Computer imaging analysis of glomerular extracellular components in patients with IgA nephropathy

Computer imaging analysis was used for quantitative evaluation of the extents, amounts and distributions of glomerular extracellular components, such as the 7S and NC-1 domains of type IV collagen, laminin (LN), fibronectin (FN) and IgA, in glomeruli from patients with IgA nephropathy. Renal biopsy specimens from 13 patients with IgA nephropathy were incubated with mouse monoclonal antibodies against the FN or non-collagenous (NC-1) domain of type IV collagen or polyclonal antiserum against the LN or 7S domain of human type IV collagen, and then stained with appropriate dilutions of FITC-labeled anti-mouse Ig antisera. Marked staining of the 7S or NC-1 domain of type IV collagen, LN or FN was detected in the glomerular capillary walls and/or mesangial areas in patients with IgA nephropathy. In particular, a prominent increase of FN was observed in the subendothelial regions of glomerular capillary walls, i.e. mesangial interposition, in the moderate or advanced stage of IgA nephropathy. Therefore, computer imaging analysis was shown to be useful for the quantitative determination of such components distributed in glomeruli from patients with IgA nephropathy.