IFN-alpha 2b Research Articles

Effects of bacillus Calmette-Guerin and interferon-alpha-2B on human bladder cancer in vitro.

The cytolytic and anti-proliferative effects of bacillus Calmette-Guerin (BCG) and/or interferon-alpha-2b (IFN-alpha-2b) on 5 human bladder carcinoma cell lines, RT4, RT112, MGH, SD and J82, were determined. The cell lines showed different sensitivities to BCG and IFN-alpha-2b. BCG had direct dose-dependent cytolytic and anti-proliferative effects on MGH, J82 and SD (grade 3 cell lines), whereas RT4 and RT112 (grades 1 and 2, respectively) were less sensitive. Surprisingly, higher concentrations of BCG enhanced cell growth of RT4. IFN-alpha-2b also had cytolytic and anti-proliferative effects on all 5 cell lines. Thus, the RT4 and RT112 cell lines that were not sensitive to BCG were highly sensitive to IFN-alpha-2b. A combination of BCG and IFN-alpha-2b had additive anti-proliferative effects on MGH, J82 and RT112. Interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) production by these 5 cell lines was measured after stimulation with BCG and/or IFN-alpha-2b, by ELISA immunoassays. Production of IL-6 and TNF-alpha was significantly increased in MGH and J82 cell lines by the combination of BCG and IFN alpha-2b. The enhanced cytolytic and anti-proliferative effects of the combination of BCG and IFN-alpha-2b may be related to the induction of cytokines.

Thymidylate synthase expression and response to neoadjuvant chemotherapy in patients with advanced head and neck cancer.

Thymidylate synthase (TS), an essential enzyme in DNA synthesis, is a target for the fluoropyrimidines, an important group of antineoplastic agents used widely in the treatment of head and neck cancer. We evaluated relationships between the level and/or pattern of tumor TS expression and response to fluorouracil (5-FU)-based neoadjuvant chemotherapy in patients with advanced head and neck cancer. Tumor specimens from 86 patients were available for this retrospective analysis. The patients were enrolled in four consecutive phase II studies that tested combinations of 5-FU, leucovorin, and cisplatin with or without added methotrexate plus piritrexim or interferon alfa-2b (IFN alpha-2b). TS protein expression in the tumors was assessed by use of the TS 106 monoclonal antibody and standard immunohistochemical staining techniques. TS immunostaining was classified according to its level of intensity (TS 0-1 = low, TS 2 = intermediate, and TS 3 = high) and according to its extent (focal pattern = less than 25% of tumor cells positive; diffuse pattern = greater than or equal to 25% of tumor cells positive). Data from 79 patients were available for an analysis of tumor TS expression and patient/tumor characteristics; 70 patients were assessable for their response to neoadjuvant chemotherapy. There was a statistically significant association between the level of tumor TS expression and the degree of tumor differentiation; a higher proportion of patients whose tumors exhibited TS 0-1 immunostaining had undifferentiated or poorly differentiated tumors than patients whose tumors exhibited TS 2 or TS 3 immunostaining (P = .04, Jonckheere-Terpstra trend test). Among the 70 patients who were assessable for response to neoadjuvant chemotherapy, TS 3 tumor immunostaining was associated with a lower rate of complete response (i.e., complete disappearance of clinically detectable disease for a minimum of 4 weeks from time of initial determination) than was TS 2 or TS 0-1 immunostaining, but this association was not statistically significant (P = .09, exact trend test); among the 39 patients who were treated with regimens that included 5-FU, leucovorin, cisplatin, and IFN alpha-2b, this inverse association between TS immunostaining intensity and response was statistically significant (P = .02, exact trend test). Tumor TS immunostaining intensity and overall survival were not found to be associated. Patients with tumors exhibiting a focal pattern of TS immunostaining have experienced significantly longer survival than patients with tumors exhibiting a diffuse pattern; for the 53 patients with diffuse tumor TS immunostaining, the median survival was 24.7 months, whereas the median survival has not yet been reached for the 22 patients with focal tumor TS immunostaining (P = .04, two-tailed logrank test). However, the survival advantage for the focal versus diffuse TS immunostaining pattern was limited to patients whose tumors also exhibited a TS 3 level of immunostaining intensity. Characterization of tumor TS expression may be of value in identifying patients with advanced head and neck cancer who would benefit from fluoropyrimidine-based neoadjuvant chemotherapy.

Local lnterferon-Alpha2b Is Not an Effective Treatment in Early-Stage Peyronie's Disease

Peyronie's disease is characterized by an acquired penile deviation that may lead to severe penile deformity. It is refractory to most conservative therapy, and surgical correction is therefore the treatment of choice once the disease process has come to a halt. Basic science, as well as our first clinical results on the use of interferons (IFNs), have been promising, suggesting a beneficial effect in the early noncalcified disease stage. From July 1994 to October 1995, 30 patients suffering from early Peyronie's disease were treated with three local injections of 3 million units of IFN-alpha 2b each into the plaque(s). The interval between the injections was 1 week. Patients were assessed clinically and ultrasonographically 6 months after the last injection. Peyronie's disease clinically improved in only 1 case, remained stable in 26 patients and worsened in 3. In 7 patients, a total of 10 plaques at different sites were detected. By ultrasonography the treated plaques now showed calcifications in 3 cases, remained unchanged in 26 and could not be detected in 1 case. Of the 10 new plaques, 2 showed calcifications. Side effects (myalgia, fever) were considerable; in 74 of 90 injections, fever > 38 degrees C occurred, and a total of 8 working days were lost. IFN-alpha 2b, given according to our regimen, is not useful for the treatment of Peyronie's disease in the early stage since the disease progress continues at different sites in about 25% of the patients, and the side effects are untolerable. Our results also demonstrate that local therapy is not indicated in Peyronie's disease.

Failure of ketoprofen and interferon combination therapy to improve interferon-resistant chronic hepatitis C.

Preliminary reports suggest that patients with interferon (IFN)-resistant chronic hepatitis C respond better to a combination of IFN-alpha and nonsteroidal anti-inflammatory drugs than to IFN alone. The efficacy of IFN combined with ketoprofen in the treatment of patients with IFN-resistant chronic hepatitis C was evaluated. Seventeen patients, nonresponsive after at least six months of treatment with IFN-alpha 2b and subsequently treated with the combination of IFN-alpha 2b plus ketoprofen for four months, were studied. Serum aminotransferases (alanine aminotransferase [ALT] and aspartate aminotransferase [AST]) and serum hepatitis C virus (HCV) RNA were analyzed before and throughout treatment. No patient normalized serum aminotransferases after combination therapy. There were no significant differences in mean serum ALT and AST levels before and after ketoprofen intervention. Serum HCV RNA became undetectable after treatment in only one patient, but was detectable again three months after treatment cessation. These results provide no convincing evidence that the combination of IFN-alpha 2b with ketoprofen improves the response to IFN in patients nonresponsive to IFN alone.

Interferon‐α therapy for individuals with normal serum alanine aminotransferase levels before treatment

While interferon (IFN) therapy is approved for patients with chronic hepatitis C infection, the effectiveness of IFN therapy for anti-hepatitis C virus (HCV)-positive individuals with normal ALT levels remains poorly understood. Twenty-five individuals (M:F = 9:16; age = 51.8 +/- 15.1 years) who showed a normal alanine aminotransferase (ALT) level (< 30 IU/L) at least 6 months before treatment and were positive for both anti-HCV and serum HCV-RNA by reverse transcription polymerase chain reaction (RT-PCR) were studied. Of these, 16 received IFN therapy for 24 weeks (780 million units total IFN-alpha 2b) and nine were followed for 12 months as controls. The serum HCV-RNA level was determined by bDNA assay and HCV genotype was detected by enzyme immunoassay. All were shown to have chronic hepatitis by liver biopsy. Six (37.5%) of 16 individuals lost serum HCV-RNA by RT-PCR 6 months after cessation of therapy (complete response; CR), while the remaining individuals were defined as non-responders (NR). Of the six individuals in the CR group, five had HCV type 2 infection, compared with none of 10 individuals in the NR group (P < 0.01). There was a trend towards a lower pretreatment viraemia level in the CR group than in the NR group. These data suggest that IFN therapy for individuals with HCV type 2 infection and normal ALT levels was effective.

Treatment of metastatic renal cell carcinoma with constant-rate floxuridine infusion plus recombinant α2b-interferon

Floxuridine (FUDR) and alpha-interferon (IFN) are active agents in advanced renal cell carcinoma, with different dose-limiting toxic effects and antitumor synergism in experimental models. The main purpose of this phase II study was to assess the activity and toxic effects of a combination of FUDR and alpha 2b-IFN in metastatic renal cell carcinoma. Metastatic renal cell carcinoma patients with measurable disease entered the study. FUDR was administered as a constant-rate continuous infusion for 14 days every 28 days at a starting daily dose of 0.1 mg/kg and with dose escalations of 0.025 mg/kg/day at each subsequent cycle if WHO > or = 2 toxicity had not occurred. IFN-alpha 2b 10 x 10(6) I.U. was administered intramuscularly 3 times per week. Forty-two patients entered the study and a total of 272 cycles of FUDR + alpha 2b-IFN were administered. In 41 evaluable patients WHO grade III-IV toxic effects included nausea and vomiting (22%), diarrhea (32%), stomatitis (12%), fatigue (27%) and anorexia (12%). It was possible to increase the initial FUDR does in 21 (50%) patients; the median FUDR dose intensity was 0.35 mg/kg/week (range 0.18-0.54). Among 39 evaluable patients, 3 (7.5%) complete and 10 (25.5%) partial responses were observed (response rate 33%, 95% confidence interval (CI) 19%-50%) which lasted a median of 13 months (5.5-40+). Responses also occurred in liver (2), in patients pretreated with systemic therapy (5) and in patients who had other unfavourable prognostic characteristics (7). Median progression-free and survival times were 9 and 16 months, respectively. In this study FUDR + alpha 2b-IFN demonstrated interesting activity in metastatic renal cell carcinoma, showing promise also in patients with unfavourable prognostic characteristics. The antitumor activity of FUDR and alpha 2b-IFN seems to be cumulative, but cumulative toxicity is also observed. These results require confirmation in randomised trials.

Neutralizing anti-interferon-alpha antibodies and response to treatment in patients with Ph+ chronic myeloid leukaemia sequentially treated with recombinant (alpha 2a) and lymphoblastoid interferon-alpha.

Neutralizing anti-IFN alpha antibodies (nIFN alpha Abs) occur in a significant proportion of patients with hairy cell leukaemia, hepatitis or solid tumours treated with recombinant IFN alpha (IFN alpha 2a or IFN alpha 2b), but information on their incidence in chronic myeloid leukaemia (CML) is scanty and their clinical relevance is not yet completely defined. By using an IFN alpha antiviral neutralization bioassay, the frequency of nIFN alpha 2a Abs was evaluated in 67Ph+ CML patients during IFN alpha 2a therapy at doses ranging from 6 to 9 MU/d. 15 patients (22%) developed nIFN alpha 2a Abs (titre ranging from 1:40 to 1:20480) and 11/15 (73%) were haematologically and/or karyotypically unresponsive to treatment. 52 patients did not develop antibodies and 11 of them (21%) were unresponsive. The negative relationship between the positivity for nIFN alpha 2a Abs and the response to treatment was highly significant (P = 0.0001). In nine nIFN alpha 2a Abs positive patients, treatment was changed from recombinant IFN alpha 2a to lymphoblastoid IFN alpha (IFN alpha-ly), at the same dose and schedule. After 9 months of IFN alpha-ly treatment a haematological response was achieved in 4/7 cases who were non-responsive to prior IFN alpha 2a therapy and was maintained in the other two patients previously responsive to IFN alpha 2a. However, no karyotypic response was observed. This data shows that a significant proportion of Ph+ CML patients receiving treatment with IFN alpha 2a can develop neutralizing antibodies and that these antibodies are associated with a loss of IFN alpha 2a efficacy. Changing the patients to treatment with lymphoblastoid IFN alpha may restore haematological response but it is not likely to induce a karyotypic response.

The biologic activity and molecular characterization of a novel synthetic interferon-alpha species, consensus interferon.

Consensus interferon (Infergen) is a wholly synthetic type I interferon (IFN), developed by scanning several interferon-alpha nonallelic subtypes and assigning the most frequently observed amino acid in each position, resulting in a consensus sequence. The antiviral, antiproliferative, NK cell activation activity, cytokine induction, and interferon-stimulated gene-induction activity of consensus interferon has been compared with naturally occurring type I interferons. In all of these comparisons, consensus interferon had a higher activity when compared, on a mass basis, with IFN-alpha 2a and IFN-alpha 2b, although the activity was the same for all of these parameters on an antiviral unit basis. That a synthetic type I interferon could have higher activities than naturally occurring molecules is surprising and may be a result of the higher affinity for the array of type I interferon receptors demonstrated for consensus interferon when compared with IFN-alpha. In contrast, consensus interferon was shown to be an inferior inducer of IL-1 beta when compared with IFN-alpha. These results may reflect differential binding to multiple accessory proteins interacting with a type I interferon receptor. These unique biologic properties may lead to a favorable clinical benefit for consensus interferon when compared with the naturally occurring recombinant molecules. Ongoing clinical trials will ascertain whether consensus interferon can be used in a wide array of disease situations, such as chronic viral infections and certain malignancies.

Regression of monoclonal B-cell expansion in patients affected by mixed cryoglobulinemia responsive to alpha-interferon therapy.

Several authors have reported on the effectiveness of alpha-interferon (IFN-alpha) in the treatment of patients with mixed cryoglobulinemia. This prompted the authors to investigate the long term effects of this drug on clinical, hematologic, and virologic parameters in a group of 20 patients (13 women and 7 men) affected by mixed cryoglobulinemia. In all patients, bone marrow biopsy, phenotyping of marrow cells, and polymerase chain reaction (PCR) immunoglobulin gene rearrangement in peripheral blood lymphocytes were performed before therapy and at the end of the follow-up. A liver biopsy was obtained in patients with biochemical signs of chronic liver disease. The presence of hepatitis C virus (HCV) RNA in serum was assessed by detection of anti-HCV antibodies, and by PCR amplification of the 5' untranslated region of HCV. The HCV genotype was also determined by PCR amplification of the core region of the virus with type-specific primers. The treatment schedule followed by all patients was 3 million units of recombinant IFN-alpha 2b 3 times weekly for 1 year. In 6 patients, the marrow histology before therapy showed a massive (more than 50%) monomorphous infiltration by plasmacytoid lymphocytes, indicating the presence of low grade non-Hodgkin's lymphoma. Anti-HCV antibodies were present in 19 (95%) subjects, and HCV-RNA was detectable in all patients. In addition, all patients affected by Type II mixed cryoglobulinemia showed a monoclonal B-cell expansion in peripheral blood mononuclear cells (PBMC). With therapy, 5 patients (25%) achieved a complete response and 11 patients (55%) a partial response, whereas minor responses were observed in the remaining 4 patients (20%). One of the complete responders and all patients showing partial responses relapsed a few months after therapy withdrawal. At the end of the follow-up, four patients had obtained a complete remission. Bone marrow examination showed that B-lymphocytic monoclonal infiltrate disappeared in three patients. Moreover, these three patients had become negative for B-cell expansion in PBMC. Lack of response, or relapse, was associated with the presence of Type II HCV. HCV may be the cause of mixed cryoglobulinemia. The disease is associated with a high prevalence of bone marrow B-cell lymphomas. IFN-alpha appears to be an effective agent for the treatment of mixed cryoglobulinemia. It also seems able to determine regression of the lymphoproliferative disorder. The HCV genotype appears to be the most important predictive factor for the response to antiviral therapy.

Inhibitory effects of interleukin-4 on human renal cell carcinoma cells in vitro: in combination with interferon-alpha, tumor necrosis factor-alpha or interleukin-2.

Immune cytokines have been shown to play important roles in regulating the growth of neoplastic cells, as well as the function of immune cells. The present study assessed the effects of interleukin (IL)-4 alone, and in combination with recombinant interferon (IFN)-alpha 2b, or with IL-2, or with tumor necrosis factor (TNF)-alpha on the in vitro proliferation of human renal cell carcinoma (RCC) cell-lines. Growth-inhibitory effects of IL-4 alone, and in combination with other cytokines, on three human RCC cell-lines, Caki-1, CURC-II, and A-498, were measured by the [3H]thymidine incorporation assay. IL-4 inhibited proliferation of all three human RCC cell-lines (P < 0.001). The maximum growth inhibition of RCC cell-lines by IL-4 alone was observed at the concentration of 1 to 3 ng/mL, depending on the cell-line. Antihuman IL-4 antisera was able to reverse the growth-inhibitory effects of IL-4 on Caki-1 in a dose-dependent manner, proving that the growth inhibition was mediated by IL-4 itself. When other cytokines were added in combination with IL-4, only IFN-alpha 2b resulted in significant additional growth inhibition (P < 0.005). However, when the proliferation was compared to that of RCC cells that were not treated with any cytokine, all combinations produced marked growth inhibition. Our data suggest that IL-4 alone, or in combination with IFN-alpha 2b, can be used to develop new strategies for treatment of human RCC.

Interferon alfa for recurrent hepatitis B infection after liver transplantation.

Reinfection with hepatitis B virus (HBV) after liver transplantation is nearly universal in patients not receiving immunoprophylaxis. Because reinfection reduces graft and patient survival, treatment of recurrent infection is important. Interferon alfa (IFN-alpha) is an effective therapy for chronic hepatitis B infection in immunocompetent patients, but its efficacy in transplant recipients has not been established. Fourteen liver transplant recipients with recurrent hepatitis B infection (hepatitis B surface antigen [HBsAg] positive in serum; hepatitis on biopsy) were treated with IFN-alpha 2b (Intron A; Schering Inc, Kenilworth, NJ) 3 million units (MU) three times weekly for 23.5 weeks (median, range 4 to 41). The primary endpoint was loss of HBV DNA by the b-DNA assay (a virological response). Before treatment, all patients were HBV DNA positive and 9 were hepatitis B e antigen (HBeAg) positive. Pretreatment HBV DNA levels were 6,760 MEq/mL (median, range 2.0 to 11,888 MEq/mL). HBV DNA levels decreased significantly with treatment (P = .03). Four patients had a complete and sustained virological response. Virological responses did not consistently correlate with biochemical response because of concomitant hepatitis C. Two patients had a serological response; 1 lost HBeAg, another lost HBeAg and HBsAg. All responders remained HBV DNA negative in follow-up (mean, 32 months; range, 23 to 40), but 1 patient required retransplantation for cirrhosis. Of the nonresponders, 1 patient required retransplantation for chronic rejection, 3 required retransplantation for recurrent hepatitis B, 3 died with recurrent hepatitis B, and 3 are alive and remain HBV DNA positive. IFN-alpha can induce a sustained serological (14%) and virological response (29%) in liver transplant recipients with recurrent HBV infection.

Virus and host factors are both important determinants of response to interferon treatment among patients with chronic hepatitis C.

Virus and host factors have both been linked to the response to interferon treatment among patients with chronic hepatitis C but their relative importance and potential interactions are unclear. Hepatitis C virus genotype and level of viraemia were determined in pretreatment sera from 65 Australian patients treated with interferon-alpha 2b (IFN-alpha 2b), 3 MU tiw for 6 months. Hepatitis C viraemia was quantitated by a competitive reverse transcription-polymerase chain reaction (RT-PCR) method and genotype was determined by a line probe assay. By univariate analysis, there were positive associations between initial (short-term) responses to IFN treatment and younger age (P = 0.004), absence of cirrhosis (P = 0.01), and injecting drug use as risk factor for infection (P = 0.05) but not gender, duration of infection, or level of viraemia. Genotype appeared to be important (P = 0.06) but failed to reach statistical significance. By multivariate analysis, absence of cirrhosis was the only significant independent predictor of treatment response (P = 0.01). Among initial responders, the factors associated with long-term response were the pretreatment HCV RNA titre and the duration of infection. There was a close association between viral genotype, but not viral load, and the severity of liver disease. An interplay of factors determines the outcome of a 6-month course of interferon treatment for hepatitis C. Severity of liver disease, but not the viral load, is the most crucial determinant of initial response to interferon, and histological severity appeared to be influenced by the viral genotype. The level of hepatitis C virus (HCV) viraemia and the duration of infection are independent determinants of long-term response by affecting the relapse rate after interferon treatment.

Interferon alpha-2b modulates beta-galactoside alpha-2,6-sialyltransferase gene expression in rat testes.

Sperm surface glycoproteins are modified during passage through the epididymis, a process believed to be important in the production of functionally mature spermatozoa. The effect of various cytokines on reproductive events has recently been investigated, with conflicting results. In the present investigation, the effect of interferon-alpha-2b (IFN alpha 2b) on sialyltransferase (ST) activity and beta-galactoside alpha-2,6-sialyltransferase (Gal 2,6-ST) mRNA expression was studied in rat testicular tissue. The results revealed the presence of Gal 2,6-ST mRNA in rat testicular tissue, similar in molecular size to that found previously in rat spleen, lung, ovary, kidney, heart, and brain. In addition, we observed that IFN alpha 2b reduced Gal 2,6-ST mRNA and ST activity in rat testes by a comparable magnitude. These findings provide insight into an additional mechanism by which cytokines may affect the reproductive system.

Efficacy, safety, and tolerance of low-dose, long-term interferon-alpha 2b and zidovudine in early-stage AIDS-associated Kaposi's sarcoma.

Seventeen male homosexual outpatients with limited but progressive AIDS-associated Kaposi's sarcoma (KS) of skin, lymph nodes, oral cavity, and gastrointestinum were consecutively enrolled in an open, nonrandomized, prospective study. Patients received low-dose IFN-alpha 2b (3 MIU t.i.w.) in combination with 250 mg ZDV b.i.d. After remission of KS, continuation of treatment as maintenance therapy was provided. Eleven (65%) of 17 patients had a complete (CR) or partial remission (PR) of KS lasting more than 24 months in four patients. Response to treatment was strongly dependent on pretreatment values of CD4+ lymphocyte counts, CR and PR occurred only in patients with pretreatment levels higher than 250 CD4+ lymphocytes per microliter. Treatment was generally well tolerated and without severe hematologic side effects attributable to the addition of IFN-alpha 2b to ZDV treatment. This study suggests that a combination of low-dose IFN-alpha 2b and ZDV is therapeutically effective and well tolerated in early stages of progressive KS.

Antiproliferative effects of bacillus Calmette-Guerin and interferon alpha 2b on human bladder cancer cells in vitro.

Direct inhibitory effects of bacillus Calmette-Guérin (BCG) and interferon alpha 2b (IFN alpha 2b) on six human bladder carcinoma cell lines, UCRU-BL-13, UCRU-BL-17, UCRU-BL-28, 5637, T24 and J82, were studied using an in vitro proliferation assay. Effects on proliferation following exposure to BCG or IFN alpha 2b were analysed by [3H]thymidine incorporation over 7 days. BCG had an antiproliferative effect on all bladder lines, while sensitivity to IFN alpha 2b varied greatly, being as remarkably low as 1 U/ml for some lines. The antiproliferative effect was greatest when cells were exposed continuously to either agent, but was still evident with a limited exposure. When clinical concentrations were simulated in vitro, BCG+IFN alpha 2b was more effective than BCG alone and as effective as a double BCG concentration. We conclude that, in addition to their immunomodulatory effects, BCG and IFN alpha 2b directly inhibit the proliferation of human bladder cancer cells, and often at extremely low concentrations.

The differential effects of three forms of interferon alfa on hepatic regeneration after partial hepatectomy in the rat

The purpose of this study was to determine whether all commercially available forms of interferon alfa (INF alpha) have the same inhibitory effect on hepatic regeneration and whether this inhibitory effect can be prevented by putrescine, a hepatic growth promotor. Adult male Sprague-Dawley rats (n = 92) received either IFN alpha-2a, 2b, n1, or saline, 0 and 18 hours after partial hepatectomy (PHx) or 16 hours before PHx. A subgroup of 29 rats being treated with IFn alpha-2a or saline also received putrescine (5, 50, or 500 mg/kg) 16 hours before PHx. Hepatic regeneration was documented by determining [3H]-thymidine incorporation into hepatic DNA (DNA synthesis), hepatic putrescine levels, and, in selected cases, ornithine decarboxylase (ODC) activity at 24 hours after PHx. The results of the study showed that hepatic regeneration was unaffected when IFN alpha was administered 0 and 18 hours after PHx. When administered at -16 hours, only IFN alpha-2a significantly inhibited DNA synthesis and was associated with decreased hepatic putrescine levels. Inhibition was dose-dependent in that a 10-fold increase in IFN alpha-2a caused a further decrease in both DNA synthesis and hepatic putrescine levels. At the higher dose, IFN alpha-2b and n1 also inhibited DNA synthesis and lowered hepatic putrescine levels and ODC activity. Exogenous putrescine (5 and 50 mg/kg) restored hepatic regenerative activity to normal but was toxic at high concentrations (500 mg/kg). These data indicate that not all commercially available forms of IFN alpha inhibit hepatic regeneration in the rat to the same extent.

Serum Lipid Levels During Interferon Therapy in Patients with Chronic Hepatitis C

Interferon-alpha (IFN-alpha) may affect lipid metabolism by stimulating hepatic fatty acid synthesis. The aim of this study was to evaluate serum lipid levels during IFN-alpha therapy in patients with biopsy-proven chronic active hepatitis C. A total of 22 patients (18 males and 4 females; age 25-55 years) received 3 MU of recombinant IFN-alpha 2b 3 times a week for 6 months. Serum lipids were determined at baseline and then every month until the end of therapy. All patients had normal serum lipid levels at baseline. No significant level of modification occurred in patients during the therapy. An increase in serum lipid levels during low-dose IFN-alpha therapy seems to be uncommon in hepatitis C virus-infected patients with baseline normal levels.

A role for chronic hepatitis C virus infection in a patient with cutaneous vasculitis, cryoglobulinemia, and chronic liver disease

A six-year history of repeated attacks of fatigue, fever, arthralgias, skin changes, Raynaud's phenomenon, and neuropathy is reported in a patient with chronic liver disease. The following diagnoses were made: (1) leukocytoclastic vasculitis; (2) acute urticaria; (3) cryoglobulinemia type II with Raynaud's phenomenon and low serum level of C4; (4) peripheral polyneuropathy; (5) sicca syndrome; and (6) chronic hepatitis C virus infection. Despite therapy with corticosteroids symptoms increased gradually over years. In the first PCR of the nested PCR analysis, HCV-RNA was exclusively detected in the cryoglobulin fraction but not in the serum supernatant, suggesting that antibodies bind HCV particles, forming circulating immune complexes. As diagnoses 1-5 are well-known organ manifestations of cryoglobulinemia, we speculated whether treatment of hepatitis C with IFN-alpha (3 million IU IFN-alpha 2b three times a week) would inhibit HCV replication, decrease the cryocrit level and thereby ameliorate organ manifestations such as neuropathy and vasculitis. During treatment with IFN-alpha only a very weak or no signal could be detected for HCV-RNA in the cryoglobulin fraction as well as in the serum supernatant. This held true also for the serum supernatant in the second PCR. In parallel, cryoglobulin level, immunoglobulins, and liver enzymes decreased substantially to normal or near normal levels. Clinical symptoms-leukocytoclastic vasculitis and neuropathy-disappeared. We conclude that chronic HCV infection is involved in the pathogenesis of cryoglobulinemia and that IFN-alpha might be an effective treatment in these patients.

Type 1 interferon as an antiinflammatory agent: inhibition of lipopolysaccharide-induced interleukin-1 beta and induction of interleukin-1 receptor antagonist.

The effect of two type 1 interferons (r-metIFN-con1 and IFN-alpha 2b) on the induction of specific cytokines and IL-1Ra in whole blood was examined. IFN-gamma was induced at low levels following treatment of diluted whole blood in some but not all subjects. IL-1Ra was induced by both r-metIFN-con1 and IFN-alpha 2b, but with 10- to 100-fold higher induction per ng IFN with r-metIFN-con1 than with IFN-alpha 2b. There was no detectable induction of TNF-alpha, IL-4, or IL-6 by either IFN. The effect of both IFN preparations was measured on LPS-induced inflammatory cytokines. Both IFN preparations inhibited the production of IL-1 beta when added to the diluted blood samples before LPS addition. However, neither IFN had any effect on IL-1 beta synthesis when added at the same time or after LPS induction. When added to total blood cells in the absence of LPS at low concentration (up to 100 pg/ml), IFN slightly stimulated IL-1 beta production, but at 1000 pg/ml or greater there was significant inhibition of IL-1 beta production. These results suggest that type I IFNs play a role in regulating the inflammatory response.

Cell-mediated cytotoxicity can be regulated by p53 tumor suppressor gene activity in vitro

The wild-type human p53 tumor suppressor gene was tested for its ability to modulate cytotoxic activity of in vitro activated peripheral blood lymphocytes. Peripheral blood mononuclear cells (PBMCs) were stimulated by phytohemagglutinin (PHA), interferon alpha 2b (IFN alpha 2b), interleukin 2 (IL-2) or their combinations to induce cytotoxicity. This stimulation significantly increased the percentage of cells expressing p53, which was at its maximum when induced by IL-2 combined with IFN alpha 2b. The role of p53 in the modulation of different aspects of cytotoxic activity of these cells was analyzed by studying the effects of p53 abrogation by antisense oligonucleotide (p53 AS) treatment in comparison with p53 sense or scrambled (missense) oligonucleotide (p53 S or p53 MS) treatment. We show that p53 plays a key role through induction of apoptosis in target cells (tumor necrosis factor pathway) rather than through osmolytic degeneration (perforin pathway) which is only slightly increased by p53 abrogation. Meanwhile, in vitro abrogation of p53 expression in PBL was found to be accompanied by an increase of CD8+ lymphocytes and an important increase of the CD56 'bright' NK cell sub-population.