Probiotic characterization of Lactobacillus isolates from canine faeces.

AIMS: There is interest in using probiotics such as Lactobacillus species to control canine intestinal infections. The bacterial species should be of canine intestinal origin exhibiting host specificity. Bacterial strains were isolated from dog faecal samples and characterized to select specific probiotics as dietary supplements in feed, promoting health status. METHODS AND RESULTS: Bacterial strains have been screened for their probiotic properties including survival to gastric and pancreatic juices and bile salts, resistance to antibiotics and antipathogenicity. Five of 14 isolated Lactobacillus strains were tolerant to gastric stress. They were also resistant to clindamycin and with a significant antimicrobial capacity towards the pathogenic strains tested, variable according to the strain. They were identified by morphological and molecular characterization comparing the 16S rRNA gene sequence with the blast database. Three strains were identified as Lactobacillus reuteri and two as Lactobacillus johnsonii. Sugar fermentation profiles and adhesion to HT29 epithelial cells have been in vitro verified on L. reuteri AI, chosen as probiotic candidate. Resistance to freeze-drying, production and subsequent in vivo administration evaluating strain permanence, were also performed. No loss of vitality has been recorded due to the freeze-drying process. The average value of recovery percentage of L. reuteri AI at the end of the administration period and after 1 week of follow-up was respectively 26·7 and 17·4% of the total Lactobacillus sp. CONCLUSIONS: Among several selected probiotic strains, L. reuteri AI proved to be the best probiotic candidate to use as a supplement for dogs. SIGNIFICANCE AND IMPACT OF THE STUDY: Control of intestinal pathogenic micro-organisms in dogs is a growing concern and the selection of autochthonous probiotic bacterial strains to overcome some of the gut problems associated with the modern domestication of animals is a valuable tool.

A new approach to the use of α-fetoprotein as surveillance test for hepatocellular carcinoma in patients with cirrhosis.

BACKGROUND: Surveillance for hepatocellular carcinoma (HCC) is recommended in patients with cirrhosis. As α-fetoprotein (AFP) is considered a poor surveillance test, we tested the performance of its changes over time. METHODS: Eighty patients were diagnosed with HCC (cases) during semiannual surveillance with ultrasonography and AFP measurement were recruited and matched for age, gender, etiology and Child-Pugh class with 160 contemporary cancer-free controls undergoing the same surveillance training group (TG). As a validation group (VG) we considered 36 subsequent patients diagnosed with HCC, matched 1 : 3 with contemporary cancer-free controls. α-Fetoprotein values at the time of HCC diagnosis (T0) and its changes over the 12 (Δ12) and 6 months (Δ6) before cancer detection were considered. RESULTS: In both TG and VG, >80% of HCCs were found at an early stage. In TG, AFP significantly increased over time only in cases. T0 AFP and a positive Δ6 were independently associated with HCC diagnosis (odds ratio: 1.031 and 2.402, respectively). The area under the curve of T0 AFP was 0.76 and its best cutoff (BC) was 10 ng ml(-1) (sensitivity 66.3%, specificity 80.6%). The combination of AFP >10 ng ml(-1) or a positive Δ6 composite α-fetoprotein index (CAI) increased the sensitivity to 80% with a negative predictive value (NPV) of 86.2%. Negative predictive value rose to 99%, considering a cancer prevalence of 3%. In the VG, the AFP-BC was again 10 ng ml(-1) (sensitivity 66.7%, specificity 88.9%), and CAI sensitivity was 80.6% with a NPV value of 90.5%. CONCLUSIONS: CAI achieves adequate sensitivity and NPV as a surveillance test for the early detection of HCC in cirrhosis.

Serum hepatitis B surface antigen monitoring in long-term lamivudine-treated hepatitis B virus patients.

Serum hepatitis B virus surface antigen (HBsAg) levels have been suggested to predict interferon response in chronic hepatitis B. A few data are available on the role of HBsAg measurement in nucleos(t)ide analogues (NA) treatment. We retrospectively investigated the relation between HBsAg changes and main treatment outcomes during long-term lamivudine treatment in hepatitis e antigen (HBeAg)-negative chronic hepatitis B. A total of 42 HBeAg-negative patients were consecutively enrolled in an open-label study on long-term lamivudine monotherapy (150 mg/die). Serum HBsAg levels were quantified every 6 months by Architect assay (Abbott Diagnostics). HBV-DNA was quantified quarterly by real-time PCR (Roche Diagnostics). The median duration of lamivudine treatment was 66 months (20-153). One patient (2%) was a primary nonresponder, 35 (83%) developed virological breakthrough (VB) and the remaining six patients (14%) were classified as long-term on-treatment responders. During treatment, HBsAg levels decreased only in long-term on-treatment responders, while no changes were observed in resistant patients. Failure to achieve a decrease of 0.7 log(10) IU/mL in serum HBsAg at month six of lamivudine had a positive predictive value of developing VB of 90% and a negative predictive value of 100%. These high predictive values were also maintained in the subgroup of patients negative for HBV-DNA at month six. The results of this study with a small sample size suggest a role of on-treatment HBsAg quantification in the management of lamivudine-treated patients. If validated prospectively in a larger patient cohort, HBsAg measurements would be a useful adjunct to optimize antiviral therapy.

Immunological modifications during treatment with thymosin alpha1 plus antiviral therapy in chronic hepatitis C.

The current standard therapy for the treatment of chronic hepatitis C virus (HCV) is the combination of peginterferon and ribavirin, although many patients fail to clear the virus and their retreatment options are still unsatisfactory. Thymosin alpha1 (Talpha1) is an immunomodulating agent that has been proposed as complementary therapy for chronic HCV, especially in the setting of difficult-to-treat patients. The aim of this study was to evaluate, in patients nonresponsive to previous Peg-based therapy, the effect of standard antiviral therapy with or without Talpha1 on peripheral lymphocyte subsets. Twenty-four patients, 12 receiving Talpha1 and 12 standard therapy, were enrolled. Peripheral subpopulations were analyzed by flow cytometry. Although the addition of Talpha1 did not seem to significantly modify the T-lymphocyte subpopulations, as comparable behaviors were observed in the CD4 and CD8 longitudinal evaluation, Talpha1 produced an earlier increase of natural killer cells. An accurate selection of HCV patients who can benefit from immunomodulation is needed.

Hepatitis C Virus-related chronic liver disease in elderly patients: an Italian cross-sectional study.

Chronic hepatitis C virus (HCV) infection has been poorly investigated in the elderly. The aim of this study was to identify the age-specific characteristics of chronic hepatitis C by comparing patients > or =65 years with those <65 years. A cross-sectional study was performed on data collected from consecutive outpatients referred for the first time to two tertiary outpatient clinics for liver diseases located in Bologna (Northern Italy) and Paola, Cosenza (Southern Italy) over a two-year period. A total of 560 anti-HCV and HCV-RNA positive patients were enrolled, of whom 174 (31%) were 65 years or older. The proportion of older patients was significantly higher in the Southern Italy centre, accounting for more than 40%. Comparison of younger and older groups showed that 51% patients > or =65 years had advanced liver disease (liver cirrhosis or hepatocellular carcinoma) compared with 26% younger patients (P < 0.0001). About half of the patients > or =65 years were not aware of their anti-HCV positive status, even if they tended to be more symptomatic than the younger group. By multivariate analysis, age > or = 65 years, alcohol consumption and diabetes were independently associated with advanced liver disease. Overall, 34 out of 174 patients (20%) > or =65 years had received antiviral treatment compared with 122 out of 386 (32%) younger patients (P = 0.003). Our results further emphasize the notion that chronic hepatitis C is becoming a disease of the elderly and that elderly patients with chronic HCV infection often have severe and underestimated disease.

Clinical trial: peg-interferon alfa-2b and ribavirin for the treatment of genotype-1 hepatitis C recurrence after liver transplantation.

BACKGROUND: Treatment of hepatitis C virus (HCV) recurrence after liver transplantation (LT) is difficult with low response rates. AIM: To assess the safety and efficacy of pegylated-interferon (PEG-IFN) alfa-2b + ribavirin (RBV) in patients with post-LT recurrent genotype-1 HCV and to establish stopping rules according to response. METHODS: Fifty-three patients with post-LT HCV recurrence were enrolled. Patients received PEG-IFN alfa-2b 1.0 micro/kg/week plus RBV 8-10 mg/kg/day for 24 weeks. Those with 'early virological response at week 24' (EVR24) continued treatment for 24 weeks (group A). Patients without EVR24 were randomized to continue (group B) or to discontinue (group C). RESULTS: Overall sustained virological response (SVR) was 26% (14/53). Alanine aminotransferase, rapid virological response, EVR12, EVR24, undetectable serum HCV-RNA at weeks 12 (cEVR12) and 24 (cEVR24) were related to SVR. cEVR12 and cEVR24 (OR: 14.7; 95% CI: 2.02-106.4) were independent predictors of SVR. All patients with SVR, had cEVR12. No patient in groups B and C achieved end-of-treatment response. One patient in group B had SVR. CONCLUSIONS: Pegylated-interferon alfa-2b was effective in one of four of patients with HCV genotype 1 after LT. Treatment should be discontinued in patients with no virological response at week 12. Further studies are needed to evaluate whether a longer treatment period may be beneficial in patients with > or =2 log10 drop in HCV-RNA at week 24.

Stem cell mobilization and collection in patients with liver cirrhosis.

BACKGROUND: Bone marrow-derived stem cells (BMSC) and granulocyte colony-stimulating factor (G-CSF) have been proved to contribute to tissue regeneration after liver injury. AIMS: To test the safety of G-CSF and define the exact dose capable of mobilizing BMSC in the majority of patients with liver cirrhosis; and to assess the feasibility of leukapheresis to collect BMSC from peripheral blood. METHODS: In this study, we treated 18 patients affected by liver cirrhosis with increasing doses of G-CSF to mobilize CD34(+) and CD133(+) BMSC into the peripheral blood. RESULTS: The dose-finding phase demonstrated that 15 microg/kg/day of G-CSF is the optimal dose to mobilize both CD34(+) and CD133(+) stem cells. Circulating BMSC were collected by a single step leukapheresis in three patients and the mean number of CD34(+) and CD133(+) cells cryopreserved was 1.3 +/- 0.7 and 1.2 +/- 0.5 x 10(6)/kg, respectively. No severe adverse events were observed during the drug administration and stem cell collection. Noteworthy is, none of the patients showed a significant modification of liver function. CONCLUSIONS: Our study demonstrates that G-CSF administration and BMSC collection from the peripheral blood is possible and safe in patients with liver cirrhosis. The optimal dose to mobilize BMSC in cirrhotics is 15 microg/kg/day. At this dose, G-CSF does not seem to modify the residual liver function in cirrhotic patients.

In vitro effect of thymosin-alpha1 and interferon-alpha on Th1 and Th2 cytokine synthesis in patients with eAg-negative chronic hepatitis B.

Thymosin alpha-1 (Talpha1) has been shown to be effective in chronic hepatitis B treatment. This study investigated the effect of Talpha1 and interferon-alpha (IFNalpha) on cytokine production by peripheral blood mononuclear cells (PBMCs) of 12 patients with eAg-negative chronic hepatitis B (HBV). We evaluated the effect of incubation with Talpha1, IFNalpha or both on the synthesis of T-helper 1 (Th1) cytokines [interleukin-2 (IL-2), IFNgamma] and Th2 cytokines (IL-4, IL-10) and of antiviral protein 2',5'-oligoadenylate synthetase (2',5'-OAS) in patients and in a group of 10 healthy controls. Concerning Th1 profile, controls showed lower IL-2 synthesis than HBV patients. In HBV setting, IFNalpha/Talpha1 combination was able to increase IL-2 production significantly, when compared with baseline condition. About the Th2-cytokines, controls showed statistically lower synthesis of IL-4 and higher production of IL-10, than HBV patients. In these latter, IFNalpha increased the synthesis of IL-10 compared with baseline. Interestingly, both Talpha1 alone and the IFNalpha/Talpha1 combination reversed this effect. Finally, compared with baseline, the synthesis of 2',5'-OAS was significantly higher in the presence of Talpha1 and IFNalpha alone, and in the presence of IFNalpha/Talpha1 association, while no differences were found between controls and HBV patients. In conclusion, in PBMCs from eAg-negative HBV patients, Talpha1 alone was able to increase the antiviral protein synthesis, while in association with IFNalpha, it stimulated the IL-2 synthesis and inhibited the IFN-induced IL-10 production. These results need further investigations, but reinforce the idea of an immunotherapeutic approach for chronic hepatitis B.

High incidence of allograft dysfunction in liver transplanted patients treated with pegylated-interferon alpha-2b and ribavirin for hepatitis C recurrence: possible de novo autoimmune hepatitis?

BACKGROUND: Interferon may trigger autoimmune disorders, including autoimmune hepatitis, in immunocompetent patients. To date, no such disorders have been described in liver transplanted patients. METHODS: 9 of 44 liver transplanted patients who had been receiving pegylated-interferon alpha-2b and ribavirin for at least 6 months for hepatitis C virus (HCV) recurrence, developed graft dysfunction despite on-treatment HCV-RNA clearance in all but one case. Laboratory, microbiological, imaging and histological evaluations were performed to identify the origin of graft dysfunction. The International Autoimmune Hepatitis scoring system was also applied. RESULTS: In all cases infections, anastomoses complications and rejection were excluded, whereas the autoimmune hepatitis score suggested a "probable autoimmune hepatitis" (score from 10 to 14). Three patients developed other definite autoimmune disorders (overlap anti-mitochondrial antibodies (AMA)-positive cholangitis, autoimmune thyroiditis and systemic lupus erythematosus, respectively). In all cases, pre-existing autoimmune hepatitis was excluded. Anti-lymphocyte antibodies in immunosuppressive induction treatment correlated with the development of the disorder, whereas the use of granulocyte colony-stimulating factor to treat interferon-induced neutropenia showed a protective role. Withdrawal of antiviral treatment and treatment with prednisone resulted in different outcomes (five remissions and four graft failures with two deaths). CONCLUSIONS: De novo autoimmune hepatitis should be considered in differential diagnosis along with rejection in liver transplanted patients developing graft dysfunction while on treatment with interferon.

Review article: alcoholic liver disease--pathophysiological aspects and risk factors.

BACKGROUND: Alcoholic liver disease has a known aetiology but a complex and incompletely known pathogenesis. It is an extremely common disease with significant morbidity and mortality, but the reason why only a relatively small proportion of heavy drinkers progress to advanced disease remains elusive. AIM: To recognize the factors responsible for the development and progression of alcoholic liver disease, in the light of current knowledge on this matter. METHODS: We performed a structured literature review identifying studies focusing on the complex pathogenetic pathway and risk factors of alcoholic liver disease. Results In addition to the cumulative amount of alcohol intake and alcohol consumption patterns, factors such as gender and ethnicity, genetic background, nutritional factors, energy metabolism abnormalities, oxidative stress, immunological mechanisms and hepatic co-morbid conditions play a key role in the genesis and progression of alcoholic liver injury. CONCLUSIONS: Understanding the pathogenesis and risk factors of alcoholic liver disease should provide insight into the development of therapeutic strategies.

Posttransplant lymphoproliferative disorders in liver transplanted patients: a report of four cases.

BACKGROUND: Posttransplant lymphoproliferative disorders (PTLDs) are an uncommon but important cause of morbidity and mortality in solid organ transplant recipients. They are often the result of Epstein-Barr virus (EBV)-induced proliferation of B-lymphocytes in the setting of immunosuppression. PATIENTS AND METHODS: We retrospectively analyzed four cases of PTLD after liver transplantation. In all patients immunosuppression was reduced and anti-CD20 monoclonal antibody (rituximab) was administered. In two of four patients, EBV viral load was positive in the peripheral blood, and gancyclovir was therefore also prescribed. Chemotherapy (CHOP) was used as a rescue in the event of treatment failure. RESULTS: Even if no severe adverse events were observed during the treatment period, our treatment approach to PTLD was not effective, and only one patient out of four is still alive. CONCLUSIONS: Well-designed clinical trials are necessary to evaluate the role of this combined approach in the treatment of PTLD in liver transplant recipients.

Pegylated interferon plus ribavirin for recurrent Hepatitis C infection after liver transplantation in naïve and non-responder patients on a stable immunosuppressive regimen.

BACKGROUND: Hepatitis C virus recurrence after liver transplantation is universal, leading to chronic hepatitis and cirrhosis. AIMS AND PATIENTS: We evaluated the efficacy and safety of pegylated interferon and ribavirin in 20 patients with recurrent Hepatitis C virus after liver transplantation (10 naïve and 10 non-responders to a previous interferon course). METHODS: Treatment consisted of pegylated interferon alfa-2b (1.0 microg/kg once weekly) and ribavirin (600 mg/daily) for at least 6 months. Therapy continued for an additional 6 months only in patients with undetectable serum Hepatitis C virus-RNA or >2 log drop from baseline levels. RESULTS: Eleven out of 20 patients (55%) completed 1 year of treatment. Nine patients (45%) had undetectable Hepatitis C virus-RNA at the end of treatment, six of them were naïves and three non-responders. In all of them, virological response persisted 6 months after discontinuation of therapy, so the sustained virological response rate was 60% in naïve patients and 30% in non-responders. CONCLUSIONS: Our results suggest that pegylated interferon plus ribavirin combination therapy may be effective in patients with post-liver transplantation recurrent chronic Hepatitis C, even in those previously non-responders to interferon plus ribavirin. These results need to be confirmed by large studies.

Cytokine profile of peripheral blood mononuclear cells from patients with different outcomes of hepatitis C virus infection.

SUMMARY: The relationship between the balance of helper T-cell type 1 (Th1) or type 2 (Th2) cytokines and the clinical course of hepatitis C virus (HCV) infection is unclear. We evaluated Th1 [interleukin (IL)-2, interferon-gamma (IFN-gamma)] and Th2 cytokine (IL-4, IL-10) and 2,5-oligoadenylate synthetase (OAS, an IFN-induced antiviral protein) production by peripheral blood mononuclear cells from 10 healthy anti-HCV-positive individuals (group A), 10 HCV-RNA-positive with persistently normal alanine aminotransferase (ALT) levels (group B), 10 HCV-RNA-positive with abnormal ALT (group C) and 10 uninfected healthy controls. IL-2 production was significantly increased in group B when compared with all the other groups. No difference was found for IFN-gamma. IL-4 was significantly higher in group C than in both group B (P = 0.0006) and controls (P = 0.004). Compared with controls, IL-10 was significantly decreased in group A (P = 0.013) and B (P = 0.004). The production of 2,5-OAS was significantly higher in group B than in A (P = 0.04) and in C (P = 0.004). Finally, in all HCV-RNA-positive patients, a significant correlation was found between ALT and both IL-2 (r = -0.78; P = 0.0008) and IL-4 (r = 0.75; P = 0.0008). IN CONCLUSION: (i) subjects who cleared HCV showed a cytokine profile similar to controls; (ii) a preferential shift towards a Th1 profile seems associated with a more favourable clinical outcome in chronic hepatitis C; and (iii) a prevalent Th2 profile seems implicated in HCV pathogenesis and severity of liver disease.

High risk of hepatocellular carcinoma in anti-HBe positive liver cirrhosis patients developing lamivudine resistance.

The emergence of drug-resistant virus in hepatitis B virus patients treated with lamivudine is well documented. However, its clinical impact in the long-term treatment of anti-HBe positive compensated cirrhotic patients is not well known. In this study, we treated 22 consecutive patients with anti-HBe compensated cirrhosis with lamivudine for a median period of 42 months. All patients responded to lamivudine, but viral breakthrough occurred in 13 patients (59%) between 9 and 42 months of therapy due to the emergence of a mutant strain. During the follow-up, 11 developed hepatocellular carcinoma. Of these, 10 occurred soon after the emergence of viral resistance, generally showing aggressive behaviour, and one in the nine long-term responder patients (P = 0.013). Lamivudine resistance was the only independent predictor of hepatocellular carcinoma development (risk ratio: 10.4; 95% CI: 1.3-84.9). Our study suggests that the occurrence of lamivudine resistance increases the risk of hepatocellular carcinoma in anti-HBe positive cirrhosis and warrants further research.

Thymosin-alpha 1 plus interferon-alpha for naive patients with chronic hepatitis C: results of a randomized controlled pilot trial.

In this pilot study, we evaluated the efficacy of interferon-alpha (IFN) plus Thymosin-alpha 1 (TA1) to that of IFN alone in naive patients with chronic hepatitis C. Twenty-two patients were randomized to receive interferon-alpha 2b (3 million units three times a week) plus thymosin-alpha l (900 microg/m2 body surface area) and 19 received interferon-alpha 2b alone at the same dose. Patients were treated for 6 months and followed up for another 6 months. Biochemical (alanine aminotransferase values) and virological (hepatitis C virus-RNA) responses to treatment were determined. Combination treatment showed significantly higher efficacy than monotherapy in achieving virological end-of-treatment response (P = 0.03). At 6-month follow up, the sustained biochemical and virological response was not different between the two groups. Our results indicate that the immune modulator TA1 may enhance the end-of-treatment response in naive patients with chronic hepatitis C. Higher doses and/ore more prolonged courses as well as the association with new interferon formulation such as pegylated interferons could improve the sustained response rates to this treatment.

Interferon-alpha combined with ketoprofen as treatment of naïve patients with chronic hepatitis C: a randomized controlled trial.

In this randomized controlled study, we evaluated the efficacy and safety of interferon-alpha combined with ketoprofen to that of interferon-alpha alone in naïve patients with chronic hepatitis C. Forty patients were randomized to receive Interferon-alpha2a (3 million units three times a week) and ketoprofen (150 mg twice a day) and 40 to receive only interferon-alpha2a at the same dose. Patients were treated for 6 months and followed up for 6 months. Response was defined by undetectable HCV-RNA in serum at the end-of-treatment and after 6 months from the completion of therapy (long term response). At the end of treatment the response was similar in the two group. However, combination treatment showed significantly higher efficacy than monotherapy in achieving long term response (10%vs 32.5%; P = 0.014). Overall adverse events were similar in the two groups. 'Flu-like syndrome was significantly less common in the ketoprofen plus interferon group which experienced a significantly higher incidence of epigastric pain'. Our results indicate that the combination of ketoprofen plus interferon is significantly more effective than interferon alone in the treatment of naïve patients with chronic hepatitis C and is well tolerated. However this combined treatment appears to be less effective than the association of pegylated IFN and ribavirin which represent the current standard treatment. Thus, the role of ketoprofen in the treatment of chronic hepatitis C needs to be further evaluated against such a treatment.

Retreatment with interferon plus ribavirin of chronic hepatitis C non-responders to interferon monotherapy: a meta-analysis of individual patient data.

BACKGROUND AND AIMS: Retreatment with a combination of alpha interferon (IFN) plus ribavirin of patients with chronic hepatitis C who did not respond to IFN monotherapy has not been assessed in large controlled studies. METHODS: To assess the effectiveness and tolerability of IFN/ribavirin retreatment of non-responders to IFN and to identify predictors of complete (biochemical and virological) sustained response, we performed a meta-analysis of individual data on 581 patients from 10 centres. Retreatment with various IFN schedules (mean total dose 544 mega units) and a fixed ribavirin dose (1000-1200 mg/daily depending on body weight) was given for 24-60 (mean 39.5) weeks. RESULTS: Biochemical end of treatment and sustained responses were observed in 271/581 (46.6%; 95% confidence interval (CI) 42.6-50.7%) and in 109/581 (18.7%; 95% CI 15.6-22.0%) cases, respectively. Two hundred and six of 532 patients (38.7%; 95% CI 34.6-42.9%) had an end of treatment complete response to retreatment while a complete sustained response occurred in 88 of 559 (15.7%; 95% CI 12.8-18.8%). Fifty four of 581 patients (9.2%; 95% CI 7.0-11.7%) stopped retreatment due to adverse effects. By logistic regression, complete sustained response was predicted independently by age <45 years (p=0.04), by normal pretreatment gamma-glutamyltransferase levels (p=0.01), and by a second course total IFN dose of at least 432 mega units (p=0.008). CONCLUSIONS: The overall low probability of effectiveness argues against indiscriminate retreatment of all IFN monotherapy non-responders with IFN/ribavirin. Patients less than 45 years old with normal gamma-glutamyltransferase levels who were retreated with high dose long course combination therapy had a complete sustained response rate of 30%.

In vitro effect of thymosin-alpha1 and interferon-alpha on Th1 and Th2 cytokine synthesis in patients with chronic hepatitis C.

Current evidence suggests that increased expression of Th1-associated cytokines is important for immune-mediated eradication of hepatitis C infection, while an increase in Th2-associated cytokines is associated with persistence of infection. In this study we evaluated the effects of thymosin-alpha1 (TA1), a naturally occurring thymic peptide, and interferon-alpha (IFN-alpha) on cytokine production in peripheral blood mononuclear cells from untreated patients with chronic hepatitis C. We examined the effect of incubation with TA1, IFN-alpha, or both, on production of Th1-associated cytokines (IL-2, IFN-gamma), Th2-associated cytokines (IL-4, IL-10), and synthesis of the antiviral protein 2',5'-oligoadenylate synthetase. TA1 treatment induced a significant increase in production of IL-2 and 2',5'-oligoadenylate synthetase. Smaller increases were also seen after treatment with IFN-alpha, while incubation with TA1 and IFN-alpha together led to an additive or synergistic effect. Incubation with TA1 resulted in a decrease in IL-4 and IL-10, whereas IFN-alpha increased these cytokines. The addition of TA1 to IFN-alpha significantly reversed this IFN-alpha-induced increase. Hence, TA1 treatment could benefit patients with hepatitis C infection by increasing the Th1-type response, fundamental for sustained clearance of hepatitis C; and by decreasing the Th2-type response, associated with persistence of viraemia.