Quantitative morphometry of lupus nephritis: the significance of collagen, tubular space, and inflammatory infiltrate.

BACKGROUND: Lupus nephritis encompasses a wide range of parenchymal injuries and severity. Better predictors of outcome are needed for patients newly diagnosed with lupus nephritis, so that an appropriate management strategy may be selected.
METHODS: A single-center cohort of first renal biopsies for lupus nephritis was chosen. Histologic sections of whole biopsy cores were stained with picro-Sirius red, and light microscopic images (x100) were digitally captured. Using a simple, freely available software package, the cortex of each biopsy was evaluated for four different parameters: area occupied by nuclei, intratubular space, fibrillary collagen, and collagenous matrix. Clinical and laboratory data were collected retrospectively from the time of biopsy and throughout follow-up.
RESULTS: A high nuclear index at initial biopsy correlated with clinical parameters of disease activity, at the time of biopsy. High collagen matrix index predicted both relapse and progression to end-stage renal disease (ESRD). The fibrillary collagen index predicted progressive disease as assessed by doubling of serum creatinine, and relapse. Increased tubular space also predicted progressive disease as determined by doubling of creatinine and renal death.
CONCLUSION: A simple automated system for objectively scoring biopsies of lupus nephritis predicts renal survival and may provide a useful adjunct to guide patient management.