Genomic testing in patients with renal disease.

Inherited kidney disease accounts for a significant proportion of chronic kidney disease and end-stage renal failure. There is increasing evidence that genetic testing for inherited kidney disease should be integrated into clinical care pathways at the earliest opportunity so that patients and their families can maximally benefit from carefully tailored care. Despite increased availability of genetic testing, the proportion of patients with renal disease undergoing genetic investigations remains low. This article introduces key concepts of genetic and genomic testing to the renal physician and addresses some common barriers to the wider integration of genetic testing in routine clinical practice to fully capitalise on recent advances in genomic medicine and improve patient outcomes.

Nesting Ecology and Colony Survival of Two Invasive Polistes Wasps (Hymenoptera: Vespidae) in New Zealand.

We examined the abundance, nesting ecology, and colony survival of two invasive species of paper wasp, Polistes dominula Christ (Hymenoptera: Vespidae) and Polistes chinensis Pérez (Hymenoptera: Vespidae), within their invaded range in New Zealand. The more recent invader, P. dominula, exhibited a strong habitat preference, reaching the highest abundances within suburban areas with an average of 87.4 wasps per 1,000 m2. Coastal habitats were also found to be suitable environments for P. dominula, although wasp abundance in these areas was comparatively lower than suburban sites at 26.5 wasps per 1,000 m2. Although P. chinensis were observed to build more nests in coastal habitats, this was not reflected in the abundance of adult wasps in these areas. Nests of P. dominula were larger and more productive, likely a result of the multiple founding and earlier emergence of workers compared to P. chinensis. Both species exhibited significant differences in nest survival, with P. dominula observed to have a higher colony survival rate, particularly in suburban habitats where this species utilized man-made substrates as nesting sites. Neither species nested within forest sites and translocated nests of P. dominula failed to thrive within forest habitats. Findings of this research suggest that P. dominula will not pose a threat to species inhabiting forested areas. Instead, biodiversity managers should focus their efforts on suburban and coastal environments as native species in these areas will require the greatest protection.

Bioclimatic Modelling Identifies Suitable Habitat for the Establishment of the Invasive European Paper Wasp (Hymenoptera: Vespidae) across the Southern Hemisphere.

Species distribution models (SDMs) are tools used by ecologists to help predict the spread of invasive species. Information provided by these models can help direct conservation and biosecurity efforts by highlighting areas likely to contain species of interest. In this study, two models were created to investigate the potential range expansion of Polistes dominula Christ (Hymenoptera: Vespidae) in the southern hemisphere. This palearctic species has spread to invade North and South America, South Africa, Australia, and more recently New Zealand. Using the BIOCLIM and MAXENT modelling methods, regions that were suitable for P. dominula were identified based on climate data across four regions in the southern hemisphere. In South America areas of central Chile, eastern Argentina, parts of Uruguay, and southern Brazil were identified as climatically suitable for the establishment of P. dominula. Similarly, southern parts of South Africa and Australia were identified by the model to be suitable as well as much of the North Island and east of the South Island of New Zealand. Based on outputs from both models, significant range expansion by P. dominula is possible across its more southern invaded ranges.

Investigating the relationship between class I HLA-specific immunoglobulin-G subclasses, Pan-IgG single antigen bead assays and complement mediated interference in sera from renal transplant recipients.

INTRODUCTION: Antibody mediated rejection is the leading cause of kidney transplant failure. Not all antibodies are harmful and some may be protective. Immunoglulin Gs, of which there are four subtypes, are detected by single antigen bead testing. The aims of this study were to characterise the IgG subclass profiles for class I HLA-specific antibodies in an uncensored post-transplant population and to determine the underlying relationship between reactivity patterns and MFI cut-offs with the pan-IgG assay. METHODS: Patients were recruited to the study who were transplanted in our centre between 2009 and 2014. Prospectively stored post-transplant serum initially underwent a Labscreen Mixed assay and those positive for class I HLA-specific antibody underwent standard SAB testing, EDTA, 1 in 10 dilution and IgG subclass modifications using the Luminex platform. A total of 4947 bead reactions from 51 patients were analysed. RESULTS: A 1 in 10 dilution was used as a comparator pan-IgG assay for summed subclass and individual subclass linear regression analyses. Using a dilution to standard assay ratio we characterised all reactions for prozone potential i.e. how likely there is to be inhibition related to complement complex formation. We stratified samples into degrees of association and were able to determine suggested MFI thresholds of Log 5.35 for the dilution assay and Log 5.05 for the summed subclass assay when considering a Log MFI of 6.9 (1000) in the standard assay. Using individual subclass dominant reactions (>70%) we were able to determine linear relationships between the 1 in 10 dilution pan-IgG assay and the individual subclass assays (excluding prozone potential reactions for IgG1/3) enabling us to suggest Log MFI thresholds of 5.03, 3.58, 4.3 and 4.05 respectively for IgG1-4. DISCUSSION: We recommend a 1 in 10 dilution as the optimum pan-IgG comparator assay for a subclass analysis. We advocate the utilisation of the summed subclass assay to determine overall relationships and potential subclass failures. Following others, we recommend serum pre-treatment of the subclass assays to mitigate prozone. We suggest cut-offs for each IgG subclass which should be used with caution given the many inhibitory influences which may include competitive inhibition for bead binding, IgM and IgA interference and under-representation of specific subclasses on the bead panel.

Investigating complement mediated interference in class I HLA-specific antibodies following renal transplantation.

INTRODUCTION: Single antigen bead testing (SAB) for HLA-specific antibody enables efficient organ allocation and aids in the diagnosis of antibody mediated rejection. In this retrospective cohort study, a population of kidney transplant recipients possessing HLA Class I antibodies was used to evaluate the best method for resolving complement interference, the so called "prozone" effect. The aim was to compare the use of EDTA versus a Biotin-Streptavidin Complex as methodological approaches for abating the prozone effect using a fixed 1 in 10 dilution as validation. METHODS: One hundred and seventeen patients transplanted in our centre between 2009 and 2014 were identified as having class I HLA-specific antibody(-ies) using a Labscreen® Mixed assay. Positive sera underwent class I HLA-specific SAB testing; for comparison a standard SAB with and without EDTA, BSC and dilution (1 in 10) modifications were utilised. Samples were processed on the Luminex platform generating 11,349 bead reactions for analysis. RESULTS: We identified sera from 23 patients giving rise to 170 bead reactions showing complement interference. Using linear modelling, we observed slightly higher MFIs on average in both EDTA and BSC modifications when compared to the standard assay, allowing the nominal threshold MFI of 2000 in the standard assay to be adjusted to 2097 and 2033 in the EDTA and BSC assays respectively. We calculated 99% prediction intervals to establish outlier bead reactions for each assay. The 1 in 10 dilution was used as a crosscheck for determining which prozone reactions were overcome by EDTA and BSC. Using ROC curve analysis, EDTA was found to be ~90% sensitive and 100% specific compared to BSC which was ~60% sensitive and 100% specific in ameliorating prozone positive reactions at the thresholds defined by linear models. DISCUSSION: Our data indicates that both EDTA and BSC are suitable assays in overcoming CMI. We recommend that all clinical laboratories adopt a validated assay designed specifically to abrogate CMI for all potential renal transplant recipients, as the standard assay is inhibited in nearly 20% of a post-transplant cohort.

A study to describe the health trajectory of patients with advanced renal disease who choose not to receive dialysis.

BACKGROUND: Some patients with end-stage renal failure (ESRF) are unlikely to benefit from dialysis and conservative management (CM) is offered as a positive alternative. Understanding the trajectory of illness by health care professionals may improve end-of-life care. METHODS: We aimed to describe the trajectory of functional status within our CM population through a prospective, observational study using the objective Timed Up and Go (TUG) test and subjective Barthel Index (BI) and health-related quality of life (HRQoL) [EuroQol 5D-5L (EQ-5D-5L)] measurements and correlating them with demographic and laboratory data and with sentinel events. RESULTS: There was a significant increase in TUG scores over the 6 months prior to death {2.24 [95% confidence interval (CI) 1.16-4.32], P = 0.017} and a significant decrease in EQ-5D-5L [-0.19 (95% CI -0.33 to -0.06), P = 0.006]. The only significant associations with mortality were serum albumin [hazard ratio (HR) 0.81 (95% CI 0.67-0.97), P = 0.024] and male gender [HR 5.94 (95% CI 1.50-23.5), P = 0.011]. CONCLUSIONS: We have shown there is a significant decline in functional status in the last 6 months before death in the CM population. Of interest, there was a significant relationship of lower serum albumin with functional decline and risk of death. We hope that with improved insight into disease trajectories we can improve our ability to identify and respond to the changes in needs of these patients, facilitate complex and sensitive end-of-life discussions and improve end-of-life care.

The DESCARTES-Nantes survey of kidney transplant recipients displaying clinical operational tolerance identifies 35 new tolerant patients and 34 almost tolerant patients.

BACKGROUND: Kidney recipients maintaining a prolonged allograft survival in the absence of immunosuppressive drugs and without evidence of rejection are supposed to be exceptional. The ERA-EDTA-DESCARTES working group together with Nantes University launched a European-wide survey to identify new patients, describe them and estimate their frequency for the first time. METHODS: Seventeen coordinators distributed a questionnaire in 256 transplant centres and 28 countries in order to report as many 'operationally tolerant' patients (TOL; defined as having a serum creatinine <1.7 mg/dL and proteinuria <1 g/day or g/g creatinine despite at least 1 year without any immunosuppressive drug) and 'almost tolerant' patients (minimally immunosuppressed patients (MIS) receiving low-dose steroids) as possible. We reported their number and the total number of kidney transplants performed at each centre to calculate their frequency. RESULTS: One hundred and forty-seven questionnaires were returned and we identified 66 TOL (61 with complete data) and 34 MIS patients. Of the 61 TOL patients, 26 were previously described by the Nantes group and 35 new patients are presented here. Most of them were noncompliant patients. At data collection, 31/35 patients were alive and 22/31 still operationally tolerant. For the remaining 9/31, 2 were restarted on immunosuppressive drugs and 7 had rising creatinine of whom 3 resumed dialysis. Considering all patients, 10-year death-censored graft survival post-immunosuppression weaning reached 85% in TOL patients and 100% in MIS patients. With 218 913 kidney recipients surveyed, cumulative incidences of operational tolerance and almost tolerance were estimated at 3 and 1.5 per 10 000 kidney recipients, respectively. CONCLUSIONS: In kidney transplantation, operational tolerance and almost tolerance are infrequent findings associated with excellent long-term death-censored graft survival.

Adiponectin gene expression in human primary adipocyte culture treated with uremic serum.

End-stage renal disease (ESRD) is accompanied by an increased rate of morbidity and mortality due to cardiovascular disease (CVD). Although renal replacement therapy is required at this stage, it is associated with additional complications such as inflammation and dyslipidemia. It has been suggested that adiponectin has anti-inflammatory properties. We studied the potential role of uremic mileu on the adiponectin expression in human primary adipocyte culture. A cohort of 18 patients with ESRD (hemo-and peritoneal dialysis) and nine healthy controls were analyzed in a prospective cross-sectional study. Single blood samples were taken pre-and post-hemodialysis and in peritoneal dialysis patients. Serum concentrations of total adiponectin (7.95 ± 1.44 µg/mL; 6.73 ± 1.2 µg/mL; 13.7 ± 3.04 µg/mL, respectively) and high molecular weight adiponectin (3.03 ± 1.95 µg/mL; 3.57 ± 2.44 14 µg/mL; 8.02 ± 5 µg/mL respectively) were measured. Other biochemical parameters (cholesterol, low-density lipoprotein cholesterol and triglycerides) were assessed in all groups of patients. Adiponectin gene expression was determined using real-time polymerase chain reaction, and was found to be lower in ESRD patients compared with healthy controls with low dose but not with high-dose treatments. Serum concentrations of total adiponectin and high molecular weight adiponectin were significantly higher in the ESRD versus control group. These results provide an initial insight into understanding the putative role of adipose tissue in contributing to the association of CVD risk in patients with chronic kidney disease.

Is blood ammonia influenced by kidney function? A prospective study.

BACKGROUND: We have investigated whether blood ammonia is increased with worsening CKD. METHODS: Fifty eight subjects with a range of CKD were recruited for analysis of plasma ammonia and other electrolytes. RESULTS: The concentrations of plasma ammonia were all within the normal reference range and there was no correlation between ammonia and CKD without any effect of dialysis. CONCLUSIONS: Blood ammonia is not elevated in or related to the severity of chronic kidney disease.

The severity of pseudohyperkalaemia is not dependent upon the stage of chronic kidney disease: a prospective study.

BACKGROUND: Pseudohyperkalaemia may result from delay in centrifugation and storage at 4°C. We investigated whether the stage of chronic kidney disease (CKD), its aetiology or medications influence this. METHODS: Seventy-seven patients with CKD were recruited. Lithium heparin plasma samples were analysed for sodium, potassium, urea and creatinine, chloride, bicarbonate, magnesium, calcium and inorganic phosphate at 0 h and after storage of whole blood at 4°C for 6 h and 20 h. K-EDTA and fluoride-EDTA samples were analysed for full blood count and glucose at 0 h. CKD stage was determined by standard criteria. RESULTS: K(+) increased on average by 1.0 and 3.6 mmol/L after 6 and 20 h storage of whole blood at 4°C, independent of cause or stage of CKD. K(+) increase at 6 h was correlated with haemoglobin but not with white blood cell count, platelet count or glucose. Patients taking ACE inhibitors and/or angiotensin receptor blockers (ARBs) had slightly higher K(+) at 0 h and increased K(+) after storage for 6 h. Na(+) decreased on average by 3.8 mmol/L at 20 h and was independent of CKD stage, and correlated with K(+) increase. CONCLUSIONS: K(+) increased significantly with time in samples stored at 4°C in all stages of CKD. This was greater in some patients on ACE inhibitors and ARBs, and increased with haemoglobin, but was not related to the stage of CKD, white blood cell count or platelet count for the samples used in this study.

'Septrin psychosis' among renal transplant patients with Pneumocystis jirovecii pneumonia.

OBJECTIVES: To report on the temporal relationship between administration of trimethoprim/sulfamethoxazole to medically immunosuppressed HIV-negative renal patients with Pneumocystis jirovecii pneumonia (PCP) and the development of an acute psychosis. METHODS: We investigated a retrospective case series of renal transplant and immunosuppressed patients with PCP within an ongoing outbreak in the northwest of England since 2009. Four patients with PCP developed psychosis following treatment with trimethoprim/sulfamethoxazole. RESULTS: Four of twenty patients developed acute psychoses following administration of trimethoprim/sulfamethoxazole, including one accidental re-challenge. Symptoms resolved within 24 h of changing the therapy. The striking temporal relationship between the initiation and discontinuation of the drug and the behavioural changes suggests a causal relationship. CONCLUSIONS: With increasing solid organ transplantation and the use of immunosuppressants, vigilance regarding trimethoprim/sulfamethoxazole dose modification is required and the routine use of therapeutic drug monitoring should be considered.

Successful management of recurrent pregnancy-related thrombotic thrombocytopaenia purpura in a renal transplant recipient.

Thrombotic thrombocytopaenic purpura (TTP) is a rare but potentially devastating complication of pregnancy. We report the first documented case of a successful treatment of recurrent TTP complicating pregnancy in a renal transplant patient.

The antiproteinuric effect of losartan is systemic blood pressure dependent.

BACKGROUND: It has been suggested that high doses of angiotensin II receptor antagonists (AIIAs) may reduce proteinuria by a non-haemodynamic action additional to their effect on systemic blood pressure. METHODS: We tested this for the AIIA losartan using a prospective single-blind randomized design in patients with proteinuria (>1 g/24 h) due to non-diabetic chronic renal failure (stable creatinine clearance >20 ml/min) and mild to moderate hypertension (130/80 < blood pressure < 160/110 mmHg). Twenty-one patients were randomized into two groups: group A received losartan 50 mg daily for 4 weeks, then 100 mg daily for 4 weeks; group B received losartan 50 mg daily for 8 weeks. Twenty-four hour ambulatory blood pressure and renal parameters were measured at baseline and at 4 and 8 weeks of treatment. RESULTS: Overall there was a 7 +/- 2 mmHg fall (mean +/- SEM) in mean daytime systolic blood pressure at 4 weeks, and a 22 +/- 7% fall in protein/creatinine ratio (both P < 0.05), with no difference between groups A and B or between 4 and 8 weeks. These two changes were highly correlated (r = 0.64, P = 0.006, taking both groups together). Changes in diastolic pressure and in night-time systolic pressure did not reach statistical significance. Changes in renal plasma flow (measured by Tc 99m MAGIII), glomerular filtration rate and filtration fraction (measured by 51Cr EDTA) did not reach statistical significance, did not differ between the two groups and did not correlate with effects on proteinuria. CONCLUSION: This study provides no evidence that the effect of losartan on proteinuria has a non-haemodynamic component.