title: A clinicopathologic study of thrombotic microangiopathy in IgA nephropathy.
abstract: Thrombotic microangiopathy (TMA) occurs in IgA nephropathy, but its clinical significance is not well described. We retrospectively examined a series of 128 patients diagnosed with IgA nephropathy between 2002 and 2008 who had a mean follow-up of 44±27 months. In our series, 53% presented with lesions of TMA, acute or organized, in arteries and/or arterioles. Among patients with TMA, 4% were normotensive, 25% had controlled hypertension, and 71% had uncontrolled hypertension. Of those with uncontrolled hypertension, 26% had malignant hypertension. Histologically, the group with TMA had a significantly greater percentage of sclerotic glomeruli and worse tubulointerstitial fibrosis than those of the group without TMA. However, a significant minority of patients had near-normal histology, with minimal tubular atrophy (20%) and/or <20% interstitial fibrosis (24%). TMA rarely occurred in the absence of significant proteinuria. During follow-up, a doubling of serum creatinine or ESRD occurred in all patients with laboratory evidence of TMA, in 42% of those with morphologic evidence but no laboratory evidence of TMA, and in 11% of those without TMA. In summary, lesions of TMA are frequent in IgA nephropathy and may occur in normotensive patients with near-normal renal histology. Although the pathophysiologic mechanisms involved remain undetermined, the current study rules out severe hypertension or advanced renal disease as sole causes.
authors: Department of Pathology, Hôpital Européen Georges Pompidou, 21, rue Leblanc 75015, Paris, France. khalil.el-karoui@inserm.fr
authors: Khalil
authors: K
authors: El Karoui
authors: Gary S
authors: GS
authors: Hill
authors: Alexandre
authors: A
authors: Karras
authors: Christian
authors: C
authors: Jacquot
authors: Luc
authors: L
authors: Moulonguet
authors: Olivier
authors: O
authors: Kourilsky
authors: Véronique
authors: V
authors: Frémeaux-Bacchi
authors: Michel
authors: M
authors: Delahousse
authors: Jean-Paul
authors: JP
authors: Duong Van Huyen
authors: Alexandre
authors: A
authors: Loupy
authors: Patrick
authors: P
authors: Bruneval
authors: Dominique
authors: D
authors: Nochy
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001808:Blood Vessels / Q000473:pathology*; D005260:Female; D005602:France / Q000453:epidemiology; D005922:Glomerulonephritis, IGA / Q000150:complications / Q000453:epidemiology* / Q000473:pathology; D006801:Humans; D006973:Hypertension / Q000150:complications; D007150:Immunohistochemistry; D007668:Kidney / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012189:Retrospective Studies; D057049:Thrombotic Microangiopathies / Q000453:epidemiology* / Q000209:etiology / Q000473:pathology; D055815:Young Adult