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Granulocyte-macrophage colony-stimulating factor (GM-CSF) was administered subcutaneously to 45 chronic hepatitis C patients, randomly assigned to receive 0.5, 1 or 2 microg GM-CSF/kg b.w. daily/6 weeks (n=30), or no treatment (n=15). Alanine transaminase (ALT) values normalized in four out of 10 (40%) patients administered 2 microg GM-CSF [1 cleared hepatitis C virus (HCV) RNA] but in none given 0.5 or 1 microg or untreated controls (P=0.0079). Following 4 weeks of rest, patients received 5 million units of interferon (IFN)alpha2b every other day/6 months, alone (n=30), or combined with 2 microg GM-CSF/daily for 3 months (n=15). At treatment end, ALT levels in patients administered the combination normalized more frequently than in those given monotherapy (73% vs 47%, P=0.089). Viraemia decreased significantly in 11/15 (73%) patients administered GM-CSF/IFNalpha2b combination (mean log HCV RNA copies/ml+/-SEM: 4.13+/-0.40 vs 5.29+/-0.23;P=0.011), and in 20/30 (67%) receiving IFNalpha2b monotherapy (4.27+/-0.28 vs 5. 31+/-0.14;P=0.004); 27% and 20% of patients given the combination and monotherapy, respectively, cleared HCV RNA. One patient in each regime had a sustained response after 12 months. 2', 5'-Oligoadenylate synthetase activity (2-5AS) increased during GM-CSF therapy (P=0.033 with the 2 microg dose). 2-5AS increased more in the GM-CSF/IFN-alpha2b combination than with IFNalpha2b monotherapy (P<0.02). GM-CSF provoked a skin reaction at the injection site, accompanied by moderate and reversible rises in eosinophil and leucocyte counts. In summary, daily s.c. GM-CSF administration is safe and shows effects against HCV; the GM-CSF/IFNalpha2b combination has an additional-but transient-antiviral activity in chronic hepatitis C., (Copyright 2000 Academic Press.)

The systemic hepatitis C virus (HCV) antigen-non-specific cytokine responses were investigated in cultures of peripheral blood mononuclear cells. Cytokines of the T helper (Th) 1 [interferon (IFN)gamma and interleukin (IL)-2] and Th2 (IL-4 and IL-10) phenotype, and the pro-inflammatory cytokines tumour necrosis factor alphaIL-1beta and IL-6, were secreted by the cells activated by the HCV antigen-independent pathway. Furthermore, these cytokine responses were shifted towards a Th1 predominance by treatment with IFN-beta and with IL-2, whereas cytokine responses were selectively amplified towards a combined Th1-Th2 profile by granulocyte-macrophage- but not by macrophage colony-stimulating factor. Moreover, pro-inflammatory cytokine production was significantly enhanced by IFN-beta and augmented dose-dependently with GM-CSF and IL-2. Therefore, these immune mediators can promote unique-as well as overlapping-systemic cytokine responses that may be relevant for immunotherapeutic interventions to control HCV infection., (Copyright 1999 Academic Press.)

The effects of ribavirin and interferon (IFN) alpha have been investigated on cultured peripheral blood mononuclear cells, obtained from 15 patients with chronic hepatitis C virus (HCV) infection. At clinically relevant serum concentrations achieved during therapeutic administration, ribavirin did inhibit moderately the mitogen-stimulated mononuclear cell proliferation and growth of the CD4+ and CD8+ T cell subsets without apparent cytolysis. The ribavirin-IFN-alpha combination showed activity against HCV with disappearance of HCV RNA in 27% of cases, and a synergy in the inducibility of the intracellular enzyme 2',5'-oligoadenylate synthetase. Such ribavirin concentrations induced modest increases in the T helper 1-like cytokine production by mononuclear cells. Higher ribavirin concentrations markedly inhibited IFN-gamma production, but augmented interleukins (IL) 2, 4, and 12 secretion. Conversely, IFN-alpha tended to suppress IL 2, 4 and 12, but enhanced IFN-gamma and IL-10 secretion. Thus, ribavirin and IFN-alpha appear to cause diverse effects on immunoregulatory cytokine secretion, and when combined, counteracted for production of IL-2 and IL-12, while upregulated mononuclear cell secretion of IFN-gamma and that of the anti-inflammatory cytokine IL-10. These findings suggest a non-cytolytic modulation of inflammatory responses induced by the drug combination, that may be relevant in the pathophysiology of chronic HCV infection.

The safety and efficacy of granulocyte-macrophage colony-stimulating factor (GM-CSF) as adjuvant therapy for interferon alpha (IFN-alpha) treatment has been evaluated in 20 non-cirrhotic patients with chronic hepatitis C virus (HCV) infection. Adjuvant therapy with GM-CSF plus IFN-alpha was associated with less myelosuppression than with IFN-alpha alone (P < .01), although the rate of local adverse reactions increased. GM-CSF adjuvant therapy led to a 50% biochemical response (transaminase values within the normal range at therapy end) and to reductions in HCV RNA concentrations (median HCV RNA reduction of 99%, range 8-100%), which were similarly observed in single IFN-alpha recipients (median HCV RNA reduction of 91%, range 38-100%). However, HCV RNA became undetectable in three biochemical responders to the GM-CSF adjuvant therapy, but in only one biochemical non-responder to IFN-alpha alone. The use of GM-CSF as adjuvant therapy is safe and, although it has not improved the biochemical response, it might potentiate the virologic response to IFN-alpha treatment alone.

Hepatitis C virus infects mononuclear leukocytes of patients with chronic hepatitis C. Treatment with rhG-CSF led to a dose-related reduction in the genomic and antigenomic hepatitis C viral strands in cultures of mitogen-stimulated, naturally-infected peripheral blood mononuclear cells from patients with chronic hepatitis C. Hepatitis C virus genomic strand of subtype 1b was suppressed in 5 of 11 cases, and concurrently with suppression of the viral antigenomic strand in two of them. The treatment also resulted in a significantly increased release of interleukin 6, but not of other cytokines. However, the biological response of hepatitis C virus-infected mononuclear cells to treatment with recombinant human granulocyte colony-stimulating factor was unrelated to any particular pattern of cytokine production.