RESUMO
Introduction: Anti-phospholipase A2 receptor (PLA2R) is detected in approximately 70% of biopsies of "primary" membranous nephropathy (MN). Crescents in MN in nonlupus patients suggest additional injury, such as antineutrophil cytoplasmic antibody (ANCA) or anti-glomerular basement membrane (anti-GBM)-associated glomerulonephritis and are postulated to reflect injury by a mechanism that unmasks cryptic epitopes leading to the second autoantibody. Methods: We studied PLA2R staining in nonlupus patients with MN and crescents. Native renal biopsies in 16 nonlupus patients with MN and crescents were stained for PLA2R. Results: The patients included 5 women and 11 men, with mean age 61 years and elevated serum creatinine (mean 4.68 mg/dL). Hematuria and proteinuria (mean 4.97 g/day) were documented in 13 patients. Two patients had positive serum anti-GBM antibody. Nine of 11 patients tested for ANCA were positive, with p-ANCA (n = 4), c-ANCA (n = 2), or both (n = 1), with 2 not specified. On average, 27% of glomeruli had crescents. One patient had an initial biopsy with MN, 4 years later had MN with crescent, and 7 years later had rebiopsy with persistent MN with crescents. One patient had ANCA-associated vasculitis, and 5 years later had MN and crescent. The remaining 14 patients had concurrent diagnoses of MN and crescents. PLA2R was positive in 5 cases, 3 with ANCA positivity, 2 with unknown ANCA status, and none with anti-GBM disease. The patient with initial MN preceding crescent was PLA2R positive; the patient with initial ANCA-associated vasculitis preceding MN was PLA2R negative. Conclusions: Most patients (64%) presented with concomitant MN and crescents, with rare occurrence of an initial disease process followed later by the second injury. PLA2R was positive in 31% of patients, suggesting most are secondary MN. Further study to determine the cryptic epitopes may shed light on the triggering mechanisms for these rare but unlikely coincidental glomerular injuries.
RESUMO
Few data are available on the accuracy of death classification in patients with end-stage renal disease (ESRD). The National Institutes of Health-funded Hemodialysis (HEMO) Study allows the opportunity to compare cause of death recorded on the Health Care Financing Administration (HCFA) Death Notification Form 2746 with death classified by the HEMO Study. The HEMO Study cause of death is determined by trained HEMO Study Outcome Review Committee physicians. In this interim analysis, there were 220 deaths coded by both classification systems. Using the HEMO Study classification system, the most common cause of death was ischemic heart disease (20.4%), followed by arrhythmia and conduction problems (10.4%), cerebrovascular disease (8.6%), and non-access-related infections (7.7%). Using the HEMO Study final death classification as the reference standard, most differences in the two classification systems were related to coding of heart disease. Sensitivity for the HCFA classification ranged from 9.1% for congestive heart failure to 91.7% for malignancy, whereas specificity values were all greater than 78%. Positive predictive values ranged from 11.8% for other heart disease and conditions to 100% for malignancy and hepatobiliary disease, whereas negative predictive values were all greater than 85%. The kappa statistic between the two death classification systems ranged from 0.12 for congestive heart failure to 0.95 for malignancy. Studies using death classification from the HCFA ESRD death notification form for deaths secondary to either cardiovascular diseases or unknown causes should be interpreted cautiously.
