IFN-alpha 2b Research Articles

Predictive value of early HCV RNA quantitation for sustained response in nonresponders receiving daily interferon and ribavirin therapy

The prognostic value of early hepatitis C virus (HCV)-RNA load was evaluated among nonresponder patients to previous interferon (IFN) therapy treated with daily IFN and ribavirin. One hundred-six nonresponders (83 men), mean age 44.8 +/- 11 years, were treated with IFN-alpha 2b 3 MU/day for 24 weeks, followed by 3 MU x 3/week for 24 weeks plus ribavirin 1-1.2 g/day for 48 weeks. HCV RNA was quantified by Versant HCV RNA 3.0 assay (Bayer). The predictive values of the baseline and the change in viral load at week 1, 4, and 12 for sustained virological responses were analyzed using receiver operating characteristic (ROC) curves, as well as predictive values of >2 log(10) drop from baseline by weeks 1, 4, and 12 in combination with undetectable HCV RNA for sustained virological response. Thirty-two patients (30.2%) were sustained virological responders. The highest area under the curve was obtained at week 4. The unquantifiable HCV RNA level, in combination with at least a 2 log(10) drop in viral load by week 4 and week 12, had a negative predictive value of 96% and 97%, respectively. Nonresponse can be predicted as early as week 4 or week 12 in nonresponders treated with daily IFN and ribavirin.

Synergistic growth inhibitory effects of interferon-α and lovastatin on bcr-abl positive leukemic cells

The chimeric bcr-abl tyrosine kinase is of crucial pathogenic importance in chronic myeloid leukemia (CML). As shown, bcr-abl activates the ras pathway by phosphorylation of adapter proteins such as Grb-2 and Crkl. Functional inhibition of p21ras might partially inhibit the mitogenic signaling by bcr-abl. By depletion of cellular mevalonate pools, p21ras proteins can be rendered non-functional as a result of deficient post-translational protein farnesylation. We investigated the pharmacologic effect of mevalonate depletion by lovastatin in conjunction with interferon-alpha 2b (INF-alpha 2b) in bcr-abl positive K562 cells. At various concentrations, both drugs synergistically reduced cell proliferation of CML line K562 in a liquid culture system as well as clonal growth of colony forming units in a patient with newly diagnosed CML. Lovastatin and IFN-alpha 2b in combination led to cell cycle arrest and resulted in significant reduction of phosphorylation on tyrosine, serine, and threonine protein residues. IFN-alpha 2b alone showed little effect on protein phosphorylation but strongly enhanced lovastatin driven loss of phosphorylation. Subsequently, DNA fragmentation occurred in 50% of cells. In conclusion, exposure to IFN-alpha 2b and lovastatin synergistically inhibited proliferation of bcr-abl positive cells and resulted in loss of protein phosphorylation and subsequent apoptosis in K562 cells. Our in vitro model suggests further investigations are required of the potential value of HMG-CoA reductase inhibitors as adjunct to therapy of CML with interferon.

High SVR rate in HCV pts with normal or increased ALT: A controlled study with IFN alpha 2B and ribavirin

High SVR rate in HCV pts with normal or increased ALT: A controlled study with IFN alpha 2B and ribavirin

On the biological relevance of MHC class II and B7 expression by tumour cells in melanoma metastases.

A large number of studies have indicated that specific immune reactivity plays a crucial role in the control of malignant melanoma. In this context, expression of MHC I, MHC II and B7 molecules by melanoma cells is seen as relevant for the immune response against the tumour. For a better understanding of the biological relevance of MHC II and B7 expression by tumour cells in metastatic melanoma, we studied the expression of these molecules in melanoma metastases in relation to the inflammatory response, regression of the tumour and survival from 27 patients treated with biochemotherapy (30 mg m−2 Cisplatin and 250 mg m−2 decarbazine (dimethyl-triazene-imidazole-carboxamide, DTIC) on days 1–3 i.v., and 107 IU IFN-α2b 3 days a week s.c., q. 28d). In 19 out of 27 lesions studied, we found expression of MHC II by the tumour cells, while only in one out of 11 tumour biopsies obtained from untreated metastatic melanoma patients, MHC II expression was detected. Expression of B7.1 and B7.2 by tumour cells was found in nine out of 24 and 19 out of 24 lesions, respectively. In all cases where B7.1 expression was found, expression of B7.2 by the tumour cells was also seen. In general, no or only few inflammatory cells positive for B7 were found. Expression of MHC II by tumour cells was positively correlated with the presence of tumour-infiltrating lymphocytes, regression of the lesion, and with time to progression (TTP) and overall survival (OS) of the patient. However, no significant correlation between B7.1 or B7.2 expression and regression of the tumour, TTP or OS was found. In light of other recent findings, these data altogether do support a role as biomarker for MHC II expression by tumour cells; however, its exact immunological pathomechanism(s) remain to be established.

1211 Advanced age and serum ribavirin level affect the degree of hemolytic anemia during the combination therapy of IFN-alpha 2B and ribavirin for chronic hepatitis C

1211 Advanced age and serum ribavirin level affect the degree of hemolytic anemia during the combination therapy of IFN-alpha 2B and ribavirin for chronic hepatitis C

Pilot study of pegylated interferon-alpha 2b in patients with essential thrombocythemia.

Interferon-alpha (IFN-alpha) has been shown to control symptoms, reduce platelet counts, and reduce the bone marrow megakaryocyte mass in patients with essential thrombocythemia (ET). A semisynthetic protein-polymer conjugate of IFN-alpha 2b (PEG-IFN2b) increases the serum half-life of IFN-alpha 2b. We conducted a pilot study of Peg-IFN2b in patients with ET. Patients with a history of persistent (greater than 2 months) platelet counts >600 x 10(9)/l, with hyperplasia of bone marrow megakaryocytes in the absence of an alternate identifiable cause of thrombocytosis were eligible. Patients were required to have either thrombohemorrhagic signs and/or symptoms if previously untreated; persistence of thrombohemorrhagic signs and/or symptoms if receiving anagrelide, IFN-alpha, or hydroxyurea; or intolerance to anagrelide, IFN-alpha, or hydroxyurea. The initial PEG-IFN2b dose was from 1.5 to 4.5 micro g/kg per week subcutaneously with subsequent dose adjustments as indicated by response and adverse events. Eleven patients (nine female, median age 54 years, range 26-69 years) were treated. PEG-IFN2b rapidly controlled platelet counts and resolved symptoms in all patients. The median duration of PEG-IFN2b therapy on-study was 9 months (range 4-17 months). No patient had signs or symptoms of thrombosis or hemorrhage while on study. After 2 months of therapy, 10 patients (91%) were in complete remission, and 11 (100%) after 4 months. One patient discontinued therapy at 4 months because of persistent grade 3 fatigue and a second at 5 months because of anxiety and depression. PEG-IFN2b has significant activity in patients with ET. Long-term follow-up of a larger cohort of patients is needed to define its role in this disease.

Is delayed normalization of alanine aminotransferase a poor prognostic predictor in chronic hepatitis C patients treated with a combined interferon and ribavirin therapy?

Decreased alanine aminotransferase (ALT) level is the accepted basic indicator of an interferon (IFN) therapeutic effect in chronic hepatitis C. This study assessed whether delayed normalization of ALT predicts a poor response to a combined therapy of IFN and ribavirin in patients with chronic hepatitis C virus (HCV) infection. Patients were treated with IFN-alpha 2b three times weekly and oral ribavirin for 24 weeks. The ALT values were assessed monthly and patterns of changes in ALT activity were analyzed. Serum HCV-RNA was checked at weeks 0, 12, 24, and 48. A total of 103 patients completed therapy and 69 (67%) of them achieved a sustained viral response (SVR). There was no significant difference in the SVR between patients with or without early normalization (week 12) of ALT level (69 vs 56%). Of the sustained responders, nine patients (13%) with delayed ALT normalization had a SVR. Nine of the 12 patients (75%) with abnormal ALT and negative HCV-RNA at week 12 had a SVR compared with none of four patients who had positive HCV-RNA at week 12 (P = 0.0192). Lack of normalization of the ALT level at week 12 does not preclude successful virological outcome in hepatitis C patients receiving a combined therapy of IFN and ribavirin. Hepatitis C virus RNA at week 12 may be a useful predictor of treatment outcome in patients without early biochemical response.

Is weekly PEG IFN Alpha 2B with ribavirin therapy better than daily IFN Alpha 2B with ribavirin therapy?

Is weekly PEG IFN Alpha 2B with ribavirin therapy better than daily IFN Alpha 2B with ribavirin therapy?

Temporal relationship between the appearance of thyroid autoantibodies and development of destructive thyroiditis in patients undergoing treatment with two different type-1 interferons for HCV-related chronic hepatitis: a prospective study.

In this prospective study we performed repeated evaluations of thyroid status in patients undergoing treatment with different preparations of recombinant interferons (IFNs), in order to identify early markers of thyroid dysfunction. Moreover, we aimed to investigate whether the development of thyroid dysfunction was related to the appearance of thyroid autoimmunity. Our study included 51 consecutive patients without pre-existing thyroid disease, admitted to our hospital for Hepatitis C virus (HCV)-related chronic hepatitis. Thirty-six patients (Gr. A) were treated with IFN-alpha 2b plus ribavirin (RIBA), whereas 15 patients (Gr. B) underwent treatment with IFN-alphacon-1 (CIFN) plus RIBA. Thyroid autoimmunity and function were prospectively evaluated before, every month during treatment and for 6 months after IFN withdrawal. At study entry, all patients were euthyroid and negative for thyroid autoantibodies. In Gr. A, 10 patients developed thyroid autoimmunity after a median period of 3 months (range: 1-6) treatment with IFN-alpha+RIBA. At the time of appearance of thyroid autoantibodies, 4 patients developed destructive thyrotoxicosis (overt in one case, subclinical in 3 cases), while other 4 patients showed a high reduction of serum TSH levels (median decrease: -75.7%, range: -61.9- -84.2), which reached the low values of normal range. After a median period of 2 months (range: 1-3) from these biochemical abnormalities, 6 patients continuing antiviral treatment developed hypothyroidism (overt in 3 cases and subclinical in the other 3). In Gr. B, 5 patients developed thyroid autoimmunity after a median period of 3 months (range: 2-10) of treatment with CIFN+RIBA. Soon after the appearance of thyroid autoantibodies, all patients developed an overt thyrotoxicosis (with hyperthyroidism in 2 cases). Antiviral treatment was discontinued in all 5 cases. Thereafter, thyroid function recovered spontaneously without significant modifications of serum TGAb and TPOAb levels until the end of the study. In conclusion our prospective study demonstrated that: 1) the appearance of thyroid autoantibodies during treatment with IFN was accompanied in most cases by the occurrence of a destructive process in the thyroid gland; 2) The clinical expression of destructive thyroiditis was more evident in patients treated with CIFN than that in patients treated with IFN; 3) The thyroid clinical outcome of these patients was strictly correlated to the continuation of cytokine treatment.

Treatment of hepatitis B virus-associated nephropathy in black children.

The efficacy of interferon (IFN) in the treatment of hepatitis B virus (HBV)-associated nephropathy in black children has not been established. Twenty-four black children with biopsy-proven HBV-associated nephropathy were recruited into the study during the period April 1997 to June 1999. Five defaulted treatment and were excluded from the primary analysis. IFNalpha 2b was administered for 16 weeks. Response to treatment was defined as loss of HBeAg, decrease in proteinuria, and prevention of deterioration in renal and liver function. A control group of 20 patients was followed up for the same period. Ten (52.6%) of the treated children responded with clearance of HBeAg by 40 weeks. None cleared HBsAg. All responders showed remission of proteinuria, 90% maintained normal renal function and 1 (10%) showed improvement of renal function. HBV DNA levels decreased in this group. Nine patients did not clear HBeAg; none showed remission of proteinuria, and two showed deterioration of renal function. Liver enzymes rose during treatment but subsequently declined irrespective of response to therapy. No serious side effects were encountered. Only 5% of controls showed spontaneous clearance of HBeAg, and none had remission of proteinuria. Black children with HBV-associated nephropathy show accelerated clearance of HBeAg with remission of proteinuria following treatment with IFNalpha 2b. IFNalpha 2b was well tolerated.

Anti-renal cell carcinoma chimeric antibody G250: cytokine enhancement of in vitro antibody-dependent cellular cytotoxicity.

The chimeric monoclonal antibody cG250 targets the G250 antigen, a transmembrane protein which is expressed on renal carcinoma cells and is identical to the MN/CAIX antigen. In vitro studies have previously demonstrated that cG250 induces antibody-dependent cellular cytotoxicity (ADCC) of G250-positive targets. In order to investigate the upregulation of ADCC mediated by cG250, ADCC was examined using effector cells cultured in the presence or absence of the cytokines interferon-gamma (IFN-gamma), interferon-alpha isoforms IFN-alpha (2a) and IFN-alpha (2b) and interleukin-2 (IL-2), and the time course of effects over a 7-day period was determined. Renal cell carcinoma lines expressing high (SK-RC-52) and low (SK-RC-09) G250 antigen levels were used as target cells, and freshly isolated peripheral blood mononuclear cells (PBMC) from a healthy donor were used as the effector cells. PBMC were incubated with the respective cytokine at a range of concentrations or with a media alone control for a period of 7 days. The ADCC activity mediated by cG250 or control isotype matched huA33 with the different PBMC treatment groups was assessed in triplicate daily. Corresponding lymphokine activated killing (LAK) activity was measured concurrently for each treatment group. Chimeric G250 specifically recognised G250 antigen on high and low expressing cell lines SK-RC-52 and SK-RC-09, and mediated specific in vitro ADCC of both lines. In the absence of cytokine stimulation, the specific ADCC of cG250 declined rapidly within three days. IL-2 strongly enhanced and maintained cG250-mediated ADCC activity and K562 cytotoxicity when applied to PBMC in culture for seven days. IFN-gamma also enhanced the ADCC of cG250 throughout the study period, but was not as effective as the IL-2 treatment, and the SK-RC-09 line displayed lower specific cytotoxicity than the SK-RC-52 cell line. In contrast, IFN-alpha 2a and 2b increased cG250-mediated ADCC and K562 cytotoxicity for only three days of the study period. The potent and sustained immune effector activity observed with cG250 and cytokines in this in vitro study suggests that the combination immunotherapy of cG250 with cytokines such as IL-2 shows promise in the treatment of renal cell carcinoma (RCC).

Novel mode of action of ribavirin (Rebetol), a drug for the treatment of chronic hepatitis C: inducting the mutation of RNA viruses

Ribavirin (Rebetol) is an antiviral agent used in combination with interferon alpha-2b (IFN alpha-2b) for the treatment of chronic hepatitis C. Ribavirin has been reported to have a broad-spectrum antiviral activity mainly against RNA viruses. The effect of ribavirin was potentiated when administered in combination with IFN alpha-2b in an antiviral assay using bovine viral diarrhea virus as a surrogate for hepatitis C virus (HCV). Inhibition of host inosine monophosphate dehydrogenase and inhibition of RNA-dependent RNA polymerase (RdRp) of RNA viruses have been reported as the modes of action of ribavirin. Recently, ribavirin has been shown to induce mutation as template for newly generated RNA after uptake in RNA by RdRp of poliovirus, which is an RNA virus as in the case of HCV. It has also been shown that the infectivity of viruses is drastically reduced by the very slight increase in mutations induced by ribavirin. This effect as a mutagen on RNA viruses is a novel mode of ribavirin, and it is thought necessary to classify ribavirin into a new antiviral drug class.

Human primary CD4 + T cells activated in the presence of IFN-alpha 2b express functional indoleamine 2,3-dioxygenase.

Indoleamine 2,3-dioxygenase (IDO) is the rate-limiting enzyme in the catabolism of tryptophan. By creating a local microenvironment in which levels of tryptophan are low, IDO-expressing antigen-presenting cells (APC) could regulate T cell activation. This may be relevant to control both viral and bacterial replication as well as neoplastic cell growth. Interferon-alpha (IFN-alpha) is an antiviral cytokine affecting cellular differentiation. In addition, it reduces proliferation of CD4(+) T cells by several molecular mechanisms. To dissect the molecular steps responsible for the INF-mediated antiproliferative activity, we sought to determine whether activated primary CD4(+) T cells in the presence of IFN-alpha would produce IDO. We demonstrate here that IDO mRNA is not present in resting CD4(+) T cells. Stimulation with anti-CD3 plus interleukin-2 (IL-2) induces expression of IDO mRNA (about 2000 copies/150,000 cells), as determined by semiquantitative RT-PCR. When cells were stimulated in the presence of IFN-alpha, expression of IDO mRNA was significantly increased (more than 12,000 copies/150,000 cells). Functional analysis of IDO activity paralleled the results obtained with RT-PCR, demonstrating increased production of active enzyme in CD4(+) T cells stimulated in the presence of IFN-alpha. Our results indicate that IFN-alpha modulates levels of IDO produced by activated CD4(+) T cells. This would likely affect bystander cells by modifying levels of tryptophan in the local microenvironment.

Thymosin alpha-1.

The pharmacology, pharmacokinetics, clinical efficacy, adverse effects, and dosage and administration of thymosin alpha-1 (TA1) are reviewed. TA1 is a synthetic polypeptide. The drug is in Phase III trials for the treatment of hepatitis C and in Phase II trials for hepatitis B. Additional possible indications are malignant melanoma, hepatocellular carcinoma, drug-resistant tuberculosis, and DiGeorge's syndrome. TA1 is thought to modulate the immune system by augmenting T-cell function. TA1 may affect thymocytes by stimulating their differentiation or by converting them to active T cells. TA1 is rapidly absorbed, achieving peak serum concentrations within two hours. Blood levels return to baseline within 24 hours, and the serum half-life is approximately 2 hours. TA1's efficacy in hepatitis B has been evaluated in 195 patients in four clinical trials. One study found hepatitis B virus (HBV) DNA clearance at six months in 9 of 17 patients receiving TA1, compared with 10 of 16 patients treated with interferon alfa-2b (IFN-alpha 2b) and 4 of 15 historical controls. An open-label trial found HBV DNA clearance in 53% of patients at six months. A randomized, controlled trial found HBV DNA clearance in 40.6% and 25.6% of patients treated with TA1 for 6 and 12 months, respectively, compared with 9.4% of untreated controls. Efficacy for hepatitis C has been evaluated in 162 patients in three clinical trials. In one trial, the number of patients who achieved normal serum alanine aminotransferase (ALT) levels did not differ significantly between TA1 and placebo. In the other two trials, combination TA1 and IFN-alpha 2b was compared with IFN-alpha 2b alone. One trial found a normal serum ALT level at six months in 71% of patients receiving combination therapy, versus 35% of patients receiving IFN-alpha 2b alone. Hepatitis C virus RNA clearance occurred in 65% of patients treated with combination therapy and 29% of patients treated with IFN-alpha 2b alone. The third trial, comparing combination TA1 and IFN-alpha 2b with IFN-alpha 2b alone and with placebo, found normalization of ALT levels at six months in 37.1% of patients receiving combination therapy, 16.2% of patients receiving IFN-alpha 2b alone, and 2.7% of patients receiving placebo. TA1 is well tolerated. Most studies observed only local irritation at the injection site. For hepatitis B and C, TA1 1.6 mg (900 micrograms/m2) should be administered subcutaneously twice a week. Clinical trials of TA1 for chronic hepatitis B or C have had mixed results. TA1 may be useful as monotherapy for hepatitis B or in combination with IFN-alpha 2b for hepatitis C, but its effects on morbidity and mortality remain to be seen.

IFN alpha 2B and ribavirin in naive patients with HCV type 1 chronic hepatitis: results after 6 months of therapy

IFN alpha 2B and ribavirin in naive patients with HCV type 1 chronic hepatitis: results after 6 months of therapy

IFN alpha 2b and ribavirin in naive patients with HCV type 1 chronic hepatitis: results after 6 months of therapy

IFN alpha 2b and ribavirin in naive patients with HCV type 1 chronic hepatitis: results after 6 months of therapy

IFNα 2b induces apoptosis and proteasome-mediated degradation of p27Kip1 in a human lung cancer cell line

IFNs are a family of cytokines involved in antiviral defense, cell growth regulation and immune activation. IFNs either inhibit cell proliferation or control apoptosis depending on factors such as cell type and state of cell differentiation. It is important to determine how IFN-induced gene products interact with other cellular proteins to produce these responses. We have investigated the effect of IFNalpha 2b on a human small cell lung carcinoma (SCLC) cell line H82. We have found that IFNalpha efficiently induces apoptosis in H82 cells. The induction of apoptosis by IFNalpha 2b is accompanied by decreased levels of c-myc and Cdk2. We have also observed that in H82 cells IFNalpha induces downregulation of p27 and this is in contrast to the upregulation of p27 observed in other cell types where IFNs induce cell cycle arrest. IFNalpha-induced downregulation of p27 is due to protein destabilization and can be prevented by the proteasome inhibitor LLnL. The data suggest that in H82 cells, IFNalpha 2b induces degradation of p27Kip1 independently of CDK2 kinase activity and through a ubiquitin or ubiquitin-related pathway and that the degradation of p27Kip1 could be a molecular event of importance for IFN-induced apoptosis in cancer cells.

Melanoma inhibitory activity (MIA), a serological marker of malignant melanoma.

Melanoma inhibitory activity (MIA) was originally identified as an 11 kDa protein secreted from malignant melanoma cells. We have shown that MIA is strongly expressed in melanoma and melanoma cell lines but not in melanocytes and normal skin. We also observed that MIA mRNA expression correlates with progressive malignancy of melanocytic tumors. Measuring MIA in serum or plasma by a sensitive and quantitative ELISA and investigating the potential of MIA serum levels as a novel marker for malignant melanomas showed that the protein can be used to monitor therapy and follow-up. The present study measured the variations in blood concentrations of MIA in 84 patients with stage II-IV melanoma by ELISA. Patients treated with repeated injections of a polyvalent melanoma vaccine (PMV), interferon-alpha-2b (IFN-alpha 2b) or interleukin-2 (IL-2) were followed during treatment duration. Before treatment, patients treated with PMV or IFN-alpha 2b had comparable low MIA concentrations, whereas most IL-2-treated patients had higher MIA levels. At the end of treatment, MIA concentrations were higher in patients with progressive disease (PD) than in patients with no clinical evidence of melanoma (NPD) for PMV, IFN-alpha 2b or IL-2 therapy (3.7 +/- 0.2 vs 11.5 +/- 5.4 ng/ml, 3.8 +/- 0.2 vs 8.3 +/- 1.7 ng/ml, and 2.3 +/- 0.7 vs 20.2 +/- 7.4 ng/ml, respectively, p < 0.05). In contrast to the stable MIA concentrations measured in NPD patients, significant increase in MIA levels were observed in PD patients over time regardless of treatment. For PMV- and IFN-alpha 2b-treated patients, a rise in MIA levels occurred significantly earlier than clinical diagnosis of melanoma recurrence. In conclusion, our data suggest that quantitation of MIA serum levels may be used for detection of both clinically apparent and non-apparent metastatic melanoma disease and for monitoring therapy.

Chronic Hepatitis C Treatment: A Review

Chronic Hepatitis C Treatment: A Review

Virologic factors related to interferon-alpha-induced thyroid dysfunction in patients with chronic hepatitis C.

Hepatitis C virus (HCV), being reported to be associated with a high prevalence of serological markers of autoimmunity in HCV-infected patients, and possibly sharing partial sequences in amino acid segments with thyroid tissue antigens, may be associated with interferon-alpha (IFN-alpha)-induced thyroid dysfunction in chronic hepatitis C patients. We conducted this study to clarify the issue. One hundred and fifty chronic hepatitis C patients with normal baseline thyroid function were treated with IFN-alpha 2a, 2b and n1 (3-6 million Units three times weekly for 24 weeks). Pretreatment sera were tested for HCV genotype and HCV RNA levels. Serum thyrotropin, total thyroxine and free thyroxine index were performed every 4 weeks for 24 weeks followed by every 8 weeks for another 24 weeks. Twenty-one (14.0%) patients developed early thyroid dysfunction (abnormal thyroid function during the first 3 months of therapy). Female gender, lower HCV RNA levels, IFN-alpha n1 and a lower IFN-alpha dose were significantly associated with early thyroid dysfunction. On multivariate analysis, gender, IFN-alpha preparation and HCV RNA levels were the significant factors associated with early thyroid dysfunction. Seven (4.7%) patients developed thyroid dysfunction during the second 3 months of IFN-alpha therapy. Taken together, 18.7% patients developed thyroid dysfunction. Female, mixed HCV genotype infection and lower HCV RNA levels were significantly associated with thyroid dysfunction. However, only gender remained significantly associated with IFN-alpha-induced thyroid dysfunction in multivariate analysis. The virologic features of HCV may be associated with thyroid dysfunction in chronic hepatitis C patients treated with IFN-alpha. Nevertheless, gender still plays the most important role in IFN-alpha-induced thyroid dysfunction.