Hypocomplementemia and membranoproliferative glomeruloneophritis in children

Area of Science:

• Pediatric Nephrology
• Epidemiology
• Immunology

Background:

• The incidence of hypocomplementemia and new cases of membranoproliferative glomerulonephritis (MPGN) in Kanagawa Prefecture, Japan, showed a declining trend between 1974 and 1997.
• A follow-up study was conducted from 1998 to 2003 to further investigate this observation.

Purpose of the Study:

• To analyze the trends in hypocomplementemia detected via school urinary screening.
• To determine the incidence of new idiopathic membranoproliferative glomerulonephritis (MPGN) diagnoses in children over an extended period.

Main Methods:

• Examined 1,230,398 urine specimens from elementary and junior high school students between 1980 and 2003.
• Measured serum C3 levels in children with abnormal urinary findings.
• Diagnosed 59 children with idiopathic MPGN between 1974 and 2003.

Main Results:

• Between 1980 and 2003, 34 out of 1546 school children with abnormal urinary findings had hypocomplementemia.
• From 1998 to 2003, only 4 out of 264 children exhibited mild hypocomplementemia (83-86 mg/dl).
• The diagnosis of idiopathic MPGN decreased from 8.8% (59 children) between 1974-2003 to only 2 new cases in 1998-2003.

Conclusions:

• The incidence of hypocomplementemia detected through school urinary screening continues to decrease.
• New diagnoses of idiopathic membranoproliferative glomerulonephritis (MPGN) in children have also significantly declined in the studied population.