Evaluation of Interstitial Fibrosis and Tubular Atrophy (IFTA) in Renal Allograft Biopsies:- Comparison of Visual Analysis with Morphometric Quantification and its Correlation with Renal Function

ABSTRACT Introduction: With the increase in number of allografts being performed, the frequency of chronic allograft nephropathy (CAN) has also increased. It is characterized clinically by a progressive decline in glomerular filtration rate, and histologically, by a progressive interstitial fibrosis (IF) and tubular atrophy (TA) which can even be seen in recipients with good allograft function. Objectives: To compare visual analysis with morphometric quantification of interstitial fibrosis and tubular atrophy (IFTA) in renal allograft biopsies and its correlation with renal function. Materials and Methods: A total of 29 renal allograft biopsies were evaluated for fibrosis and tubular atrophy by light microscopy by visual method on Masson’s trichrome-stained and PAS-stained sections, respectively, as well as by computer-assisted morphometry. IFTA was graded as per Banff working classification of renal allograft pathology, which includes a four-point estimate of the prevalence of IF (ci score) and for tubular atrophy (ct score). The estimation of IF and TA by the two methods was correlated with the renal function state; the serum creatinine level. Result: The percentage of IFTA showed statistically significant correlation between manual and morphometric methods (P < 0.001). Each of the method was correlated with serum creatinine level. IF showed a good correlation with serum creatinine by both the methods; however, no correlation could be established between TA and serum creatinine by either method. Conclusion: When calculating scoring IFTA as per Banff criteria, by either the visual method or the morphometric method, there was a significant correlation between the two methods. However when expressed only as a percentage of total area, the visual method was associated with slight overestimation of both the parameters.