PMC6308376_01
Patient renal biopsy tissue stained with (a) hematoxylin and eosin, showing a large circumferential cellular crescent associated with compression of the glomerular tuft, and (b) by immunohistochemistry for IgA, showing linear IgA deposition along the glomerular basement membrane, Bowman's capsule, and mesangial matrix.
gr1.jpg
PMC6308376_01_gr1.jpg
fig1
Histopathological examination revealed acute diffuse and global crescentic glomerulonephritis on the background of moderate chronic damage (Figure 1a). There was no deposition of IgG in glomeruli, but there was linear deposition of complement C3 and IgA along the GBM as well as the Bowman's capsule, the glomerular mesangium, and the tubular basement membranes (Figure 1b).
Indirect immunofluorescence staining of primate kidney sections (Euroimmun, product number FB 1250-1010) incubated overnight at 4  C with (left) control patient serum with IgG antibodies against the noncollagenous domain of the alpha3 chain of type IV collagen, (center) patient acute, and (right) patient convalescent serum. Patient's and control sera (diluted 1:10) antibody binding was visualized with Alexa Fluor 647-labeled secondary antibodies (diluted 1:1000) to human IgA (diluted 1:250; center, right) or IgG (diluted 1:500, left).
gr2.jpg
PMC6308376_01_gr2.jpg
fig2
IgA anti-GBM antibodies, we modified an indirect immunofluorescence method, using patient serum to stain primate kidney sections, which confirmed prominent linear IgA binding to the glomerular and tubular basement membranes and to the Bowman's capsule, accompanied by weaker IgA binding to mesangial areas with the patient's acute serum (Figure 2). It was reassuring that there was no such staining with convalescent serum obtained 9 months after treatment initiation (Figure 2), allowing him to be placed on the transplant waiting list.