Immunotactoid glomerulopathy is a rare disease defined by glomerular microtubular immunoglobulin deposits. Since management and long-term outcomes remain poorly described, we retrospectively analyzed results of 27 adults from 21 departments of nephrology in France accrued over 19 years. Inclusion criteria were presence of glomerular Congo red-negative monotypic immunoglobulin deposits with ultrastructural microtubular organization, without evidence for cryoglobulinemic glomerulonephritis. Baseline manifestations of this cohort included: proteinuria (median 6.0 g/day), nephrotic syndrome (70%), microscopic hematuria (74%) and hypertension (56%) with a median serum creatinine of 1.5 mg/dL. Nineteen patients had detectable serum and/or urine monoclonal gammopathy. A bone marrow and/or peripheral blood clonal disorder was identified in 18 cases (16 lymphocytic and 2 plasmacytic disorders). Hematologic diagnosis was chronic/small lymphocytic lymphoma in 13, and monoclonal gammopathy of renal significance in 14 cases. Kidney biopsy showed atypical membranous in 16 or membranoproliferative glomerulonephritis in 11 cases, with microtubular monotypic IgG deposits (kappa in 17 of 27 cases), most commonly IgG1. Identical intracytoplasmic microtubules were observed in clonal lymphocytes from 5 of 10 tested patients. Among 21 patients who received alkylating agents, rituximab-based or bortezomib-based chemotherapy, 18 achieved a kidney response. After a median follow-up of 40 months, 16 patients had sustained kidney response, 7 had reached end-stage kidney disease, and 6 died. Chronic/small lymphocytic lymphoma appears as a common underlying condition in immunotactoid glomerulopathy, but clonal detection remains inconstant with routine techniques in patients with monoclonal gammopathy of renal significance. Thus, early diagnosis and hematological response after clone-targeted chemotherapy was associated with favorable outcomes. Hence, thorough pathologic and hematologic workup is key to the management of immunotactoid glomerulopathy.

The antiviral molecule acyclovir can be responsible of severe renal dysfunction. Intratubular crystal precipitation of the drug may represent a major pathogenetic mechanism.Observation. - A 30-year old, immunocompetent woman was admitted in the neurology unit for a viral meningo-encephalitic syndrome. Intravenous acyclovir was delivered at the close of 45 mg/kg per day. Despite a neurological improvement, she developed an acute renal insufficiency with the serum creatinine increasing from 63 to 385 mu mol/L within 12 days. The urine study revealed great amounts of birefringent crystals which were typical of acyclovir derived crystals according to the spectrophotometric examination. Withdrawal of acyclovir treatment in combination with oral and parenteral hydration resulted in a complete recovery of the renal function. The conditions favouring acyclovir-induced nephrotoxicity are discussed. (C) 2009 Association Societe de nephrologie. Published by Elsevier Masson SAS. All rights reserved.

Erosive spondyloarthropathy (ESA) is common in long-term hemodialysed patients. However, it has been little recognized in peritoneal dialysis (PD) patients. In a retrospective study, we found severe ESA in 7 of the 87 (8%) patients undergoing PD in our center. Characteristics of our population were advanced age and short duration of dialysis (27±20 months). ESA patients were older than non ESA (74±4 vs 68±11 yrs,p<0.01). Secondary hyperparathyroidism and dialysis amyloid arthropathy were also possible pathogenic factors. Patients were followed for 4 years or until death and remained stable in most ESA cases. We conclude that ESA is age-related, is as frequent in PD as in HD populations and is not related to one single underlying mechanism.