[Kimura's disease: an unrecognized cause of adult-onset nephrotic syndrome with minimal change disease]. / La maladie de Kimura: une cause méconnue de syndrome néphrotique à lésions glomérulaires minimes de l'adulte.

Kimura's disease (KD) is an angiolymphoid proliferative disorder of soft tissue with eosinophilia, with a predilection for head and neck regions in young Oriental men. Kidney disease is thought to be rare in KD. About a case of adult-onset nephrotic syndrome with minimal change disease, we comment Kimura's disease and its associated kidney damage. Kimura disease should be suspected and included in the diagnosis of adult-onset nephrotic syndrome with minimal change disease.

Acute tubular necrosis associated with mTOR inhibitor therapy: a real entity biopsy-proven.

BACKGROUND: The protein kinase mTOR (mammalian target of rapamycin) is a critical regulator of cellular metabolism, growth, and proliferation. Inhibitors of mTOR have immunosuppressive and anti-cancer effects, but their effects on the progression of kidney disease are not fully understood. Their most common side-effects include stomatitis, rash, dyslipidemia, hyperglycemia, fatigue, and pneumonitis. However, to the best of our knowledge these agents have not been previously reported to cause severe acute kidney injury (AKI). CASE PRESENTATION: We describe four cases of patients with cancer who developed AKI after starting mTOR inhibitor therapy. A kidney biopsy showed acute tubular necrosis (ATN) with prominent tubular dysfunction. Withdrawal of the drug leads to a rapid recovery in two cases. However, a fixed renal dysfunction was noted in the other two cases, one of which will remain dialysis-dependent. Such patients lead to a broad differential diagnosis of AKI including prerenal AKI, ATN, cancer-related GN, and drug-induced acute interstitial nephritis. Accurate history, physical examination, laboratory data, and kidney biopsy are highlighted in establishing the correct diagnosis in such patients. CONCLUSIONS: ATN have not been reported with mTOR inhibitor use. These cases demonstrated a potentially new and serious adverse consequence occurring with the use of an mTOR inhibitor, of which physicians need to be aware.

[Myeloproliferative neoplasms related glomerulopathy]. / Glomérulopathies associées aux syndromes myéloprolifératifs.

Myeloproliferative neoplasms (MPNs, formerly called chronic myeloproliferative disorders) are clonal hematopoietic stem cell disorders characterized by the expansion of one or more of the myeloid lineages, including polymorphonuclear, erythroid, megakaryocytic, and mastocytic. The major complications of MPN are transformation into acute myeloid leukemia (occurring particularly in chronic myelogenous leukemia) and thrombotic and hemorrhagic events (most commonly observed in polycythemia vera and essential thrombocythemia). Renal involvement by MPN is infrequent. MPN-related glomerulopathy enlarges the spectrum of glomerular diseases associated with haematological neoplasms. MPN-related glomerulopathy is an under recognized late renal complication of MPN with poor prognosis. It is characterized clinically by heavy proteinuria and renal insufficiency. The histologic features of MPN-related glomerulopathy include variable degree of mesangial sclerosis and hypercellularity, segmental sclerosis, features of chronic thrombotic microangiopathy, and intracapillary hematopoietic cell infiltration. PDGF and TGFß likely have a crucial role in the pathogenesis of MPN-related glomerulopathy. Furthermore, aggregation of circulating hematopoietic cells within glomerular capillaries could potentially result in endothelial injury and morphologic changes resembling chronic thrombotic microangiopathy. Greater awareness of this entity is needed to define diagnosis and possible therapies.

Eculizumab for atypical hemolytic uremic syndrome recurrence in renal transplantation.

Eculizumab (anti-C5) has been sporadically reported as an efficient therapy for atypical hemolytic uremic syndrome (aHUS). However, the lack of series precludes any firm conclusion about the optimal use of anti-C5 for preventing or treating aHUS posttransplant aHUS recurrence. We thoroughly studied 22 renal transplant recipients with aHUS who received off-label therapy with anti-C5, including 12 cases, which have not been reported yet. Nine patients, all carrying a complement genetic abnormality associated with a high risk of aHUS recurrence, received prophylactic anti-C5 therapy to prevent posttransplant recurrence. Eight of them had a successful recurrence-free posttransplant course and achieved a satisfactory graft function, while the remaining patient experienced early arterial thrombosis of the graft. Thirteen renal transplant recipients were given anti-C5 for posttransplant aHUS recurrence. A complete reversal of aHUS activity was obtained in all of them. Importantly, the delay of anti-C5 initiation after the onset of the aHUS episode inversely correlated with the degree of renal function improvement. Three patients in whom anti-C5 was subsequently stopped experienced a relapse. Altogether these data suggest that long-term eculizumab is highly effective for preventing and treating posttransplant aHUS recurrence. Our study also indicates that anti-C5 should be promptly started if a recurrence occurs.