Role of anti-interferon antibodies in breakthrough occurrence during alpha 2a and 2b therapy in patients with chronic hepatitis C

Autoantibodies to Interferons in Infectious Diseases

Anti-cytokine autoantibodies and, in particular, anti-type I interferons are increasingly described in association with immunodeficient, autoimmune, and immune-dysregulated conditions. Their presence in otherwise healthy individuals may result in a phenotype characterized by a predisposition to infections with several agents. For instance, anti-type I interferon autoantibodies are implicated in Coronavirus Disease 19 (COVID-19) pathogenesis and found preferentially in patients with critical disease. However, autoantibodies were also described in the serum of patients with viral, bacterial, and fungal infections not associated with COVID-19. In this review, we provide an overview of anti-cytokine autoantibodies identified to date and their clinical associations; we also discuss whether they can act as enemies or friends, i.e., are capable of acting in a beneficial or harmful way, and if they may be linked to gender or immunosenescence. Understanding the mechanisms underlying the production of autoantibodies could improve the approach to treating some infections, focusing not only on pathogens, but also on the possibility of a low degree of autoimmunity in patients.

[Anti-cytokine autoantibodies: Review of the literature]

Anti-cytokine antibodies (ACA) are an emerging cause of acquired immunodeficiency, especially in previously healthy adults. The most frequently reported are anti-IFN-γ responsible for disseminated non-tuberculous mycobacteria infections, and anti-GM-CSF mainly in mycobacteria, cryptococcosis and nocardiosis infections. The presence of anti-IFN-α in severe COVID-19 infections has recently been described. The search for and detection of these ACAs in an unusual infection situation makes it possible to set up specific therapies in addition to the anti-infective treatment. ACAs are also frequent in various autoimmune pathologies where, in addition to being indicators of the breakdown of immune tolerance, they can modulate the activity of the disease according to their cytokine target. In this review of the literature, we will focus on the epidemiology and the clinical impact of these ACAs in healthy subjects and in infectious or dysimmune diseases.

Longitudinal analyses of the effects of neutralizing antibodies on interferon beta-1b in relapsing-remitting multiple sclerosis

We have analysed data on exacerbation rates, Expanded Disability Status Scale (EDSS) scores, and lesion burdens using the results of two neutralizing antibody (NA B) assays (C PE and MxA) from the pivotal relapsing-remitting multiple sclerosis (MS) trial of interferon beta-1b (IFNB) with a longitudinal appro ach, where the influence of NA Bs in individual patients is assessed by comparing responses during NAB- positive and NA B-negative periods. There are apparent influences on exacerbation rate related to dose of IFNB, titer level, and duration of positivity. With the MxA assay, exacerbation rates after switching to NA B-positive status are estimated to be 28% higher [95% confidence interval (CI): (-15%, 92%)] and -2% higher [95% CI: (-21%, 21%)] on the low- and high-dose IFNB arms, respectively. When compared with all NA B-negative periods, exacerbation rates during NA B-positive periods are estimated to be 29% higher [95% C I: (0%, 67%)] and 18% higher [95% CI: (0%, 40%)] on the low- and high-dose IFNB arms, respectively. When NA B-positive patients again become NA B-negative, no evidence of increased exacerbation rates could then be demonstrated. More detailed exploratory analyses indicate that the effects are most evident in the approximately 20% of patients developing high titers. In these patients, the influence of NABs may be self-limited, as titers often diminish or NA Bs become undetectable with time.

Predictive factors for 24 weeks sustained virologic response (SVR24) and viral relapse in patients treated with simeprevir plus peginterferon and ribavirin

BACKGROUND

Simeprevir with peginterferon and ribavirin has been used for the treatment of chronic hepatitis caused by genotype 1 hepatitis C virus (HCV). We explored the predictive factors for sustained virological response (SVR) and viral relapse using datasets from four Japanese phase 3 studies (CONCERTO).

METHODS

We used a multiple logistic regression model. First, an integrated dataset comprising 357 patients was analyzed. Subsequently, prior treatment-naïve and relapser (223 patients) and nonresponder (134 patients) of interferon-based treatment subsets were analyzed to identify predictors of SVR. A subset of nonresponders (106 patients) who were treated ≥24 weeks was also analyzed to identify predictors for viral relapse.

RESULTS

In the integrated dataset, prior treatment response was significantly associated with SVR. In subset analyses, interleukin-28B (IL28B) TT genotype and undetectable plasma HCV RNA level at week 4 were associated in treatment-naïve patients and relapsers [odds ratio (OR); 4.106 and 3.701, respectively]. In the nonresponders, the IL28B TT genotype population was very small, and inosine triphosphatase (ITPA) and undetectable plasma HCV RNA at week 4 were associated (OR; 2.506 and 3.333, respectively). Furthermore, ribavirin dose intensity (RBV-DI) and detectable plasma HCV RNA at week 4 were significantly associated with viral relapse (OR; 0.327 and 2.922, respectively).

CONCLUSION

IL28B and plasma HCV RNA level at week 4 were clinically relevant predictive factors for SVR in treatment-naïve patients and relapsers. Moreover, RBV-DI and plasma HCV level at week 4 were identified as relevant predictive factors for viral relapse in nonresponders.

Factors associated with the response to interferon-based antiviral therapies for chronic hepatitis C

Hepatitis C virus (HCV) infection is a major health concern worldwide. Interferon-α (IFN-α) therapy has been the main antiviral treatment for more than 20 years. Because of its established antitumor effects, IFN-based treatments for chronic HCV infection still have a clinical impact, particularly for patients with high risk conditions of developing hepatocellular carcinoma, such as older age and advanced liver fibrosis. As a result of exhaustive research, several viral factors, including NS5A amino acid mutations such as the IFN sensitivity-determining region and the IFN/ribavirin resistance-determining region, and mutations of amino acids in the core protein region (core 70 and 91) were shown to be associated with the response to IFN-α treatment. In addition, among the host factors related to the response to IFN-α treatment, polymorphisms of the interleukin-28B gene were identified to be the most important factor. In this article, we review the factors associated with the efficacy of IFN-α treatment for chronic HCV infection. In addition, our recent findings regarding the possible involvement of anti-IFN-α neutralizing antibodies in a non-response to pegylated-IFN-α treatment are also described.

A comparative study of variants of pegylated interferon alpha in treatment of chronic HCV patients

HCV infection presents a vast burden in the regions of high prevalence such as Egypt, where most HCV isolates are genotype 4b. Combined treatment of three variants of pegylated interferon and ribavirin is still the standard of care in Egypt. However, no conclusive data confirming their efficacy are available. Here, 60 chronic HCV patients were randomized for ribavirin plus Peg Intron (PEG-IFNα-2b), Pegasys (PEG-IFNα-2a) or Reiveron Retard (PEG-IFNα-2a). Serum interferon and antibody (Ab) levels were measured, and responses and costs were compared. Serum interferon levels were higher in Pegasys group (1625.1 ng/mL) followed by Reiveron Retard (1076.5 ng/mL), and Peg Intron group (857.72 ng/mL). Moreover, Ab levels were the lowest in Reiveron Retard group (318.4 ng/mL), followed by Peg Intron (439.93 ng/mL), and Pegasys cases (610.83 ng/mL). The best 24-week response rates were detected in the Pegasys group (73.3%), followed by Peg Intron (66.67%), and Reiveron Retard (40%). Treatment with both Pegasys and Peg Intron were most cost-effective. Furthermore, Pegasys was superior in both 6-month response and serum interferon, despite having higher Ab levels (more antigenicity). Our data have notable clinical implications and suggest that Pegasys may be a superior choice of interferon therapy for chronic HCV under low socioeconomic conditions.

Anti-interferon-α neutralizing antibody induced telaprevir resistance under the interferon-α plus telaprevir treatment in vitro

Although the development of anti-interferon (IFN)-α neutralizing antibodies (NAbs) is likely to be a common clinical problem for patients with various diseases treated with IFN, anti-IFN-α NAb has been exceptionally considered to have no clinical significance in the treatment of chronic hepatitis C with pegylated IFN-α (Peg-IFN-α). However, we recently clarified that the presence of NAb was associated with a non-response to the Peg-IFN plus ribavirin (RBV) therapy. In this study, we used the HCV-replicon system with genotype 1b, and investigated the role of anti-IFN-α NAb in the response to telaprevir (TVR)-containing new antiviral therapy for hepatitis C virus (HCV). Anti-IFN-α NAb-positive sera specifically inhibited the anti-HCV effects of IFN-α, without any effect on the activity of IFN-β in vitro. The NAb-positive sera also inhibited the IFN-α-dependent induction of interferon-stimulated genes, MxA and OAS-1, in a dose-dependent manner. Although TVR monotherapy decreased the HCV-RNA in vitro, the HCV-RNA was increased again with the development of TVR-resistant mutations. When IFN-α was administrated with TVR, the replication of HCV was continuously suppressed for more than a month. However, in the presence of anti-IFN-α NAb-positive sera, even when IFN-α was combined with TVR, the levels of HCV-RNA exhibited a time-course similar to that with TVR monotherapy, and HCV with TVR-resistant mutations emerged. In conclusion, our findings suggest that the presence of IFN-α NAb decreases the antiviral effects of IFN-α and may be related to the development of TVR-resistant mutated viruses.

The recombinant vaccinia virus gene product, B18R, neutralizes interferon alpha and alleviates histopathological complications in an HIV encephalitis mouse model

Interferon-alpha (IFN-α) has been identified as a neurotoxin that plays a prominent role in human immunodeficiency virus (HIV)-associated neurocognitive disorders and HIV encephalitis (HIVE) pathology. IFN-α is associated with cognitive dysfunction in other inflammatory diseases where IFN-α is upregulated. Trials of monoclonal anti-IFN-α antibodies have been generally disappointing possibly due to high specificity to limited IFN-α subtypes and low affinity. We investigated a novel IFN-α inhibitor, B18R, in an HIVE/severe combined immunodeficiency (SCID) mouse model. Immunostaining for B18R in systemically treated HIVE/SCID mice suggested the ability of B18R to cross the blood-brain barrier (BBB). Real-time PCR indicated that B18R treatment resulted in a decrease in gene expression associated with IFN-α signaling in the brain. Mice treated with B18R were found to have decreased mouse mononuclear phagocytes and significant retention of neuronal arborization compared to untreated HIVE/SCID mice. Increased mononuclear phagocytes and decreased neuronal arborization are key features of HIVE. These results suggest that B18R crosses the BBB, blocks IFN-α signaling, and it prevents key features of HIVE pathology. These data suggest that the high affinity and broad IFN-α subtype specificity of B18R make it a viable alternative to monoclonal antibodies for the inhibition of IFN-α in the immune-suppressed environment.

Anti-interferon-α neutralizing antibody is associated with nonresponse to pegylated interferon-α plus ribavirin in chronic hepatitis C

Pegylated interferon-α (PEG-IFN-α) plus ribavirin (RBV) treatment fails to achieve a sustained virological response (SVR) in approximately 20-50% of patients with chronic hepatitis C virus (HCV) infection. We assessed the contribution of an anti-IFN-α neutralizing antibody (NAb) on the nonresponse to treatment. NAbs were detected using an antiviral assay that assessed the neutralizing effects of serum samples against IFN. Serum samples were obtained at the end of the treatment and evaluated for the presence of NAbs using recombinant IFN-α as a standard. We studied 129 PEG-IFN-α/RBV-treated patients. In the 82 end-of-treatment responders, no NAbs were detected. Of the 47 patients who did not respond, seven (15%) were positive for NAbs. We also examined an additional 83 patients who had not responded to PEG-IFN-α treatment, and detected 12 with NAbs. Patients with good IFN-responsive characteristics, including HCV genotype 2/3 and major allele homozygotes for interleukin-28B, were included in the 19 patients with NAbs. No NAbs interfered with the antiviral activity of natural human IFN-β (nIFN-β) and re-treatement of patients with NAbs with nIFN-β/RBV achieved SVR. Our analyses revealed that the emergence of anti-IFN-α NAbs was a candidate causal factor of PEG-IFN-α-treatment failure. Therefore, these antibodies should be assayed in patients who do not respond to PEG-IFN-α therapy, and if detected, other effective treatments, i.e., medications that are not neutralized by anti-IFN-α NAbs, should be considered.

Neutralizing antibodies to interferon-α and circulating interferon in patients with chronic hepatitis C non-responding to pegylated interferon plus ribavirin re-treated by pegylated interferon-α-2a and ribavirin (ANRS HC16 GAMMATRI substudy)

A lack of antiviral response in patients with chronic hepatitis C treated with pegylated (PEG)-interferon (IFN)-α-2a + ribavirin (RIBA) may be explained by neutralizing antibodies to IFN-α-2a. The aim of this study was to assess neutralizing antibodies to IFN-α-2a and IFN levels in non-responder patients who were re-treated by PEG IFN-α-2a and RIBA for 12 weeks. Non-responders to a first-line treatment of PEG IFN-α-2a + RIBA were included for treatment with PEG IFN-α-2a (180 µg/week) + RIBA (1,000 mg/day if <75 kg, 1,200 mg otherwise) for 48 weeks. HCV RNA was measured at week 12. IFN levels and neutralizing antibodies to IFN-α-2a were measured retrospectively on stored sera at baseline and weeks 4 and 12, using a quantitative sandwich ELISA for neutralizing antibodies to IFN-α-2a. Twenty-three patients were non-responders and 19 patients were responders at week 12 of the initial phase of the second-line treatment. Non-responders and responders did not differ statistically: baseline age (median age 47 vs. 50 years), HCV RNA (median 6.8 vs. 6.4 log(10) copies/ml), gender (70% vs. 73% males), genotype (genotype 1: 91% vs. 80%). The median IFN-α-2a levels (pg/ml) at weeks 0, 4, and 12 (interquartile range) did not differ between the 19 responders to initial phase of second-line treatment and the 23 non-responders: <3.3 (<3.3-371.4), 1457.3 (106.8-3284.8), and 1,652 (90.8-5,000); 84.5 (3.3-277.4), 1407.4 (120.2-2443.4), and 1620.1 (120.2-2287.1), respectively. Among non-selected consecutive non-responder patients, re-treatment with PEG IFN-α-2a + RIBA is associated with virological response regardless of the presence of antibody-mediated resistance to conventional IFN treatment.

A novel strategy to reduce the immunogenicity of biological therapies

Biological therapies, even humanized mAbs, may induce antiglobulin responses that impair efficacy. We tested a novel strategy to induce tolerance to a therapeutic mAb. Twenty patients with relapsing-remitting multiple sclerosis received an initial cycle of alemtuzumab (Campath-1H), up to 120 mg over 5 d, preceded by 500 mg SM3. This Ab differs from alemtuzumab by a single point mutation and is designed not to bind to cells. Twelve months later, they received a second cycle of alemtuzumab, up to 72 mg over 3 d. One month after that, 4 of 19 (21%) patients had detectable serum anti-alemtuzumab Abs compared with 145 of 197 (74%) patients who received two cycles of alemtuzumab without SM3 in the phase 2 CAMMS223 trial (p < 0.001). The efficacy and safety profile of alemtuzumab was unaffected by SM3 pretreatment. Long-lasting "high-zone" tolerance to a biological therapy may be induced by pretreatment with a high i.v. dose of a drug variant, altered to reduce target-binding.

One-step assay for quantification of neutralizing antibodies to biopharmaceuticals

Assessment of immunogenicity is an important part of biopharmaceutical drug safety evaluation and a prerequisite for the development of less immunogenic and safer biopharmaceuticals since anti-drug antibodies can impair the activity and compromise the safety of biopharmaceuticals. Although regulatory authorities recommend cell-based assays for detection of neutralizing antibodies (NAbs), such assays are difficult to standardize, and ill adapted to high-throughput analysis. These limitations have been overcome by the development of a unique one-step cell-based assay that allows both drug activity and drug NAbs to be quantified rapidly and with a high degree of precision simply be adding reporter cells to a sample. The reporter cells have been engineered to express firefly luciferase (FL) under the control of a drug-responsive promoter, and to express the drug of interest, the production of which is normalized relative to the expression of Renilla luciferase (RL) transcribed from a common doxycycline-inducible promoter. Residual drug levels present in a sample are first quantified by determination of FL expression, autocrine drug synthesis is then induced, and NAb activity is quantified from the difference in the ratio of FL/RL expression in the presence or absence of the sample. Since assay results are normalized relative to the expression of an internal standard, results are independent of cell number or differences in cell viability thus affording a high degree of assay precision and reducing serum matrix effects to a minimum. This unique assay platform is ideally suited for high-throughput analysis, is applicable to most biopharmaceuticals, and will facilitate standardization and comparison of immunogenicity data. The performance of the one-step assay is illustrated for interferon alpha2 (IFNalpha2) used widely to treated chronic hepatitis C (HCV) infection and neoplastic disease.

Treatment failure in hepatitis C: mechanisms of non-response

Hepatitis C virus (HCV) has evolved remarkable mechanisms that favor viral persistence by interfering with host innate and adaptive immune responses. These same mechanisms are likely to contribute to resistance to exogenously administered interferon used for HCV treatment. We review the host innate and adaptive immune responses in the context of HCV infection as well as the strategies by which these responses are subverted by the virus. In addition, the contribution of host factors, such as race and insulin resistance, to interferon non-responsiveness is discussed. Our progress in understanding the molecular underpinnings of interferon treatment failure in HCV infection has resulted in several promising and novel treatment strategies for HCV treatment non-responders.

Interferon-alpha2a and Vogt-Koyanagi-Harada disease: a double-edged sword?

Successful therapy based on the use of interferon-alpha has been reported in different types of severe chronic uveitis. The immunomodulatory effects of this drug, combined with its antiviral properties seem to contribute to its efficacy in the treatment of different forms of severe and refractory uveitis such as Vogt-Koyanagi-Harada disease, Behçet-associated uveitis, or even human herpes virus 8 (HHV-8) associated uveitis. At the same time, severe ocular complications have been reported in patients treated with interferon-alpha for chronic viral hepatitis C. Among these complications, six cases of Vogt-Koyanagi-Harada-like disease have been described.We report a small case series of two patients with refractory Vogt-Koyanagi-Harada disease, treated with interferon-alpha and discuss the potential benefits or detrimental role of interferon therapy in these patients.

Treatment of Relapsers after Combination Therapy for Chronic Hepatitis C

Sustained virologic response rates are significantly higher in patients who have relapsed after a previous course of therapy compared with patients who did not respond. A meta-analysis of combination therapy in patients who failed IFN monotherapy reported SVR rates of 52% in relapsers to prior therapy and 16% in nonresponders. Similarly, relapsers after combination standard IFN and RBV therapy have higher SVR rates than combination of therapy nonresponders when treated with pegylated interferon and ribavirin. For this reason, patients who relapse after a previous course of therapy should be considered potential candidates for retreatment. Factors that have been associated with SVR in these patients include genotype non-I, low viral loads, and lesser degrees of fibrosis. The course of treatment in all patients who have relapsed after prior therapy should be reviewed to identify possible reasons for failure to achieve an SVR. In particular, optimal dosing of PEG IFN and RBV and the occurrence and timing of treatment dose reductions during prior therapy should be reviewed. The reasons for dose reduction should be addressed before initiating another course of therapy in an effort to optimize the chance for a SVR. Patients who had dose reduction for depression, anemia, or neutropenia, should be considered for antidepressants, erythropoietin, or, if neutropenia is severe, granulocyte colony stimulating factor therapy, respectively, during retreatment. Prolongation of therapy beyond 48 weeks in patients with relapse after a standard course of PEG IFN and RBV may offer a chance of SVR. Novel agents currently in development, including protease and polymerase inhibitors, may prove to be therapeutic options for these patients in the future.

Rapid and simple detection of IFN-neutralizing antibodies in chronic hepatitis C non-responsive to IFN-α

Different mechanisms have been proposed for the failure of interferon (IFN) therapy in patients with chronic hepatitis C and multiple sclerosis, for example, the presence of IFN-neutralizing antibodies. In this study, a novel assay system based on the IFN-inducible Mx-promoter was used to detect IFN-neutralizing antibodies in sera of patients with chronic hepatitis C. To monitor IFN bioactivity in IFN-treated patients, a real-time RT-PCR for MxA gene expression in PBMCs was established. Using these two methods, patients with chronic hepatitis C virus (HCV) infection receiving IFN therapy and patients with treatment induced HCV clearance were monitored. Importantly, neutralizing anti-IFN antibodies were detected in the sera of 3 of 38 chronically HCV-infected patients who failed to respond to therapy but none in sera of patients who cleared HCV after IFN therapy. Interestingly, the presence of these antibodies correlated with the lack of MxA induction in PBMCs after initiation of IFN-alpha therapy. Retrospective analysis of one patient's sera revealed that the anti-IFN-alpha antibodies had already developed after the first of four unsuccessful IFN therapies, suggesting that neutralizing antibodies may have contributed to the failure of previous IFN treatments. In summary, a novel screening assay was established that may be helpful for testing IFN non-responders for the presence of clinically relevant anti-IFN-alpha antibodies and for selecting alternative IFN preparations not neutralized by these antibodies.

Therapy-induced antibodies against the antiviral and antiproliferative effects of interferons in patients with chronic hepatitis C virus infection

Sera from 86 patients with chronic hepatitis C virus (HCV) infection treated with recombinant interferons-alpha (rIFN-alpha) were screened for IFN-binding and antiviral effect-neutralizing antibodies. Out of the 61 patients treated with rIFN-alpha2b, 46% had binding and 28% had neutralizing antibodies. 44% of the 25 patients treated with rIFN-alpha2a developed binding antibodies and 24% had neutralizing antibodies. Contradictory data were observed concerning the appearance of anti-IFN antibodies and the outcome of IFN therapy. A significantly higher number of the patients with a sustained response to rIFN-alpha2b therapy formed antibodies than the number among the non-responder patients. At the same time, in the patients treated with rIFN-alpha2a, opposite data were found. The activity of the antibodies in some sera was studied against the antiproliferative effect of IFNs on Daudi cells by measuring the [3H]thymidine incorporation. The binding antibodies without neutralization of the antiviral effect of the IFNs inhibited the antiproliferative activity of the rIFNs, similarly to antibodies having both IFN-binding and antiviral effect-neutralizing capacities. At the same time, the antiproliferative effect of the natural IFN was less affected. It is suggested that the antiproliferative assay is more sensitive than the antiviral method for demonstration of the presence of antibodies exerting an inhibitory effect on the biological activities of IFN.

Treatment of relapsers after combination therapy for chronic hepatitis C

A significant number of patients with chronic hepatitis C relapse after treatment. As therapy for CHC has improved over the last decade, the issue of retreating patients who did not achieve a sustained virologic response with previous treatment regimens frequently arises. Several studies have assessed the efficacy of pegylated interferon (IFN) and ribavirin (RBV) combination therapy in IFN and RBV therapy relapsers. Patients who have relapsed after therapy have significantly higher SVR rates than those who are nonresponders to therapy and should be considered candidates for retreatment. Predictors of a favorable response to therapy in naïve patients appear to also predict response to therapy in patients who have relapsed previously.

IFN-alpha antibodies in patients with age-related macular degeneration treated with recombinant human IFN-alpha2a

We tested for development of binding and neutralizing antibodies to interferon-alpha (IFN-alpha) during IFN-alpha2a therapy of patients with age-related macular degeneration (AMD) of the eyes. Antibodies were investigated retrospectively in sera of 34 patients treated with 3 x 10(6) IU IFN-alpha2a (Roceron-A), Hoffmann La-Roche, Basel, Switzerland) three times weekly for periods of 8-16 weeks with or without a drug-free 4-12-week intermission. Additionally, 10 patients were investigated prospectively; 7 received 1.5-6 x 10(6) IU IFN-alpha2a three times weekly for 12 months, and 3 received placebo. Binding antibodies were tested by molecular size and protein G affinity chromatography using 125I-IFN-alpha2a. Neutralizing activities were tested by antiviral neutralization bioassay. IgG antibodies were detected in 24 of 34 IFN-alpha2a-treated patients (71%). Significantly higher anti-IFN-alpha levels were observed in patients who after discontinuation were readministered IFN-alpha2a (p < 0.02). Three of the IFN-alpha2a-treated patients in the prospective study had high and 1 had low antibody titers. Neutralizing antibody titers were high against IFN-alpha2a and IFN-alpha2c and low against lymphoblastoid and leukocyte IFN-alpha. Impaired clinical responses were observed in antibody-positive patients (p < 0.01). The development of neutralizing anti-IFN-alpha antibodies in patients with AMD during recombinant human IFN-alpha therapy may explain the often poor clinical effect of IFN-alpha treatment.

Does interferon and ribavirin combination therapy increase the rate of treatment response in children with hepatitis C?

BACKGROUND

Interferon-alpha was the first accepted treatment of chronic hepatitis C. In recent years, adding ribavirin has produced better response rates in adult patients than monotherapy with interferon-alpha. Whether adding ribavirin also improves treatment results in pediatric patients remains unclear.

METHODS

Twelve patients were given 3 million U/m 2 subcutaneous interferon-alpha three times weekly and 15 mg/kg oral ribavirin daily, and 10 patients were given only 3 million U/m 2 subcutaneous interferon-alpha three times weekly for a total of 12 months.

RESULTS

The dropout rate was 22.8% (25% for patients receiving combination treatment versus 20% for those receiving monotherapy). At the end of treatment, viral clearance was achieved in 50% of the patients who received combination treatment versus 30% of those who received monotherapy. After 12 months of posttreatment follow-up, sustained response rates were 30% and 41.7%, respectively. Of those who responded to treatment, 66.7% had received ribavirin whereas 37.5% of nonresponders had received ribavirin therapy.

CONCLUSION

Adding ribavirin to interferon treatment improved end-of-treatment response rates in children with chronic hepatitis C. Tolerance of treatment was similar to tolerance of monotherapy. However, studies of greater numbers of pediatric patients with longer follow-up periods are necessary to determine prolonged sustained response.

Total serum IgE levels in chronic hepatitis C: influence of interferon alpha therapy

BACKGROUND

Liver disease has been considered a prominent cause of IgE elevation. No data on serum IgE levels in chronic hepatitis C have been reported. Interferon-alpha is a standard therapy for chronic hepatitis C. Cytokine use is a promising type of immunomodulation in the treatment of IgE-mediated diseases. The effects of interferon-alpha therapy on serum IgE have not been fully evaluated. The aim of the study was to evaluate both serum IgE levels in patients with chronic hepatitis C and the course of these levels after interferon-alpha therapy.

PATIENTS AND METHODS

Serum IgE was determined in 100 adult patients with chronic hepatitis C (24 atopics according to positive skin prick tests and 76 nonatopics) and in 75 healthy controls (25 atopics and 50 nonatopics). Serum IgE measurements were repeated at 1 and 3 months of therapy with recombinant interferon-alpha (3 x 106 units s.c. 3 times weekly) in 34 of these patients.

RESULTS

Serum IgE levels were similar in chronic hepatitis C patients and in controls when adjusted for atopic status. Among patients with chronic hepatitis C, serum IgE levels were unrelated to liver necroinflammatory activity. A modest but statistically significant increase of IgE values was observed after interferon-alpha therapy, particularly in patients with no virological response.

CONCLUSIONS

Chronic hepatitis C is not a significant cause of increased total serum IgE values. Serum IgE increase in some patients with liver disease may be related to the cause of liver injury and not to liver disease per se. Interferon-alpha therapy in patients with chronic hepatitis C is followed by no modification or even a moderate increase of serum IgE values.

Viral, host and interferon-related factors modulating the effect of interferon therapy for hepatitis C virus infection

The estimated prevalence of hepatitis C virus infection in the US is approximately 1.8%. Although interferon monotherapy and combination therapy of interferon with ribavirin represent mainstay for treating HCV infection, the rate of sustained virologic response remains suboptimal. The growing evidence suggested that the clinical sequence and treatment response of chronic hepatitis C are determined by a dynamic, complex tripartite relationship among HCV infection, the host immune response, and the effect of different interferon regimens. The treatment response is associated with various viral factors including the pretreatment viral level, dynamic change of viral level during treatment, viral genotype quasispecies and nucleotide mutation in nonstructural protein 5A of hepatitis C virus. Host factors that may affect treatment response include age, gender, race, HLA alleles and the host immune responses. Interferon regimens, including type, dose, frequency and duration of treatment and combination of interferon with other anti-HCV agents also alter the therapeutic response. Understanding these complicated interaction may provide better insights into the mechanism(s) of interferon response, leading to more effective clinical application of interferon therapy.

Methodological issues in papers on IFN therapy: time for reappraisal

We conducted an analytical review of 194 full papers on interferon (IFN) therapy for chronic hepatitis C to evaluate current methodology (i.e. study design, criteria for evaluating the efficacy of therapy and predictors of response). Of the papers evaluated, 64 were randomized controlled trials (RCT), 40 were non-randomized controlled trials (NRCT) and 90 were observational studies (OS). The methodological analysis was focused mainly on clinical trials. The number of patients enrolled in RCT was higher compared with the number enrolled in NRCT. Uniform enrolment criteria were used in less than 50% of the trials. Only 20% of RCT and 2.5% of NRCT used criteria for defining sample size. The response rate was calculated on an intention-to-treat basis in 36 of the RCT and in 14 of the NRCT. The outcome of treatment and the criteria employed to define the response to treatment were found to be far from standardized. In 51.5% of the RCT and 42.5% of the NRCT, normalization of alanine aminotransferase (ALT) level at the end of follow-up was the only marker of response studied. Only 57.6% of the trials considered histological evidence as an important outcome. Among the clinical trials, 71.1% evaluated predictors of good response to IFN therapy. In 51% of the OS, ALT normalization by the end of follow-up was the only criterion for defining response. In conclusion, to ensure a high level of reliability in comparing or combining the results of different studies, some basic general requirements must be followed when planning trials on antiviral therapy.