Urinary cell levels of mRNA for OX40, OX40L, PD-1, PD-L1, or PD-L2 and acute rejection of human renal allografts.

BACKGROUND: The positive costimulatory proteins OX40 and OX40L and negative regulatory proteins programmed death (PD)-1, PD ligand 1, and PD ligand 2 have emerged as significant regulators of acute rejection in experimental transplantation models. METHODS: We obtained 21 urine specimens from 21 renal allograft recipients with graft dysfunction and biopsy-confirmed acute rejection and 25 specimens from 25 recipients with stable graft function and normal biopsy results (stable). Urinary cell levels of mRNAs were measured using real-time quantitative polymerase chain reaction assays, and the levels were correlated with allograft status and outcomes. RESULTS: Levels of OX40 mRNA (P<0.0001, Mann-Whitney test), OX40L mRNA (P=0.0004), and PD-1 mRNA (P=0.004), but not the mRNA levels of PD ligand 1 (P=0.08) or PD ligand 2 (P=0.20), were significantly higher in the urinary cells from the acute rejection group than the stable group. Receiver operating characteristic curve analysis demonstrated that acute rejection is predicted with a sensitivity of 95% and a specificity of 92% (area under the curve=0.98, 95% confidence interval 0.96-1.0, P<0.0001) using a combination of levels of mRNA for OX40, OX40L, PD-1, and levels of mRNA for the previously identified biomarker Foxp3. Within the acute rejection group, levels of mRNA for OX40 (P=0.0002), OX40L (P=0.0004), and Foxp3 (P=0.04) predicted acute rejection reversal, whereas only OX40 mRNA levels (P=0.04) predicted graft loss after acute rejection. CONCLUSION: A linear combination of urinary cell levels of mRNA for OX40, OX40L, PD-1, and Foxp3 was a strong predictor of acute rejection in human renal allograft biopsies. This prediction model should be validated using an independent cohort of renal allograft recipients.

[Proteins C and S of coagulation: new markers of thrombotic risk in nephrotic syndromes?]. / Protéines C et S de la coagulation: des nouveaux marqueurs du risque thrombotique au cours des syndromes néphrotiques?

Thromboembolic events remain one of the most serious complications in patients with nephrotic syndrome (NS). The natural anticoagulant system protein C-protein S was evaluated in patients with proteinuria and NS. Protein C levels were found to be normal or increased in NS. Protein C levels correlated positively with proteinuria, cholesterol and triglycerides and negatively with serum albumin. All of the 17 patients with NS exhibited urinary loss of protein C. Total protein S and C4BP were increased in mild and moderate forms of NS. Free protein S was identical in controls and NS patients. Nine of ten patients had urinary loss of protein S. No correlation was found between protein S and the various usual biologic parameters of NS. However, two patients with NS and thrombosis of the renal veins had an acquired deficit in either free protein S or protein C. Thus, in some patients, an acquired deficit in free protein S and/or protein C may contribute to the development of thrombotic complications in NS.