Summary We retrospectively reviewed the clinicopathological features of a series of 68 renal AA amyloidosis observations collected between 1990 and 2005. The amyloidogenic disease was a chronic ...infection (40.8%), a chronic inflammation (38%), a tumor (9.9%), a hereditary disease (9.9%), or was undetermined in 1.4% of cases. Nephrotic syndrome and renal insufficiency were noted in 63.1% and 75% of patients, respectively. The distribution pattern of glomerular amyloid deposits was mesangial segmental (14.7%), mesangial nodular (26.5%), mesangiocapillary (32.3%), and hilar (26.5%). Glomerular form was observed in 80.9% of cases and vascular form in 19.1%. AA amyloidosis-related inflammation was noted in 30 patients (44.1%) and appeared as a multinucleated giant cell reaction (27.9%) or a glomerular inflammatory infiltrate (25%), including glomerular crescents (17.6%). At the end of follow-up, 26 patients (38.2%) showed end-stage renal disease. The clinical presentation of glomerular and vascular forms was distinct with a clear predominance of proteinuria in glomerular form. Inflammatory reaction was preferentially observed in biopsies with a codeposition of immunoglobulin chains and/or complement factors in AA amyloid deposits. The distribution pattern of glomerular amyloid deposits and glomerular inflammatory reaction were independent factors influencing proteinuria level. Tubular atrophy, abundance, and distribution pattern of glomerular amyloid deposits at the time of biopsy were independent predictors of renal outcome. In conclusion, the glomerular involvement appeared as the determining histological factor for clinical manifestations and outcome of renal AA amyloidosis. AA amyloidosis-related inflammation could partly result from an immune response directed against AA fibrils and could induce amyloid resolution and crescents.
Summary The objective of the study was to investigate the role of endothelin-1 in the pathogenesis of scleroderma renal crisis in patients with systemic sclerosis. We used immunohistochemical ...analysis with anti–endothelin-1 and anti–von Willebrand factor antibodies in comparing kidney biopsies from patients with systemic sclerosis and scleroderma renal crisis (n = 14); from normal kidneys (n = 5); and from patients with typical hemolytic uremic syndrome and thrombotic microangiopathy (n = 5), antiphospholipid syndrome (n = 6), diabetic nephropathy (n = 5), minimal change disease with cyclosporine toxicity (n = 5), or nephroangiosclerosis (n = 5). Kidney biopsies from all systemic sclerosis patients presented specific lesions: glomerular lesions with thickened capillary walls (n = 6, 42.8%), mesangiolysis (n = 3, 21.4%), fibrin thrombi (n = 3, 21.4%), hypertrophy of juxtaglomerular apparatus (n = 5, 35.7%), arteriolar lesions showing mucinous intimal thickening and lumen mucoid occlusions (n = 13, 92.8%), proliferation of intimal cells (ie, “onion-skin” lesions; n = 13, 92.8%), fibrinoid necrosis (n = 3, 21.4%), and fibrin thrombosis (n = 4, 28.6%). Chronic lesions in large arteries showed modifications such as fibrous intimal thickening (n = 13, 92.8%). The pattern of endothelial staining for endothelin-1 in both glomeruli and arteriolar lesions appears to be specific for scleroderma renal crisis. Glomerular endothelin-1 staining without arteriolar staining was seen in hemolytic uremic syndrome; and isolated arteriolar staining (without glomerular staining) was seen in a number of conditions including antiphospholipid nephropathy, cyclosporine toxicity, and diabetic nephropathy. Endothelin-1 is overexpressed in glomeruli and arterioles of patients with scleroderma renal crisis, which suggests that endothelin-1 might be a therapeutic target in this condition.
Summary Membranoproliferative glomerulonephritis type II is a rare renal disease, associated with uncontrolled activation of the complement alternative pathway because of C3 nephritic factor. ...Abnormalities in factor H have been rarely described in patients with membranoproliferative glomerulonephritis type II. We report the clinical history, molecular defect, and histologic description of 3 patients with factor H deficiency and various types of membranoproliferative glomerulonephritis. The 3 patients presented with severely decreased C3. Circulating factor H was undetectable. Complete factor H deficiency (CFH) was due to homozygous complement factor H mutations in short consesus repeat (SCR) 7, 10, and 11. Age at onset was 1 (patient 1), 17 (patient 2), and 33 years (patient 3). Symptoms at diagnosis included proteinuria of 0.5, 2.4, and 11 g/d, respectively, microhematuria, and normal renal function in all cases. The estimated glomerular filtration rate at last follow-up was 25, 43, and 112 mL/min per 1.73 m2 , at ages of 29, 24, and 37 years, respectively. Renal biopsies disclosed a membranoproliferative glomerulonephritis type II with atypical discontinuous dense deposits in patient 1; a membranoproliferative glomerulonephritis type I with immunoglobin G (IgG), C1q, and abundant C3 deposits in patient 2; and a membranoproliferative glomerulonephritis with isolated C3 deposits without dense deposits in patient 3. This report of factor H–deficient patients emphasizes the diversity of the histologic lesions associated with factor H deficiencies and the role of the alternative pathway in several subtypes of membranoproliferative glomerulonephritis.
Mutations of the UMOD gene, which encodes the uromodulin protein, are associated with tubulointerstitial nephritis and hyperuricemia. UMOD mutations impair uromodulin folding, resulting in its ...retention within the endoplasmic reticulum (ER) of renal tubular cells. The aim of this study was to investigate whether mutant uromodulin accumulation in epithelial tubular cells is associated with ER stress. We characterized tubular expression of uromodulin and the ER stress surrogate marker Grp78 by immunohistochemistry in kidney biopsy specimens from 7 patients with UMOD -related kidney disease. We compared this population with 5 patients with familial tubulointerstitial nephritis not related to UMOD mutation. All biopsy specimens from patients carrying the UMOD mutation showed strong heterogeneous cytoplasmic expression of uromodulin in cells of the thick ascending limb of the loop of Henle. In the same tubules, Grp78 was highly expressed in a perinuclear pattern. In contrast, in all kidney biopsy specimens from patients without UMOD mutations, uromodulin staining showed normal apical expression and Grp78 expression was not increased. Our observations support the hypothesis that ER accumulation of mutant uromodulin may cause ER stress, providing a potential mechanism for the progression of UMOD -related kidney disease.
Summary A 39-year-old female patient was admitted to explore chronic renal failure. Clinical history included silicone breast implants. Clinical examination was normal. Urinalysis revealed tubular ...proteinuria with Bence-Jones κ protein. Monoclonal immunoglobulin G κ and free monoclonal κ -light chains (LCs) were revealed by serum protein immunoelectrophoresis. Bone marrow aspiration with karyotype analysis and skeletal radiologic survey were normal. Kidney biopsy revealed a peculiar pattern of proximal tubular cells with hypertrophy and clarification initially diagnosed as an osmotic nephrosis. Immunofluorescence study, including immunoglobulin LCs conjugates was normal. Immunoelectron microscopy finally revealed a crystalline LC proximal tubulopathy κ. Our case presents some peculiarities: the absence of hematologic malignancy sign and the young patient's age. The silicone breast implants have been reported to be involved in the generation of monoclonal gammopathy.
Systemic-onset juvenile idiopathic arthritis is an inflammatory disease of unknown cause and is not commonly associated with kidney involvement. We describe 3 patients with systemic-onset juvenile ...idiopathic arthritis with high disease activity who developed antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis 1-6 years after the onset of systemic-onset juvenile idiopathic arthritis. Renal and systemic-onset juvenile idiopathic arthritis remission occurred in one patient under anti–interleukin 1 (anti–IL-1) treatment associated with immunosuppressive drugs. The other 2 patients developed end-stage renal disease, and one of those patients died. This report suggests that the diagnosis of ANCA-associated glomerulonephritis must be considered in patients with systemic-onset juvenile idiopathic arthritis with persistently active systemic disease who present with proteinuria. Furthermore, use of an anti–IL-1 agent might be an effective therapeutic option.
Lupus nephritis (LN) is a severe and frequent complication of systemic lupus erythematosus. For decades, cyclophosphamide-based regimens have been the gold standard in treating patients with LN. ...However, cyclophosphamide use is associated with increased morbidity and mortality, and thus alternative treatments are needed. We report 3 cases of severe class IV LN successfully treated with rituximab as an induction, as well as a long-term maintenance, treatment. Complete remission of LN, documented by means of a control kidney biopsy, occurred in all patients and was maintained during follow-up using rituximab as sole maintenance treatment. No severe infectious complications were observed during treatment with rituximab. Our data suggest that rituximab may prove to be an optimal maintenance treatment in patients with severe LN.
We report the first cases of atypical hemolytic and uremic syndrome associated with complement factor H (CFH) deficiency in native kidneys and glomerulonephritis with isolated C3 deposits after ...kidney transplantation. Two boys developed atypical hemolytic and uremic syndrome at 16 and 11 months of age, associated with low C3 and CFH levels. Both rapidly progressed to end-stage renal failure and received a kidney transplant. Patient 1 had combined CFH and complement factor I ( CFI ) heterozygous mutations and a membrane cofactor protein (gene symbol, CD46) gene polymorphism. Five years posttransplantation, an allograft biopsy specimen showed numerous mesangial and extramembranous C3 deposits, although the patient had no biological sign of glomerulopathy. Nine years after transplantation, he was well with stable kidney function. Patient 2, who had a homozygous CFH mutation, developed glomerulonephritis with isolated C3 deposits 5 months after kidney transplantation while he was treated for early recurrence of hemolytic anemia. Four years later, the second kidney transplant biopsy specimen showed recurrence of thrombotic microangiopathy. Six years posttransplantation, kidney function was stable and complete blood cell count was normal with regular plasma therapy. These observations suggest that constitutional dysregulation of the alternative pathway is associated with a wide spectrum of kidney diseases, and glomerulonephritis with isolated C3 deposits and thrombotic microangiopathy may be different expressions of the same condition. Several factors could influence the disease, such as degree of CFH haploinsufficiency and other complement alternative pathway regulator abnormalities, such as a membrane cofactor protein polymorphism.
Collapsing glomerulopathy is an aggressive kidney disease with rapid progression toward end-stage renal disease. Rare cases of de novo collapsing glomerulopathy have been reported during the ...post-transplant course and, in some instances, have been associated with renal graft vascular lesions. This finding raises the important question of whether ischemia could induce podocyte transdifferentiation, a hypothesis supported by evidence of hypoxia-inducible factor–dependent podocyte proliferation in HIV-associated nephropathy. We describe here 3 HIV-negative kidney transplant recipients in whom early graft biopsy performed in the vicinity of segmental graft infarction disclosed the typical features of glomerular collapse. Podocyte transdifferentiation was characterized by hallmark lesions, such as loss of mature podocyte phenotype, podocyte proliferation, and acquisition of a macrophage-like phenotype. Together, these data suggest that acute glomerular ischemia may lead to glomerular collapse in kidney transplants.
Alagille syndrome (AGS; Online Mendelian Inheritance in Man no. 118450) is a multisystem autosomal dominant disorder with highly variable expression characterized by chronic cholestasis caused by a ...paucity of interlobular bile ducts, skeletal abnormalities, peculiar facies, ocular abnormalities, and cardiovascular disorders. AGS is diagnosed almost exclusively in children in the setting of predominant liver manifestations or, more rarely, in their adult relatives. We report 2 patients in whom AGS was diagnosed in adulthood during the workup of renal disease in the absence of a well-defined familial history. Renal disease caused by AGS probably is underdiagnosed in adult patients.
