Vincent Esnault

Antineutrophil cytoplasmic antibody (ANCA) tests are used to diagnose and monitor inflammatory activity in the primary systemic small vessel vasculitides. ANCA is best demonstrated in these diseases by using a combination of indirect immunofluorescence (IIF) of normal peripheral blood neutrophils and enzyme-linked immunosorbent assays (ELISAs) that detect ANCA specific for proteinase 3 (PR3) or myeloperoxidase (MPO). For ANCA testing in "new" patients, IIF must be performed on all serum samples. Serum samples containing ANCA, any other cytoplasmic fluorescence, or an antinuclear antibody (ANA) that results in homogeneous or peripheral nuclear fluorescence then should be tested in ELISAs for PR3-ANCA and MPO-ANCA. Optimally, ELISAs for PR3-ANCA and MPO-ANCA should be performed on all serum samples. Inclusion of the most recent positive sample in the IIF or ELISA may help demonstrate a change in antibody level. Reports should use recommended terms. Any report of positive neutrophil fluorescence issued before the ELISA results are available should indicate that positive fluorescence alone is not specific for the diagnosis of Wegener granulomatosis or microscopic polyangiitis and that decisions about treatment should not be based solely on the ANCA results.

AIM: The aim of this study was to develop and validate a prognostic score for 6-month mortality in elderly patients starting dialysis for end-stage renal disease. METHODS: Using data from the French Rein registry, we developed a prognostic score in a training sample of 2500 patients aged 75 years or older who started dialysis between 2002 and 2006, which we validated in a similar sample of 1642 patients. Multivariate logistic regression with 500 bootstrap samples allowed us to select risk factors from 19 demographic and baseline clinical variables. RESULTS: The overall 6-month mortality was 19%. Age was not associated with early mortality. Nine risk factors were selected and points assigned for the score were as follows: body mass index <18.5 kg/m2 (2 points), diabetes (1), congestive heart failure stages III to IV (2), peripheral vascular disease stages III to IV (2), dysrhythmia (1), active malignancy (1), severe behavioural disorder (2), total dependency for transfers (3) and unplanned dialysis (2). The median score was 2. Mortality rates ranged from 8% in the lowest risk group (0 point) to 70% in the highest risk group (> or =9 points) and 17% in the median group (2 points). Seventeen percent of all deaths occurred after withdrawal from dialysis, ranging from 0% for a score of 0-1 to 15% for a score of 7 or higher. CONCLUSIONS: This simple clinical score effectively predicts short-term prognosis among elderly patients starting dialysis. It should help to illuminate clinical decision making, but cannot be used to withhold dialysis. It ought to only be used by nephrologists to facilitate the discussion with the patients and their families.

The phospholipase A2 receptor (PLA2R1) is the major autoantigen in idiopathic membranous nephropathy. However, the value of anti-PLA2R1 antibody titers in predicting patient outcomes is unknown. Here, we screened serum samples from 50 patients positive for PLA2R1 for immunoreactivity against a series of PLA2R1 deletion mutants covering the extracellular domains. We identified reactive epitopes in the cysteine-rich (CysR), C-type lectin domain 1 (CTLD1), and C-type lectin domain 7 (CTLD7) domains and confirmed the reactivity with soluble forms of each domain. We then used ELISAs to stratify 69 patients positive for PLA2R1 by serum reactivity to one or more of these domains: CysR (n=23), CysRC1 (n=14), and CysRC1C7 (n=32). Median ELISA titers measured using the full-length PLA2R1 antigens were not statistically different between subgroups. Patients with anti-CysR-restricted activity were younger (P=0.008), had less nephrotic range proteinuria (P=0.02), and exhibited a higher rate of spontaneous remission (P=0.03) and lower rates of renal failure progression (P=0.002) and ESRD (P=0.01) during follow-up. Overall, 31 of 69 patients had poor renal prognosis (urinary protein/creatinine ratio >4 g/g or eGFR<45 ml/min per 1.73 m(2) at end of follow-up). High anti-PLA2R1 activity and epitope spreading beyond the CysR epitope were independent risk factors of poor renal prognosis in multivariable Cox regression analysis. Epitope spreading during follow-up associated with disease worsening (n=3), whereas reverse spreading from a CysRC1C7 profile back to a CysR profile associated with favorable outcome (n=1). We conclude that analysis of the PLA2R1 epitope profile and spreading is a powerful tool for monitoring disease severity and stratifying patients by renal prognosis.