High Doses Of Interferon Research Articles

Action of peripheral or intrathyroidal lymphocytes on autologous thyrocytes cultured in follicles in collagen gel.

We have studied the action of peripheral blood lymphocytes (PBLs) and intrathyroidal lymphocytes (ITLs) on the biochemical and hormonal metabolism of autologous thyrocytes cultured in follicles in a collagen gel. The production of tumour necrosis factor alpha (TNF-alpha) in culture was also measured. Thyroid tissues and lymphocytes were obtained from ten patients with Graves' disease and from five control subjects. Lymphocyte-induced cytotoxicity was evaluated in autologous thyrocytes cultured in a collagen gel by several tests; neutral red uptake, lactate dehydrogenase activity and glutathione level. Hormonal metabolism was assessed by evaluating tri-iodothyronine (T3) and total cAMP production under TSH stimulation. TNF-alpha levels were measured in supernatants after 5 days of coculture. PBLs altered biochemical metabolism, T3 synthesis and cAMP production in autologous thyroid follicles. These inhibitions were greater than those obtained with ITLs. No difference was seen between cells obtained from patients with Graves' disease and those from normal subjects. TNF-alpha levels secreted by PBLs were higher than those secreted by ITLs. The concentrations of this cytokine decreased in coculture. Significant correlations were observed between the decrease in biochemical and hormonal parameters and TNF-alpha levels. Exogenous TNF-alpha and high doses of interferon gamma inhibited follicle metabolism, especially hormone secretion. In conclusion, thyrocytes cultured in follicles provide a more sensitive model than monolayer cultures for analysis of lymphocyte-induced interactions. Lymphocytes gradually inhibit the biochemical and hormonal metabolism of autologous thyroid follicles depending on the isolation method. These alterations may be particularly attributed to TNF-alpha secreted by lymphocytes. The cytokine-induced inhibition of thyroid hormonal function apparently involves the adenylate cyclase system.

Transfusion-associated chronic hepatitis C: Alpha-n 1 interferon for 6 vs. 12 months

Aims: To compare the long-term effects of brief and prolonged therapy with alpha-n 1 interferon for transfusion-associated chronic hepatitis C. Methods: One hundred and sixteen subjects (male/female 48 68 , mean age 46.9 years) were studied. Sixty patients were randomised to brief treatment (group 1: interferon 5 Mu/msq. t.i.w. for 2 months, then 3 Mu/msq. t.i.w. for 4 months), and 56 to prolonged treatment (group 2: interferon 5 Mu/msq. t.i.w. for 2 months, then 3 Mu/msq. t.i.w. for 10 months). All were followed for 12 months after stopping interferon. Results: The early response rate was 47.4% (Group 1 [45%], Group 2 [50%]). No “breakthrough” reactivations were observed. The early response rate was 19% in patients with and 63% in patients without cirrhosis. Twenty-three (19.8%) subjects stopped therapy. Among 54 evaluable early responders, 21 had a sustained response. The rate of sustained response was comparable in group 1 (18.3%) and group 2 (18.2%). All sustained response subjects and some non-responders were HCV-RNA negative at the end of follow-up. Histological improvement was seen only after sustained response. Cirrhosis developed in 20% of non-responders. Overall, interferon induced a long-lasting remission of chronic hepatitis C in about one every five patients. Conclusions: In a population predominantly infected by hepatitis C virus type 1, 12 months of therapy with high doses of interferon does not confer any additional benefit on the early response or sustained response rates as compared to a 6-month course.

The Differential Response to Interferon γ by Normal and Transformed Endothelial Cells

Interferon γ, a multifunctional cytokine secreted by activated T lymphocytes and NK cells, induces normal endothelial cell apoptosis which is inhibited by the activation of protein kinase C. Interestingly, interferon exerts a dual effect on transformed endothelial cell proliferation: at low concentrations it stimulates their growth, while at high concentrations it exerts an inhibitory effect. The different response of normal and transformed endothelial cells correlates with the levels of interferon receptor: when expressed at high levels -such as in normal cells- interferon promotes apoptosis; on the contrary, when cells possess a low number of receptors - such as transformed cells - the cytokine promotes cell growth. Since interferon induces it own receptor, we anticipate that transformed cells exposed to high doses of interferon may upregulate the receptor and, consequently, respond to the cytokine with a reduction in cell viability.

Theoretical analysis of the regulation of interferon expression during priming and blocking

Interferon superinduction, in the case of cell pretreatment with low doses of interferon (priming), may be explained by activation of 2′,5′-oligoadenylate synthetase and endonuclease L, since the latter, as expected, leads to a more rapid amplification of the standard scheme of interferon induction based on the antirepression mechanism. In the given case, endonuclease L will further increase the degradation rates for messages, which encode repressor proteins controlling interferon gene expression. Under ordinary induction, these messages are destroyed only by short-lived nuclease activated by double-stranded RNA. Cell pretreatment with high doses of interferon (blocking) considerably increases the concentrations of protein kinase and 2′,5′-oligoadenylate synthetase in the cell. However, it seems that during blocking protein kinase plays the main role in inhibition of interferon synthesis, and this leads to almost complete depression of translation in the cell. When protein kinase is not sufficiently activated, blocking does not occur since treatment of cells with high concentrations of interferon does not hinder priming induced by 2′,5′-oligoadenylate synthetase and endonuclease L. The proposed model is consistent with the findings that both interferon-treated primed and blocked cells are able to produce interferon more rapidly than normal cells. The analysis, based on a computer simulation model, suggests that priming and blocking of interferon may be based on processes controlling its induction and antiviral activity.

Possible Role of Mutant Forms of HBV in Pathogenesis and Persistence of Disease

A young woman developed arthritis and leukocytoclastic vasculitis, followed by hepatitis due to a precore mutant strain of hepatitis B virus (HBV) incapable of synthesizing HBe antigen. Tests for antibodies to HCV were persistently negative. Treatment of the patient with alpha interferon initially led to a severe exacerbation of hepatitis. Later, higher doses of interferon were tolerated and were associated with reduction of HBV replication and improvement in liver histopathology and serum aminotransferases. After interferon therapy, sequencing of HBV DNA from a repeat liver biopsy showed a cluster of new mutations, which may have led to alterations in immunodominant epitopes of viral proteins. The findings suggest that a "naturally occurring" mutant form of HBV was associated with chronic hepatitis and vasculitis in the patient, and that the immunological pressure on HBV produced by therapy with interferon may have led to other mutations in the viral genome with persistence of low-level HBV infection.

Interferon and multiple myeloma.

In vivo and in vitro studies are used to investigate interferon's use treating human multiple myeloma. In vitro studies demonstrate that the production of monoclonal immunoglobulin by myeloma plasma cells is reduced by alpha interferon; furthermore, interferon alpha seems to inhibit myeloma cell lines development. In vivo studies using interferon in the treatment of multiple myeloma experimentally reproduced in mice show low percentages of mortality among mice treated with high doses of interferon as opposed to high mortality among those treated with low doses. Clinical trials to evaluate the interferon efficacy in the treatment of human multiple myeloma demonstrate that the therapy of previously untreated patients using interferon is not useful because the response rate is lower than that of chemotherapy. There is no homogeneity of results of combined chemotherapy plus interferon as induction treatment of previously untreated patients. Homogeneous results are also not obtained using interferon alone or in combination with chemotherapy as a second induction treatment of relapsed patients. However, interferon seems to be effective as maintenance therapy of a response obtained with previous chemotherapy.

Long-term response to higher doses of interferon (IFN) alfa-2b treatment of patients with chronic hepatitis C: A randomized multicenter trial

Long-term response to higher doses of interferon (IFN) alfa-2b treatment of patients with chronic hepatitis C: A randomized multicenter trial

Other approaches to the treatment of chronic viral hepatitis

Interferon (IFN) therapy of chronic hepatitis C has proved useful in recent years. A major goal in the treatment of hepatitis C is the prevention of the high relapse rate after cessation of therapy and the improvement of the response rate in non-responders. Several approaches can be tried. The administration of higher doses of IFN results in an increase in the response rate, but does not prevent ultimate relapse. Similarly, prolongation of the treatment period gives better results, but one third of cases still relapse. In these cases, re-treatment results in ALT normalization once again, but does not prevent subsequent relapse; in non-responders to IFN, re-treatment will not lead to improvement of the response rate. Analysis of the viral genome reveals its presence in serum in spite of the normalization of ALT values. The role of HCV genome heterogeneity in the response to IFN needs to be assessed and it is necessary to find other antiviral agents that are able to clear HCV from all relevant hosts (serum, liver tissue and mononuclear cells).

Interferon alpha-2b treatment of chronic posttransfusion non-A, non-B/C hepatitis: Long-term outcome and effect of increased interferon doses in non-responders

The biochemical and histological long-term outcome of interferon alpha-2b treatment for chronic posttransfusion non-A, non-B/C hepatitis was evaluated in a randomized study. 4/19 treated patients had a sustained response with normal serum alanine aminotransferases (s-ALAT) levels during follow-up, at present for 18-20 months after the end of interferon treatment. None of 11 responders with biochemical relapse normalized their s-ALAT levels during 1 year follow-up after treatment. Histological changes were assessed by a scoring system. The scores for portal inflammation, piecemeal necrosis and fibrosis were essentially unchanged in all treated patients between biopsies taken at the end of treatment and 1 year later. Six non-responders to 3 million units (MU) alpha-2b interferon thrice weekly (t.i.w.) were given 6 MU t.i.w. for at least 8 weeks. None normalized the s-ALAT levels during treatment with the higher dose, instead the side effects were much more pronounced, an obstacle to the usefulness of higher interferon doses. The biochemical non-responders had higher pretreatment histologic inflammation scores indicating a more severe infection. They also had a higher body weight and seemed to have prominent macrovesicular steatosis more often than responders, a finding that could contribute to raised aminotransferases, thereby in some of the non-responders, masking a positive biochemical effect of interferon treatment.

Beta-Interferon Therapy in Patients with Poor-Prognosis Kaposi Sarcoma Related to the Acquired Immunodeficiency Syndrome (AIDS)

To study the efficacy of high doses of beta-ser-interferon (recombinant human 17-serine beta-interferon) in patients with human immunodeficiency virus (HIV) infection and Kaposi sarcoma. A nonrandomized, controlled trial of two high-dose regimens of beta-ser-interferon administered until tumor progression, toxicity, or an acquired immunodeficiency syndrome (AIDS)-defining opportunistic infection occurred. An AIDS treatment clinic at a tertiary care center. A sequential sample of 39 patients with biopsy-proven, AIDS-related Kaposi sarcoma were enrolled during a 2-year period. Thirty-eight patients were evaluable for response. Most patients (35 of 38) had one or more of the following clinical or laboratory predictors for a poor response to interferon therapy: HIV p24 antigenemia, low CD4 cell numbers, elevated beta 2-microglobulin levels, previous opportunistic infections, or previous systemic chemotherapy. Beta-ser-interferon was self-administered subcutaneously at home 5 days per week. The first 21 patients used 90 million IU/d, and the remainder used 180 million IU/d. Six patients (16%) had a major clinical response, and 15 (39%) had stable disease for prolonged periods. Toxicities were minimal; the major toxicity was a skin reaction at the injection site. The HIV p24 antigen level declined more than 50% in 8 of the 19 patients with initial values greater than 50 pg/mL. Antiretroviral activity and antitumor activity were seen only in patients with normal initial beta 2-microglobulin levels. Minimal changes were seen in CD4 and CD8 cell numbers. Only 1 patient had an opportunistic infection while on study, but five other patients developed infections after treatment was discontinued for an incidence of six opportunistic infections in 285 patient-observation months. The high doses of interferon did not improve the major response rate in patients with poor-prognosis, AIDS-related Kaposi sarcoma. There was, however, a suggestion of antiviral activity in patients with normal beta 2-microglobulin levels and a decrease in the expected incidence of opportunistic infections.

Recombinant human interferon alfa-2a in community-acquired non-A, non-B chronic active hepatitis. Preliminary results of a randomized, controlled trial

A randomized, controlled trial was undertaken to evaluate the response to recombinant interferon alfa-2a in patients with hepatitis B surface antigen negative chronic active hepatitis of unknown aetiology (community-acquired non-A, non-B hepatitis). Thirty patients were treated with thrice weekly interferon in a dose of 6 million units for 1 month, followed by 3 million units for 3 months and 1 million units maintenance therapy for 8 months. Patients who relapsed were returned to the previously effective dose. A control group of 30 patients received no treatment and were followed up for 12 months. Overall, 21/30 (70%) of treated patients had a complete response, with normalization of serum aminotransferase levels, and a further three (10%) had a partial response (a decrease to less than 50% of baseline levels). No significant changes were observed in the control patients. Five (24%) of the 21 complete responders relapsed during months 2-4 and 8/21 (38%) relapsed during maintenance therapy. Three (23%) of these 13 patients had a return to normal serum aminotransferase levels when the dose was increased and 7/13 (54%) demonstrated a significant decrease. In a retrospective analysis of patients' sera for antibody to hepatitis C virus, 23/26 patients testing positive were treatment responders compared to 1/4 antibody negative patients. Our results suggest that interferon alfa-2a is an effective treatment for community-acquired non-A, non-B hepatitis, but reactivation during treatment occurred in 62% of patients. We recommend use of a higher dose of interferon for at least 1 year with long-term follow up in order to exclude early or late reactivation after treatment withdrawal.

Interferon-mediated inhibition of retroviral infection: use of a defective retrovirus carrying a drug-resistance gene

We here report the results of an investigation of the effect of interferon on the establishment of new infections by a retrovirus. For this study, we used an infectious but replication-incompetent retrovirus carrying a drug-resistance gene and assayed for infectivity by measuring drug-resistant colony formation. Mouse interferon-β inhibited retroviral infection of mouse CG1 cells in a dose-dependent manner. However, a higher dose of interferon was needed for eliciting the antiretroviral effects than for action against vesicular stomatitis virus. The degree of antiretroviral effect was comparable over at least a 100-fold range of multiplicity of infection and the effect was most pronounced when the cells were continuously treated with interferon before infections and during infection and drug-selection.

Recombinant human interferon (IFN) alpha-2b in chronic myelogenous leukaemia: dose dependency of response and frequency of neutralizing anti-interferon antibodies.

Twenty-seven patients with Philadelphia chromosome positive chronic myelogenous leukaemia in the chronic phase were treated with low doses of recombinant interferon (IFN) alpha-2b. Ten patients entered a complete and six a partial haematologic remission with a median duration of 5.8 and 9.1 months respectively. Five minor cytogenetic responses were observed. These results are inferior compared to other studies with higher interferon-doses. Fever was an acute side effect after injection of IFN, limb pains and fatigue occurred protractedly. Haematologic side effects, nonspecific EEG changes, weight loss, and development of pulmonary infiltrates were observed in later periods of the treatment. Eight patients developed neutralizing anti-IFN antibodies after 4.2-20.4 months (median 12.8 months). Anti-IFN antibodies were associated with relapse or refractoriness to IFN treatment: five out of nine patients with rising WBC after initial fall had antibodies, while four did not. Two out of four patients with primary non-response had IFN-antibodies. These results may indicate a serious problem in the long-term treatment of CML with recombinant interferon.

Regulation of two interferon‐inducible human genes by interferon, poly(rI) · poly(rC) and viruses

The IFI-56K and IFI-54K genes are transcriptionally stimulated when cells are treated by interferon. We have previously shown that the IFI-56K gene is in addition directly induced by poly(rI).poly(rC), and inducer of interferon-beta. Since the regulation of the IFI-56K and IFI-54K genes by interferon are very much alike, we tested whether the IFI-54K gene is also directly regulated by poly(rI).poly(rC). Treatment of various cell lines with poly(rI).poly(rC) leads to a clear accumulation of the IFI-54K mRNA to a level which sometimes even exceeds that obtained with high doses of interferon. Several interferon-resistant cell lines were investigated for the inducibility of both the IFI-56K and IFI-54K genes by interferons, poly(rI).poly(rC) and viruses (which are the natural inducers of interferon-alpha and -beta). Both genes appear to be coordinately regulated by these inducers. It was thus interesting to search for common regulatory element(s) in the control region of these two genes. The IFI-54K gene promoter region was isolated, from which a 520-base-pair segment was sequenced and compared with the promoter region of the IFI-56K gene that we had previously sequenced. The only homology was found is a well conserved 19-bp segment located just upstream of the TATA box of these genes; interestingly, this sequence is also homologous to the minimal region needed for the inducibility by poly(rI).poly(rC) of the interferon-beta gene. This conserved sequence might be responsible for the coordinate induction of the IFI-56K and IFI-54K genes by interferon, poly(rI).poly(rC) and viruses.

Use of recombinant bovine alpha 1 interferon in reducing respiratory disease induced by bovine herpesvirus type 1.

Intranasal or intramuscular treatment of calves with recombinant bovine alpha 1 interferon before challenge with bovine herpesvirus type 1 and Pasteurella haemolytica reduced clinical signs, number of sick days, lung lesions, and weight loss. The effective dose was determined to be relatively broad within the range of 1 to 50 mg per animal. No adverse effects were observed even at high doses of interferon (50 mg per animal). Administration before virus infection was more effective than administration at the same time as virus infection. Although interferon administration had dramatic effects on the survival of animals, it did not have much effect on virus secretion in the upper respiratory tract. Therefore, the mechanism by which interferon reduces the susceptibility of animals to viral-bacterial synergy was postulated to be via its immunomodulatory effects.

Current and future uses of recombinant interferon alpha in the treatment of low-grade non-Hodgkin's lymphoma.

Recombinant and natural forms of interferon alpha have been shown to bring about tumor regressions in patients with low-grade non-Hodgkin's lymphoma. Complete and partial response rates in up to 50% of patients have been documented. Although these studies are encouraging, interferon alpha's role in the current management of patients with low-grade non-Hodgkin's lymphoma is not apparent. The high doses of interferon that were used in some of the recent studies were not well tolerated by these patients. Current studies using interferon in patients with low-grade non-Hodgkin's lymphomas are evaluating lower, and perhaps better tolerated doses of interferon. In addition, in vitro studies have documented additive and sometimes synergistic antitumor effects of interferon in combination with cytotoxic drugs. This approach is being extended to the clinic, and trials are now underway evaluating combinations of interferon and various cytotoxic drugs known from previous studies to be active in patients with low-grade non-Hodgkin's lymphomas. This report reviews studies using interferon alone in these patients, and discusses ongoing and proposed studies for the future use of interferon in treating this disease.

Interferon Inhibits the Growth ofLegionella micdadeiin Mouse L Cells

The intracellular growth of Legionella micdadei was inhibited in mouse L cells treated with interferon (IFN). This IFN-mediated restriction was dose-dependent and required preincubation of the L cells with high doses of IFN (1,000 U/ml) for maximal inhibition. Incubation of L. micdadei with IFN alone had no detectable effect on growth of the bacteria. The IFN-mediated growth restriction was not dependent upon tryptophan concentration in the culture medium.

Biological activities of human recombinant interferon α/β targeted by anti-Epstein-Barr virus monoclonal antibodies

The requirement of high doses of interferon (IFN) during therapy severely restrict its application. Thus a model using an Epstein-Barr virus (EBV) membrane antigen (MA) specific monoclonal antibody (MAb) was developed to assess the feasibility of coupling minimal amounts of IFN to a MAb and specifically delivering the IFN to the target cells. Coupled IFN was first shown to retain fully both its anti-viral and antiproliferative properties when tested on human tumor cell lines QIMR-WIL (EBV-MA +) and the U-266 (EBV-MA −1). A series of in vitro pulsing experiments demonstrated the specific targeting of both the anti-viral and anti-proliferative properties of IFN to the EBV-MA + QIMR-WIL cells and not EBV-MA −1 cell lines.

Effects of several species of human leukocyte interferon on cytotoxic activity of NK cells and monocytes

Ten species of purified human leukocyte interferon were tested for their ability to modulate the cytolytic activity of natural killer (NK) cells and the cytolytic and cytostatic activities of monocytes. The interferon species were tested at several antiviral titers and examined for quantitative differences in their ability to modulate immunological function. At the higher doses of interferon (i.e., greater than 500 units) all of the interferon species demonstrated significant augmentation of cytolysis and cytostasis. However, when low levels (i.e., 10-50 units) of interferon were employed, appreciable differences between the various interferon species were seen. A similar pattern of relative potency among the various species of pure leukocyte interferon was seen for augmentation of cytolysis by monocytes and NK cells. In contrast, a different pattern of relative potency was observed for augmentation of cytostasis. These results demonstrated substantial quantitative differences (as much as 100-fold) in the ability of the various species of human leukocyte interferon to induce significant levels of augmentation of these cell-mediated functions. Such results should have significant impact in choosing a specific interferon species for appropriate clinical trials.

The ppp(A2'p)nA and protein kinase systems in wild-type and interferon-resistant Daudi cells.

Daudi cells, a human lymphoblastoid line, are exceptionally sensitive to the growth inhibitory effects of interferon, 1 unit/ml being sufficient to inhibit cell growth. In addition, interferon treatment of these cells severely inhibits the incorporation of exogenous thymidine into DNA and causes cells to accumulate in the G1(G0) at the expense of the S phase of the cell cycle. The possible involvement of ppp(A2'p)nA(n = 2 to less than or equal to 4) in these effects has been investigated. No (less than 1 nM) ppp(A2'p)nA or (A2'p)nA or alternative products of the ppp(A2'p)nA synthetase [e.g. NAD (2'pA)2] were detected in interferon-treated cells. In addition no evidence was obtained for the occurrence of ppp(A2'p)nA-mediated ribosomal RNA cleavage in these cells even after several days of treatment with relatively high doses of interferon. A line of Daudi cells which is resistant to all three of the above effects of interferon was selected. The wild type and resistant lines were compared with respect to the ppp(A2'p)nA and interferon and double-stranded RNA (dsRNA)-mediated protein kinase systems. The resistant line was not receptor-negative as it responded to interferon by the production of elevated levels of the ppp(A2'p)nA synthetase similar to those observed in extracts from wild-type cells. There was no detectable difference between the lines in the levels of the (2'-5')phosphodiesterase responsible for the degradation of ppp(A2'p)nA. There was, however, about a twofold increase in the ppp(A2'p)nA-dependent endoribonuclease activity in response to interferon with extracts from the wild-type but not the resistant cells. In addition, although the dsRNA-dependent protein kinase activity increased in both types of cell there was a striking reduction in the level of protein phosphorylation in general in response to interferon with material from the wild-type but not the resistant cells.