Recombinant Interferon-alpha Research Articles

Pegylated Interferon-ALFA-2A (PEG-IFN-α-2A; PEGASYS) Therapy Renders High Clinical and Molecular Response Rates in Patients with Essential Thrombocythemia (ET) and Polycythemia VERA (PV)

Patients with high-risk essential thrombocythemia (ET) and polycythemia vera (PV) are typically managed with cytoreductive agents such as recombinant interferon-alpha (IFN-α), hydroxyurea (HU), and anagrelide (AG). Despite the significant activity of IFN-α in ET and PV, this agent is frequently hindered by poor tolerance and inconvenient dosing schedules. PEG-IFN-α is formulated by covalently attaching polymers of ethylene glycol to the native IFN-α molecule, resulting in decreased renal excretion and increased serum half-life that allows for weekly administration. On this basis, we are conducting a phase II study of subcutaneous PEG-IFN-α-2a (Pegasys) for patients with ET or PV. A total of 76 patients have been enrolled and treated thus far (36 ET, 40 PV). Median age is 53 years (range, 18–77), time from diagnosis to PEG-IFN-α-2a 49 months (range, 0–355), WBC count 8.7×109/L (range, 3.7–27.8), hemoglobin 13.5 g/dL (range, 8.9–18.8), and platelet count 554×109/L (range, 140–1641). Prior therapies (median 1; range 0–6) included HU (n=44), AG (n=29), IFN-α (n=11: 5 oral and 6 sc), imatinib (n=7), and dasatinib (n=1). PEG-IFN-α-2a was the initial therapy in 13 patients that refused therapy with HU. The JAK2 V617F mutation was detected in 20 (56%) of 36 ET and in 37 (92.5%) of 40 PV patients. Nine (12%) patients had abnormal cytogenetics. Initial starting dose of PEG-IFN-α-2a was 450 mcg/week, but that was modified to the current starting dose of 90 mcg/week. Dose modifications are allowed according to response or toxicity. Patients are currently receiving 450 mcg (n=1), 270 mcg (n=3), 180 mcg (n=14), 135 mcg (n=8), 90 mcg (n=27), and 45 mcg (n=7). After a median follow-up of 23 months (range, 2–38), 63 (85%) of 74 assessable patients have responded. The median time to response was 4 weeks (range, 0.5–26). Complete response (CR) was achieved by 60 (81%) patients (for ET: platelets <440×109/L, off HU and AG, in the absence of thromboembolic events; for PV: Hb <15 g/dL, off HU and AG, no phlebotomy, with disappearance of splenomegaly) whereas 3 (4%) patients (1 PV, 2 ET) had a partial response ([PR]; no phlebotomy, off HU and AG, but still palpable spleen). Of 5 assessable patients with abnormal karyotype at the start of the study, 2 reverted to diploid cytogenetics. The mutant JAK2 V617F to total JAK2 ratio was determined by quantitative pyrosequencing assay in all 76 patients prior to PEG-IFN-α-2a and was repeated at least once during therapy in 41 JAK2 V617F-positive patients. Overall, 23 (56%) had >10% reduction in JAK2 V617F expression, including 14 (34%) who had a >50% reduction. In 5 (11%) of the latter the mutant allele became undetectable. PEG-IFN-α-2a was well tolerated in most patients. Thirty-nine episodes of grade 3–4 toxicity were reported: neutropenia (n=15), elevated transaminases (n=5), infection (n=4), fatigue (n=3), pain (n=3), cardiac (n=2), and anemia, thrombocytopenia, depression, shortness of breath, pruritus, thrombosis, and dizziness in 1 case each. Sixteen (21%) patients were taken off study after a median of 8 months (range, 2–26) on PEG-IFN-α-2a but only 7 (9%) of them due to due to therapy-related toxicities: grade 3 neutropenia, anorexia, depression, ischemic retinopathy, dyspnea, confusion, and pruritic rash. In conclusion, PEG-IFN-α-2a therapy results in remarkable clinical activity with an acceptable toxicity profile in advanced, previously treated, patients with ET or PV. Clinical responses are frequently accompanied by significant reduction of JAK2 V617F allele burden, which becomes undetectable in a proportion of them, suggesting selective targeting of the malignant clone.

Biologic agents in the management of inflammatory eye diseases

Biologics are a new class of drugs that comprise recombinant cytokines and monoclonal antibodies directed against selected cell-surface markers. They include the tumor necrosis factor-alpha inhibitors infliximab, etanercept, and adalimumab; the antilymphocyte drugs rituximab and alemtuzumab; the interleukin-2 receptor blocker daclizumab; and recombinant interferon-alpha. This article reviews the rationale and current evidence for their use in uveitis, scleritis, and orbital inflammation.

Thyroid autoimmunity and hypothyroidism during long-term treatment with recombinant interferon-alpha.

Forty-five patients with myeloproliferative or myelodysplastic syndromes, treated with recombinant interferon-alpha (rIFN-alpha) for a minimum of 1 up to 4 years, were examined for the occurrence of thyroid autoimmunity. During treatment, the rate of thyroid autoimmunity rose to more than 20%. The decrease in severity and frequency of thyroid autoimmunity after withdrawal of IFN shows that this is a potentially reversible side effect. The key determinant for the manifestation of this IFN-related autoimmune phenomenon seems to be a predisposition for autoimmunity, since patients with initially detectable thyroid antibodies are prone to exacerbations of thyroid autoimmunity. Concurrent with thyroid autoimmunity, hypothyroidism occurred but did not correlate with the levels of thyroid antibodies, although severe hypothyroidism in two patients was accompanied by increased levels of thyroid antibodies. This investigation shows that thyroid autoimmunity and consecutively hypothyroidism must be expected in certain patients treated with rIFN-alpha during long periods. Furthermore, it may be assumed that IFN-alpha does not induce the development of autoimmunity, but rather enhances the levels of pre-existent thyroid antibodies.

The effect of recombinant interferon-alpha on lymphocyte subpopulations and HLA-DR expression on liver tissue of HBV-positive individuals

Interferon-alpha (IFN-alpha) has been reported to be beneficial in the treatment of chronic active hepatitis occurring as a result of hepatitis B virus (HBV) infection. Treatment with IFN-alpha has been proposed as a means of reducing the high rate of allograft infection in clinical liver transplantation in patients transplanted for HBV-related chronic active hepatitis and cirrhosis who are positive for hepatitis B surface antigen (HBsAg). We obtained resected whole livers from two groups of patients who received liver transplants. Group A consisted of 11 patients who were HBsAg+ but were not treated with IFN-alpha, and group B consisted of 10 patients who were also HBsAg+ but received IFN-alpha therapy for 29.4 +/- 5.6 days prior to orthotopic liver transplantation. No differences between the two groups existed in terms of a variety of demographic and clinical characteristics. The liver tissue was stained with monoclonal antibodies to cell surface antigens unique to different mononuclear cell populations by the avidin-biotin-immunoperoxidase technique to determine the effect of IFN-alpha on the lymphocyte subsets as well as HLA antigen expression on liver-infiltrating mononuclear cells. The number of HLA-DR+ lymphocytes in the liver was significantly increased (P less than 0.005) within the portal areas in group B compared with that found in group A (84 +/- 14 versus 33 +/- 5 per one high-power field). Moreover, the intensity of the HLA-DR antigen expression on lymphocytes in the portal areas (P less than 0.02) and in the hepatic lobule (P less than 0.05) was greater in group B than in group A. The number of natural killer (NK) cells was increased in the portal areas (P less than 0.05) of group B compared with group A. These alterations in the lymphocyte and NK cell populations present in the liver in response to IFN-alpha therapy presumably reflect an IFN-alpha-induced enhancement of the immune response to virus-infected cells.

Characterization of anti-interferon-alpha antibodies appearing during recombinant interferon-alpha 2a treatment.

Patients with malignant midgut carcinoid tumours received recombinant interferon-alpha 2a (rIFN-alpha 2a) or rIFN-alpha 2a and chemotherapy (streptozocin and doxorubicin) for 6 months, and then rIFN-alpha 2a alone. Antibodies, mainly of IgG type, binding to rIFN-alpha 2a developed in nine of 22 patients (41%), as determined by immunoassay. In seven patients, antibodies also neutralized the biologic (anti-viral) activity of rIFN-alpha 2a. Anti-IFN-alpha 2a antibodies were equally frequent in both sexes and treatment groups, but were not observed in those patients (n = 8) that had previously received other types of IFN. Antibodies appeared after a median of 6 months of rIFN-alpha 2a treatment and had a median duration of 6 months. The anti-IFN-alpha 2a antibody titres declined with time with no obvious relation to change of therapy, also during continued IFN-alpha 2a treatment. High titres of neutralizing antibodies appeared to impair anti-tumoural effects in individual potential responders. Anti-IFN-alpha 2a antibodies further examined in six patients bound to native IFN-alpha subtypes present in both allogenic and autologous leucocyte IFN-alpha. Such autoantibodies neutralized the biologic activity of autologous IFN-alpha in two patients, and in a third were partially neutralizing.

Cytotoxicity of human natural killer (NK) cell subsets for Plasmodium falciparum erythrocytic schizonts: stimulation by cytokines and inhibition by neomycin

Quantification of human peripheral blood NK subsets has been made in a group of Kenyan adults and children with acute P. falciparum malaria. Results were compared with data obtained from three age- and sex-matched control cohorts: parasitaemic but asymptomatic children; aparasitaemic children and adults; and adult Caucasians with no previous history of malaria. Separated NK subsets were tested in vitro for cytotoxicity to erythrocytic schizonts of P. falciparum in the presence and absence of cytokines. There was a statistically significant quantitative and qualitative depression of the CD3-CD56+ subset in patients with acute malaria and this was accompanied by an expansion of the 'non-functional' CD3-CD57+CD16-CD56- subset. Both CD3-CD16+ and CD3-CD56+ NK cells from all patients and donors lysed schizonts, and this cytotoxicity was enhanced by the addition of recombinant interferon-alpha and/or IL-2, notably with the CD3-CD56+ subset. Interestingly, asymptomatic donors had the highest levels of CD3-CD56+ NK cells, which also demonstrated an enhanced response to cytokine stimulation. Cytotoxicity to schizonts was accompanied by the release of soluble NK cell lytic factors. Neomycin suppressed cytotoxicity in a dose-dependent manner, indicating that the lysis of schizonts by NK cells involves phospholipase C-mediated phosphoinositide metabolism. Our findings define a role for NK cells in immunity to malaria through the lysis of infected erythrocytes as a first-line defence against the parasite.

Natural killer cell cytotoxicity is enhanced by very low doses of rIL-2 and rIFN-α in patients with renal cell carcinoma

Very low doses of recombinant interleukin-2 (rIL-2) and interferon-alpha (rIFN-alpha) induce, in patients with advanced renal cell carcinoma (RCC) clinical response rate and median survival time comparable to other protocols, other than immunological response in terms of expansion of NK cells and cT lymphocytes. The aim of this pilot study was to verify whether very low dose immunotherapy can enhance NK cell cytotoxicity against tumoral target cells. Eight patients with advanced and 13 patients with localised disease received 4-week cycles of rIL-2 (total dose per week 7 MIU/m(2), s.c.) and rIFN-alpha (total dose per week 3.6 MUI/m(2), i.m.) according to the scheme proposed by Buzio et al. Neutrophils, monocytes, eosinophils, NK cells (CD56+bright, CD56+dimmer, CD3-CD56 +), NK-T cells (CD3+CD56+), Th-lymphocytes, cT-lymphocytes, HLA-DR+ and CD25+ lymphocytes and NK cell cytotoxicity were evaluated before and after cycle. The treatment led to the significant expansion of eosinophils (P < 0.001), NK cells (P < 0.001), CD56+bright (P < 0.001), CD56+dimmer (P < 0.001), Th-lymphocytes (P = 0.001), cT-lymphocytes (P = 0.014), HLA-DR+ (P = 0.007) and CD25+(P = 0.002) cells. Neutrophils significantly decreased (P = 0.001), whereas no significant effect was observed on monocytes (P = 0.22) or NK-T cells (P = 0.20). Patients with localised disease responded significantly better to treatment than metastatic patients in terms of the expansion of CD56+bright (P = 0.038), DR+ (P = 0.021), CD25+ (P = 0.006) and Th-lymphocytes (P = 0.014). The NK cell cytotoxicity was significantly increased by the immunotherapy in the whole population (P = 0.021) and similarly in the two groups of patients (P = 0.860); a reverse relation, even if not significant, was seen between the variation of NK-T cells and NK cells cytotoxicity (r = -0.39; P = 0.074).

Improving the yield of soluble 6xHis-tagged interferon-α via the addition of repressor of the araBAD promoter system in Escherichia coli

The inhibition of inclusion body formation in Escherichia coli by the addition of alpha-D-glucopyranoside or D-fucose after induction improved the purification yield of soluble recombinant interferon-alpha. When D-fucose was added after induction, more soluble 6xHis-tagged interferon-alpha could be purified compared to when methyl alpha-D-glucopyranoside was added. It was shown that, on the basis of 1 mg dry cell weight, 16.6 microg of soluble 6xHis-tagged interferon-alpha was purified when D-fucose was added after induction and 6 ml nickel-chelated agarose gel column was used. This was about 15 times greater than when induction only was performed and 1 ml nickel-chelated agarose gel was used.

Serious psychiatric adverse events in chronic Hepatitis C patients treated with Pegylated or recombinant Interferon-Alpha plus Ribavirin

The purpose of this observational study was an assessment of the incidence and types of serious psychiatric adverse events (SPAE) associated with the interferon-α (IFN-α) plus ribavirin (RV) therapy in chronic hepatitis C (CHC) patients with compensated liver function and without psychotic or bipolar disorder, without substance abuse or an organic brain disorder at the enrollment. Method. SPAE were defined as psychiatric consequences of IFN-α+RV therapy that resulted in discontinuation of the therapy, psychiatric hospitalisation or initiation of chronic psychiatric disorders. Results. A group of 273 patients (144 males and 129 females aged 18-69 years, mean 41) was prospectively observed. Psychiatric assessment prior to the therapy was done in 240 patients (88%). Recombinant IFN-α was used in 89 patients and 184 were treated with pegylated IFN-α. Overall SPAE were present in ten patients (3,7% of the sample). Eight of them received recombinant IFN-α (Fisher's exact test: p<0,01). One suicidal attempt and two cases of psychotic disorders occurred. Mixed states prevailed among serious affective disorders induced with the IFN-α+RV therapy. Premature cessation of the therapy due to SPAE occurred significantly more often in patients treated with recombinant IFN-α than in those treated with pegylated IFN-α (four vs none; Fisher's exact test: p=0,01). Conclusions. SPAE in CHC patients on the IFN-α+RV therapy arise rarely. However, potentially severe psychiatric consequences of the treatment in some patients point to necessity of psychiatric monitoring during the therapy. Treatment with pegylated IFN-α may be associated with less SPAE than treatment with recombinant IFN-α in CHC patients.

Preparation of chitosan microparticles and study of their interaction with interferon

Chitosan with viscosity average molecular weights of 340, 281, 199, 137, and 42 kDa was used to prepare microparticles by precipitation coacervation. Acid and enzymatic hydrolysis yielded chitosan samples with a deacetylation degree of 0.85 +/- 0.03. The chitosan microparticles were 0.85-1.7 microm in size and had a zeta-potential of 30.7-38 +/- 0.1 mV. Testing the microparticles for toxicity showed that they caused no death of animals. Interaction of recombinant alpha-2 interferon with the microparticles was studied by sorption from solutions. The maximum adsorption efficiency of interferon was 88% and the capacity of microparticles was 11.8-12.7 microg/mg.

Methamphetamine enhances Hepatitis C virus replication in human hepatocytes

Very little is known about the interactions between hepatitis C virus (HCV) and methamphetamine, which is a highly abused psychostimulant and a known risk factor for human immunodeficiency virus (HIV)/HCV infection. This study examined whether methamphetamine has the ability to inhibit innate immunity in the host cells, facilitating HCV replication in human hepatocytes. Methamphetamine inhibited intracellular interferon alpha expression in human hepatocytes, which was associated with the increase in HCV replication. In addition, methamphetamine also compromised the anti-HCV effect of recombinant interferon alpha. Further investigation of mechanism(s) responsible for the methamphetamine action revealed that methamphetamine was able to inhibit the expression of the signal transducer and activator of transcription 1, a key modulator in interferon-mediated immune and biological responses. Methamphetamine also down-regulated the expression of interferon regulatory factor-5, a crucial transcriptional factor that activates the interferon pathway. These in vitro findings that methamphetamine compromises interferon alpha-mediated innate immunity against HCV infection indicate that methamphetamine may have a cofactor role in the immunopathogenesis of HCV disease.

Abrupt onset of type 1 diabetes mellitus during recombinant interferon-alpha 2b therapy in a patient with chronic hepatitis B

We describe a case of a 33-year-old female patient with chronic hepatitis B who developed type 1 diabetes mellitus (DM) after a 13-mo period of treatment with recombinant human interferon-alpha (IFN-alpha) 2b. The patient presented with polydipsia, polyuria, hyperglycemia, diabetic ketoacidosis, combined with C-peptide secretion deficiency and positive islet cell autoantibody (ICAb). IFN-alpha 2b treatment was terminated and instead insulin treatment was initiated. Five months after cessation of the recombinant human IFN-alpha 2b therapy, the patient remained insulin-dependent. Her serum HBV DNA became negative and serum transaminase returned to the normal level after a 10-mo period of IFN therapy. Type 1 DM induced by IFN-alpha is relatively rare in patients with chronic hepatitis B. We should pay more attention to patients on IFN-alpha therapy to avoid destruction of pancreatic beta cells. This is the first case report from China.

Enhanced Circulating Half-Life and Antitumor Activity of a Site-Specific Pegylated Interferon-α Protein Therapeutic

Recombinant interferon alpha-2 (IFN-alpha2) has proven useful for treating a variety of human cancers and viral diseases. IFN-alpha2 has a short circulating half-life in vivo, which necessitates daily or thrice weekly administration to patients. It is possible to extend the circulating half-life of IFN-alpha2 by random modification of lysine residues in the protein with polyethylene glycol (PEG); however, such preparations have heterogeneous structures and low specific activities, and may not provide optimal therapeutic benefits to patients. A long-acting, site-specific, monoPEGylated IFN-alpha2 protein has now been created by targeted attachment of a 20 kDa or a 40 kDa maleimide-PEG to a cysteine analogue of IFN-alpha2, M111C. In vitro bioactivities of the purified 20 kDa and 40 kDa PEG-M111C proteins were within 2- to 3-fold of those of wild type IFN-alpha2 and 7- to 10-fold better than that of a 40 kDa PEG IFN-alpha2 protein created using nontargeted, amine-PEGylation methodology. The 20 kDa and 40 kDa PEG-M111C proteins demonstrated 26- to 38-fold longer half-lives, respectively, than IFN-alpha2 following subcutaneous administration to rats. The 20 kDa PEG M111C protein inhibited growth of human NIH:OVCAR-3 cells transplanted into nude mice by >90%, as measured by tumor size, tumor weight, and number of animals with detectable tumors at necropsy, and was significantly more effective than a comparable dose of IFN-alpha2. These data extend our previous findings that bioactivity of IFN-alpha2 can be largely preserved by targeted attachment of PEG moieties to nonessential sites in the protein and provide evidence that site-specific PEGylated IFN-alpha2 proteins possess enhanced tumoricidal properties in vivo.

The application of the small doses of the human recombinant alpha-2 interferon oromucosal for the patients with seasonal atopy (bronchial asthma and allergic rhinoconjunctivitis)

The application of the small doses of the human recombinant alpha-2 interferon oromucosal for the patients with seasonal atopy (bronchial asthma and allergic rhinoconjunctivitis)

P004 Changes in thymic recent output function in patients with acute myeloid leukemia

The influence of recombinant human interferon alpha 2a (rIFN alpha), recombinant human interferon beta 1 (rIFN beta), and recombinant human interferon gamma (rIFN gamma) on human dermal microvascular endothelial cells (HDMEC) cultured in vitro was studied in various rIFN concentrations (0.1 lU/ml-104 IU/ml) over 2,3,4,6,8, and 10 d. Cell morphology and ultrastructure, cell proliferation, expression of class II alloantigens (HLA-DR and HLA-DQ), and intercellular adhesion molecule-1 (ICAM-1) were investigated using an in vitro technique established in our laboratory. All rIFN tested induced alterations of typical HDMEC morphology; the cells became spindle-shaped and fibroblastoid, although they maintained their endothelial cell marker expression. Also, all IFN dose- and time-dependently inhibited the proliferation of HDMEC in vitro (rIFN alpha> beta> gamma), whereby rIFN alpha exerted the strongest growth-inhibitory effect. Alkaline phosphatase anti-alkaline phosphatase (APAAP) immunocytochemistry of the cultured cells showed dose- and time-dependent stimulation of ICAM-1 and class II antigen expression only by rIFN gamma (HLA-DR> HLA-DQ), rIFN alpha and beta did not exert any immunomodulatory activity on HDMEC in vitro. These results indicate that HDMEC are an important target for the action of IFN. Besides growth inhibition, it seems that rIFN gamma in particular may be involved in the modulation of leucocyte adhesion and trafficking by altering the immunophenotype of the endothelial cell population.

Study of the relapse of patients with chronic hepatitis B undergoing first and repeated recombinant interferon-alpha therapy during long-term follow up

To investigate the relapse of patients with chronic hepatitis B (CHB) undergoing first and repeated recombinant interferon-alpha (rIFN-alpha) therapy during long-term follow up. Five hundred and twenty three patients with chronic hepatitis B including 403 hepatitis B e-antigen (HBeAg) positive patients and 120 HBeAg negative ones were treated with 5MU recombinant interferon-alpha 1b (rIFN-alpha1b) subcutaneously thrice weekly for 6 - 25 (median 10) months. For each patient, serum alanine aminotransferase (ALT) was measured biochemically and serum HBV DNA level was detected by fluorescent-quantitative PCR, HBeAg with enzyme immunoassay every 1 - 3 month during therapy and every 3 - 6 month during the follow up period. Some of the individuals who relapsed during the follow-up period were treated with interferon-alpha repeatedly. Ratios of early response to interferon-alpha were similar in HBeAg positive patients (55.8%, 225/403), and HBeAg negative patients (64.2%, 77/120) at the end of naive treatment (chi(2) = 2.633, P = 0.105). 39.4% (119/302) of early responders relapsed during 39 +/- 22-month follow up, and relapse rates in HBeAg negative group (55.8%, 43/77) were higher than those in HBeAg positive group (33.8%, 76/225) at the end of follow up (chi(2) = 19.335, P = 0.000). Divided the follow-up period into six fragments as 1 - 12 months, 13 - 24 months, 25 - 36 months, 37 - 48 months, 48 - 60 months and > or = 61 months, we found that the differences of relapse incidence were significant (chi(2) = 73.518, df = 5, P = 0.000), and accumulative relapse rates were significant too (chi(2) = 32.167, df = 5, P = 0.000) in all follow-up periods. Constituent ratios of HBeAg in relapsed patients of every follow-up period were similar. 57 relapsed individuals (25 in HBeAg positive group and 32 in HBeAg negative group) were retreated with interferon-alpha, and complete response were achieved in all cases at the end of repeated therapy. The relapse rates in HBeAg positive group (52.0%, 13/25) were higher than in HBeAg negative group (21.9%, 7/32) during the follow-up period after the end of retreatment (chi(2) = 5.592, P = 0.018). Rates of early response to interferon-alpha therapy were similar in HBeAg positive and HBeAg negative patients at the end of nave treatment, and relapse rates in HBeAg negative group were higher than in HBeAg positive group during long term follow-up. Combined response was achieved in all relapse cases received repeated interferon-alpha therapy at the end of retreatment. The relapse rates in HBeAg positive group were higher than in HBeAg negative group during the follow-up period after repeated therapy.

Investigating Toll-Like Receptor Agonists for Potential To Treat Hepatitis C Virus Infection

Toll-like receptors (TLRs) are key mediators of innate immunity, and their activation by microbial components leads to the production of cytokines and interferons. Recombinant alpha interferon has been used to treat several viral diseases and is the current standard of care for hepatitis C virus (HCV) infection. Recently, agonists of TLR7 and TLR9 have been shown to have clinical efficacy in HCV patients, and this is correlated with their ability to induce endogenous type I interferon production. We have carried out a comprehensive study of agonists of TLRs 1 to 9 to determine if any additional TLRs can induce antiviral molecules from human peripheral blood mononuclear cells (PBMCs). The agonists were incubated with PBMCs, and the supernatant was then removed and added to HCV replicon cells to assess antiviral activity. Agonists of TLRs 3, 4, 7, 8, and 9 were found to be potent inducers of antiviral activity in PBMC supernatants, and the activity correlated with the induction of alpha interferon and the interferon-induced antiviral biomarker 2',5'-oligoadenylate synthase. Antiviral activity of TLR7 and TLR8 agonists was blocked by an antibody that binds to the type I interferon receptor, confirming that the antiviral activity results from type I interferon induction. TLR4 and TLR8 agonists were found to strongly induce the proinflammatory cytokines interleukin 1beta and tumor necrosis factor alpha at concentrations similar to those inducing antiviral activity. This raises concerns about adverse side effects if these were to be used as antiviral agents. We therefore conclude that TLRs 3, 7, and 9 represent the most attractive targets for the development of new HCV therapies.

Effect of human recombinant interferon alpha 2b (Viferon) in treatment of severe bacterial infections in neonates. (B32)

Abstract Neonates have decreased cytotoxic mechanisms and low levels of endogenous interferon production. Aim: Clinical efficacy and mechanisms of adjunctive immunotherapy with human recombinant interferon alpha 2b (Viferon) were studied in neonates suffering from severe bacterial infections. Design. 48 neonates with bacterial pneumonia were observed in NICU. 23 infants (group 1) were treated with Viferon-1, 150,000 IU per suppositorium q8h per rectum during 7 days in addition to combined antibacterial and supportive therapy. 25 babies (group 2) received the same basic therapy plus placebo instead of Viferon in similar way. Results. Clinical course of pneumonia was more favourable in neonates treated with Viferon. The duration of central venous line usage and total parenteral nutrition were significantly less in group 1 than in group 2. Inflammatory signs in blood analyses were significantly decreased after the treatment with Viferon in comparison with placebo-group. Infants treated with Viferon had significantly higher levels of CD3+, CD4+ and CD25+-lymphocytes, higher serum levels of IFN, elevation of mitogen-induced IFN-gamma production after Viferon than infants from group 2. Conclusion. Immunotherapy with Viferon improves the clinical course of severe bacterial infections and restores the balance in immune system of infected newborn infants.

The inhibition of aggregation of recombinant human consensus interferon-α mutant during Pichia pastoris fermentation

Lower induction temperature and polyoxyethylene sorbitan monolaurate (Tween-20) were successfully used to inhibit the aggregation of recombinant human consensus interferon-alpha mutant (cIFN) during Pichia pastoris fermentation. When the induction temperature was decreased from 30 to 20 degrees C, the cIFN secreted into the medium was in the form of monomers instead of aggregates. The maximum specific activity at 20 degrees C was 4.04 times as high as that at 30 degrees C. There was no obvious effect on the cell growth at 20 degrees C, but the total protein level was decreased. Similar inhibition effect on cIFN aggregation was observed when 0.2 g l(-1) Tween-20 was added during induction. Furthermore, there was a synergistic effect found between induction temperature and Tween-20 on the inhibition of cIFN aggregation. The maximum specific activity with Tween-20 at 20 degrees C was 19.9-fold higher than that without Tween-20 at 30 degrees C.

Complete remission of multiple myeloma after autoimmune hemolytic anemia: Possible association with interferon‐α

A patient with multiple myeloma (MM) was being maintained on human recombinant interferon-alpha (INF-alpha) after VAD and autologous bone marrow transplantation (pretreated with melphalan). An episode of immune thrombocytopenia and (Coombs positive) autoimmune hemolytic anemia (AIHA) was noted while on maintenance INF-alpha, which remitted when it was withdrawn. Following this event, he achieved a state of stable disease that persists (more than 3 years) with no specific myeloma treatment. This sequence of events suggests a relationship between an immunological reaction induced by INF-alpha and the prolonged phase of stable disease.