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

EVIDENCE FOR THE EXISTENCE OF GANGLIOSIDE MOLECULES ON PNEUMOCYSTIS-CARINII FROM HUMAN LUNGS

This study was undertaken to assess whether glycolipid antigens (particularly gangliosides) are associated with Pneumocystis carinii obtained from human lungs. Gangliosides were extracted, purified in high performance thin-layer chromatography and stained with resorcinol. Two resorcinol-positive bands, co-migrating with GM1 and GD1a were demonstrated, suggesting the existence of ganglioside molecules on P. carinii. No resorcinol-positive bands were revealed in the pulmonary control tissue. In addition, an antiserum obtained from rabbits immunized with P. carinii antigen reacted with gangliosides GM1 and GD1a, as revealed by a dot immunobinding assay. This reactivity was inhibited by first incubating the antiserum with ganglioside micelles. Furthermore, anti-glycosphingolipid antibodies (aGM1) reacted with the bands of 200 and 55 kDa of P. carinii antigen. These results suggest that ganglioside antigens expressed on P. carinii can trigger specific immune responses

GM3 AS A TARGET OF ANTI-LYMPHOCYTIC GANGLIOSIDE ANTIBODIES IN AIDS PATIENTS

IgG antibodies reacting with the GM3-comigrating band extracted from pooled AIDS lymphocytes were detected in 33.3% of AIDS patients sera, in 8% of asymptomatic anti-HIV-positive subjects, in none of the sera obtained from asymptomatic anti-HIV-negative drug abusers, from patients with acute B and chronic C hepatitis, and from healthy donors. All positive sera reacted selectively with the GM3-comigrating band obtained from AIDS lymphocytes but not with the corresponding band from normal lymphocytes. The lymphocytic ganglioside autoantigen was revealed as GM3. In addition, two main data were shown: (a) AIDS lymphocytes have an increased concentration of GM3 and (b) the ceramide of AIDS lymphocytic GM3 has a different percentual composition of fatty acids in contrast to control cells. It is suggested that these quantitative and qualitative changes might be responsible for the appearance of circulating anti-lymphocytic GM3 antibodies