IN-VITRO BROMODEOXYURIDINE LABELING OF RENAL BIOPSY SPECIMENS - CORRELATION BETWEEN LABELING INDEXES AND TUBULAR DAMAGE

Aims-To examine the correlation between bromodeoxyuridine (BrdU) label ling indices (LI) and tubular damage in renal biopsy specimens; to eva luate the diagnostic and prognostic potential of measuring cell prolif eration in a variety of renal lesions. Methods-In vitro BrdU labelling of renal biopsy specimens was undertaken and labelled cells were dete cted in routinely fixed, paraffin wax embedded sections by immunohisto chemistry. The BrdU LI were calculated as percentages for the three ty pes of tubular cells-proximal and distal convoluted tubules and medull a (LI/PCT, LI/DCT, LI/Med)-and a total tubular BrdU LI (LI/Tub) was al so calculated for each biopsy specimen. Histological features indicati ve of tubular damage were also scored and a total tubular damage score obtained for each biopsy specimen. Results-The one hour labelling pro cess did not affect tissue morphology or impede subsequent diagnosis. Four biopsy specimens were obtained from three renal transplant recipi ents. Diagnosis of 19 non-transplant biopsy specimens revealed a varie ty of renal lesions. Total tubular damage scores ranged from 0 to 25 a nd the LI/Tub ranged from 0 to 3.68% in all 23 biopsy specimens. Analy ses of variance showed highly significant correlations between the tot al tubular damage score and both LI/Tub (p = 0.004) and LI/PCT (p 0.00 4); a weaker correlation was found between the total tubular damage sc ore and LI/DCT (p = 0.013). Conclusions-A correlation was found betwee n tubular damage and BrdU LI. This was most clearly seen in the proxim al tubules. However, as the study was limited to a few examples of spe cific forms of glomerular or interstitial disease, firm conclusions ab out the value of BrdU labelling in routine diagnosis and prognosis cou ld not be drawn.