The Oxford Classification of IgA nephropathy (IgAN) includes the following four histologic components: mesangial (M) and endocapillary (E) hypercellularity, segmental sclerosis (S) and interstitial fibrosis/tubular atrophy (T). These combine to form the MEST score and are independently associated with renal outcome. Current prediction and risk stratification in IgAN requires clinical data over 2 years of follow-up. Using modern prediction tools, we examined whether combining MEST with cross-sectional clinical data at biopsy provides earlier risk prediction in IgAN than current best methods that use 2 years of follow-up data. We used a cohort of 901 adults with IgAN from the Oxford derivation and North American validation studies and the VALIGA study followed for a median of 5.6 years to analyze the primary outcome (50% decrease in eGFR or ESRD) using Cox regression models. Covariates of clinical data at biopsy (eGFR, proteinuria, MAP) with or without MEST, and then 2-year clinical data alone (2-year average of proteinuria/MAP, eGFR at biopsy) were considered. There was significant improvement in prediction by adding MEST to clinical data at biopsy. The combination predicted the outcome as well as the 2-year clinical data alone, with comparable calibration curves. This effect did not change in subgroups treated or not with RAS blockade or immunosuppression. Thus, combining the MEST score with cross-sectional clinical data at biopsy provides earlier risk prediction in IgAN than our current best methods.

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Background Acute renal infarction is a rare condition whose diagnosis is often delayed. Major risk factors include atrial fibrillation, valvular or ischemic heart disease, renal artery thrombosis/dissection and coagulopathy. MethodsWe reviewed the medical records of 18 patients admitted to our Nephrology Department between 1999 and 2015 for acute renal infarction diagnosed by computed tomography. Tc-99m dimercaptosuccinic acid (DMSA) scintigraphy was performed in some patients during follow-up to assess parenchymal lesions and estimate differential kidney function. ResultsMean age was 59.8 years. Major associated risk factors included hypertension (44 %), obesity (33 %), atrial fibrillation (28 %), peripheral vascular disease (17 %), smoking (17 %), prior thromboembolic event (11 %), diabetes (11 %), estroprogestinic therapy (11 %). Seventy-two percent of patients presented with flank pain. Mean serum creatinine was 1.2 ± 0.6 mg/dl. Acute kidney injury occurred as the initial manifestation in two patients. Patients were managed conservatively, with low molecular weight heparin (83 %) or aspirin (11 %). At the end of follow-up serum creatinine was 1.1 ± 0.3 mg/dl; one patient remained on chronic hemodialysis. 58 % of patients who underwent renal scintigraphy after a median of 8 months had a reduced contribution of the previously affected kidney to total renal function. ConclusionRisk factors associated with the development of chronic kidney disease following renal infarction are unknown. In our subjects, renal function remained stable in all but one patient who developed end stage renal disease. Further studies should focus on etiology and evolution of kidney function in patients with acute renal infarction. IntroductionAcute renal infarction, due to an abrupt interruption of renal arterial flow, is a rare condition with an estimated incidence of 0.004-0.007 % in the Emergency Department setting [1,2]. Non-specific clinical presentation mimicking other pathologic states (e.g. urolithiasis, acute pyelonephritis, other acute abdominal diseases) often causes a delay in the diagnosis, which may increase the risk of impaired renal failure [3][4][5]. Radiologic diagnosis of renal infarction is based on enhanced contrast computed tomography (CT), which typically indicates the presence of a wedge-shaped hypodense area in the peripheral region [2]. Major risk factors for renal infarction include atrial fibrillation, valvular or ischemic heart disease, renal artery thrombosis/dissection and coagulopathy. Etiology remains unknown in many cases [4,6,7]. We describe the clinical and radiological characteristics and renal prognosis of 18 patients with acute renal infarction.

Our data suggest that in APN it is not always possible to routinely document urinary infection in a clinical setting. This finding could be explained by previous antibiotic treatment, low bacterial growth or atypical pathogens. Systematic CT or NMR is necessary to exclude evolution into abscesses, which cannot be suspected on clinical grounds or by ultrasound examination and may also develop in the absence of risk factors.

IgG4-related disease (IgG4-RD) is a recently recognized disorder, characterized by elevated serum IgG4 concentrations, dense tissue infiltration of IgG4-positive plasma cells and storiform fibrosis. Treatment is usually based on steroids, however, relapses and long-term adverse effects are frequent. We prospectively studied 5 consecutive patients with histologically-proven IgG4-RD and renal involvement, treated with an extended Rituximab protocol combined with steroids. Two doses of intravenous cyclophosphamide were added in 4 patients.Five patients with IgG-RD were investigated: three had tubulointerstitial nephritis (TIN), while two had retroperitoneal fibrosis (RPF). In the patients with TIN, renal biospy was repeated after 1 year.In the patients with TIN, estimated glomerular filtration rate (eGFR) at 12 months increased from 9 to 24 ml/min per 1.73 m2; IgG/IgG4 decreased from 3,236/665 to 706/51 mg/dl; C3/C4 increased from 49/6 to 99/27 mg/dl; CD20+ B-cells decreased from 8.7% to 0.5%; Regulatory T-cells decreased from 7.2% to 2.5%. These functional and immunologic changes persisted at 24 months and in two patients at 36 months. A repeat renal biopsy in the patients with TIN showed a dramatic decrease in interstitial plasma cell infiltrate with normalization of IgG4/IgG positive plasma cells. The patients with RPF showed a huge regression of retroperitoneal tissue.In this sample of patients with aggressive IgG4-RD and renal involvement, treatment aimed at depleting B cells and decreasing antibody and cytokine production was associated with a substantial, persistent increase in eGFR, and a definite improvement in immunologic, radiologic and histological parameters.