Increased plasma angiogenin level is associated and may contribute to decreased T-cell zeta-chain expression in hemodialysis patients

Abstract

Hemodialysis (HD) patients are characterized by impaired T-cell function at least in part because of T-cell zeta-chain downregulation due to inflammation. Angiogenin responds as an acute phase reactant, is increased in HD patients, suppresses T-cell function and increased angiogenin level is co-localized with T-cell zeta-chain downregulation in various pathologies. Angiogenin can inhibit translation of proteins, which lack internal ribosomal entry sites in the corresponding mRNAs. In this study, the possible effect of angiogenin on T-cell zeta-chain downregulation was evaluated. Thirty HD patients and 21 healthy volunteers participated. T-cell zeta-chain expression was assessed with flow cytometry, plasma angiogenin and serum IL-6 with ELISA and serum C-reactive protein with an immunoturbidimetric method. Two available software tools were used for predicting the presence or not of internal ribosomal entry sites in T-cell zeta-chain mRNA sequence. In silico analysis of T-cell zeta-chain mRNA sequence failed to reveal the presence of internal ribosomal entry sites. T-cell zeta-chain expression was lower in HD patients than in healthy volunteers (1.86 ± 0.63 vs. 4.73 ± 3.22). In HD patients, C-reactive protein as well as IL-6 were higher than in healthy volunteers (10.04 ± 15.13 mg/L vs. 3.43 ± 0.98 mg/L and 15.06 ± 13.08 pg/mL vs. 2.11 ± 2.10 pg/mL respectively). Angiogenin was higher in HD patients than in healthy volunteers (483.20 ± 154.07 ng/mL vs. 259.98 ± 64.15 ng/mL). Neither C-reactive protein, nor IL-6 was associated with angiogenin or T-cell zeta-chain expression. Angiogenin concentration was negatively related to the expression of T-cell zeta-chain (r = -0.410, P = 0.025). Increased angiogenin may contribute to decreased T-cell zeta-chain expression in HD patients.