[Evaluation of urinary factor H excretion in patients with idiopathic membranous nephropathy].
BACKGROUND
The complement system plays an important role in renal pathogenesis, and C5b-9, a terminal complement complex, is regarded as the principal mediator of proteinuria in idiopathic membranous nephropathy(MN). Since factor H regulates complement activation at the C3 step and is a crucial factor in complement-mediated tissue injury, the urinary excretion of factor H in patients with idiopathic MN was investigated.


METHODS
Seven patients with biopsy-proven idiopathic MN were studied for twenty-four weeks. Urinary factor H levels were measured by ELISA from regularly collected urine samples, and then evaluated and compared with assays of urinary protein and C5b-9 excretion.


RESULTS
During the study, five patients were treated with steroid therapy. All seven patients maintained stable renal function and showed a decline in urinary protein excretion. The mean level of urinary factor H was markedly elevated (156.1 +/- 47.1 U/mg U-Cr) before treatment (0 week), and gradually declined to 127.2 +/- 43.5 U/mg U-Cr at 12 weeks, and to 64.7 +/- 26.9 U/mg U-Cr) at 24 weeks. This followed decreases in urinary protein and urinary C5b-9 excretion. Percent change in urinary factor H level significantly decreased 24 weeks after treatment without affecting the plasma factor H level.


CONCLUSIONS
These results suggest that factor H contributes to the regulatory mechanism of in situ complement activation, and thus the study of urinary factor H levels, as well as urinary C5b-9, may be significant in idiopathic MN.
Endo
Morito
M
Faculty of Human Health Science, Hachinohe University, Aomori, Japan.
Fuke
Yoshinobu
Y
Ohi
Hiroyuki
H
Satomura
Atsushi
A
Fukuda
Noboru
N
Fujita
Takayuki
T
Matsumoto
Koichi
K
D000328:Adult; D015415:Biomarkers / Q000652:urine; D017242:Complement Factor H / Q000652:urine*; D015938:Complement Membrane Attack Complex / Q000652:urine; D005260:Female; D015433:Glomerulonephritis, Membranous / Q000175:diagnosis* / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011507:Proteinuria / Q000175:diagnosis / Q000209:etiology
D015415:Biomarkers; D015938:Complement Membrane Attack Complex; D017242:Complement Factor H