idiopathic membranous nephropathy is a relatively common cause of nephrotic syndrome in nondiabetic adults . in our centre , 28% of native renal biopsies performed in the setting of nephrotic syndrome yielded a diagnosis of idiopathic membranous nephropathy . an autoimmune basis for idiopathic membranous nephropathy has been established with the recent identification of the m - type phospholipase receptor ( pla2r ) as the major antigen . histological findings which favour idiopathic membranous nephropathy over secondary disease include igg4-positive immune complexes and exclusively subepithelial deposits . . the remainder may develop progressive renal failure and may ultimately require renal replacement therapy . patients are typically risk stratified for disease progression on the basis of renal function and degree of proteinuria . those at low or intermediate risk of progression are managed conservatively , at least in the short term , with renin - angiotensin - aldosterone blockade , blood pressure control , lipid control and , if specifically indicated , anticoagulation . transplantation is the preferred modality of renal replacement therapy in those patients that reach end - stage kidney disease . the disease is known to recur in some transplant recipients and may lead to significant graft dysfunction or failure . despite the significant burden of membranous nephropathy worldwide , many questions regarding recurrent disease remain . we performed a national retrospective cohort study of all renal transplant recipients with a primary diagnosis of idiopathic membranous nephropathy . we aimed to establish patterns of disease recurrence and to identify factors associated with disease recurrence . using the irish national renal transplant database , which contains longitudinal information on all renal transplant recipients in ireland , we identified a consecutive cohort of patients with idiopathic membranous nephropathy in receipt of a renal transplant between 1982 and 2010 . patients of all ages were included if they had a biopsy - proven diagnosis of membranous nephropathy and lacked clinical or histological features of secondary disease . many of the light microscopic features of membranous nephropathy , such as basement membrane thickening and tubulo - interstitial change , are not specific for membranous nephropathy . with that in mind , the diagnosis of recurrent membranous nephropathy relied on identification of typical subepithelial immune complex deposits by light or electron microscopy , with characteristic igg staining on immunofluorescence . histologic changes were graded ( stage i  iv ) depending on the location of the immune complex deposits and the extent of glomerular basement membrane thickening . all tests were two - sided , and a p value of < 0.05 was considered to be statistically significant . patients were excluded if their initial biopsy was unavailable for review or if there were features to suggest secondary membranous glomerulonephritis . patients were also excluded if they had been lost to follow up during the intervening years . the mean age at the time of first transplant was 49.8 years ( range 2068 years ) . one patient was transplanted in a preemptive fashion ; the mean duration of dialysis prior to transplantation was 2.75 years .   in terms of first transplantation , the majority ( n = 30 ) were from deceased donors ; three of these were dual kidney transplants from extended criteria donors . all patients had induction immunosuppression in the form of high - dose steroid and an il-2 receptor blocker . maintenance immunosppresssion was with low - dose corticosteroid , an antimetablite and a calcineurin inhibitor in combination . the causes of death were cardiovascular disease , gastric malignancy , and lung malignancy in two cases . there were no other reported malignancies among the patient group . one case was due to early thrombosis / infarction ; another due to severe rejection . recurrent disease was deemed the major contributing factor to graft failure in five cases ( figure 2 ) . the median time between diagnosis of recurrent disease and graft loss in these cases was 15 months ( range 549 months ) . with regard to posttransplant surgical complications , there was one case of early transplant thrombosis / infarction . there were two cases of anastomotic leak in the early post - operative period . transplant biopsies were performed if clinically indicated to investigate proteinuria , haematuria , or deteriorating graft function . the majority of these were banff class 1a , managed with steroids and augmented baseline immunosuppression . renal function and proteinuria at the time of biopsy can be seen in table 2 . the median time to recurrence was 46 months with a range of 5120 months ( figure 1 ) . the nephrotic syndrome , abated and this patient continues to enjoy good graft function three years later . the third case had recurrent membranous disease identified two years after engraftment , which led to graft failure four years posttransplantation . duration of dialysis , hla mismatch , pra % and treatment for acute rejection were not independent predictors of disease recurrence . age was significantly associated with recurrence , with younger patients more likely to develop recurrence ( table 1 ) . membranous nephropathy is thought to recur in 3045% of transplanted patients [ 9 , 10 ] . recurrence typically occurs in the second or third year posttransplant [ 9 , 10 ] . we found a smaller number of recurrences , with a slightly later onset . this was likely due to the fact that biopsies were performed on the basis of clinical indications , and not in a surveillance manner . there are conflicting data regarding the theory that living donor transplants are at increased risk of recurrence [ 11 , 12 ] . our results indicated that younger age at time of transplant may predict development of clinically significant disease recurrence . this is thought to be due to the fact that younger patients are more likely to have genetic factors underlying disease and also because they live longer therefore have more time to develop recurrence . as with primary membranous nephropathy the effect of recurrent disease on graft survival varies between studies , but , in general , graft survival appears largely similar to that of other transplanted patients . a surveillance biopsy study found that recurrent disease may be present with less than one gram of proteinuria . there is evidence that subclinical disease is progressive and therefore may have important clinical implications in time . the role of plar antibodies in the identification of recurrent disease has yet to be fully clarified .   with regard to treatment , there are anecdotal reports of successful resolution of immune deposits and proteinuria with rituximab [ 9 , 10 ] . however , as the rates of spontaneous remission and disease progression are unclear , the benefits from rituximab administration are ill - defined . future studies using surveillance biopsies and pla2r antibodies / antigens may find a predictive model for recurrent disease . randomised trials comparing rituximab to conservative management are required to further clarify the natural history of the disease and the role of rituximab in its management . almost one third of transplanted patients with membranous nephropathy have clinically significant disease recurrence at ten years . as long - term renal transplant survival improves , the relative contribution of recurrent disease to graft loss is likely to increase further . over half of we look forward to future clinical trials which will deepen our insight into this complex disease .
background . the natural history of idiopathic membranous 
 nephropathy and recurrent disease in transplants is variable . 
 we performed a retrospective cohort study of renal transplant recipients with a primary diagnosis of idiopathic membranous nephropathy . 
 we aimed to establish patterns of disease recurrence and to identify factors associated with disease recurrence . 
 methods . 
 we accessed the irish renal transplant database to identify patients with biopsy - proven idiopathic membranous nephropathy in receipt of a renal transplant between 1982 and 2010 . 
 a detailed medical chart review was performed in all cases , and a senior renal histopathologist reviewed all histology specimens . 
 results . 
 the outcomes of 32 patients , in receipt of 36 grafts , are reported . 
 there was a male preponderance ( n = 29 ) . 
 significant graft dysfunction , directly attributable to recurrent disease , was evident in 31% of cases at 10 years . 
 there was no significant association between time on dialysis , hla mismatch , occurrence of rejection , and the development of recurrent membranous disease . 
 one patient was retransplanted twice ; all three grafts were lost to aggressive recurrent membranous disease . 
 conclusions . 
 it remains difficult to identify those that will develop recurrent membranous nephropathy . 
 almost one third of patients in this cohort developed clinically significant recurrent disease at 10 years .