title: Urine IgG2/IgG4-ratio indicates the significance of the charge selective properties of the glomerular capillary wall for the macromolecular transport in glomerular diseases.
abstract: BACKGROUND
  Alterations of the charge-selective properties of the glomerular capillary wall are important constituents of the pathogenesis of many glomerular diseases. Thus, differences in the degree of such changes could be of help in understanding the mechanisms governing the transport of macromolecules across the glomerular capillary wall.
  
  
  METHODS
  The ratio between urine concentrations of neutral IgG2 and negatively charged IgG4 (IgG2/IgG4-ratio) was measured in 150 proteinuric patients and 21 healthy controls. The patients were subdivided into seven biopsy verified diagnostic groups.
  
  
  RESULTS
  The study revealed decreased IgG2/ IgG4-ratio in membranous glomerulonephritis (0.57) compared to healthy controls (2.09) and to all other diagnosis groups; crescentic necrotizing glomerulonephritis (1.28), diffuse proliferative glomerulonephritis (1.10), IgA nephropathy (1.11), mesangial proliferative glomerulonephritis (1.55), minimal change nephropathy (1.00), and nephrosclerosis secondary to hypertension (1.06). Although not statistically significant, there was a tendency towards lower IgG2/IgG4-ratio values in all the studied glomerular diseases compared to healthy controls.
  
  
  CONCLUSIONS
  Since IgG is transported entirely through the large pores of the glomerular basement membrane decreased IgG2/IgG4-ratio implies that this pathway is strongly influenced by the charge-selective properties of the glomerular capillary wall. The conclusion that could be drawn from that is that the large pore radius must be discrete, in the order of 80-90 A, and thus not non-discriminatory to macromolecules as previously thought.
authors.affiliation: Department of Nephrology, Lund University Hospital, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Tencer
authors.forename: O
authors.initials: O
authors.lastname: Torffvit
authors.forename: H
authors.initials: H
authors.lastname: Thysell
authors.forename: B
authors.initials: B
authors.lastname: Rippe
authors.forename: A
authors.initials: A
authors.lastname: Grubb
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001692:Biological Transport; D002648:Child; D005260:Female; D005921:Glomerulonephritis / Q000378:metabolism*; D006801:Humans; D007074:Immunoglobulin G / Q000145:classification* / Q000652:urine*; D007678:Kidney Glomerulus / Q000378:metabolism*; D046911:Macromolecular Substances; D008297:Male; D008875:Middle Aged
chemical_list: D007074:Immunoglobulin G; D046911:Macromolecular Substances