitlisted patients (68% male, age 70 ± 4 years) and 115 older KTR at 1 year after transplantation (73% male, age 70 ± 4 years). Both mental (48.5 ± 8.4 versus 51.2 ± 7.7, p = 0.009) and physical (47.4 ± 8.5 versus 52.1 ± 7.2, p < 0.001) HRQoL were higher among included KTR, compared to the waitlisted patients. In paired analyses among 46 patients with HRQoL-data both before and after transplantation, there was a trend towards increased mental HRQoL (49.1 ± 8.4 to 51.6 ± 7.5, p = 0.054), and significantly increased physical HRQoL (48.1 ± 8.0 to 52.4 ± 6.7, p = 0.001) after transplantation. Among all assessed factors, the number of patient-reported immunosuppressive drug-related side effects was most strongly negatively associated with both mental and physical HRQoL. In conclusion, HRQoL is significantly higher among older KTR after kidney transplantation compared to older waitlisted patients.

Antibody and T-Cell Responses 6 Months After Coronavirus Disease 2019 Messenger RNA-1273 Vaccination in Patients With Chronic Kidney Disease, on Dialysis, or Living With a Kidney Transplant.

BACKGROUND: The immune response to COVID-19 vaccination is inferior in kidney transplant recipients (KTRs) and to a lesser extent in patients on dialysis or with chronic kidney disease (CKD). We assessed the immune response 6 months after mRNA-1273 vaccination in kidney patients and compared this to controls. METHODS: A total of 152 participants with CKD stages G4/5 (eGFR <30 mL/min/1.73 m2), 145 participants on dialysis, 267 KTRs, and 181 controls were included. SARS-CoV-2 Spike S1 specific IgG antibodies were measured using fluorescent bead-based multiplex-immunoassay, neutralizing antibodies to ancestral, Delta, and Omicron (BA.1) variants by plaque reduction, and T-cell responses by interferon-γ release assay. RESULTS: At 6 months after vaccination, S1-specific antibodies were detected in 100% of controls, 98.7% of CKD G4/5 patients, 95.1% of dialysis patients, and 56.6% of KTRs. These figures were comparable to the response rates at 28 days, but antibody levels waned significantly. Neutralization of the ancestral and Delta variants was detected in most participants, whereas neutralization of Omicron was mostly absent. S-specific T-cell responses were detected at 6 months in 75.0% of controls, 69.4% of CKD G4/5 patients, 52.6% of dialysis patients, and 12.9% of KTRs. T-cell responses at 6 months were significantly lower than responses at 28 days. CONCLUSIONS: Although seropositivity rates at 6 months were comparable to rates at 28 days after vaccination, significantly decreased antibody levels and T-cell responses were observed. The combination of low antibody levels, reduced T-cell responses, and absent neutralization of the newly emerging variants indicates the need for additional boosts or alternative vaccination strategies in KTRs. CLINICAL TRIALS REGISTRATION: NCT04741386.

The role of interleukin-21 in COVID-19 vaccine-induced B cell-mediated immune responses in patients with kidney disease and kidney transplant recipients.

T-cell-mediated help to B cells is required for the development of humoral responses, in which the cytokine interleukin (IL)-21 is key. Here, we studied the mRNA-1273 vaccine-induced SARS-CoV-2-specific memory T-cell IL-21 response, memory B cell response, and immunoglobulin (Ig)G antibody levels in peripheral blood at 28 days after the second vaccination by ELISpot and the fluorescent bead-based multiplex immunoassay, respectively. We included 40 patients with chronic kidney disease (CKD), 34 patients on dialysis, 63 kidney transplant recipients (KTR), and 47 controls. We found that KTR, but not patients with CKD and those receiving dialysis, showed a significantly lower number of SARS-CoV-2-specific IL-21 producing T cells than controls (P < .001). KTR and patients with CKD showed lower numbers of SARS-CoV-2-specific IgG-producing memory B cells when compared with controls (P < .001 and P = .01, respectively). The T-cell IL-21 response was positively associated with the SARS-CoV-2-specific B cell response and the SARS-CoV-2 spike S1-specific IgG antibody levels (both Pearson r = 0.5; P < .001). In addition, SARS-CoV-2-specific B cell responses were shown to be IL-21 dependent. Taken together, we show that IL-21 signaling is important in eliciting robust B cell-mediated immune responses in patients with kidney disease and KTR.

Nephrotoxicity of iopamidol is associated with mitochondrial impairment in human cell and teleost models.

Iopamidol is a nonionic, low-osmolar iodinated contrast agent used for angiography. Its clinical use is associated with renal dysfunction. Patients suffering from preexisting kidney disease have an increased risk of renal failure upon iopamidol administration. Studies in animals confirmed renal toxicity, but the involved mechanisms remain unclear. Therefore, the aim of the present study was to use human embryonic kidney cells (HEK293T) as a general cell model of mitochondrial damage, as well as, zebrafish larvae, and isolated proximal tubules of killifish to investigate factors promoting renal tubular toxicity of iopamidol with a focus on mitochondrial damage. Results from in vitro HEK293T cell-based assays indicate that iopamidol affects mitochondrial function Treatment with iopamidol induces ATP depletion, reduces the mitochondrial membrane potential, and elevates mitochondrial superoxide and reactive oxygen species accumulation. Similar results were obtained with gentamicin sulfate and cadmium chloride, two well-known model compounds associated with renal tubular toxicity. Confocal microscopy confirms changes in mitochondrial morphology, such as mitochondrial fission. Importantly, these results were confirmed in proximal renal tubular epithelial cells using ex vivo and in vivo teleost models. In conclusion, this study provides evidence for iopamidol-induced mitochondrial damage in proximal renal epithelial cells. Teleost models allow studying proximal tubular toxicity with translational relevance for humans.

Kidney utilization in the Netherlands - do we optimally use our donor organs?

BACKGROUND: To ensure optimal utilization of deceased donor kidneys, it is important to understand the precise reasons why kidneys are discarded. In this study we aimed to obtain a comprehensive overview of kidney utilization and discard during the entire donation process in the Netherlands. METHODS: In this retrospective cohort study we analysed kidney utilization of 3856 kidneys in the Netherlands between 1 January 2015 and 31 December 2020. For every kidney that was not transplanted, we determined the moment of and reason for discard through a unique case-by-case assessment. RESULTS: Kidney discard according to the traditional definition (procured but not transplanted) was 7.8%. However, when kidneys that seemed medically suitable at the beginning of the donation process were also included, many more potential donor kidneys were lost and the total non-utilization was 24.4%. Subjectively presumed impaired organ quality was responsible for 34.2% of all discarded kidneys. Two-thirds of kidneys discarded due to acute kidney injury (AKI) had only AKI stage 1 or 2. CONCLUSION: The classical definition of organ discard underestimates the non-utilization of deceased donor kidneys. Strategies to improve kidney utilization could be a revision of the maximum allowed agonal time in donation after circulatory death, careful consideration in reporting and accepting kidneys from donors with AKI and a prospectively filled registry of detailed organ discard reasons, including the 'silent' non-utilization before procurement.

Prediction of measured GFR after living kidney donation from pre-donation parameters.

BACKGROUND: One of the challenges in living kidney donor screening is to estimate remaining kidney function after donation. Here we developed a new model to predict post-donation measured glomerular filtration rate (mGFR) from pre-donation serum creatinine, age and sex. METHODS: In the prospective development cohort (TransplantLines, n = 511), several prediction models were constructed and tested for accuracy, precision and predictive capacity for short- and long-term post-donation 125I-iothalamate mGFR. The model with optimal performance was further tested in specific high-risk subgroups (pre-donation eGFR <90 mL/min/1.73 m2, a declining 5-year post-donation mGFR slope or age >65 years) and validated in internal (n = 509) and external (Mayo Clinic, n = 1087) cohorts. RESULTS: In the development cohort, pre-donation estimated GFR (eGFR) was 86 ± 14 mL/min/1.73 m2 and post-donation mGFR was 64 ± 11 mL/min/1.73 m2. Donors with a pre-donation eGFR ≥90 mL/min/1.73 m2 (present in 43%) had a mean post-donation mGFR of 69 ± 10 mL/min/1.73 m2 and 5% of these donors reached an mGFR <55 mL/min/1.73 m2. A model using pre-donation serum creatinine, age and sex performed optimally, predicting mGFR with good accuracy (mean bias 2.56 mL/min/1.73 m2, R2 = 0.29, root mean square error = 11.61) and precision [bias interquartile range (IQR) 14 mL/min/1.73 m2] in the external validation cohort. This model also performed well in donors with pre-donation eGFR <90 mL/min/1.73 m2 [bias 0.35 mL/min/1.73 m2 (IQR 10)], in donors with a negative post-donation mGFR slope [bias 4.75 mL/min/1.73 m2 (IQR 13)] and in donors >65 years of age [bias 0.003 mL/min/1.73 m2 (IQR 9)]. CONCLUSIONS: We developed a novel post-donation mGFR prediction model based on pre-donation serum creatinine, age and sex.

The impact of pre-transplantation nephrectomy on quality of life in patients with autosomal dominant polycystic kidney disease.

PURPOSE: In selected ADPKD patients, a nephrectomy is required in the work-up for a kidney transplantation. Because the impact of this procedure is unknown, we investigated the effect of pre-transplantation nephrectomy on quality of life in this group. METHODS: In this retrospective cohort study all ADPKD patients, ≥ 18 years, who received a kidney transplantation in 2 ADPKD expertise centers between January 2000 and January 2016, were asked to participate. Quality of life was assessed using three validated questionnaires on three time points. Nephrectomy was performed in preparation for transplantation. RESULTS: Two hundred seventy-six ADPKD patients (53 ± 9 years, 56.2% male) were included. 98 patients (35.5%) underwent native nephrectomy in preparation for transplantation, of which 43 underwent bilateral nephrectomy. Pre-transplantation, ADPKD-IS scores were worse in the nephrectomy group vs. no-nephrectomy group (physical: 2.9 vs. 2.3, p < 0.001; emotional: 2.0 vs. 1.8, p = 0.03; fatigue: 3.0 vs. 2.3, p = 0.01). Post-transplantation and post-nephrectomy, ADPKD-IS scores improved significantly in both groups, with a significantly higher improvement in the nephrectomy group. During follow-up, all scores were still better compared to pre-transplantation. Observed physical QoL (ADPKD-IS physical 1.3 vs. 1.7, p = 0.04; SF-36 physical 50.0 vs. 41.3, p = 0.03) was better post-transplantation after bilateral nephrectomy compared to unilateral nephrectomy. In retrospect, 19.7% of patients would have liked to undergo a nephrectomy, while the decision not to perform nephrectomy was made by the treating physician. CONCLUSION: This study shows that pre-transplantation nephrectomy improves quality of life in selected ADPKD patients. Bilateral nephrectomy may be preferred, although the risk of additional complications should be weighted.

The Need for Routine Native Nephrectomy in the Workup for Kidney Transplantation in Autosomal Dominant Polycystic Kidney Disease Patients.

INTRODUCTION: There is no consensus if nor when a native nephrectomy should be performed in the workup for kidney transplantation in ADPKD patients. In our PKD Expertise Center, a restrictive approach is pursued in which nephrectomy is performed only in patients with severe complaints, i.e., in case of serious volume-related complaints, lack of space for the allograft, recurrent cyst infections, persistent cyst bleedings, or chronic refractory pain. We analyzed in a retrospective cohort study whether this approach is justified. METHODS: All ADPKD patients who received kidney transplantation between January 2000 and January 2019 were reviewed. Patients were subdivided into three groups: no nephrectomy (no-Nx), nephrectomy performed before (pre-Tx), or after kidney transplantation (post-Tx). Simultaneous nephrectomy together with transplantation were not performed in our center. RESULTS: 391 patients (54 ± 9 years, 55% male) were included. The majority of patients did not undergo a nephrectomy (n = 257, 65.7%). A nephrectomy was performed pre-Tx in 114 patients (29.2%). After Tx, nephrectomy was performed in only 30 patients (7.7%, median 4.4 years post-Tx). Surgery-related complication rates did not differ between both groups (38.3% pre-Tx vs. 27.0% post-Tx, p = 0.2), nor were there any differences in 10-year patient survival (74.4% pre-Tx vs. 80.7% post-Tx vs. 67.6% no-Nx, p = 0.4), as well as in 10-year death-censored graft survival (84.4% pre-Tx vs. 85.5% post-Tx vs. 90.0% no-Nx, p = 0.9). CONCLUSIONS: This study indicates that with a restrictive nephrectomy policy in the workup for kidney transplantation, only a part of ADPKD patients need a native nephrectomy.

Zebrafish (Danio rerio) larva as an in vivo vertebrate model to study renal function.

There is an increasing interest in using zebrafish (Danio rerio) larva as a vertebrate screening model to study drug disposition. As the pronephric kidney of zebrafish larvae shares high similarity with the anatomy of nephrons in higher vertebrates including humans, we explored in this study whether 3- to 4-day-old zebrafish larvae have a fully functional pronephron. Intravenous injection of fluorescent polyethylene glycol and dextran derivatives of different molecular weight revealed a cutoff of 4.4-7.6 nm in hydrodynamic diameter for passive glomerular filtration, which is in agreement with corresponding values in rodents and humans. Distal tubular reabsorption of a FITC-folate conjugate, covalently modified with PEG2000, via folate receptor 1 was shown. Transport experiments of fluorescent substrates were assessed in the presence and absence of specific inhibitors in the blood systems. Thereby, functional expression in the proximal tubule of organic anion transporter oat (slc22) multidrug resistance-associated protein mrp1 (abcc1), mrp2 (abcc2), mrp4 (abcc4), and zebrafish larva p-glycoprotein analog abcb4 was shown. In addition, nonrenal clearance of fluorescent substrates and plasma protein binding characteristics were assessed in vivo. The results of transporter experiments were confirmed by extrapolation to ex vivo experiments in killifish (Fundulus heteroclitus) proximal kidney tubules. We conclude that the zebrafish larva has a fully functional pronephron at 96 h postfertilization and is therefore an attractive translational vertebrate screening model to bridge the gap between cell culture-based test systems and pharmacokinetic experiments in higher vertebrates.NEW & NOTEWORTHY The study of renal function remains a challenge. In vitro cell-based assays are approved to study, e.g., ABC/SLC-mediated drug transport but do not cover other renal functions such as glomerular filtration. Here, in vivo studies combined with in vitro assays are needed, which are time consuming and expensive. In view of these limitations, our proof-of-concept study demonstrates that the zebrafish larva is a translational in vivo test model that allows for mechanistic investigations to study renal function.

Early increase in single-kidney glomerular filtration rate after living kidney donation predicts long-term kidney function.

Single-kidney glomerular filtration rate (GFR) increases after living kidney donation due to compensatory hyperfiltration and structural changes. The implications of inter-individual variability in this increase in single-kidney GFR are unknown. Here, we aimed to identify determinants of the increase in single-kidney GFR at three-month postdonation, and to investigate its relationship with long-term kidney function. In a cohort study in 1024 donors, we found considerable inter-individual variability of the early increase in remaining single-kidney estimated GFR (eGFR) (median [25th-75th percentile]) 12 [8-18] mL/min/1.73m2. Predonation eGFR, age, and cortical kidney volume measured by CT were the main determinants of the early postdonation increase in single-kidney eGFR. Individuals with a stronger early increase in single-kidney eGFR had a significantly higher five-year postdonation eGFR, independent of predonation eGFR and age. Addition of the postdonation increase in single-kidney eGFR to a model including predonation eGFR and age significantly improved prediction of a five-year postdonation eGFR under 50 mL/min/1.73m2. Results at ten-year follow-up were comparable, while accounting for left-right differences in kidney volume did not materially change the results. Internal validation using 125I-iothalamate-based measured GFR in 529 donors and external validation using eGFR data in 647 donors yielded highly similar results. Thus, individuals with a more pronounced increase in single-kidney GFR had better long-term kidney function, independent of predonation GFR and age. Hence, the early postdonation increase in single-kidney GFR, considered indicative for kidney reserve capacity, may have additional value to eGFR and age to personalize follow-up intensity after living kidney donation.

CD163 and CD206 expression define distinct macrophage subsets involved in active ANCA-associated glomerulonephritis.

INTRODUCTION: Macrophages are key players in the immunopathology of anti-neutrophil cytoplasmic antibody (ANCA) mediated-vasculitis (AAV) with glomerulonephritis (ANCA GN). Different macrophage phenotypes are expected to play distinct roles in ANCA GN. Macrophages expressing CD163 and CD206 are found in lesions associated with ANCA GN. Hence, we aimed to investigate the clinicopathological significance of CD206 and CD163 in ANCA GN in a multicenter retrospective cohort study. MATERIAL AND METHODS: Patients with ANCA-associated vasculitis, with clinical data, serum and urine samples were included from three cohorts. Serum soluble CD206 (ssCD206) and urinary soluble CD163 (usCD163) levels were measured. Human kidney tissue samples (n = 53) were stained for CD206 and CD163 using immunohistochemistry and immunofluorescence, and findings were correlated with clinical and pathological data. RESULTS: In total, 210 patients were included (i.e., ANCA GN, n = 134; AAV without GN, n = 24; AAV in remission n = 52). Increased levels of both ssCD206 and usCD163 were seen in ANCA GN. High levels of ssCD206 declined after reaching remission, however, ssCD206 did not improve the accuracy of usCD163 to detect ANCA GN. Soluble markers correlated with histopathological findings. CD163+CD206- macrophages were found in the glomerulus and may play pivotal roles in glomerulonephritis, whereas CD206+CD163- and CD206+CD163+ macrophages were located tubulointerstitially and likely play a more prominent role in ANCA-associated tubulointerstitial inflammation. In ANCA GN patients increasing levels of ssCD206 increased the risk for end-stage renal disease and mortality. CONCLUSIONS: Our results confirm and extend the notion that CD206+ and CD163+ macrophages are prominent components of the cellular infiltrate in ANCA GN. We found distinct macrophage phenotypes that may play distinct roles in the immunopathology of ANCA GN and elaborate on a potential mechanism underlying the findings of this study. usCD163 remains an excellent marker to detect active ANCA GN, whereas ssCD206 seems a more prominent marker for risk prediction.

Identification of novel inner membrane complex and apical annuli proteins of the malaria parasite Plasmodium falciparum.

The inner membrane complex (IMC) is a defining feature of apicomplexan parasites, which confers stability and shape to the cell, functions as a scaffolding compartment during the formation of daughter cells and plays an important role in motility and invasion during different life cycle stages of these single-celled organisms. To explore the IMC proteome of the malaria parasite Plasmodium falciparum we applied a proximity-dependent biotin identification (BioID)-based proteomics approach, using the established IMC marker protein Photosensitized INA-Labelled protein 1 (PhIL1) as bait in asexual blood-stage parasites. Subsequent mass spectrometry-based peptide identification revealed enrichment of 12 known IMC proteins and several uncharacterized candidate proteins. We validated nine of these previously uncharacterized proteins by endogenous GFP-tagging. Six of these represent new IMC proteins, while three proteins have a distinct apical localization that most likely represents structures described as apical annuli in Toxoplasma gondii. Additionally, various Kelch13 interacting candidates were identified, suggesting an association of the Kelch13 compartment and the IMC in schizont and merozoite stages. This work extends the number of validated IMC proteins in the malaria parasite and reveals for the first time the existence of apical annuli proteins in P. falciparum. Additionally, it provides evidence for a spatial association between the Kelch13 compartment and the IMC in late blood-stage parasites.

Longitudinal monitoring of BKPyV miRNA levels in kidney transplant recipients with BKPyV-related pathology reflects viral DNA levels and remain high in viremia patients after clearance of viral DNA.

INTRODUCTION: It is unclear whether polyomavirus BK (BKPyV) microribonucleic acid (miRNA) measurement has additional diagnostic and predictive value in kidney transplant recipients (KTR) as compared to current methods of monitoring BKPyV DNA loads. PATIENTS AND METHODS: A retrospective, longitudinal study was performed in 30 KTR with BKPyV viruria (n = 10), BKPyV viremia (n = 10), or BKPyV-associated neuropathy (BKPyVAN) (n = 10). Bkv-miR-B1-3p and 5p and BKPyV DNA load were measured in urine and plasma and compared using receiver operating characteristic (ROC) curves. RESULTS: Levels of Bkv-miR-B1-3p and 5p and BKPyV DNA correlated strongly. Overall, mostly analog courses of urinary and plasma miRNA and DNA loads were observed. Areas under the ROC curves were not significantly different between miRNAs and DNA. Only, in contrast to BKPyV DNA load, BKPyV miRNA levels increased from 6 to 12 months in the viremia group, while in the BKPyVAN group, a decline was seen in both DNA and miRNA. CONCLUSIONS: In this study, we could not demonstrate an additional value of BKPyV miRNA detection compared to BKPyV DNA monitoring in the early phase after kidney transplantation. We did observe significant differences between the viremia and the BKPyVAN groups during follow-up. This study was performed with a small number of patients and therefore results should be verified in a larger patient cohort. Furthermore, future studies with larger patient groups are necessary to elucidate final clinical value of these data.

Implementing evidence into practice to improve chronic lung disease management in Indigenous Australians: the breathe easy, walk easy, lungs for life (BE WELL) project (protocol).

BACKGROUND: Strong evidence exists for the benefits of pulmonary rehabilitation (PR) for people with chronic obstructive pulmonary disease (COPD), however the availability of culturally safe PR for Aboriginal and Torres Strait Islander (Indigenous) Peoples is limited. The study aims to determine whether PR can be implemented within Aboriginal Community Controlled Health Services (ACCHS) to improve outcomes for Indigenous people with COPD. METHODS: Multi-centre cohort study using participatory action research guided by the Knowledge-to-Action Framework. ACCHS supportive of enhancing services for chronic lung disease will be recruited. Aboriginal Health Workers (AHW) and the exercise physiologist (EP) or physiotherapist (PT) within these ACCHS will attend a workshop aimed at increasing knowledge and skills related to management of COPD and the provision of PR. Indigenous people with COPD will be invited to attend an 8-week, twice weekly, supervised PR program. OUTCOMES: AHW, EP/PT knowledge, skills and confidence in the assessment and management of COPD will be measured before and immediately after the BE WELL workshop and at 3, 6 and 12 months using a survey. PR participant measures will be exercise capacity (6-minute walk test (6MWT), health-related quality of life and health status at commencement and completion of an 8-week PR program. Secondary outcomes will include: number, length and cost of hospitalisations for a COPD exacerbation in 12-months prior and 12-months post PR; local contextual factors influencing implementation of PR; specific respiratory services provided by ACCHS to manage COPD prior to project commencement and at project completion. Repeated measures ANOVA will be used to evaluate changes in knowledge and confidence over time of AHWs and EP/PTs. Paired t-tests will be used to evaluate change in patient outcomes from pre- to post-PR. Number of hospital admissions in the 12 months before and after the PR will be compared using unpaired t-tests. DISCUSSION: Pulmonary rehabilitation is an essential component of best-practice management of COPD and is recommended in COPD guidelines. Indigenous peoples have limited access to culturally safe PR programs. This study will evaluate whether PR can be implemented within ACCHS and improve outcomes for Indigenous people with COPD. Trial registration Australian New Zealand Clinical Trials Registry (ANZCTR) ACTRN12617001337369, Registered 2nd September 2017 https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=373585&isClinicalTrial=False.