Clinicopathological characteristics of patients with immunoglobulin A nephropathy showing acute exacerbations after favorable long-term clinical courses.
BACKGROUND
Sometimes, acute and progressive proteinuria increases occur in patients with IgA nephropathy (IgAN) after favorable long-term clinical courses of >10 years, but their clinical and histological characteristics are not well understood.


METHODS
We retrospectively selected 20 IgAN patients who had been followed for >10 years after their initial biopsies ((1st)Bx) and underwent second biopsies ((2nd)Bx), because their proteinuria increased to >1 g/day. Eight patients with acute exacerbations (Group A) showed acute proteinuria increases after long periods of mild proteinuria. Their clinicopathological characteristics were analyzed as a case series and were compared with those in Group B that comprised 12 patients with persistent proteinuria.


RESULTS
Group A experienced acute proteinuria increases and significant hematuria increases compared with the -1-year (P = 0.006) and -3-year (P = 0.010) time points before the (2nd)Bx, which contrasted to the clinical course in Group B. In Group A, glomerulosclerosis (GS) and the arteriosclerosis score did not differ between the (2nd)Bx and the (1st)Bx, and most patients (88 %) showed cellular and/or fibrocellular crescents within the (2nd)Bx. Compared with Group B, the (2nd)Bx revealed that the percentage of cellular and/or fibrocellular crescents (P = 0.001) was significantly higher, whereas the percentage of GS (P = 0.012) and the arteriosclerosis score (P = 0.020) were significantly lower in Group A.


CONCLUSIONS
Rapid proteinuria and hematuria increases, and acute histological lesions characterize acute exacerbations in IgAN after favorable long-term clinical courses.
Division of Kidney and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo, Japan.
Mai
M
Tanaka
Division of Kidney and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo, Japan. yoichimiyazaki@jikei.ac.jp.
Yoichi
Y
Miyazaki
Division of Kidney and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo, Japan.
Kentaro
K
Koike
Division of Kidney and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo, Japan.
Hiroyuki
H
Ueda
Division of Kidney and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo, Japan.
Nobuo
N
Tsuboi
Division of Kidney and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo, Japan.
Keita
K
Hirano
Division of Kidney and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo, Japan.
Hideo
H
Okonogi
Division of Kidney and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo, Japan.
Makoto
M
Ogura
Division of Kidney and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo, Japan.
Tetsuya
T
Kawamura
Division of Kidney and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo, Japan.
Takashi
T
Yokoo
D000328:Adult; D001706:Biopsy; D002648:Child; D005260:Female; D005922:Glomerulonephritis, IGA / Q000473:pathology*; D006801:Humans; D007668:Kidney / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011507:Proteinuria / Q000473:pathology*; D012189:Retrospective Studies; D055815:Young Adult
Crescents; IgA nephropathy; Prognosis; Recurrence