Roberta Fenoglio

Decreased Kidney Function and Crystal Deposition in the Tubules After Kidney Transplant

Adenine phosphoribosyltransferase (APRT) deficiency is an autosomal recessive purine enzyme defect that results in the inability to utilize adenine, which consequently is oxidized by xanthine dehydrogenase to 2,8-dihydroxyadenine (2,8-DHA), an extremely insoluble substance eventually leading to crystalluria, nephrolithiasis, and kidney injury. We describe a case of APRT deficiency not diagnosed until the evaluation of a poorly functioning kidney transplant in a 67-year-old white woman. After the transplant, there was delayed transplant function, urine specimens showed crystals with unusual appearance, and the transplant biopsy specimen showed intratubular obstruction by crystals identified as 2,8-DHA using infrared spectroscopy. APRT enzymatic activity was undetectable in red blood cell lysates, and analysis of the APRT gene showed 1 heterozygous sequence variant, a duplication of T at position 1832. The patient was treated with allopurinol, 300 mg/d, and transplant function progressively normalized. Because patients with undiagnosed APRT deficiency who undergo kidney transplant may risk losing the transplant because of an otherwise treatable disease, increased physician awareness may hasten the diagnosis and limit the morbidity associated with this disease.

New insights into immune mechanisms underlying response to Rituximab in patients with membranous nephropathy: A prospective study and a review of the literature.

BACKGROUND Idiopathic membranous nephropathy (MN) is a common immune-mediated glomerular disease and the main cause of nephrotic syndrome (NS) in Caucasian adults. Rituximab (RTX) has been reported to safely reduce proteinuria in patients with primary MN and severe NS. However, the effects of RTX treatment on T-cells including regulatory T-cells (Treg) in MN have not been fully determined. METHODS Seventeen patients [mean age 67 (29-86) years, 6 women, 11 men] with biopsy-proven MN, and persistent proteinuria >3.5 g/24h were prospectively enrolled and received RTX, 375 mg/m(2) (iv) on days 1, 8, 15 and 22. Changes in circulating B and T cell homeostasis were examined in the peripheral blood by flow-cytometry studies; serum levels of IL-35 were measured using a high-sensitivity ELISA kits (baseline, at month 3, 6, 9 and 12). RESULTS Patients had been followed-up for a mean of 36.3 months (24-48). Proteinuria decreased from 5.6 (3.5-8) g/24h to 2.4 (0.06-13) g/24h at 6 months (p<0.05) and to 1.3 (0.06-8) at 12 months (p<0.01), respectively after therapy with RTX. Four patients received a 2nd course of RTX (one at 6 months because of persistent NS, and three at 12, 18, or 30 months for relapse). The three relapsing patients became proteinuria-free (<0.5 g/24h) in the following 6 months. Serum creatinine remained stable during the follow-up: median 1mg/dl (0.7-1.6) at 12 months and 1.1 (0.7-1.7) at 24 months as compared to 1 (0.5-2.4) at baseline. At 6 months after RTX, complete remission (CR) was observed in 7 patients, partial remission (PR) in 4, while 6 were non responders (NR) non responder (NR). At the end of the follow-up, 14 patients were in CR, 1 in PR, while 2 were NR. In the T-cell compartment, upon detection of B cell depletion, there was an increase in Treg up to 10-fold when comparing baseline and at month 12 (mean ± SD 1.2 ± 0.6%, and 5.8 ± 0.7% p=0.02, respectively). When stratifying patients in responders (CR+PR) and NRs at month 12, we observed a significant increase in Treg cells from month 6 which persisted till 12 months only in the responder group (5.5 ± 0.6% and 1.1 ± 0.6%, p=0.04, respectively in responders and NRs). A statistically significant decrease in the levels of active T-lymphocytes (HLA-DR+CD8+ cells) was observed, with a maximum reached at 12 months after treatment with RTX [6 ± 1.1% baseline, 4.7 ± 1.7% at 6 months (p=0.043) and 1.5 ± 1.4% at 12 months (p=0.05)]. A marked increase in IL-35 levels [defined as delta >40% (serum values at 6 months minus baseline values)] was seen in 68% of the patients who achieved clinical response (CR or PR) at 12 month, but in none of the patients who failed to respond (p=0.034). CONCLUSION Our findings and data from literature support the idea that RTX can be envisaged as a first-line therapy for patients at risk of progression because of persistent NS due to idiopathic MN. Insights into the putative T cell-related mechanisms of action have been discussed.

Rituximab therapy for IgA-vasculitis with nephritis: a case series and review of the literature.

Henoch–Schonlein purpura, also called IgA-vasculitis, is a systemic small vessels vasculitis with immunoglobulin A1-dominant immune deposits. The optimal treatment remains controversial. Because IgA-vasculitis is characterized by leukocyte infiltration of the blood vessel walls along with immunoglobulin A deposition, and because glucocorticosteroids inhibit inflammatory processes, early administration of glucocorticosteroids has been postulated to be effective, but this indication remains controversial. Immunosuppressive agents (azathioprine, cyclophosphamide, cyclosporine, mycophenolate) have been used in combination with glucocorticosteroids without definitive evidence of effectiveness. The efficacy of rituximab in adult IgA-vasculitis has been reported in few cases. We described a monocentric experience on the use of rituximab in adult IgA-vasculitis with biopsy-proven nephritis. The patients achieved a complete remission of nephritis and syndromic manifestations, and no patients experienced adverse reactions. These data have been compared with the limited literature nowadays available.

Cholesterol crystal embolism syndrome in dialysis patients: an emerging clinical diagnosis?

Background: Cholesterol crystal embolism syndrome (CCE) is an increasing end-stage renal disease cause. Few cases have been described on dialysis, despite the high prevalence of the predisposing factors. Methods: The diagnostic criteria of the present study were: skin lesions, myalgia, fatigue, fever and acute inflammatory serologic signs, in the presence of severe vasculopathy. The precipitating factors were: anticoagulation, endovascular intervention and ulcerated atherosclerotic plaque. Results: Between October 2003 and September 2005, CCE was diagnosed in 6 dialysis patients (of 200–210 on chronic treatment): 5 males, 1 female, median age 59.5 years (47–70) and end-stage renal disease follow-up 11.5 years (3–25). All had severe vasculopathy, 5 cardiopathy, and 4 were failed graft recipients. The treatment included: peritoneal dialysis, daily dialysis, ‘conventional’ hemodialysis (2 cases) and hemodiafiltration. The diagnosis was based on the clinical-laboratory picture in 1 patient. In the 5 others clues were present (dicumarol therapy, angioplasty, femoral artery thrombosis, CCE predialysis and ulcerated aortic plaque). The therapeutic approach consisted of corticosteroids (5 cases), statins (4 cases) and prostaglandin analogues (4 cases). Conclusion: The differential diagnosis of CCE should also be considered in dialysis patients (necrotic lesions, limb pain and vasculitis-like signs).

Gadolinium-associated nephrogenic systemic fibrosis in patients with renal failure: the need for an interdisciplinary helping network

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Brief Report : Rituximab for the Treatment of Adult-Onset IgA Vasculitis (Henoch-Schönlein)

Adult‐onset IgA vasculitis (Henoch‐Schönlein) (IgAV) is a rare systemic vasculitis characterized by IgA1‐dominant deposits. The treatment of adult‐onset IgAV is controversial and is based on the combination of glucocorticoids and immunosuppressive agents, but many patients have refractory or relapsing disease despite treatment. Rituximab (RTX) is a B cell–depleting antibody of proven efficacy in antineutrophil cytoplasmic antibody–associated vasculitis. We undertook this study to test the efficacy and safety of RTX in a multicenter cohort of patients with adult‐onset IgAV.

The challenge of treating hepatitis C virus-associated cryoglobulinemic vasculitis in the era of anti-CD20 monoclonal antibodies and direct antiviral agents

Mixed cryoglobulinemia syndrome (MC) is a systemic vasculitis involving kidneys, joints, skin, and peripheral nerves. While many autoimmune, lymphoproliferative, and neoplastic disorders have been associated with this disorder, hepatitis C virus (HCV) is known to be the etiologic agent in the majority of patients. Therefore, clinical research has focused on anti-viral drugs and, more recently, on the new, highly potent Direct-acting Antiviral Agents (DAAs). These drugs assure sustained virologic response (SVR) rates >90%. Nevertheless, data on their efficacy in patients with HCV-associated cryoglobulinemic vasculitis are disappointing, possibly due to the inability of the drugs to suppress the immune-mediated process once it has been triggered. Despite the potential risk of exacerbation of the infection, immunosuppression has traditionally been regarded as the first-line intervention in cryoglobulinemic vasculitis, especially if renal involvement is severe. Biologic agents have raised hopes for more manageable therapeutic approaches, and Rituximab (RTX), an anti CD20 monoclonal antibody, is the most widely used biologic drug. It has proved to be safer than conventional immunosuppressants, thus substantially changing the natural history of HCV-associated cryoglobulinemic vasculitis by providing long-term remission, especially with intensive regimens. The present review focuses on the new therapeutic opportunities offered by the combination of biological drugs, mainly Rituximab, with DAAs.

Chronic kidney disease and anticoagulation: from vitamin K antagonists and heparins to direct oral anticoagulant agents.

Anticoagulation in patients with impaired kidney function can be challenging since drugs’ pharmacokinetics and bioavailability are altered in this setting. Patients with chronic kidney disease (CKD) treated with conventional anticoagulant agents [vitamin K antagonist (VKA), low-molecular weight heparin (LMWH) or unfractionated heparin (UFH)] are at high risk of bleeding events (both non-major and major clinically relevant bleeding). While anticoagulation reduces the risk of thromboembolic events, the co-existing bleeding risk and the fact that the most commonly used anticoagulation agents are eliminated via the kidneys pose additional challenges. More recently, two classes of direct oral anticoagulant agents (DOACs) have been investigated for the prevention and management of venous thromboembolic events: the direct factor Xa inhibitors rivaroxaban, apixaban and edoxaban, and the direct thrombin inhibitor dabigatran. In this review, we discuss the complex challenges and the practical considerations associated with the management of anticoagulation treatment in patients with CKD, with a special focus on DOACs.

The missing medullary sponge kidney

To the Editor: In a recent interesting review regarding etiologic mechanisms of stone formation,1 no mention was made of the role of medullary sponge kidney (MSK), characterized by ectasia and cystic formation in the medullary collecting precalyceal ducts.

The “4 plus 2” rituximab protocol makes maintenance treatment unneeded in patients with refractory ANCA-associated vasculitis: A 10 years observation study

Background ANCA associated vasculitides (AAV) often present with a chronic relapsing course. Relapse leads to increased immunosuppressive exposure and consequent toxicity. While two randomized controlled trials have shown rituximab (RTX) to be the most effective induction treatment in patients with relapsing disease, the optimal treatment duration and RTX dose remain debated. Whether to administer a maintenance dose to every patient, at a fixed time interval or on the basis of B cell count and ANCA titre or only when disease manifestations do occur is still debated as well. Methods 11 patients (5 with granulomatosis with polyangiitis, 4 with microscopic polyangiitis-MPA-, and 2 with eosinophilic granulomatosis with polyangiitis -EGPA-) intolerant or refractory to conventional therapies including cyclophosphamide were enrolled. All patients received the so called “improved 4+2” RTX scheme as a rescue therapy. Following RTX administration, immunosuppressive drugs were rapidly tapered and no immunosuppressive maintenance therapy had been given. Results After a mean follow-up of 85 months since the “4+2” RTX protocol: four out of 11 patients (37%, 1 EGPA and 3 MPA, all MPO-positive) remained in remission after one cycle of “4+2” RTX infusion protocol with no relapse for a median 66 months [60–108]). Seven relapsing patients were re-treated once with RTX (again as monotherapy with the same protocol) after a median of 54 months (24-96). Following re-treatment, they again showed complete remission over a median of 32 months (12-96) of observation. Conclusion In one of the longest-term observation (85 months) studies, sustained clinical remission without immunosuppressive maintenance therapy (and a negligible dose of prednisone since the 5thmonth) was obtained by the “4 + 2” RTX infusion protocol in patients with ANCA-associated vasculitis intolerant or refractory to conventional therapy.