Specific antigen-based stratification of membranous nephropathy in patients after haematopoietic stem cell allotransplantation - a case series and literature review.

BACKGROUND: Nephrotic syndrome (NS) is a rare complication that can occur after haematopoietic stem cell transplantation (HSCT). In patients with membranous nephropathy (MN) who have undergone allogeneic HSCT, a new antigen called protocadherin FAT1 has been identified. Our objective is to present a case series of MN patients after HSCT with a novel antigen-based stratification. CASE PRESENTATIONS: Patients who developed full-blown NS due to MN after an HSCT were enrolled in the University Hospital Centre Zagreb study. The first two patients were treated with an HSCT for acute myeloid leukaemia, and both developed NS after cessation of graft versus host disease (GVHD) prophylaxis. The first patient had reduced kidney function, while the second had completely preserved function. Kidney biopsy showed MN with only subepithelial deposits. A thorough examination revealed that there was no secondary cause of the disease. The patients achieved complete remission after undergoing immunosuppression treatment. The third patient underwent HSCT for acute lymphoblastic leukaemia. He developed both acute and chronic GVHD and also experienced avascular hip necrosis. After sixteen years, the patient developed NS with preserved kidney function. The kidney specimen showed membranous nephropathy (MN) with mesangial and subepithelial deposits. Extensive research was conducted, but no secondary cause for the MN was detected. All three cases tested negative for anti-PLA2R antibodies. Biopsy tissue samples were analysed using laser microdissection and tandem mass spectrometry of glomeruli for the detection of different specific antigens. Patients one and two tested positive for FAT1, whereas patient three tested positive for PCSK6. CONCLUSIONS: MN can develop at various time intervals after HSCT. Specific antigen testing can help establish the relationship between MN and HSCT. In the future, serum testing for anti-FAT1 antibodies in HSCT patients could be significant in diagnosing FAT1-associated MN, similar to how anti-PLA2R antibodies are significant in diagnosing PLA2R-associated MN.

Successful Endovascular Treatment of Postbiopsy AVF in Transplanted Kidneys: Lessons Learned from Two Cases in Multiorgan Transplant Recipients.

Allograft biopsy is a cornerstone in the management of transplanted kidneys. It is a safe procedure, often performed in the outpatient setting. A rare complication is formation of a postbiopsy arteriovenous fistula (AVF). We present here a report of two cases of postbiopsy AVFs treated endovascularly. Selective embolization is a safe and effective method of treatment of postbiopsy AVFs in renal allografts.

First Characterization of ADAMTS-4 in Kidney Tissue and Plasma of Patients with Chronic Kidney Disease-A Potential Novel Diagnostic Indicator.

Background: We have previously shown that metzincin protease ADAMTS-4 accompanies renal fibrogenesis, as it appears in the blood of hemodialysis patients. Methods: Native kidney (NKB) and kidney transplant (TXCI) biopsy samples as well as plasma from patients with various stages of CKD were compared to controls. In paired analysis, 15 TXCI samples were compared with their zero-time biopsies (TX0). Tissues were evaluated and scored (interstitial fibrosis and tubular atrophy (IFTA) for NKB and Banff ci for TXCI). Immunohistochemical (IHC) staining for ADAMTS-4 and BMP-1 was performed. Plasma ADAMTS-4 was detected using ELISA. Results: ADAMTS-4 IHC expression was significantly higher in interstitial compartment (INT) of NKB and TXCI group in peritubular capillaries (PTC) and interstitial stroma (INT). Patients with higher stages of interstitial fibrosis (ci > 1 and IFTA > 1) expressed ADAMTS-4 in INT more frequently in both groups (p = 0.005; p = 0.013; respectively). In paired comparison, TXCI samples expressed ADAMTS-4 in INT and PTC more often than TX0. ADAMTS-4 plasma concentration varied significantly across CKD stages, being highest in CKD 2 and 3 compared to other groups (p = 0.0064). Hemodialysis patients had higher concentrations of ADAMTS-4 compared to peritoneal dialysis (p < 0.00001). Conclusion: ADAMTS-4 might have a significant role in CKD as a potential novel diagnostic indicator.

Two novel variants in the lecithin:cholesterol acyltransferase gene resulted in classic LCAT deficiency.

Background and aims: We report the first two cases of familial lecithin:cholesterol acyltransferase (LCAT) deficiency in Croatia with classical clinical and biochemical features. Patients and methods: A 30-year-old man with nephrotic syndrome, corneal opacities, hepatosplenomegaly, anemia, low high-density lipoprotein (HDL)-cholesterol levels and arterial hypertension (blood pressure >200/100 mmHg) was admitted to our department. At admission, he had an elevated creatinine serum level (233 µmol/L), proteinuria of 12 g in 24-h urine (g/24 h), 3-7 erythrocytes in urine sediment and notable anemia (hemoglobin level 90 g/l). His HDL-cholesterol was significantly low (0.42 mmol/L). Besides chronic kidney disease (CKD), other secondary causes of hypertension were ruled out. The patient was previously diagnosed with membranous nephropathy and treated unsuccessfully with immunosuppressive agents (steroids, cyclosporine, cyclophosphamide). Re-evaluation of histopathological findings of kidney biopsy revealed massive deposition of lipid material in the glomerular basal membrane and in the mesangial region. His 4-year younger brother was also evaluated due to corneal opacities and new-onset arterial hypertension. Nephrotic range proteinuria with preserved global renal function was determined. He also had very low HDL-cholesterol levels. Results: Kidney biopsies from both patients were consistent with LCAT deficiency. The disease was confirmed by measurement of LCAT enzyme activity, plasma cholesterol esterification rate, and genetic testing. Two novel missense variants in the LCAT gene (c.496G > A and c.1138T  >  C) were found. Conclusions: To our knowledge, the presented cases are the first reported cases of genetic LCAT deficiency in Croatia. Given the clinical presentation, the complete lack of LCAT activity and cholesterol esterification rate, diagnosis of familial LCAT deficiency was made.

Acute Kidney Failure as a Single Complication of Varicella Virus Infection in an Adult Patient.

BACKGROUND: Varicella zoster virus (VZV) is distributed worldwide and is highly contagious. In adults and immunosuppressed patients of any age, the clinical course is much more severe. The most severe complications are pneumonia (the main cause of lethal outcomes in this infection), encephalitis, and very rarely Reye syndrome and hepatitis. CASE PRESENTATION: We present a 59-year-old man who came to the emergency department due to varicella and diarrhea. During initial evaluation acute kidney failure (AKF) was diagnosed, and the patient was admitted to the intensive care unit. Continuous renal replacement therapy was applied, and the patient was treated with acyclovir in adjusted doses; renal biopsy revealed acute tubular necrosis. Complete renal function recovery was established after 12 days. CONCLUSION: VZV infection occurs in a range of clinical scenarios, sometimes presenting only with mild symptoms, but in some other setting it can result in severe AKF even in healthy kidneys. Acute VZV infection can lead to isolated, clinically significant kidney failure. The administration of continuous renal replacement therapy and adjusted doses of acyclovir has a favorable effect on the course of the infection, with complete recovery of kidney function.

Chronic dietary exposure to aristolochic acid and kidney function in native farmers from a Croatian endemic area and Bosnian immigrants.

BACKGROUND AND OBJECTIVES: Improvements in agricultural practices in Croatia have reduced exposure to consumption of aristolochic acid-contaminated flour and development of endemic (Balkan) nephropathy. Therefore, it was hypothesized that Bosnian immigrants who settled in an endemic area in Croatia 15-30 years ago would be at lower risk of developing endemic nephropathy because of reduced exposure to aristolochic acid. To test this hypothesis, past and present exposure to aristolochic acid, proximal tubule damage as a hallmark of endemic nephropathy, and prevalence of CKD in Bosnian immigrants were analyzed. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: In this cross-sectional observational study from 2005 to 2010, 2161 farmers were divided into groups: indigenous inhabitants from endemic nephropathy and nonendemic nephropathy villages and Bosnian immigrants; α-1 microglobulin-to-creatinine ratio >31.5 mg/g and eGFR<60 ml/min per 1.73 m(2) were considered to be abnormal. RESULTS: CKD and proximal tubule damage prevalence was significantly lower in Bosnian immigrants than inhabitants of endemic nephropathy villages (6.9% versus 16.6%; P<0.001; 1.3% versus 7.3%; P=0.003, respectively); 20 years ago, Bosnian immigrants observed fewer Aristolochia clematitis in cultivated fields (41.9% versus 67.8%) and fewer seeds among wheat seeds (6.1% versus 35.6%) and ate more purchased than homemade bread compared with Croatian farmers from endemic nephropathy villages (38.5% versus 14.8%, P<0.001). Both Croatian farmers and Bosnian immigrants observe significantly fewer Aristolochia plants growing in their fields compared with 15-30 years ago. Prior aristolochic acid exposure was associated with proximal tubule damage (odds ratio, 1.64; 95% confidence interval, 1.04 to 2.58; P=0.02), whereas present exposure was not (odds ratio, 1.31; 95% confidence interval, 0.75 to 2.30; P=0.33). Furthermore, immigrant status was an independent negative predictor of proximal tubule damage (odds ratio, 0.40; 95% confidence interval, 0.19 to 0.86; P=0.02). CONCLUSIONS: Bosnian immigrants and autochthonous Croats residing in endemic areas are exposed significantly less to ingestion of aristolochic acid than in the past. The prevalence of endemic nephropathy and its associated urothelial cancers is predicted to decrease over time.

Kidney volume and albuminuria as markers of birth weight-blood pressure relationship in essential hypertension.

Our aim was to analyze whether birth weight contributes to future hypertension through reduced kidney volume, and whether albuminuria could be a marker of this pathway. We included 103 patients with newly diagnosed essential hypertension and 92 normotensive controls. Blood pressure (BP) was measured using a mercury sphygmomanometer and a ABP monitor. Kidney volume was determined by ultrasound. Data on birth weight were obtained from mothers. Albuminuria was determined in 24-hour urine samples. Hypertensive patients had lower birth weight and higher albuminuria than normotensives. There was no difference in kidney volume between the two groups. We found a negative correlation between birth weight and systolic BP in the hypertensive group. BP was significantly correlated with BMI and albuminuria in the hypertensive group. Multiple regression analysis had shown the greatest impact of BMI on BP and had also demonstrated that 24-hour systolic BP showed the greatest risk for developing albuminuria in hypertensive patients. In conclusion, birth weight influences BP values in adult age, but it is not mediated by a reduced kidney volume. A strong correlation, independent of birth weight, was observed between albuminuria and BP values. Increased BMI is the most important independent risk factor responsible for BP increase, even in an early phase of essential hypertension.

[Clinical characteristics of patients with renovascular hypertension]. / Klinicke osobitosti bolesnika s renovaskularnom hipertenzijom.

The aim of our study was to show the value of comparing clinical parameters in patients with renovascular hypertension (RVH) and essential hypertension (EH). We examined the differences between renovascular hypertension patients with atherosclerosis (ATH) and those with fibromuscular dysplasia (FMD). The diagnosis of renovascular hypertension was established on the basis of renal angiography finding, which also defined the type of stenosis (ATH or FMD). Our patient group included 108 patients with atherosclerotic RVH (46 male / 62 female, median age 53 yrs), 16 patients with FMD (3 male / 13 female, median age 49 yrs), and 106 patients with EH (61 male / 45 female, median age 38 yrs). In comparison with patients with EH, patients with atherosclerotic RVH were found to be more frequently of female gender with lower body weight and height, older, and more frequently on therapy with antihypertensives. Their hypertension was of later onset and more severe stage. All those differences were statistically significant (P < 0.05). When analysis by genders was performed, women were more frequently smokers and had higher serum cholesterol levels, which is an explanation for higher proportion of female gender in atherosclerotic RVH patients. In patients with fibromuscular dysplasia a higher proportion of female gender was also present, but in comparison with ATH patients their hypertension was more often of a less than 5 years duration and they had lower serum creatinine and triglyceride levels. Our results are in agreement with the results of other authors who showed clinical parameters to be useful in screening of patients for further diagnostic procedure. This stresses the importance of good history, physical examination and well-chosen laboratory tests. They can't clearly establish or exclude the diagnosis of renovascular hypertension, but this approach could more easily point out those hypertensive patients who require a thorough work-up. Clinical parameters could furthermore help in determining the type of treatment of RVH.