Serum level of transforming growth factor-beta1 (TGF-beta1) and the expression of TGF-beta receptor type II in peripheral blood mononuclear cells in patients with autoimmune hepatitis.

BACKGROUND/AIMS: To evaluate the association of the immunosuppressive effects of transforming growth factor-beta1 (TGF-beta1) with abnormalities in immune regulation in autoimmune hepatitis (AIH), we investigated the serum level of TGF-beta1 and expression of TGF-beta receptor type II (TbetaRII) in peripheral blood mononuclear cells (PBMC) in patients with AIH.

METHODOLOGY

Twenty-two patients with AIH were included in this study. Serum levels of total TGF-beta1 were determined using a specific enzyme-linked immunosorbent assay (ELISA). The expression levels of TbetaRII mRNA were semi-quantitatively determined by ribonuclease (RNase) protection assay specific for TbetaRII.

RESULTS

The mean serum level of TGF-beta1 in patients with AIH (230+/-95 ng/mL) was higher than that of healthy controls (137+/-81 ng/mL, p=0.012). The expression level of TbetaRII mRNA in PBMC obtained from AIH patients (0.131+/-0.046) was lower than that in PBMC of patients with chronic hepatitis C (0.186+/-0.074, p=0.019) and that of healthy subjects (0.188+/-0.060, p=0.013).

CONCLUSIONS

The present study of TbetaRII mRNA expression in PBMC from patients with AIH suggested that the decreased expression of TbetaRII might contribute partially to abnormalities in immune regulation observed in patients with AIH, despite concomitant up-regulation of TGF-beta1 production.