"Eculizumab First" in the Management of Posttransplant Thrombotic Microangiopathy.

Introduction: Posttransplant thrombotic microangiopathy (PT-TMA) is an uncommon event that characterizes approximately 3% to 14% of kidney transplants (KTs), and that is associated with a higher risk of delayed graft function and graft loss. PT-TMA occurs more frequently within the first 3 months after transplant and can be a manifestation of de novo disease or the recurrence of previous atypical hemolytic uremic syndrome (aHUS). Abnormalities in complement regulation genes could explain the increased susceptibility of some patients to PT-TMA. Eculizumab is a humanized monoclonal antibody that inhibits the formation of the membrane attack complex C5b-9. The aim of this study is to evaluate the efficacy of eculizumab as treatment for PT-TMA. Methods: We retrospectively analyzed clinical records of 45 KT patients who received eculizumab immediately after the clinical diagnosis of PT-TMA. Results: Kidney biopsy was performed in 91.1% of patients, and complement genetic study was performed in 64.4%. Of the kidney biopsies, 85.4% showed signs of TMA; genetic analysis revealed 1 pathogenetic variant, 2 variants of uncertain significance, 1 likely benign variant, 8 risk polymorphisms, and 27 risk haplotypes. After 2 weeks from the treatment starting, hemoglobin and platelets significantly increased. A remarkable improvement in kidney function was also observed. After 6 months, 28.8% of patients had a complete renal recovery whereas 44.4% had a partial recovery. Conclusion: This is, to our knowledge, the largest series of KT patients with PT-TMA treated with eculizumab. These data suggest that eculizumab is associated with a normalization of hemolysis indices and an important and progressive improvement of graft function.

Rituximab as possible therapy in TNF inhibitor-induced IgA vasculitis with severe renal involvement.

BACKGROUND: We observe the increasing use of tumor necrosis factor (TNF) inhibitors in patients affected by chronic inflammatory diseases. These drugs provide good control of symptoms, contributing to significant improvement in the quality of life in individuals with high disease burden. On the other hand, along with their wider use and longer follow-up periods the number of reports regarding their adverse effects is also increasing. The reported complications include drug-induced vasculitis with possible kidney involvement. In the literature we can distinguish more frequently described ANCA-associated vasculitis and more rarely occurring immunoglobulin A vasculitis. Although uncommon, such complications may present with potentially life-threatening vital organ dysfunction; therefore, adequate monitoring and effective therapy are necessary. CASE PRESENTATION: We report two cases of TNF inhibitor-induced vasculitis with severe acute worsening of renal function and significant proteinuria. The first patient was receiving golimumab therapy for ankylosing spondylitis and the second patient was treated with adalimumab for psoriasis and psoriatic arthritis. In the second case dialysis treatment was necessary and the patient presented recurrence of vasculitis after rechallenge with adalimumab. Both patients underwent renal biopsy which showed findings compatible with drug-induced IgA vasculitis and both were treated successfully with corticosteroids and rituximab. CONCLUSIONS: To the best of our knowledge this is the first report of rituximab use in drug-induced IgA vasculitis with renal involvement. Combination of corticosteroids and rituximab can be an effective therapy in case of vasculitis with kidney failure and a preferable option for selected patients with drug-induced IgA vasculitis compared to cyclophosphamide. More studies are necessary to establish suitable short- and long-term treatment. Given the rarity of this disorder, case reports and case series can provide practical guidance until additional studies become available.

Rare Single Nucleotide and Copy Number Variants and the Etiology of Congenital Obstructive Uropathy: Implications for Genetic Diagnosis.

SIGNIFICANCE STATEMENT: Congenital obstructive uropathy (COU) is a prevalent human developmental defect with highly heterogeneous clinical presentations and outcomes. Genetics may refine diagnosis, prognosis, and treatment, but the genomic architecture of COU is largely unknown. Comprehensive genomic screening study of 733 cases with three distinct COU subphenotypes revealed disease etiology in 10.0% of them. We detected no significant differences in the overall diagnostic yield among COU subphenotypes, with characteristic variable expressivity of several mutant genes. Our findings therefore may legitimize a genetic first diagnostic approach for COU, especially when burdening clinical and imaging characterization is not complete or available. BACKGROUND: Congenital obstructive uropathy (COU) is a common cause of developmental defects of the urinary tract, with heterogeneous clinical presentation and outcome. Genetic analysis has the potential to elucidate the underlying diagnosis and help risk stratification. METHODS: We performed a comprehensive genomic screen of 733 independent COU cases, which consisted of individuals with ureteropelvic junction obstruction ( n =321), ureterovesical junction obstruction/congenital megaureter ( n =178), and COU not otherwise specified (COU-NOS; n =234). RESULTS: We identified pathogenic single nucleotide variants (SNVs) in 53 (7.2%) cases and genomic disorders (GDs) in 23 (3.1%) cases. We detected no significant differences in the overall diagnostic yield between COU sub-phenotypes, and pathogenic SNVs in several genes were associated to any of the three categories. Hence, although COU may appear phenotypically heterogeneous, COU phenotypes are likely to share common molecular bases. On the other hand, mutations in TNXB were more often identified in COU-NOS cases, demonstrating the diagnostic challenge in discriminating COU from hydronephrosis secondary to vesicoureteral reflux, particularly when diagnostic imaging is incomplete. Pathogenic SNVs in only six genes were found in more than one individual, supporting high genetic heterogeneity. Finally, convergence between data on SNVs and GDs suggest MYH11 as a dosage-sensitive gene possibly correlating with severity of COU. CONCLUSIONS: We established a genomic diagnosis in 10.0% of COU individuals. The findings underscore the urgent need to identify novel genetic susceptibility factors to COU to better define the natural history of the remaining 90% of cases without a molecular diagnosis.

Histological findings of diabetic kidneys transplanted in non-diabetic recipients: a case series.

BACKGROUND: Diabetic donors are recognized as a reliable source of organs, although the discard rate of kidneys is still high. Few data are available on the histological evolution of these organs especially on kidneys transplanted into non-diabetic patients who remain euglycemic. METHODS: We describe the histological evolution of ten kidney biopsies performed on non-diabetic recipients of diabetic donors. RESULTS: Mean donor age was 69 ± 7 years, 60% were males. Two donors were treated with insulin, eight with oral antidiabetic drugs. Mean recipient age was 59.9 ± 7 years, 70% were males. The pre-existing diabetic lesions identified in the pre-implantation biopsies, encompassed all histological classes, and were associated with mild IF/TA and vascular damages. The median follow-up was 59.5 [IQR 32.5-99.0] months; at follow-up, 40% of cases did not change histologic classification, two patients with class IIb downgraded to IIa or I and one with class III downgraded to IIb. Conversely, three cases showed a worsening, from class 0 to I, I to IIb or from IIa to IIb. We also observed a moderate evolution of IF/TA and vascular damages. At follow-up visit, estimated GFR was stable (50.7 mL/min vs. 54.8 at baseline) and proteinuria was mild (51.1 ± 78.6 mg/day). CONCLUSIONS: Kidneys from diabetic donors show variable evolution of the histologic features of diabetic nephropathy after transplant. This variability may be associated to recipients characteristics such as euglycemic milieu, in case of improvement, or obesity and hypertension, in case of worsening of histologic lesions.

Renal Vessel Extension With Cryopreserved Vascular Grafts: Overcoming Surgical Pitfalls in Living Donor Kidney Transplant.

In LDKT, right kidneys and kidneys with anomalous vascularization are often deferred because of concerns on complications and vascular reconstructions. To date, only few reports have examined renal vessel extension with cryopreserved vascular grafts in LDKT. The aim of this study is to investigate the effect of renal vessel extension on short-term outcomes and ischemia times in LDKT. From 2012 to 2020, recipients of LDKT with renal vessels extension were compared with standard LDKT recipients. Subset analysis of rights grafts and grafts with anomalous vascularization, with or without renal vessel extension, was performed. Recipients of LDKT with (n = 54) and without (n = 91) vascular extension experienced similar hospital stays, surgical complications and DGF rates. For grafts with multiple vessels, renal vessel extension granted a faster implantation time (44±5 vs. 72±14 min), which resulted comparable to that of standard anatomy grafts. Right kidney grafts with vascular extension had a faster implantation time compared to right kidney grafts without vascular lengthening (43±5 vs. 58±9 min), and a comparable implantation time to left kidney grafts. Renal vessel extension with cryopreserved vascular grafts allows faster implantation time in right kidney grafts or grafts with anomalous vascularization, maintaining similar surgical and functional outcomes.

Vitamin D and the Kidney: Two Players, One Console.

Vitamin D belongs to the group of liposoluble steroids mainly involved in bone metabolism by modulating calcium and phosphorus absorption or reabsorption at various levels, as well as parathyroid hormone production. Recent evidence has shown the extra-bone effects of vitamin D, including glucose homeostasis, cardiovascular protection, and anti-inflammatory and antiproliferative effects. This narrative review provides an overall view of vitamin D's role in different settings, with a special focus on chronic kidney disease and kidney transplant.

A roadmap to parathyroidectomy for kidney transplant candidates.

Chronic kidney disease mineral and bone disorder may persist after successful kidney transplantation. Persistent hyperparathyroidism has been identified in up to 80% of patients throughout the first year after kidney transplantation. International guidelines lack strict recommendations about the management of persistent hyperparathyroidism. However, it is associated with adverse graft and patient outcomes, including higher fracture risk and an increased risk of all-cause mortality and allograft loss. Secondary hyperparathyroidism may be treated medically (vitamin D, phosphate binders and calcimimetics) or surgically (parathyroidectomy). Guideline recommendations suggest medical therapy first but do not clarify optimal parathyroid hormone targets or indications and timing of parathyroidectomy. There are no clear guidelines or long-term studies about the impact of hyperparathyroidism therapy. Parathyroidectomy is more effective than medical treatment, although it is associated with increased short-term risks. Ideally parathyroidectomy should be performed before kidney transplantation to prevent persistent hyperparathyroidism and improve graft outcomes. We now propose a roadmap for the management of secondary hyperparathyroidism in patients eligible for kidney transplantation that includes the indications and timing (pre- or post-kidney transplantation) of parathyroidectomy, the evaluation of parathyroid gland size and the integration of parathyroid gland size in the decision-making process by a multidisciplinary team of nephrologists, radiologists and surgeons.

Current Perspectives in ABO-Incompatible Kidney Transplant.

For a long time, ABO incompatible living donor kidney transplantation has been considered contraindicated, due to the presence of isohemagglutinins, natural antibodies reacting with non-self ABO antigens. However, as the demand for kidney transplantation is constantly growing, methods to expand the donor pool have become increasingly important. Thus, in the last decades, specific desensitization strategies for ABOi transplantation have been developed. Nowadays, these regimens consist of transient removal of preformed anti-A or anti-B antibodies by using plasmapheresis or immunoadsorption and B-cell immunity modulation by CD20+ cells depletion with rituximab, in association with maintenance immunosuppression including corticosteroids, tacrolimus and mycophenolate mofetil. The outcome in ABOi kidney transplantation have markedly improved over the years. In fact, although randomized trials are still lacking, recent meta analysis has revealed that there is no difference in terms of graft and patient's survival between ABOi and ABO compatible kidney transplant, even in the long term. However, many concerns still exist, because ABOi kidney transplantation is associated with an increased risk of bleeding and infectious complications, partly related to the effects of extracorporeal treatments and the strong immunosuppression. Thus, a continuous improvement in desensitization strategies, with the aim of minimize the immunosuppressive burden, on the basis of immune pathogenesis, antibodies titers and/or ABO blood group, is warranted. In this review, we discuss the main immune mechanisms involved in ABOi kidney transplantation, the pathogenesis of tolerance and the desensitization regimens, including immunoadsorption and plasmapheresis and the immunosuppressive protocol. Finally, we provide an overview on outcome and future perspectives in ABOi kidney transplant.

Erratum to: A roadmap to parathyroidectomy for kidney transplant candidates.

[This corrects the article DOI: 10.1093/ckj/sfac050.].

The Role of Vitamin K in CKD-MBD.

PURPOSE OF REVIEW: We describe the mechanism of action of vitamin K, and its implication in cardiovascular disease, bone fractures, and inflammation to underline its protective role, especially in chronic kidney disease (CKD). RECENT FINDINGS: Vitamin K acts as a coenzyme of y-glutamyl carboxylase, transforming undercarboxylated in carboxylated vitamin K-dependent proteins. Furthermore, through the binding of the nuclear steroid and xenobiotic receptor, it activates the expression of genes that encode proteins involved in the maintenance of bone quality and bone remodeling. There are three main types of K vitamers: phylloquinone, menaquinones, and menadione. CKD patients, for several conditions typical of the disease, are characterized by lower levels of vitamin K than the general populations, with a resulting higher prevalence of bone fractures, vascular calcifications, and mortality. Therefore, the definition of vitamin K dosage is an important issue, potentially leading to reduced bone fractures and improved vascular calcifications in the general population and CKD patients.

Bone Mineral Density Changes in Long-Term Kidney Transplant Recipients: A Real-Life Cohort Study of Native Vitamin D Supplementation.

Vitamin D insufficiency has been associated with reduced bone mineral density (BMD) in kidney transplant patients (KTRs). However, the efficacy of vitamin D supplementation on BMD remains poorly defined, especially for long-term KTRs. We aimed to investigate the effect of native vitamin D supplementation on the BMD of KTRs during a 2-year follow-up. Demographic, clinical, and laboratory data were collected. BMD was evaluated with standard DEXA that was performed at baseline (before vitamin D supplementation) and at the end of study period. BMD was assessed at lumbar vertebral bodies (LV) and right femoral neck (FN) by a single operator. According to WHO criteria, results were expressed as the T-score (standard deviation (SD) relative to young healthy adults) and Z-score (SD relative to age-matched controls). Osteoporosis and osteopenia were defined as a T-score ≤ -2.5 SD and a T-score < -1 and a > -2.5 SD, respectively. Based on plasma levels, 25-OH-vitamin D (25-OH-D) was supplemented as recommended for the general population. Data from 100 KTRs were analyzed. The mean study period was 27.7 ± 3.4 months. At study inception, 25-OH-D insufficiency and deficiency were recorded in 65 and 35 patients. At the basal DEXA, the percentage of osteopenia and osteoporosis was 43.3% and 18.6% at LV and 54.1% and 12.2% at FN, respectively. At the end of the study, no differences in the Z-score and T-score gains were observed. During linear mixed model analysis, native vitamin D supplementation was found to have a negative nitration with Z-score changes at the right femoral neck in KTRs (p < 0.05). The mean dose of administered cholecalciferol was 13.396 ± 7.537 UI per week; increased 25-OH-D levels were found (p < 0.0001). Either low BMD or 25-OH-vitamin D concentration was observed in long-term KTRs. Prolonged supplementation with 25-OH-D did not modify BMD, Z-score, or T-score.

Denosumab-Induced Hypocalcemia and Hyperparathyroidism in de novo Kidney Transplant Recipients.

INTRODUCTION: Denosumab represents a realistic treatment option to increase bone mineral density in kidney transplant recipients (KTRs). It is still unknown how and at what extent posttransplantation bone disease and graft function influence the effects of denosumab on mineral metabolism indexes. In this study, we analyze risk factors of hypocalcemia and parathyroid hormone (PTH) increase after denosumab administration in eighteen de novo KTRs and its management before and after this treatment. METHODS: We conducted a monocentric, observational, prospective study on de novo KTRs. All KTRs enrolled received a single 60 mg subcutaneous dose of denosumab every 6 months. Before kidney transplantation, no patients were treated with calcio-mimetic. After kidney transplantation and before antiresorptive therapy, no patients were treated with calcio-mimetic drugs and/or vitamin D receptor agonists, while all patients received nutritional vitamin D supplementation (from 1,000 IU to 1,500 IU daily). RESULTS: Hypocalcemia was related to the degree of lumbar osteoporosis (p = 0.047); the increase in the PTH level was correlated to baseline bone turnover markers (bone alkaline phosphatase, serum osteocalcin, and ß-C-terminal telopeptide), the 25 OH status, and eGFR. The introduction of calcitriol, after the PTH increase, in addition to cholecalciferol was necessary to ensure an adequate control of serum calcium and PTH during a follow-up of 15 months. Following the treatment with denosumab, it was observed an improvement of areal bone mineral density both at lumbar and femoral sites with a mean percentual increase of 1.74% and 0.25%, respectively. CONCLUSIONS: Denosumab is an effective treatment for bone disease in KTRs. In our study, the increase in PTH is not a transient event but prolonged throughout the follow-up period and requires continuous supplementation therapy with calcitriol.

Vitamin D Effects on Bone Homeostasis and Cardiovascular System in Patients with Chronic Kidney Disease and Renal Transplant Recipients.

Poor vitamin D status is common in patients with impaired renal function and represents one main component of the complex scenario of chronic kidney disease-mineral and bone disorder (CKD-MBD). Therapeutic and dietary efforts to limit the consequences of uremia-associated vitamin D deficiency are a current hot topic for researchers and clinicians in the nephrology area. Evidence indicates that the low levels of vitamin D in patients with CKD stage above 4 (GFR < 15 mL/min) have a multifactorial origin, mainly related to uremic malnutrition, namely impaired gastrointestinal absorption, dietary restrictions (low-protein and low-phosphate diets), and proteinuria. This condition is further worsened by the compromised response of CKD patients to high-dose cholecalciferol supplementation due to the defective activation of renal hydroxylation of vitamin D. Currently, the literature lacks large and interventional studies on the so-called non-calcemic activities of vitamin D and, above all, the modulation of renal and cardiovascular functions and immune response. Here, we review the current state of the art of the benefits of supplementation with native vitamin D in various clinical settings of nephrological interest: CKD, dialysis, and renal transplant, with a special focus on the effects on bone homeostasis and cardiovascular outcomes.

Shape-Sensing of Beam Elements Undergoing Material Nonlinearities.

The use of in situ strain measurements to reconstruct the deformed shape of structures is a key technology for real-time monitoring. A particularly promising, versatile and computationally efficient method is the inverse finite element method (iFEM), which can be used to reconstruct the displacement field of beam elements, plate and shell structures from some discrete strain measurements. The iFEM does not require the knowledge of the material properties. Nevertheless, it has always been applied to structures with linear material constitutive behavior. In the present work, advances are proposed to use the method also for concrete structures in civil engineering field such as bridges normally characterized by material nonlinearities due to the behavior of both steel and concrete. The effectiveness of iFEM, for simply supported reinforced concrete beam and continuous beams with load conditions that determine the yielding of reinforcing steel, is studied. In order to assess the influence on displacements and strains reconstructions, different measurement stations and mesh configurations are considered. Hybrid procedures employing iFEM analysis supported by bending moment-curvature relationship are proposed in case of lack of input data in plastic zones. The reliability of the results obtained is tested and commented on to highlight the effectiveness of the approach.

Application of Inverse Finite Element Method to Shape Sensing of Curved Beams.

Curved beam, plate, and shell finite elements are commonly used in the finite element modeling of a wide range of civil and mechanical engineering structures. In civil engineering, curved elements are used to model tunnels, arch bridges, pipelines, and domes. Such structures provide a more efficient load transfer than their straight/flat counterparts due to the additional strength provided by their curved geometry. The load transfer is characterized by the bending, shear, and membrane actions. In this paper, a higher-order curved inverse beam element is developed for the inverse Finite Element Method (iFEM), which is aimed at reconstructing the deformed structural shapes based on real-time, in situ strain measurements. The proposed two-node inverse beam element is based on the quintic-degree polynomial shape functions that interpolate the kinematic variables. The element is C2 continuous and has rapid convergence characteristics. To assess the element predictive capabilities, several circular arch structures subjected to static loading are analyzed, under the assumption of linear elasticity and isotropic material behavior. Comparisons between direct FEM and iFEM results are presented. It is demonstrated that the present inverse beam finite element is both efficient and accurate, requiring only a few element subdivisions to reconstruct an accurate displacement field of shallow and deep curved beams.

The Off-Target Effects, Electrolyte and Mineral Disorders of SGLT2i.

The sodium-glucose cotransporter 2 inhibitors (SGLT2i) are a relatively new class of antidiabetic drugs that, in addition to emerging as an effective hypoglycemic treatment, have been shown to improve, in several trials, both renal and cardiovascular outcomes. In consideration of the renal site of action and the associated osmotic diuresis, a negative sodium balance has been postulated during SGLT2i administration. Although it is presumable that sodium and water depletion may contribute to some positive actions of SGLT2i, evidence is far from being conclusive and the real physiologic effects of SGLT2i on sodium remain largely unknown. Indeed, no study has yet investigated how SGLT2i change sodium balance in the long term and especially the pathways through which the natriuretic effect is expressed. Furthermore, recently, several experimental studies have identified different pathways, not directly linked to tubular sodium handling, which could contribute to the renal and cardiovascular benefits associated with SGLT2i. These compounds may also modulate urinary chloride, potassium, magnesium, phosphate, and calcium excretion. Some changes in electrolyte homeostasis are transient, whereas others may persist, suggesting that the administration of SGLT2i may affect mineral and electrolyte balances in exposed subjects. This paper will review the evidence of SGLT2i action on sodium transporters, their off-target effects and their potential role on kidney protection as well as their influence on electrolytes and mineral homeostasis.

A case report of IgG4-related disease: an insidious path to the diagnosis through kidney, heart and brain.

BACKGROUND: IgG4-related disease, described around the years 2000 as a form of autoimmune pancreatitis, is now increasingly accepted as a systemic syndrome. The diagnosis is based on both comprehensive and organ-specific criteria. For the kidney, Mayo clinic classification and the guidelines of the Japanese Nephrology Society are used. Ultimately, together with parameters that characterize every organ or apparatus involved, the key element is the confirmation of growing levels of IgG4 in blood or in tissues. CASE PRESENTATION: We describe a male patient with chronic renal failure associated to hypertension without proteinuria. IgG4-related disease was diagnosed through renal biopsy. After an initial positive response to steroids, he presented tinnitus, and histological assessment showed cerebral and subsequently cardiac damage, both IgG4-related. This case appears unique for the type of histologically documented cardiac and neurological parenchymal involvement, and at the same time, exemplifies the subtle and pernicious course of the disease. Frequently, blurred and non-specific signs prevail. Here, kidney damage was associated with minimal urinary findings, slowly progressive renal dysfunction and other factors that can be equivocated in the differential diagnosis. Neurological involvement was represented by tinnitus alone, while cardiac alterations were completely asymptomatic. CONCLUSIONS: This report is representative of the neurological and cardiac changes described in the literature for IgG4-related disease, which may be correlated or not with the renal form and highlights the need, in some cases, of targeted therapeutic approaches. In addition to glucocorticoids, as in this case, rituximab may be necessary.

Designing Reinforced Concrete Beams Containing Supplementary Cementitious Materials.

If supplementary cementitious materials (SCMs) are used as binders, the environmental impact produced by cement-based composites can be reduced. Following the substitution strategy to increase sustainability, several studies have been carried out with the aim of measuring the mechanical properties of different concrete systems, in which a portion of Portland cement was substituted with SCMs, such as fly ashes. On the other hand, studies on the structural behavior of reinforced concrete (RC) elements made with SCMs are very scarce. For this reason, in this paper, a new procedure is introduced with the aim of fulfil a new limit state of sustainability, in accordance with the serviceability and ultimate limit states required by building codes. Although the environmental impact of concrete decreases with the reduction of cement content, the proposed approach shows that the carbon dioxide emission of an RC beam is not a monotonic function of the substitution rate of cement with SCMs. On the contrary, there are favorable values of such substitution rates, which fall within a well-defined range.

Folic Acid and Vitamin B12 Administration in CKD, Why Not?

Patients affected by chronic kidney disease (CKD) or end-stage renal disease (ESRD) experience a huge cardiovascular risk and cardiovascular events represent the leading causes of death. Since traditional risk factors cannot fully explain such increased cardiovascular risk, interest in non-traditional risk factors, such as hyperhomocysteinemia and folic acid and vitamin B12 metabolism impairment, is growing. Although elevated homocysteine blood levels are often seen in patients with CKD and ESRD, whether hyperhomocysteinemia represents a reliable cardiovascular and mortality risk marker or a therapeutic target in this population is still unclear. In addition, folic acid and vitamin B12 could not only be mere cofactors in the homocysteine metabolism; they may have a direct action in determining tissue damage and cardiovascular risk. The purpose of this review was to highlight homocysteine, folic acid and vitamin B12 metabolism impairment in CKD and ESRD and to summarize available evidences on hyperhomocysteinemia, folic acid and vitamin B12 as cardiovascular risk markers, therapeutic target and risk factors for CKD progression.

Treatment with rituximab in idiopathic membranous nephropathy.

BACKGROUND: Rituximab represents a valid therapeutic option to induce remission in patients with primary glomerulonephritis. Despite several studies proving its efficacy in improving outcomes in patients with membranous nephropathy (MN), its role in therapeutic protocols is not yet defined. METHODS: We studied 38 patients with idiopathic MN treated with rituximab (in 13 patients as first-line therapy, in the remaining 25 after conventional immunosuppressive therapy). The patients were analyzed for a 15-month median (interquartile range 7.7-30.2) follow-up, with serial monitoring of 24-h proteinuria, renal function and circulating CD19+ B cells. RESULTS: The percentages of patients who achieved complete remission, partial remission and the composite endpoint (complete or partial remission) were 39.5% (15 patients), 36.8% (14 patients) and 76.3% (29 patients), respectively. The 24-h proteinuria was reduced significantly during the entire period of follow-up (from a baseline value of 6.1 to 0.9 g/day in the last visit; P < 0.01), while albuminemia increased constantly (from a baseline value of 2.6 to 3.5 g/dL in the last observation; P < 0.01). Renal function did not significantly change during the observation period. Circulating CD19+ B cells were reduced significantly from the baseline value to the 24-month value (P < 0.01); data about anti-phospholipase A2 receptor antibodies were available in 14 patients, 10 of which experienced a decreasing trend after treatment. No significant adverse events were described during and after infusions. CONCLUSIONS: The present study confirmed that treatment with rituximab was remarkably safe and allowed for a large percentage of complete or partial remissions in patients with MN.