Facilitation of Renal Allograft Biopsy Evaluation by Using Combined CD3 and PAS Special Stains
Zhongxin Yu, Jeanne Frazier, William F Kern, Martin Turman. University of Oklahoma, Oklahoma City, OK
Background: Renal biopsy plays an important role in transplant allograft management. Based on the mechanisms causing allograft injury, renal transplant rejection can be roughly divided into two categories, antibody-mediated rejection and T-cell-mediated rejection. The diagnosis of T-cell-mediated rejection is based on the observation of tubulitis, arteritis, and interstitial lymphocytic infiltrates. Most laboratories use routine H&E and PAS stains to evaluate these inflammations. However, assessment sometimes can be difficult and may be not accurate when the cellular rejection is complicated by other renal injuries. Some pathologists utilize CD3, a pan T-cell marker, immunohistochemical stain (IHC) to help identify the T-lymphocytic infiltrates. However, routine IHC is usually performed without a counterstain which gives an indistinguishable background so that one cannot readily determine the location of the T-lymphocytic infiltrates, i.e., on the tubular epithelium (tubulitis) or merely in the interstitium. To resolve this issue, we developed a method that uses combined CD3 and PAS special stains.
Design: 10 previous transplant renal biopsy cases were selected for method validation. All subsequent transplant renal biopsies (more than 30 cases) were tested for the new combined CD3 and PAS method. Formalin-fixed paraffin-embedded tissue blocks were cut at 2 µm thick and embedded on positive charged slides. The slides were first stained with anti-CD3 polyclonal antibody, and then stained with PAS. The entire procedure was performed using Ventana automated system and took about 3 to 4 hours.
Results: In comparison to routine PAS stain alone or CD3 IHC without counterstain, the combined CD3 and PAS method clearly highlights the location and the intensity of the T-lymphocytic infiltrates; thus it has significantly facilitated our ability to evaluate T-cell mediated rejection in renal allografts.
Conclusions: This new method has greatly facilitated our work in pathological evaluation of renal transplant biopsy. We think this method is easy to perform and has a great potential to be adapted in daily practice for renal transplant biopsy evaluation.
Category: Kidney (does not include tumors)
Wednesday, March 21, 2012 1:00 PM
Poster Session VI # 306, Wednesday Afternoon