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[Treatment of leukemias and lymphomas with interferons: III. Trial treatment of meningeal localizations of acute leukemia and non-Hodgkin's lymphomas with beta interferon administered by the intrathecal route].

Six patients with pure meningeal relapse of acute lymphoblastic leukemia (ALL) (5 patients) or leukemic lymphosarcoma (LS) (non Hodgkin's lymphoma) (NHL) (1 patient) were treated with intrathecal (I.T.) human fibroblastic interferon (IF beta), one vial (1.3 million units) every other day or every day up to remission or failure. Tolerance was excellent in all six patients with no local or general side effects. 5 patients had no improvement of their meningeal blast infiltrations after 5 to 8 injections and were given IT chemotherapy. The sixth patient achieved a complete remission (CR) after 11 injections, and was maintained in CR for eleven months under systemic and IT chemotherapy. IF cannot be proposed as standard treatment for meningeal leukemia, but we may be able to select a population of patients in which it could be indicated. Its combination with methotrexate and arabinoside cytosine, the two agents used IT which are S-dependent, has to be studied for a possible potentiation. Moreover, its good tolerance would permit its use in severe meningeal viral diseases.

Acute Disease↗

[Treatment of leukemias and lymphomas by interferons: II. Phase II of the trial treatment of chronic lymphoid leukemia by human interferon alpha+].

Nine patients with chronic lymphoid leukemia (CLL) were treated with subcutaneous human (leukocyte) interferon alpha (IF alpha). In the first part of the study, 7 patients received intermittent 10 day courses, with free intervals of 10 to 15 days and with a rising dose in the same patient from cycle to cycle, if tolerance permits, from 1.5 to 6 X 10(6) units daily. As we observed a decrease of peripheral lymphocytosis with low doses, and as high doses gave more side-effect in the second part of the study, 4 patients (including two who had previously received intermittent courses) were treated for three months or more at a dose of 1.5 X 10(6) units daily. Tumor mass reduction was seen in only three patients, but significant decrease in peripheral lymphocytosis was seen in 7 patients sustained in the continuous treatment group with relapse at treatment discontinuation in one patient and despite continuation in another. Immune monitoring with currently available T, B, NK and macrophage tests, showed, in this population of patients, a very good correlation between NK cell activity and clinical response. Further studies are warranted to determine the best modalities of treatment as well as the population of patients likely to benefit from it, and the possible special respective indications of IF, and of the other treatments of CLL. One can already consider as a reasonable indication CLL presentations with myeloid insufficiency as IF is not myelotoxic, contrary to chemotherapy.

Drug Evaluation↗

Effects of human fibroblast interferon on human tumors transplanted into nude mice: sensitivity of human tumors to interferon.

The antitumor effect of human fibroblast interferon (HuIFN-beta) was examined using a nude mouse-human tumor xenograft group. Eight subcutaneously transplanted tumors--one line each of ovarian carcinoma, laryngeal carcinoma, carcinoma of the nasopharynx and hepatoma, and two lines each of lung carcinoma and melanoma--were used. HuIFN-beta at 1 X 10(5) IU/mouse was injected subcutaneously around the tumor or into the tumor itself. In the former case, statistically significant growth-suppressive effects were observed in one lung carcinoma (PC-12) and both melanomas (AM-1 and SK-14), but no effect was seen on the other five tumors. Further studies were made to ascertain the effects of intratumoral injections. Increased growth inhibition was observed in both melanomas (AM-1 and SK-14), but not in lung cancer (PC-12). Complete regression was seen in 3 of 8 mice carrying SK-14. The sensitivity of tumors to HuIFN-beta was correlated to the inhibitory effect of HuIFN-beta on cell division detected by histological observation.

Animals↗

[Interferons. Treatment of malignant hemopathies with interferons].

Interferons (INF) are glycoproteins with protean antiviral, immunomodulator, and antiproliferative actions. In Haematology, IFN-alpha is the most widely used. Diffusion into the spleen, bone marrow and liver is good. Hairy cell leukemia is probably the malignant blood disorder which responds best to IFN. At some time during their treatment, nearly 90% of the patients require IFN. Treatment initiation is indicated when pancytopenia (polynuclear neutrophils below 1 x 10(9)/L) develops or in case of a very voluminous spleen. IFN-alpha 2a, 2b and 2c are active (leukocyte IFN is used less often, as is IFN-beta; IFN-gamma is ineffective). The standard dose is 3 x 10(6) U, three times a week for 12 weeks. Smaller doses and maintenance treatment is sometimes proposed. Haematological remission occurs in almost all cases, if not a misdiagnosis must be considered (villous lymphocyte lymphoma). Relapse usually occurs at the end of treatment, but sensitivity to IFN is not altered and final survival is improved. Nearly 90% of the patients are alive at 4 years. Although IFN is active in chronic myeloid leukemia, research in this area continues. Clinical trials have reported haematologic relapse in 90% and complete cytogenetic response in 15 to 35% of the patients. The effect on Ph+ cells is not observed with classical chemotherapies. Initial dose is generally 5 x 10(6) U/m2/day. High doses are not always well tolerated, but cytogenetic response is only seen in patients in haematologic and cytopenic remission. IFN therapy improves survival over classical treatments (median 62 versus 39 months). Survival is better after good cytogenetic response or complete remission. Combined chemo-IFN therapy is currently under study in an attempt to improve cytogenetic response. In terms of the molecular biology however, residual disease is almost always present and relapse is frequent.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗

Interleukin-4 enhances interferon-gamma synthesis but inhibits development of interferon-gamma-producing cells.

Interleukin-4 (IL-4) is antagonistic for many of the activities of interferon-gamma (IFN-gamma) and, as well as suppressing the development of T-helper type-1 (Th1) cells, has been reported to block directly the synthesis of IFN-gamma in human lymphocytes. However, IL-4 transgenic mice produce increased amounts of IFN-gamma as well as IL-4. We have compared the ability of rat IL-4 to regulate IFN-gamma secretion in short-term cultures of spleen cells with its effect on the differentiation of T lymphocytes into IFN-gamma-producing, or Th1-type, cells. Normal rat spleen cells were stimulated using a variety of mitogens and ovalbumin antigen, with or without IL-4, for 12-24 hr and the levels of IFN-gamma in the supernatants measured by enzyme-linked immunosorbent assay (ELISA). The results show that when normal rat splenocytes were stimulated with phytohaemagglutinin (PHA) or concavalin A (Con A), IL-4 enhanced secretion of IFN-gamma after 12-24 hr. This enhancement was also apparent when splenocytes from animals immunized 10 days previously with alum-precipitated ovalbumin were stimulated with ovalbumin in vitro, and appeared to be mediated primarily via CD+ T cells. In contrast, when spleen cells were maximally stimulated with phorbol myristate acetate (PMA) and ionomycin, addition of IL-4 had no effect on the amount of IFN-gamma secreted. When splenocytes were stimulated with Con A for 4 days in the presence of IL-4, and restimulated with PMA and ionomycin, IFN-gamma secretion was greatly suppressed. Our results indicate that IL-4 exerts differential effects on IFN-gamma secretion and on the development of IFN-gamma-producing lymphocytes.

Animals↗

Human interferon-gamma has three domains associated with its antiviral function: a neutralizing epitope typing scheme for human interferon-gamma.

An antiviral activity-neutralizing monoclonal antibody (mAb), MIF3037, was developed by the immunization of BALB/c mice with recombinant human interferon-gamma (rhuIFN-gamma). Its neutralizing activity suggests that its epitope may be at or adjacent to a functional domain on the huIFN-gamma. MIF3037 was compared with representative mAb of previously identified epitope-specific groups in a competitive binding assay. In an attempt to determine if there are other functional epitopes recognized by mAb developed with different preparations of huIFN-gamma or different hybridoma screening methods, 14 additional mAb contributed by five other laboratories were similarly analysed. Based on their ability to bind to huIFN-gamma, all the neutralizing mAb except MIF3037 may be classified into three previously defined groups: E1, E2 and E1/E2. Monoclonal antibodies of the E1 group do not compete with those of the E2 group for huIFN-gamma binding, indicating that the E1 and E2 epitopes are distinct domains on the huIFN-gamma important for the antiviral function. Monoclonal antibodies of the E1/E2 group compete with some of the mAb of E1 and/or E2 groups and may bind to regions of the huIFN-gamma that partially overlap the E1 and E2 epitopes. MIF3037 demonstrated no competitive binding inhibition with mAb of the previously identified epitope specificity groups and, therefore, must represent a distinct functional epitope, E3. The huIFN-gamma, therefore, must have at least three distinct functional domains; none of these appeared to be responsible for cell surface receptor binding. Based on this finding, the epitope typing scheme must be extended to include the E3 epitope. The epitope specificity relationships of 13 neutralizing mAb developed by five other laboratories were established which allows correlation of results obtained with these mAb by different laboratories. The location of the epitopes of four widely studied mAb, 69B, 73A, 113B and 220A12, have been deduced based on their competition with the E1 mAb which have recently been mapped.

Animals↗

[Pharmacokinetics of intratumoral interferon-gamma activity following subcutaneous administration of recombinant interferon-gamma in a patient with metastatic brain tumor derived from renal cancer].

Pharmacokinetic studies of intratumoral interferon (IFN)-gamma activity were performed 1 week and 1 month after subcutaneous (s.c.) administration of recombinant IFN-gamma (specific activity = 1 x 10(7) units/mg protein) to a patient with metastatic brain tumor in the right occipital lobe derived from primary renal cancer. The patient, a 54-year-old man, underwent total removal of the lesion on April 10, 1991, with placement of an indwelling Ommaya Reservoir in the tumor cavity. The histological diagnosis was clear-cell carcinoma. His postoperative course was uneventful. Due to detection of a new ring-like enhancing mass in the right temporal lobe on serial CT examination on May 27, radiotherapy was discontinued immediately after delivery of a total dose of 30 Gy. Recombinant IFN-gamma was then administered s.c. at a dose of 3 x 10(6) units/day for 6 weeks, and induced a partial response. During IFN-gamma therapy, IFN-gamma activity in intratumoral fluid was measured 0 min, 30 min, 90 min and 6 hours after s.c. injection of IFN-gamma. The level of IFN activity was determined by an enzyme-linked immunosorbent assay. Intra-tumoral IFN-gamma activity gradually increased, and showed the highest of measured values at 6 hours after administration, while serum IFN activity decreased rapidly with a half-life of 30 min. The patient was discharged on July 30, but died from complications of aspiration pneumonia on September 2, 1991.

Adenocarcinoma, Clear Cell↗

[Interferon treatment of chronic hepatitis C--assessment of predictive factors to the effect of interferon treatment using multivariate analysis with the logistic regression model].

We treated 156 chronic hepatitis C patients with alpha-interferon (IFN) and assessed the response rate and the predictive factors to the effect of IFN treatment. Complete response (CR) rate was 39.1%, and CR with serum HCV-RNA disappearance rate was 29%. CR to IFN treatment was dependent on HCV serotype and serum HCV-RNA. Patients of serotype II and low serum HCV-RNA were effective to IFN treatment.

Adult↗

Interferon-gamma down-regulates the lipoprotein(a)/apoprotein(a) receptor activity on macrophage foam cells. Evidence for disruption of ligand-induced receptor recycling by interferon-gamma.

Cholesterol loading of macrophages, such as occurs in atheroma foam cells, has recently been shown to upregulate a novel receptor activity that mediates the internalization degradation of the atherogenic lipoprotein, lipoprotein(a) (Lp(a)), and its protein moiety, apoprotein(a), (apo(a)). Herein, the regulation of this receptor activity by macrophage activation and interferon-gamma (IFN-gamma) was investigated. Compared with control foam cells, 125I-recombinant-apo(a) (r-apo(a)) degradation assayed after 5 h of incubation was 3-6-fold less in foam cells derived from thioglycollate- or concanavalin A-elicited mouse peritoneal macrophages. In vitro treatment of foam cells derived from resident mouse peritoneal macrophages or from human monocyte-derived macrophages with IFN-gamma also led to a substantial decrease in the ability of these cells to degrade 125I-rapo(a); similar results were obtained with 125I-Lp(a). In contrast, IFN-gamma-treated foam cells that were incubated for 10 min with 125I-r-apo(a) and then chased for 2 h in the absence of ligand degraded similar amounts of 125I-r-apo(a) as untreated foam cells. To reconcile these data, we hypothesized that the apo(a) receptor activity undergoes ligand-induced recycling and that IFN-gamma disrupts this recycling. To test this idea, control and IFN-gamma-treated foam cells were incubated for 10 min with unlabeled r-apo(a), and then 125I-r-apo(a) receptor activity was assayed at various times thereafter. Untreated foam cells showed clear evidence of ligand-induced recycling of the apo(a) receptor activity, whereas recycling was markedly diminished in the IFN-gamma-treated foam cells. Thus, by disrupting ligand-induced receptor recycling, IFN-gamma leads to down-regulation of the foam cell Lp(a)/apo(a) receptor activity. Since T cells are known to be present in atherosclerotic lesions, these findings raise the possibility that the degradation by atheroma foam cells of Lp(a) and other possible ligands for the receptor may be reversibly regulated by IFN-gamma.

Animals↗

Interferon alpha 2b but not interferon alpha 2a detected in human genomic DNA.

The presence of the genes for human interferon (IFN)-alpha 2a and IFN-alpha 2b subvariants in human genomic DNA was studied using polymerase chain reaction (PCR). The respective genes differ in the coding sequence only at the position 137, adenine (2A) being substituted by guanine (2B). IFN-alpha 2-sequences were selectively amplified from the placental genomic DNA using specific primers. When sequencing the mixture of PCR-derived clones, at the position 137 guanine, specific for subvariant 2b could be detected. This indicates that, at least in the genome analyzed, only sequence coding for IFN-alpha 2b was found. Our finding supports the view, that genes for IFN-alpha 2a and IFN-alpha 2b seem to be rather allelic than occurring at distinct loci.

Base Sequence↗

[A case of subacute sclerosing panencephalitis treated with intraventricular interferon--the side effects of interferon-alpha to the central nervous system].

A patient with subacute sclerosing panencephalitis (SSPE) was treated with an intraventricular alpha interferon (IFN-alpha) through an Ommaya reservoir. A 17-year-old boy, who had a history of measles exposure at age 1, showed forgetfulness, difficulties in calculation, reading and writing. Two months later he developed generalized convulsions and myoclonic spasms. He was admitted to the National Saigata Hospital in May 20, 1992. On admission, anti-measles antibody titer in the CSF was 1:16 by complement-fixation method. His EEG revealed a periodic synchronous discharge. Therefore, the diagnosis of SSPE was confirmed. An Ommaya reservoir was implanted on July 7, 1992, and an intraventricular administration of INF-alpha was begun after two weeks. The dose of INF-alpha was gradually increased from 1.0 x 10(6) IU/m2 to 2.0 x 10(6) IU/m2 twice a week. Fever, vomiting and anorexia were developed when the INF-alpha injection was first started. When he received a total dose of 8.0 x 10(6) IU, he became bed ridden for remarkable lethargy. The lethargy was continued for about 10 days despite the therapy was interrupted, and then he gradually became alert. The frequency of myoclonus became more frequent and mentality got worse, so the treatment with INF-alpha was tried again in decreasing the dose to 1.0 x 10(6) IU/m2 twice a week. However, be became drowsy again after he received a total of 7.5 x 10(6) IU. With intramuscular or intravenous administrations of the high doses of INF-alpha (> or = 1.0 x 10(7) IU), significant neurological abnormalities were reported to occur.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Antitumor potential of interferon-gamma: retroviral expression of mouse interferon-gamma cDNA in two kinds of highly metastatic mouse tumor lines reduces their tumorigenicity.

The antitumor effects of interferon (IFN)-gamma were examined in two types of malignant metastatic mouse tumor cell lines following their transfection with the IFN-gamma gene by retroviral gene transfer. In both ovarian and lung tumor lines, but more markedly in the latter, subcutaneous (s.c.) tumor progression of the IFN-gamma-producing cells was profoundly suppressed in the normal syngeneic as well as in athymic nude mice. In addition, experimental metastasis via the tail vein of the IFN-gamma producers was also suppressed. Lung tumor suppression was abolished by X-irradiation of the syngeneic mice or by the administration of antiasialoganglioside GM1 antibodies into the nude mice. These results suggest that tumor suppression is due to the effect of the tumor-derived IFN-gamma on the host antitumor mechanisms including natural killer cells. Moreover, tumorigenicity of several unrelated tumor cells was significantly reduced when s.c. injected as a mixture with the apparently benign IFN-gamma-producing lung tumor cells, so that such 'non-malignant' IFN-gamma-producing cells may have therapeutic benefit against certain other malignant tumors.

Animals↗

IFP 35 is an interferon-induced leucine zipper protein that undergoes interferon-regulated cellular redistribution.

We have isolated a new human cDNA, named IFP 35, whose expression is regulated by interferons (IFN). Induction of IFP 35 mRNA in HeLa cells by IFN is due, at least in part, to increased transcription. In response to IFN treatment, the expression of IFP 35 mRNA is seen in a wide range of different cell types, including fibroblasts, macrophages, and epithelial cells. The cDNA sequence encodes a 282-amino acid protein with a deduced molecular mass of 31,130 Da. In vitro translation of mRNA obtained by both in vitro transcription and hybrid selection resulted in the synthesis of a 35-kDa protein. Antisera raised against IFP 35 recognized a protein with an apparent molecular mass of 35 kDa in HeLa cells. Amino acid sequence analysis revealed a leucine zipper motif in an alpha-helical configuration at the extreme amino terminus of IFP 35. Notable IFP 35 is a unique novel leucine zipper protein in that it lacks a basic domain critical for DNA binding. IFP 35 can specifically form homodimers in vitro. Western blot analysis of fractionated cell extracts indicates increased nuclear localization following IFN treatment.

Amino Acid Sequence↗

Differential effect of type I interferons on hematopoietic progenitor cells: failure of interferons to inhibit IL-3-stimulated normal and CML myeloid progenitors.

We observed a differential effect of type I interferons (IFNs) in inhibiting the proliferation of various hematopoietic progenitor cell types. Upon stimulation with interleukin-3 (IL-3), IFN-alpha and IFN-beta failed to inhibit colony formation of myeloid progenitors (day-14 colony-forming units-granulocyte/macrophage [CFU-GM]) obtained from peripheral blood (PB) and bone marrow (BM) of untreated chronic myelogenous leukemia (CML) patients in chronic phase even at IFN doses as high as 10,000 U/mL. In contrast, day-7 CFU-GM stimulated with granulocyte colony-stimulating factor (G-CSF) and burst-forming units-erythroid (BFU-E) were readily inhibited by moderate doses of IFNs. IFN-resistant myeloid progenitor cells were also detected in normal BM but not in normal PB cells. When suboptimal doses of IL-3 were used in clonal progenitor cell assays, day-14 CFU-GM were not protected from the inhibitory action of IFN. The failure of IFN to inhibit immature myeloid progenitors was confirmed in normal and CML cells highly enriched in CD34-expressing cells. Combinations of growth factors were required for sufficient colony formation in these cells, whereas IL-3 alone provided only an inadequate stimulation, which was further inhibited by IFN. In purified CD34+ cells, day-14 CFU-GM were protected from IFN-mediated inhibition only upon stimulation with stem cell factor (SCF) in combination with IL-3 or G-CSF.

Antigens, CD34↗

Interleukin 4 and interferon gamma costimulate the expansion of early human myeloid colony-forming cells. Proposal of a model for the regulation of myelopoiesis by interleukin 4 and interferon gamma and its integration with the regulation of the immune response.

We have previously shown that interleukin 4 (IL-4) and interferon gamma (INF-gamma) reciprocally regulate the production of granulocytes and monocytes from mature monopotential hematopoietic progenitor cells, while at the level of the very primitive stem cells IFN-gamma is a selective inhibitor of proliferation and differentiation, and IL-4 has weak stimulatory effects. We investigated the effects of IL-4 and IFN-gamma on the expansion in suspension culture of myeloid colony-forming cells (CFCs) induced by either IL-3 or IL-1+IL-3, using on the one hand more differentiated CD34+HLA-DR strongly positive (HLA-DR++) and on the other hand more primitive Cd34+HLA-DR weakly positive (HLA-DR+/-) human bone marrow cells. It is shown that both IL-4 and IFN-gamma stimulate the IL-3- and IL-3+IL-1-induced expansion of the number of CFCs in the HLA-DR+/- population. In the presence, but not in the absence of IL-1, additive effects of IL-4 and IFN-gamma were seen. We could not demonstrate any IL-3-like effect by IL-4 on early human hematopoietic progenitors. No expansion of CFC number was seen in the HLA-DR++ population. Based on these data and on data which we have published previously, a model for the regulation of myelopoiesis by IL-4 and IFN-gamma is proposed. In this model, IL-4 and IFN-gamma, which are both immune recognition induced inflammatory cytokines, both stimulate the expansion and recruitment of early myeloid progenitors, whereas at the level of their terminal differentiation, the balance between both cytokines determines whether preferentially monocytes/macrophages (IFN-gamma) or granulocytes (IL-4) are being produced. At the level of the most primitive cells, the inhibitory action of IFN-gamma might prevent differentiative exhaustion of the stem cell compartment in situations of hematopoietic stress.

Antibody Formation↗

Interferon-alpha and hydroxyurea in early chronic myeloid leukemia: a comparative analysis of the Italian and German chronic myeloid leukemia trials with interferon-alpha.

In 1994, the Italian and the German Chronic myeloid leukemia (CML) trials comparing interferon-alpha (IFN-alpha) with conventional chemotherapy were published. The survival advantage in favor of IFN-alpha compared with hydroxyurea (HU; 72 v 52 months) was significant in the Italian (P < .002), but not in the German trial (66 v 56 months, P < .44). We set up a collaborative study to identify the reasons for the different outcomes. There are major differences in the trial protocols concerning admission criteria, treatment strategy, and definitions. The German patients were older and more seriously sick. Fifty-two of the 327 patients in the German IFN and HU arms did not fulfil Italian admission criteria, and 41 of the 322 Italian patients did not fulfil German admission criteria. Using mutually uniform admission criteria, the median survival times of the IFN patients are 76 (Italian) and 72 (German) months (P = .56). The Italian group administered IFN combined with HU as needed, whereas the German group strictly used IFN as monotherapy with rerandomization to busulfan (BU) or HU after IFN resistance or intolerability. The differences seen between the Italian and the German trial results can be accounted for by objective differences in study design, especially the admission criteria, treatment strategy, and bias due to intention to treat analysis. The detailed analysis of the data suggests that the combination of IFN with HU as needed is more effective than either agent alone.

Adult↗

Retreatment of hepatitis C interferon non-responders with larger doses of interferon with and without phlebotomy.

BACKGROUND/AIMS: Interferon a (IFN) is the only agent currently approved by the FDA for the treatment of chronic viral hepatitis due to hepatitis C (HCV). Unfortunately, less than half the patients with HCV treated with IFN respond. Worse yet, half or more of those who do respond relapse when the agent is withdrawn. MATERIALS AND METHODS: In this prospective randomized study, 30 individuals who had failed to respond to a standard course of IFN therapy consisting of 3 MU IFN administered 3 x week for 6 months were randomized to receive a second 6 month course of either 5 MU IFN daily or 5 MU IFN plus regular phlebotomies at weekly intervals to achieve a hemoglobin level of between 10-11 g/dl. The response rates defined as HCV-RNA negativity after 6 months of therapy and after 6 months of follow-up without IFN were determined. RESULTS: Both groups experienced a significant reduction in their serum ALT levels (p < 0.01) and Knodell scores with treatment. A greater number of responders were found in the phlebotomy plus IFN group than in the IFN alone group whether the response was defined by the serum ALT level or presence or absence of HCV-RNA in serum at the end of treatment and follow-up. CONCLUSIONS: The results of this study suggest that both an increased IFN dose coupled with more frequent dosing of IFN alone and combined with phlebotomy treatment are effective at obtaining a response to IFN in individuals with HCV disease who previously have failed to respond to a standard treatment regimen.

Female↗

Incidence of antibodies to interferon-beta in patients treated with recombinant human interferon-beta 1a from mammalian cells.

Patients receiving recombinant human interferon-beta 1a (IFN-beta 1a) produced in Chinese hamster ovary (CHO) cells were tested for the formation of neutralizing antibodies (NABs) to IFN-beta. Samples were tested in an enzyme-linked immunosorbent assay (ELISA), and if positive were then tested for neutralization of antiviral activity in an IFN-beta bioassay. A total of 793 patients with viral diseases, premalignant and malignant diseases, and multiple sclerosis received IFN-beta 1a in clinical studies. Long-term studies included 56 patients with cancer treated for 6 or 12 months and 334 patients with multiple sclerosis (MS) at the end of one year of treatment. All of the NAB-positive patients were found in the latter. Positivity in a single specimen was found in 14.4% of the MS patients. The incidence of sustained neutralizing antibody titres (i.e. positive in two tests at least 6 months apart) was 6.9% in this group. Comparison with results from other studies suggests that CHO-derived IFN-beta 1a induces less neutralizing antibody than IFN-beta 1b produced in E. coli.

Animals↗