Undetectable phospho-STAT1 in peripheral blood mononuclear cells from patients with chronic hepatitis C who do not respond to interferon-alpha therapy

SUMMARY. The a-defensin genes promoter regions contain a putative nuclear factors of activated T cells (NFAT)-binding site and it is known that hepatitis C virus (HCV) core protein activates the interleukin (IL)-2 gene transcription through the NFAT pathway. The aims of this study were to investigate if HCV affects the a-defensin expression in peripheral human mononuclear cells (PBMCs) and to evaluate the existence of a correlation between a-defensins and liver damage in patients with chronic hepatitis C. Ninety patients with chronic hepatitis C, 30 with chronic hepatitis B and 25 healthy controls were enrolled. a-Defensins were identified and quantified in PBMCs by mass spectrometry, enzymelinked immunosorbent assay, antibacterial activity and mRNA levels. PBMCs from three patients and controls were stimulated with HCV core protein, hepatitis B virus core antigen and the a-defensin mRNAs level was quantified. We found that HCV core protein activates in vitro the a-defensin transcription. a-Defensin levels in patients with chronic hepatitis C (mean ± SD ¼ 1.103 ± 0.765 ng/106 cells), chronic hepatitis B (0.53 ± 0.15) and healthy controls (0.217 ± 0.09) resulted significantly different (P < 0.001). In patients with chronic hepatitis C, the a-defensin levels and antibacterial activity correlate with the liver fibrosis. Our data suggest that HCV induces a-defensin expression. The high linear correlation of a-defensin levels with advancing fibrosis makes the measure of these peptides a reliable marker to evaluate fibrosis stage. Keywords: a-defensin, chronic hepatitis, hepatitis C vir

Inhibition of protein S by autoantibodies in patients with acquired protein S deficiency

This study was undertaken to analyze antibodies to protein S (PS) in patients with an acquired PS deficiency. Plasma from symptomatic patients with acquired (n = 14) or congenital (n = 10) PS deficiency and LD healthy donors was screened for PS antibodies by immunoblotting and for anti-phospholipid antibodies. PS antibodies (IgG) were detected in five of the patients with acquired PS deficiency. These antibodies belonged to the G1 and G4 immunoglobulin subclasses. IgG fractions from the same 5 patients were shown to inhibit PS activity. The inhibition of PS activity by the 5 IgG fractions was shown to be time- and dose-dependent and was abolished following incubation with purified PS, while no effect was found after absorption with cardiolipin micelles. In addition, anticardiolipin monoclonal or human purified antibodies, failed to exert significant PS inhibition. These findings demonstrate that anti-PS antibodies are able to inhibit PS activity and that this is independent of anti-phospholipid antibodies. Given the clinical features of the patients, these antibodies should be regarded as an expression of the broad autoimmune syndrome involving the phospholipid-binding plasma proteins