Molecular markers in subclinical acute rejection of renal transplants

Abstract

In this study, we evaluated the expression of molecular markers of acute rejection in protocol biopsies of patients with and without subclinical acute rejection (SAR). Protocol biopsies were performed at 2 months (n = 21) and 12 months (n = 14) after kidney transplantation in patients with stable allograft function. After biopsy tissue RNA isolation, reverse transcription and polymerase chain reaction (RT-PCR) for the glyceraldehyde 3-phospate dehydrogenase (GAPDH), perforin, granzyme B and Fas ligand genes were performed. The Banff 97 classification was used for histological diagnosis. Creatinine concentrations at 2 months were significantly higher in patients with SAR (1.46 +/- 0.27 x 1.18 +/- 0.24; p < 0.02). Perforin transcripts were found in 15 biopsy specimens, 10 of which had histological signs of SAR (p = 0.06). Granzyme B expression was found in 10 specimens, nine of which had SAR (p < 0.01). Fas ligand was expressed in seven specimens, and six of them were classified as SAR (p < 0.01). Perforin expression had the highest sensitivity (81%) for the diagnosis of SAR. Granzyme B and Fas ligand had specificity of 90%. At 12 months, there was no significant difference in creatinine concentrations for patients with and without previous SAR (1.63 +/- 0.57 x 1.28 +/- 0.31; p = 0.10). Molecular analysis revealed that there was no statistically significant difference in the expression of perforin and granzyme B in patients with and without SAR. Fas ligand expression was observed in five samples, four of which had histological signs of SAR (p = 0.03). At 12 months, perforin expression had the highest sensitivity (83%), and Fas ligand, the highest specificity (88%) for the diagnosis of SAR. We concluded that the expression of genes that encode proteins involved in the cytolytic attack against the allograft is increased in kidneys with SAR. These findings support the understanding that SAR is an active immune process potentially deleterious to renal allografts.

Perforin, Granzyme B, and Fas Ligand for Molecular Diagnosis of Acute Renal-Allograft Rejection: Analyses on Serial Biopsies Suggest Methodological Issues

“…borderline changes. Studies have investigated whether diagnosis of AR (even subclinical forms) can be improved by analyzing the expression of various immune activation transcripts in biopsies (8,12,(15)(16)(17). A study on 18 genes involved in host-mediated cellular response in renal biopsies from AR patients found a high expression of P, GB and FL by comparison with NR (17).…”

“…A reason for our discouraging results might lie in a different performance of our quantitative procedures. Most of previous studies in this field were carried out with competitive RT-PCR (9,10,12,17) and more recently, with real-time RT-PCR (20 -23, 33). Two considerations make us confident of the reliability of our conclusions based on the comparative RT/PCR, however.…”

Diagnostic Performance of Fas Ligand mRNA Expression for Acute Rejection after Kidney Transplantation: A Systematic Review and Meta-Analysis

“…As this state of sub-clinical rejection could prove detrimental to long-term graft function, a role for surveillance biopsies of stable grafts with intent-to-treat sub-clinical rejection should be considered. This conclusion was supported by Dias et al[32], who showed that FASL expression has a higher SPE (88%) than granzyme B and perforin for the diagnosis of sub-clinical AR 12 months after kidney transplantation. Herein we synthesized data investigating sub-clinical AR, and showed a high pooled SPE (0.95), but a poor SEN (0.46).…”

“…After a carefully review and exclusion of studies considered to lack suitability, 12 studies published between 1997 and 2008 met the inclusion criteria[26–37]. Of the 12 studies, Lipman[27] and Dias et al[32] evaluated the expression of molecular markers of AR in protocol biopsies of patients with and without subclinical AR; 2 studies[28, 31] detected the FASL expression in both graft biopsy and PBL samples, and 1 study [37] detected FASL in both urine and PBL samples. In the current study, we retrieved each group as an independent data set for a total of 15 data sets and 496 subjects.…”

Performance of Polymerase Chain Reaction Techniques Detecting Perforin in the Diagnosis of Acute Renal Rejection: A Meta-Analysis

“…Only 4 reports were published prior to 2000 [9], [26], [29], [30], one of them contained 2 data sets which made it 5 data sets in this subgroup. The remaining 10 reports (12 data sets) were published after 2000 [25], [27], [28], [31]–[37]. The DOR of studies before the year 2000 was 43.52 while the DOR of studies after 2000 was 24.90.…”