Nitrotyrosine positive graft-infiltrating cells associate significantly with acute rejection in kidney transplantation

• Type: Article in International Scientific Journal
• Date: 2001

Authors

Xavier, P (Author) Other; José Oliveira (Author) FMUP; Aires, P (Author) Other; Sampaio, S (Author) Other; Pestana M (Author) FMUP; Mendes, AA (Author) Other

Journal

Title: European Journal of Immunogenetics

Vol. 28

Final page: 252

ISSN: 0960-7420

Publisher: Blackwell

Indexing

Scopus - 0 Citations

Other information

Authenticus ID: P-008-PXP

Abstract (EN): Nitric oxide (NO) plays a significant role in acute inflammatory/immunologic process. NO is very unstable but may be indirectly evaluated by studying protein nitrosylation. Previously we have shown that pre- and during acute rejection of kidney transplants (TX) a significant rise in monocyte-macrophage numbers is observed in fine-needle aspiration biopsy (FNAB) samples. Monocyte-macrophage play an important role in acute rejection through the synthesis of chemokines and cytokines and NO. However, they may perform house-keeping functions, specially important post-ischemia reperfusion injury in cadaver kidney transplants. We hypothesized that nitrotyrosine positive cell number should be raised in FNAB samples during acute rejection of TX. Thirty-six TX from cadaver donors were studied, all treated with cyclosporine, MMF and prednisolone. They were divided into group I (acute rejection, n=12) and group II (rejection-free, n=24). FNAB was done on first day of acute rejection and on day seven post-TX in group II. Every rejection episode was confirmed by a classical core biopsy all occurred during the first month post-TX. Following cytocentrifiigation cytospins were kept at -70°C until testing. Immunolabeling was performed by the labeled streptavidin-biotin immunoenzymatic antigen detection system (LAB) using an undiluted sheep anti-nitrotyrosine antibody, from OXIS® and a biotinylated goat anti-mouse as second antibody. Besides counting all nitrotyrosine-positive cells we also counted all renal parenchymal cells present in each cytopreparation to obtain the ratio of nitrotyrosine-positive over renal cells. Group I showed 31± 35 nitrotyrosine positive cells and ratio 1.15 ± 1.69; in group II we counted 17 ± 18 positive cells and the corresponding ratio was 0.10± 0.156 (P<0.05). We defined empirically as cut-off a ratio >0.2; the true positives were 100 % and the false positives were 13% and true negatives 87%. We conclude that nitrotyrosine positive cells are significantly up-regulated in FNAB samples during acute rejection. The predicted quantities of NO synthesized during the early days post-TX from cadaver donors may be too low to induce a signicant up-regulation of protein nitrosylation. The analysis of FNAB samples with nitrotyrosine labeling may assist in clearly differentiating the presence of monocytes associated with unspecific inflammation from those committed in anti-graft immune response. © 2001 Blackwell Science Ltd.

Language: English

Type (Professor's evaluation): Scientific