The spectrum of renal involvement in patients with inflammatory myopathies.

Data regarding the incidence and outcome of renal involvement in patients with inflammatory myopathies (IM) remain scarce. We assessed the incidence and causes of acute kidney injury (AKI) and chronic kidney disease (CKD) in 150 patients with dermatomyositis, polymyositis, and antisynthetase syndrome followed in 3 French referral centers. Renal involvement occurred in 35 (23.3%) patients: AKI in 16 (10.7%), and CKD in 31 (20.7%) patients. The main cause of AKI was drug or myoglobinuria-induced acute tubular necrosis. Male sex, cardiovascular risk factors, cardiac involvement, and initial proteinuria >0.3 g/d were associated with the occurrence of AKI. The outcome of patients with AKI was poor: 13 (81%) progressed to CKD and 2 (12.5%) reached end-stage renal disease. In multivariate survival analysis, age at IM onset, male sex, a history of cardiovascular events, and a previous episode of AKI were associated with the risk of CKD. We also identified 14 IM patients who underwent a kidney biopsy in 10 nephrology centers. Renal pathology disclosed a wide range of renal disorders, mainly immune-complex glomerulonephritis. We identified in 5 patients a peculiar pattern of severe acute renal vascular damage consisting mainly of edematous thickening of the intima of arterioles. We found that AKI and CKD are frequent in patients with IM. Prevention of AKI is crucial in these patients, as AKI is a major contributor to their relatively high risk of CKD. A peculiar pattern of acute vascular damage is part of the spectrum of renal diseases associated with IM.

Safety and efficacy of rituximab treatment for vasculitis in hepatitis B virus-associated type II cryoglobulinemia: a case report.

INTRODUCTION: Systemic B-cell depletion and clinical remission of the systemic effects of cryoglobulins have already been achieved using rituximab in hepatitis C virus-positive immunocompetent patients. Conversely, to the best of our knowledge there are no reports in the literature regarding the use of rituximab in hepatitis B virus-associated cryoglobulinemia. CASE PRESENTATION: We report here the case of a 60-year-old Caucasian man who presented with hepatitis B virus-associated type II cryoglobulinemia with severe multisystem disease, including membranoproliferative glomerulonephritis with acute renal failure. The vasculitis was refractory to conventional and antiviral therapy but rituximab use led to a fall in cryoglobulin levels and disease control. The B-cell depletion was safe and efficient to induce a complete remission of the disease. CONCLUSION: Our case highlights the benefit and the efficacy of rituximab in association with antiviral therapy in small vessel vasculitis related to hepatitis B virus-associated mixed cryoglobulinemia.

Hereditary renal amyloidosis caused by a new variant lysozyme W64R in a French family.

BACKGROUND: The number of proteins with mutations resulting in amyloidosis has continued to increase. Five proteins--transthyretin, fibrinogen alpha-A chain, apolipoprotein AI, lysozyme, apolipoprotein AII, cystatin C and gelsolin--can be associated with hereditary amyloidosis involving the kidney. METHODS: A French family with a history of autosomal dominant hereditary amyloidosis with early sicca syndrome and nephropathy leading to renal failure after the fifth to the seventh decade was studied. Several tissue specimens obtained from the proband and his relatives were examined. Immunohistochemistry was performed on paraffin embedded sections using the indirect immunoperoxidase technique. We searched for mutations in the five exons and flanking introns of the lysozyme gene. RESULTS: Amyloid deposits from the bowel, labial salivary gland and kidney were intensively stained by anti-lysozyme antibody. Sequence analysis of lysozyme exon 2 from the affected individuals revealed a nucleotide substitution predicting a substitution of the amino acid at position 64 in the mature protein from tryptophane, an aromatic residue to the cationic residue arginine (W64R). CONCLUSION: We report a novel mutation (W64R) of the lysozyme that is associated with hereditary amyloidosis and prominent nephropathy. Since the treatment of hereditary amyloidosis greatly varies with the nature of the amyloid protein, thorough characterization of the latter is crucial for the management of the disease.