Macrophage index predicts short-term renal allograft function and graft survival.

The ability to predict renal allograft dysfunction in the short term and predict graft survival by quantifying the macrophage infiltrate in allograft renal biopsies is described. Renal allograft biopsies performed for cause in 41 consecutive patients were scored for macrophages (macrophage index, MI) by use of a modified Banff score of inflammation (BSI), and the impact of the MI on serum creatinine (SCr) levels 3 months post-biopsy (post-Bx) and on graft survival was quantified. Biopsies were stained for macrophages, individual lesions semiquantified and MI, BSI and chronic allograft damage index (CADI) obtained. The effects of pathologic indices on 3 month post-Bx SCr and graft survival were quantified by multivariate analysis and Cox regression. Glomerular and interstitial macrophage scores correlated inversely with graft survival. MI predicted an increase in SCr 3 months post-Bx (P=0.02). MI >3 (hazard ratio 23.13, P=0.003) also had a powerful negative predictive value on graft survival.