title: Histological evidence of neuraminidase involvement in acute nephritis: desialized leukocytes infiltrate the kidney in acute post-streptococcal glomerulonephritis.
abstract: Serum neuraminidase (NA, sialidase) activity has been demonstrated in acute poststreptococcal glomerulonephritis (APSGN) and implicated in the pathogenesis of the disease. Recent investigations show that neuraminidase-treated leukocytes accumulate preferentially in kidneys; therefore, we were interested in knowing if desialized cells infiltrate the kidney in APSGN. We first tested the capacity of peanut agglutinin lectin (PNA) to detect injected NA-treated leukocytes in the kidney of rats. NA-treated leukocytes were transfused and desialized cells were identified with fluorescein-conjugated peanut lectin (FITC-PNA) in renal tissue. PNA positive cells were identified in rat kidneys 3 hours after injection (glomeruli: 1.67 +/- 0.19 cells/g.c.s.; interstitium: 0.50 +/- 0.12 cells/int). Sections from available renal biopsy material of APSGN (n = 11), other glomerulonephritis (n = 28) and normal kidneys (n = 5) were double-stained with FITC-PNA and with monoclonal antibody to the CD11b molecule, which is expressed on polymorphonuclear and monocytes the main types of infiltrating cells during APSGN. Desialized (FITC-PNA positive) cells were found in the glomeruli (2.17 +/- SEM 0.22 cells per glomerular cross section, g.c.s.) and interstitium (0.61 +/- 0.15 cells per 0.0625 mm2, int) in all biopsies of APSGN. Only in 2 of 28 other glomerulonephritis showed desialized cells. More than 80% of the PNA positive cells in APSGN expressed the CD11b molecule and the infiltration was more intense in early biopsies. In conclusion, desialized leukocytes represent a significant part of the inflammatory infiltrate in APSGN. This finding gives support for a role of NA in the disease and provides clinical validation for a mechanism of renal cellular infiltration suggested by experimental observations.
authors.affiliation: Servicio de Nefrología, Hospital Universitario, Maracaibo, Venezuela.
authors.forename: C
authors.initials: C
authors.lastname: Marín
authors.forename: J
authors.initials: J
authors.lastname: Mosquera
authors.forename: B
authors.initials: B
authors.lastname: Rodríguez-Iturbe
mesh_terms: D000818:Animals; D001706:Biopsy; D005921:Glomerulonephritis / Q000378:metabolism* / Q000473:pathology; D006651:Histocytochemistry; D006801:Humans; D007678:Kidney Glomerulus / Q000502:physiology*; D007962:Leukocytes / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D008297:Male; D009439:Neuraminidase / Q000494:pharmacology / Q000502:physiology*; D051381:Rats; D011917:Rats, Inbred Lew; D012189:Retrospective Studies; D013290:Streptococcal Infections / Q000150:complications*; D013997:Time Factors
chemical_list: D009439:Neuraminidase