Atypical hemolytic uremic syndrome : update on the complement system and what is new

Atypical hemolytic uremic syndrome (aHUS) is a rare disease of microangiopathic hemolytic anemia, thrombocytopenia, and predominant renal impairment. It is characterized by the absence of Shiga toxin-producing bacteria as a triggering factor. During the last decade, aHUS has been demonstrated to be a disorder of the complement alternative pathway dysregulation, as there is a growing list of mutations and polymorphisms in the genes encoding the complement regulatory proteins that alone or in combination may lead to aHUS. Approximately 60% of aHUS patients have so-called 'loss-of-function' mutations in the genes encoding the complement regulatory proteins, which normally protect host cells from complement activation: complement factor H (CFH), factor I (CFI) and membrane cofactor protein (MCP or CD46), or have 'gain-of-function' mutations in the genes encoding the complement factor B or C3. In addition, approximately 10% of aHUS patients have a functional CFH deficiency due to anti-CFH antibodies. Recent advances in understanding the pathogenesis of aHUS have led to a revised classification of the syndrome. Normal plasma levels of CFH and CFI do not preclude the presence of a mutation in these genes. Further, genotype-phenotype correlations of aHUS have clinical significance in predicting renal recovery and transplant outcome. Therefore, it is important to make a comprehensive analysis and perform genetic screening of the complement system in patients with aHUS to allow a more precise approach, especially before transplantation. This may also provide opportunities for more specific treatments in the near future, as complement inhibition could represent a therapeutic target in these patients who have a considerably poor prognosis in terms of both mortality and progression to end-stage renal disease and a great risk of disease recurrence after transplantation

Haemolytic uraemic syndrome caused by factor H mutation: is single kidney transplantation under intensive plasmatherapy an option?

Complement factor H (CFH) mutation is one of the causes of atypical haemolytic uraemic syndrome (aHUS). Patients with CFH mutation-associated aHUS progress often to end-stage renal disease despite plasma exchange therapy. When such patients are transplanted, aHUS recurs almost invariably and causes graft failure making the rationale of single kidney allograft transplantation questionable. Since CFH is synthesized mostly by the liver, combined liver-kidney transplantation has been recommended. However, fatal outcomes have been reported using this strategy. We report a case of successful single kidney allograft transplantation in a patient with a CFH gene mutation (R1210C), who had end-stage renal failure after three flares of aHUS treated with plasma exchange. He received peri- and postoperative infusions of fresh frozen plasma, which to date has prevented recurrence of the disease. He has preserved renal function 1-year post-transplan

Case Report: Lipoprotein Glomerulopathy Complicated by Atypical Hemolytic Uremic Syndrome.

Lipoprotein glomerulopathy (LPG) is a rare inherited disease caused by mutations in the APOE gene, encoding apolipoprotein E (apoE). Atypical hemolytic uremic syndrome (aHUS) is a thrombotic microangiopathy (TMA) characterized by overactivation of the alternative complement pathway. Here we report the case of a 21-year-old man with LPG who developed aHUS. A functional complement assay demonstrated an overactivation of the complement system. Complementary genetic analysis revealed a homozygous aHUS risk allele for complement factor-H related 1 (CFHR1), CFHR1*B. To the best of our knowledge, this is the first report of an aHUS in a patient with LPG

Bile Cast Nephropathy: The Unknown Dangers of Online Shopping

Renal dysfunction in the setting of cholestatic liver disease is multifactorial but most often due to decreased kidney perfusion from intravascular volume depletion, acute tubular injury/necrosis, and hepatorenal syndrome. Drug-induced hepatotoxicity may be associated with a cholestatic injury pattern. We report a case of a 56-year-old man with a diagnosis of bile cast nephropathy, as a complication of drug-induced severe hyperbilirubinemia due to the abuse of intramuscular anabolic steroids bought on the internet to increase muscular mass for bodybuilding training. Kidney biopsy showed the histological pattern of diffuse potentially reversible tubular damage with intratubular bile casts obstructing the renal tubules. The patient developed acute kidney injury and needed dialysis treatment for 4 weeks until renal function recovered. The severity of the kidney injury and the requirement of hemodialysis observed in our patient are unique and have not been previously described. As full recovery of renal function is suspected with decreasing bilirubin levels, early recognition and treatment of the underlying disease is essential

Correlation of serum and urinary matrix metalloproteases/tissue inhibitors of metalloproteases with subclinical allograft fibrosis in renal transplantation

Progressive interstitial fibrosis and tubular atrophy (IF/TA) is a leading cause of chronic allograft dysfunction. Increased extracellular matrix remodeling regulated by matrix metalloproteases (MMPs) and their inhibitors (TIMPs) has been implicated in the development of IF/TA. The aim of this study was to investigate whether urinary/serum MMPs/TIMPs correlate with subclinical IF/TA detected in surveillance biopsies within the first 6months post-transplant. We measured eight different MMPs/TIMPs simultaneously in urine and serum samples from patients classified as normal histology (n=15), IF/TA 1 (n=15) and IF/TA 2-3 (n=10). There was no difference in urinary MMPs/TIMPs among the three groups, and only 1/8 serum MMPs/TIMPs (i.e. MMP-1) was significantly elevated in biopsies with IF/TA 2-3 (p=0.01). In addition, urinary/serum MMPs/TIMPs were not different between surveillance biopsies demonstrating an early development of IF/TA (i.e. delta IF/TA≥1 compared to a previous biopsy obtained three months before; n=11) and stable grade of IF/TA (i.e. delta IF/TA=0; n=20). Next, we investigated whether urinary/serum MMP/TIMP levels are elevated during acute subclinical tubulitis in surveillance biopsies obtained within the first 6months post-transplant (n=25). Compared to biopsies with normal histology, serum MMPs/TIMPs were not different; however, all urinary MMP/TIMP levels were numerically higher during subclinical tubulitis (MMP-1, MMP-7, TIMP-1 with p≤0.04). We conclude that urinary/serum MMPs/TIMPs do hardly correlate with existing or early developing IF/TA in surveillance biopsies obtained within the first 6months post-transplant. This could be explained by the dynamic process of extracellular matrix remodeling, which seems to be active during acute tubulo-interstitial injury/inflammation, but not in quiescent IF/TA

Haemolytic uraemic syndrome caused by factor H mutation : is single kidney transplantation under intensive plasmatherapy an option?

Complement factor H (CFH) mutation is one of the causes of atypical haemolytic uraemic syndrome (aHUS). Patients with CFH mutation-associated aHUS progress often to end-stage renal disease despite plasma exchange therapy. When such patients are transplanted, aHUS recurs almost invariably and causes graft failure making the rationale of single kidney allograft transplantation questionable. Since CFH is synthesized mostly by the liver, combined liver-kidney transplantation has been recommended. However, fatal outcomes have been reported using this strategy. We report a case of successful single kidney allograft transplantation in a patient with a CFH gene mutation (R1210C), who had end-stage renal failure after three flares of aHUS treated with plasma exchange. He received peri- and postoperative infusions of fresh frozen plasma, which to date has prevented recurrence of the disease. He has preserved renal function 1-year post-transplant

Outcome of kidney transplantation from senior deceased donors: a single centre study

BACKGROUND: Addressing the current demographic development, the efficacy and safety of kidney transplantations from very senior donors needs to be carefully evaluated. The aim of this study was to analyse patient and graft outcomes of kidney allograft recipients stratified by donor age. METHODS: We retrospectively investigated n = 491 patients from a prospective, observational renal transplant cohort. Patients with kidneys from very old donors (n = 75, aged >70 years), elderly donors (n = 158, between 60–70 years), and regular donors (n = 258, aged <60 years) were investigated. The primary outcome was death-censored graft survival within the predefined donor age groups. RESULTS: Overall, n = 57 death-censored graft losses occurred. Graft loss was proportionally highest in the very old donor group (n = 11/75), but this did not reach statistical significance when compared to the elderly (14/158) and regular donor groups (32/258); (p = 0.37). Kaplan-Meier analysis demonstrated that 3-year/5-year death-censored graft survival in the very old donor group was 96%/86% and did not differ from the other age groups (p = 0.44). Median estimated glomerular filtration rate (eGFR), calculated by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula (in ml/min/1.73 m2 of body surface) 12 months post-transplant did not differ between the elderly donor and very old donor groups (p = 0.53). However, patients who received regular donor kidneys had higher median eGFR compared to recipients in both the elderly and very old donor groups (p <0.0001). During follow-up, 31% of patients developed at least one acute rejection episode. Time-to-event analysis demonstrated no difference in occurrence of any acute rejection event across all three groups (p = 0.11). CONCLUSIONS: This study demonstrates that kidney transplantation from carefully selected very old donors seems a valid option with reasonable short- and mid-term outcomes

Differences Between Centers in Psychosocial Evaluations for Living Kidney Donors Do Not Influence Outcome: Results From an Observational Multicenter Study

Rather little is known about how psychosocial evaluations for living kidney donation (LKD) are performed. We aimed to explore whether Swiss transplant centers (STCs) vary regarding the rate of living kidney donors refused for psychosocial reasons, the psychosocial evaluation process, and the characteristics of the donors. Methods: We investigated 310 consecutive candidates for LKD in 4 of 6 existing STC during mandatory psychosocial evaluations. We registered (i) sociodemographic data, (ii) the type of the decision-making process regarding LKD (ie, snap decision, postponed, deliberate, other), (iii) the evaluator's perception of the donor's emotional bonding and his/her conflicts with the recipient, (iv) the donor's prognosis from a psychosocial perspective, (v) time taken for the psychosocial evaluation, and (vi) its result (eligible, eligible with additional requirements, not eligible). Results: Centers had comparable proportions of noneligible donors (2.9%-6.0%) but differed significantly in the percentage of donors accepted with additional requirements (3.4%-66%, P < 0.001). Significant differences emerged between centers regarding the time needed for evaluation (75-160 min [interquartile range (IQR) 75-180 min] per single exploration, P < 0.001), the perception of the donor's emotional bonding (visual analogue scale [VAS] 8-9 [IQR 6-10], P < 0.001), his/her conflicts with the recipient (VAS 1.5-2 [IQR 0-3], P = 0.006), the donor's psychosocial prognosis (VAS 8-9 [IQR 7-10], P < 0.001), and the type of decision concerning LKD (59%-82% with snap decision "yes," P = 0.008). However, despite differences in the psychosocial evaluation process, the rates of patients accepted for transplantation (eligible and eligible with additional requirements versus noneligible) were comparable across STC (P = 0.72). Conclusions: Our results emphasize that it is more important to establish clear guidelines to identify potential psychosocial risks than to stringently standardize the procedure for psychosocial evaluation of living kidney donors

Adherence to, and patient convenience of, prolonged-release tacrolimus in stable kidney and liver transplant recipients after conversion from immediate-release tacrolimus in routine clinical practice in Switzerland

Non-adherence to immunosuppressive therapy in patients following solid organ transplantation is associated with an increased risk of transplant rejection and graft loss. A high pill burden can adversely affect patients’ implementation of their treatment regimens and may lead to omitting doses of medication. The aim of this study was to investigate medication implementation adherence in liver and kidney transplant recipients converted from twice-daily, immediate-release tacrolimus to once-daily, prolonged-release tacrolimus