Glomerular binding sites for peanut agglutinin in acute poststreptococcal glomerulonephritis.

Streptococcal neuraminidase may be responsible for the development of auto-immune reactivity in acute poststreptococcal glomerulonephritis (APSGN). Neuraminidase may react with immunoglobulins in the circulation and with sialic acid-rich sites in the endothelial and epithelial glomerular capillary, therefore, extrinsic or intrinsic sialic acid-depleted substrate may be localized in the glomeruli. We studied renal biopsies from 17 patients with APSGN, 48 patients with other renal pathologies and 2 normal kidneys for the capacity to bind fluorescein-labelled peanut agglutinin (PNA) lectin. PNA has specificity for galactosyl radicals which are exposed after sialic acid removal. We similarly studied the kidneys of rats at intervals ranging from hours to 32 days after an intravenous injection of 0.02 units of neuraminidase per g of body weight. Five biopsies of APSGN patients and 2 biopsies from patients with renal pathologies different from APSGN showed glomerular PNA binding. Of APSGN patients, 4 corresponded to the 5 patients biopsied within 30 days of the beginning of the disease and only 1 biopsy was positive in the 12 patients who were biopsied later. The PNA binding predominated in the mesangium and the pattern was irregular and speckled. These findings suggest that sialic-acid depleted material is present in the glomeruli, early in the course of APSGN.