Mercury-induced membranous nephropathy: clinical and pathological features.
OBJECTIVE
Long-term contact with mercury may induce membranous nephropathy (MN); however, the clinical pathologic features and pathogenesis of mercury-induced MN have not been investigated.


METHODS
The present study retrospectively evaluated 11 cases of mercury-induced MN to analyze its causes and its clinical and pathologic features.


RESULTS
A total of 10 women and 1 man ages 15 to 45 years were enrolled in the present study. Mercury exposure was caused by mercury-containing pills (five patients), skin lightening cream (four patients), hair-dyeing agents (one patient), and mercury vapor (one patient). The duration of contact with mercury ranged from 2 to 60 months, and the urinary mercury concentrations were 1.5 to 50 times higher than reference values. All patients presented with proteinuria and normal renal function; three had nephrotic syndrome. Light microscopy revealed thickened glomerular basement membrane and mildly proliferative mesangial cells. Acute tubulointerstitial injury occurred in three patients. The immunofluorescence findings showed granular deposits of IgG and C3 along the glomerular capillary wall, mostly accompanied by deposits of C4 and C1q. IgG1 and IgG4 (predominantly IgG1) deposits were observed along the glomerular capillary loops. Nine patients reached complete remission in follow-up after withdrawal from mercury exposure.


CONCLUSIONS
Deposits of IgG1 subclasses in renal tissues indicated that the pathogenesis of mercury-induced MN differs from that of idiopathic MN. It is important that clinicians are aware that mercury exposure should be considered a possible cause of membranous nephropathy.
Li
Shi-Jun
SJ
Professor of Medicine, Research Institute of Nephrology, Jinling Hospital, Nanjing University School of Medicine, Nanjing 21002, China.
Zhang
Su-Hua
SH
Chen
Hui-Ping
HP
Zeng
Cai-Hong
CH
Zheng
Chun-Xia
CX
Li
Lei-Shi
LS
Liu
Zhi-Hong
ZH
D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000652:urine; D001706:Biopsy; D003165:Complement System Proteins / Q000032:analysis; D005260:Female; D005455:Fluorescent Antibody Technique; D015433:Glomerulonephritis, Membranous / Q000139:chemically induced / Q000276:immunology / Q000473:pathology* / Q000628:therapy / Q000652:urine; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D007678:Kidney Glomerulus / Q000187:drug effects / Q000276:immunology / Q000473:pathology*; D008297:Male; D008628:Mercury / Q000009:adverse effects* / Q000652:urine; D008630:Mercury Poisoning / Q000276:immunology / Q000473:pathology* / Q000628:therapy / Q000652:urine; D008875:Middle Aged; D009404:Nephrotic Syndrome / Q000139:chemically induced / Q000473:pathology; D011507:Proteinuria / Q000139:chemically induced / Q000473:pathology; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
D015415:Biomarkers; D007074:Immunoglobulin G; D003165:Complement System Proteins; D008628:Mercury