Production d’interféron alpha dans le sérum des très jeunes nourrissons lors d’infections virales

IFN-alpha detection is useful in some clinical circumstances, but its use has never been validated in young infants with viral infections.

OBJECTIVE

The authors wanted to determine it there was any difference in the assessment of IFN-alpha production between infants under or over six months of age.

PATIENTS AND METHOD

A series of 233 children with identified common viral infections who had been assessed for IFN-alpha production was retrospectively analyzed. The viral infections were enteroviral meningitis (n =103), respiratory syncytial virus infections (n =60), and rotavirus gastroenteritis (n =70). Data collected from the group of infants under six months of age (n =105) was compared to that of the older children (n =128). Qualitative and quantitative values of interferon-alpha were determined for each group.

RESULTS

Interferon-alpha was detected in very young infants (81.9% of cases) as often as in the older age group (80.3% of cases), for any of the three viral infections (P =0.3-0.63). The mean level of interferon-alpha production detected was not lower in the youngest group, and even higher in the group under six months of age with enteroviral meningitis.

CONCLUSION

Interferon-alpha detection in very young infants is efficient and may be useful to differentiate between viral and bacterial infection particularly when the etiological diagnosis appears uncertain.

An Essential Role for IFN-α in the Overexpression of Fas Ligand on MRL/lpr Lymphocytes and on Their Spontaneous Fas-Mediated Cytotoxic Potential

Lymphocytes from aged autoimmune MRL/lpr mice overexpress Fas ligand (FasL), and are cytotoxic against Fas+ target cells. This cytotoxic potential is only partly due to FasL, as wild-type MRL+/+ lymphocytes are not able to kill Fas+ targets after induction of FasL. In addition, serum levels of interferon-alpha (IFN-alpha) increase in parallel with the Fas-dependent cytotoxic potential of lymphocytes from MRL/lpr mice as they age. To understand the mechanisms underlying these observations, combined suppression subtractive hybridization (SSH) and RT-PCR were used to study differential gene expression in splenocytes from MRL/lpr mice compared with splenocytes from MRL+/+ mice. Twenty-two genes were upregulated transcriptionally in MRL/lpr splenocytes compared with their MRL+/+ counterparts. Furthermore, 9 of these genes were also upregulated after treatment of MRL/lpr splenocytes with IFN-alpha, and 4 were strongly downregulated. MRL/lpr lymphocytes were also found to be hyperresponsive to IFN-alpha. Thus, MRL/lpr lymphocytes overexpressed mRNA for the IFN-alpha receptor (IFNAR-1 and IFNAR-2) chains of the IFN-alpha/beta receptor and exhibited high endogenous levels of both Stat1 and phosphorylated Stat1 proteins. Lymphocytes from young MRL/lpr mice, with low Fas-dependent cytotoxic activity, were found to become highly cytotoxic against Fas+ targets after treatment with IFN-alpha. These data suggest that IFN-alpha plays an important role in the physiopathology of the systemic lupus erythematosus (SLE)-like syndrome that occurs in MRL/lpr mice.

Expansion of bone marrow IFN-alpha-producing dendritic cells in New Zealand Black (NZB) mice: high level expression of TLR9 and secretion of IFN-alpha in NZB bone marrow

Patients with systemic lupus erythematosus have elevated IFN-alpha production. Furthermore, sera IFN-alpha levels correlate with disease activity. We have focused our attention on whether this phenotype is also seen in the New Zealand Black (NZB) mice and simultaneously addressed the underlying mechanisms. Specifically, we analyzed: 1) levels of sera IFN-alpha after type A CpG ODN 2216 injection in autoimmunity-prone NZB and control mice, and 2) levels of IFN-alpha synthesized by IFN-alpha-producing dendritic cells (IPDCs) using highly enriched populations of CD11c+B220+ IPDCs derived from NZB and control mice; IPDCs are divided into two subpopulations (CD4+CD11c+B220+ and CD4-CD11c+B220+). Our data demonstrate that NZB mice produced higher levels of sera IFN-alpha after type A CpG ODN 2216 injection when compared with control mice (p < 0.01). In addition, the cell numbers, frequency, and TLR9 mRNA levels of CD4+ and CD4- IPDC were markedly increased in the bone marrow (BM) of NZB mice. Upon in vitro stimulation with TLR9 ligand-CpG ODN 2216, higher levels of IFN-alpha were synthesized by IPDCs from the BM of NZB. The major contributor of IFN-alpha was the CD4-CD11c+B220+ IPDC subpopulation. Furthermore, NZB BM IPDCs manifest impaired expression of homing chemokine CCR7 and CD62L, and IL-12 production. These data on the functional characteristics of the IPDC lineages explain in part the mechanism of hyper-IFN-alpha production and help clarify the mechanism for the expansion of NZB BM IPDCs.

[Naso-subcutaneous application of the polycomponent vaccine VP-4 for the treatment of patients with bronchial asthma and chronic obstructive bronchitis]

Bacterial polycomponent vaccine (VP-4) earlier developed at the Mechnikov Research Institute for Vaccines and Sera on the basis of antigenic complexes of Klebsiella pneumoniae, Proteus vulgaris, Escherichia coli, Staphylococcus aureus was used within the program of clinical trials, for the treatment of 30 patients aged 16-59 years with the atopic and mixed form of bronchial asthma and chronic obstructive bronchitis by the combined naso-subcutaneous application. A good therapeutic effect produced by the vaccine was registered in 83.3% of the patients. It was manifested by a lower frequency of acute respiratory diseases and bronchopulmonary diseases as well as decreased need in antibiotic therapy. In the group of comparison a good effect was noted in 40% of the patients during 6 months of observation (statistically significant difference). Side effects caused by the administration of the vaccine were transitory, had mainly local character and disappeared without any treatment. In 1 patient the development of anaphylactic shock was observed. The positive effect of vaccine VP-4 could be attributed to the improved indices of cell-mediated immunity, an increased synthesis of alpha- and gamma-interferon, a droped level of IgE and specific IgG antibodies to Staphylococcus sp., Klebsiella sp., Proteus sp., Escherichia coli.

Therapy-induced antibodies against the antiviral and antiproliferative effects of interferons in patients with chronic hepatitis C virus infection

Sera from 86 patients with chronic hepatitis C virus (HCV) infection treated with recombinant interferons-alpha (rIFN-alpha) were screened for IFN-binding and antiviral effect-neutralizing antibodies. Out of the 61 patients treated with rIFN-alpha2b, 46% had binding and 28% had neutralizing antibodies. 44% of the 25 patients treated with rIFN-alpha2a developed binding antibodies and 24% had neutralizing antibodies. Contradictory data were observed concerning the appearance of anti-IFN antibodies and the outcome of IFN therapy. A significantly higher number of the patients with a sustained response to rIFN-alpha2b therapy formed antibodies than the number among the non-responder patients. At the same time, in the patients treated with rIFN-alpha2a, opposite data were found. The activity of the antibodies in some sera was studied against the antiproliferative effect of IFNs on Daudi cells by measuring the [3H]thymidine incorporation. The binding antibodies without neutralization of the antiviral effect of the IFNs inhibited the antiproliferative activity of the rIFNs, similarly to antibodies having both IFN-binding and antiviral effect-neutralizing capacities. At the same time, the antiproliferative effect of the natural IFN was less affected. It is suggested that the antiproliferative assay is more sensitive than the antiviral method for demonstration of the presence of antibodies exerting an inhibitory effect on the biological activities of IFN.

Convenient biological assay for polyethylene glycol-interferons in patients with hepatitis C

The vesicular stomatitis virus cytopathic effect reduction assay is suitable to quantify polyethylene glycol-alpha interferon 2a (PEG-IFN-alpha 2a) and PEG-IFN-alpha 2b. Human serum and ribavirin did not interfere with the assay. This bioassay was successfully used for assaying PEG-IFN-alpha 2a and PEG-IFN-alpha 2b in serum samples from patients undergoing combination therapy.

Proinflammatory cytokines and chemokines in humans with Japanese encephalitis

BACKGROUND

Japanese encephalitis virus (JEV), the mosquito-borne flavivirus, annually causes an estimated 35,000-50,000 encephalitis cases and 10,000-15,000 deaths in Asia, and there is no antiviral treatment. The role played by the immune response in determining the outcome of human infection with JEV is poorly understood, although, in animal models of flavivirus encephalitis, unregulated proinflammatory cytokine responses can be detrimental.

METHODS

We studied the innate, cellular, and humoral immune responses in 118 patients infected with JEV, of whom 13 (11%) died.

RESULTS

Levels of interferon (IFN)- alpha , the proinflammatory cytokine interleukin (IL)-6, and the chemokine IL-8 were all higher in the cerebrospinal fluid (CSF) of the nonsurvivors than of the survivors (P=.04, P=.006, and P=.04, respectively), as were both the IL-6 : IL-4 ratio in CSF (a marker of the balance of pro- and anti-inflammatory cytokines) and the level of the chemokine RANTES (regulated on activation, normally T cell expressed and secreted) in plasma (P=.03). In contrast, levels of immunoglobulin (Ig) M and IgG in CSF and of IgM in plasma were higher in the survivors (P=.035, P=.003, and P=.009, respectively). Levels of IFN- gamma and nitric oxide did not vary with outcome.

CONCLUSIONS

During JEV infection, elevated levels of proinflammatory cytokines and chemokines are associated with a poor outcome, but whether they are simply a correlate of severe disease or contribute to pathogenesis remains to be determined.

The heterogeneity of neuropsychiatric systemic lupus erythematosus is reflected in lack of association with cerebrospinal fluid cytokine profiles

The objective was to study the occurrence of autoantibodies and cytokines in serum and cerebrospinal fluid (CSF) in neuropsychiatric systemic lupus erythematosus (NPSLE). In total, 28 consecutive patients with NPSLE and 16 systemic lupus erythematosus (SLE) patients without neuropsychiatric involvement (non-NPSLE) were studied. IFN-alpha, IL-6, IL-10, soluble terminal complement complex (TCC), anti-ribosomal P protein antibodies (anti-P) and anti-cardiolipin antibodies (aCL) were measured in serum and CSF by immunoassays. Analyses of white blood cell differential count, CSF-albumin/serum-albumin ratio, IgG-index in CSF and isoelectric focusing in serum and CSF were also performed. CSF specimens from 23 healthy individuals were used as controls. IFN-alpha was elevated in the CSF of 5 of 28 NPSLE patients compared to three of 14 among the non-NPSLE patients. IL-6 was elevated in CSF in three of 26 NPSLE patients. Normal concentration of IL-10 was found in CSF in all 27 NPSLE-patients analysed. IFN-alpha in serum was elevated in 18 of 28 NPSLE patients. No distinct clinical phenotype was related to elevated cytokine concentration in serum or CSF. One patient with cerebral involvement complicated by progressive multifocal leukoencephalopathy displayed a very high IFN-alpha concentration in serum. High concentration of TCC was present in CSF from only one patient with systemic vasculitis and focal cerebral symptoms. In conclusion, the results of this study suggest that the diagnostic value of serum and CSF concentrations of IFN-alpha, IL-10, IL-6 and TCC is limited in unselected neuropsychiatric SLE, probably due to the heterogeneity of NPSLE pathogenesis.

Association between IFNA genotype and the risk of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is characterized by multisystem inflammation and production of autoantibodies, which can generate immune complexes and may cause tissue damage through the recognition of an autoantigen. Although many factors have been proposed, such as genetic factors, environmental factors, hormonal action, viruses, and dysregulation of cytokine production, the cause of this disease is not well understood. It has been reported that the levels of interferon (IFN)-alpha in the sera of some SLE patients are elevated and that IFN-alpha induces maturation of monocytes into highly active antigen-presenting dendritic cells (DCs). We analyzed the association between IFN-alpha genotype and the risk of SLE to clarify whether IFN-alpha plays a central role in susceptibility to SLE. The results showed that no IFN-alpha genotype was significantly associated with the risk of SLE.

Interferon-alpha receptor 1 mRNA expression in peripheral blood mononuclear cells is associated with response to interferon-alpha therapy of patients with chronic hepatitis C

Interferon (IFN)-alpha receptor mRNA expression in liver of patients with chronic hepatitis C has been shown to be a response to IFN-alpha therapy. The objective of the present study was to determine whether the expression of mRNA for subunit 1 of the IFN-alpha receptor (IFNAR1) in peripheral blood mononuclear cells (PBMC) is associated with the response to IFN-alpha in patients with chronic hepatitis C. Thirty patients with positive anti-HCV and HCV-RNA, and abnormal levels of alanine aminotransferase in serum were selected and treated with IFN-alpha 2b for one year. Those with HBV or HIV infection, or using alcohol were not included. Thirteen discontinued the treatment and were not evaluated. The IFN-alpha response was monitored on the basis of alanine aminotransferase level and positivity for HCV-RNA in serum. IFNAR1-mRNA expression in PBMC was measured by reverse transcription-polymerase chain reaction before and during the first three months of therapy. The results are reported as IFNAR1-mRNA/beta-actin-mRNA ratio (mean +/- SD). Before treatment, responder patients had significantly higher IFNAR1-mRNA expression in PBMC (0.67 +/- 0.15; N = 5; P < 0.05) compared to non-responders (0.35 +/- 0.17; N = 12) and controls (0.30 +/- 0.16; N = 9). Moreover, IFNAR1-mRNA levels were significantly reduced after 3 months of treatment in responders, whereas there were no differences in IFNAR1 expression in non-responders during IFN-alpha therapy. Basal IFNAR1-mRNA expression was not correlated with the serum level of alanine and aspartate aminotransferases or the presence of cirrhosis. The present results suggest that IFNAR1-mRNA expression in PBMC is associated with IFN-alpha response to hepatitis C and may be useful for monitoring therapy in patients with chronic hepatitis C.

Malaria Blood Stage Parasites Activate Human Plasmacytoid Dendritic Cells and Murine Dendritic Cells through a Toll-Like Receptor 9-Dependent Pathway

A common feature of severe Plasmodium falciparum infection is the increased systemic release of proinflammatory cytokines that contributes to the pathogenesis of malaria. Using human blood, we found that blood stage schizonts or soluble schizont extracts activated plasmacytoid dendritic cells (PDCs) to up-regulate CD86 expression and produce IFN-alpha. IFN-alpha production was also detected in malaria-infected patients, but the levels of circulating PDCs were markedly reduced, possibly because of schizont-stimulated up-regulation of CCR7, which is critical for PDC migration. The schizont-stimulated PDCs elicited a poor T cell response, but promoted gamma delta T cell proliferation and IFN-gamma production. The schizont immune stimulatory effects could be reproduced using murine DCs and required the Toll-like receptor 9 (TLR9)-MyD88 signaling pathway. Although the only known TLR9 ligand is CpG motifs in pathogen DNA, the activity of the soluble schizont extract was far greater than that of schizont DNA, and it was heat labile and precipitable with ammonium sulfate, unlike the activity of bacterial DNA. These results demonstrate that schizont extracts contain a novel and previously unknown ligand for TLR9 and suggest that the stimulatory effects of this ligand on PDCs may play a key role in immunoregulation and immunopathogenesis of human falciparum malaria.

Immune responses to HTLV-I(ACH) during acute infection of pig-tailed macaques

Human T cell lymphotropic virus type 1 (HTLV-I) is causally linked to adult T cell leukemia/lymphoma (ATL) and a chronic progressive neurological disease, HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). A nonhuman primate model that reproduces disease symptoms seen in HTLV-I-infected humans might facilitate identification of initial immune responses to the virus and an understanding of pathogenic mechanisms in HTLV-I-related disease. Previously, we showed that infection of pig-tailed macaques with HTLV-I(ACH) is associated with multiple signs of disease characteristic of both HAM/TSP and ATL. We report here that within the first few weeks after HTLV-I(ACH) infection of pig-tailed macaques, serum concentrations of interferon (IFN)-alpha increased and interleukin-12 decreased transiently, levels of nitric oxide were elevated, and activation of CD4(+) and CD8(+) lymphocytes and CD16(+) natural killer cells in peripheral blood were observed. HTLV-I(ACH) infection elicited virus-specific antibodies in all four animals within 4 to 6 weeks; however, Tax-specific lymphoproliferative responses were not detected until 25-29 weeks after infection in all four macaques. IFN-gamma production by peripheral blood cells stimulated with a Tax or Gag peptide was detected to varying degrees in all four animals by ELISPOT assay. Peripheral blood lymphocytes from one animal that developed only a marginal antigen-specific cellular response were unresponsive to mitogen stimulation during the last few weeks preceding its death from a rapidly progressive disease syndrome associated with HTLV-I(ACH) infection of pig-tailed macaques. The results show that during the first few months after HTLV-I(ACH) infection, activation of both innate and adaptive immunity, limited virus-specific cellular responses, sustained immune system activation, and, in some cases, immunodeficiency were evident. Thus, this animal model might be valuable for understanding early stages of infection and causes of immune system dysregulation in HTLV-I-infected humans.

Effect of autologous salvaged blood on postoperative natural killer cell precursor frequency

BACKGROUND

Immunosuppression after major surgery increases the risk of infections. Natural killer cells play a pivotal part in defence against infection. We aimed to investigate the immunomodulatory effects of different types of postoperative blood transfusion by use of a new assay for measuring the frequency of peripheral blood natural killer precursor cells (NKpf assay).

METHODS

We measured the natural killer cell precursor (NKp) frequency before and 5 days after surgery in 120 patients undergoing joint replacement surgery. The patients were assigned to one of five groups according to the type of transfusion received: non-transfused (n=32), allogeneic non-leukodepleted blood (eight), allogeneic leukodepleted blood (30), autologous predeposited blood (ten), and autologous salvaged blood collected within the first 24 h after surgery (40). We also measured interferon gamma and interleukin 10 concentrations before and after surgery.

FINDINGS

The mean postoperative NKp frequency for all patients was lower than the preoperative values, except in patients receiving autologous salvaged blood, which was higher than all other groups (p<0.0001). Postoperative NKp frequencies for patients receiving allogeneic or autologous predeposited blood responded similarly (p=0.99), but these patients had lower NKp frequencies than did the non-transfused group (p<0.0001). Postoperative interferon gamma concentrations were higher in the autologous salvaged blood group (p<0.0001) than in other groups, which did not differ from each other. Interleukin 10 concentrations were similar across all groups (p=0.49).

INTERPRETATION

Immunosuppression associated with surgery and blood loss was reflected in a reduced frequency of NKp and decreased interferon gamma. This immunosuppression was reversed by transfusion of autologous salvaged blood, suggesting that this fluid contained immunostimulants.

Association between IFNA genotype and the risk of sarcoidosis

Sarcoidosis is known to be a systemic granulomatous disorder characterized by a cell-mediated Th1-type inflammatory response. To identify a key genetic factor in the pathogenesis of sarcoidosis, we investigated single nucleotide polymorphisms within 10 candidate genes involved in type 1 immune process ( IFNA17, IFNB, IFNG, IFNGR1, IFNGR2, IL12B, IL12RB1, IL12RB2, ETA-1, and NRAMP1) in an association-based study of 102 Japanese patients with sarcoidosis, 114 with tuberculosis, and 110 control subjects. After correction for multiple testing, an IFNA17 polymorphism (551T-->G) was found to be associated with susceptibility to sarcoidosis (odds ratio 3.27 [95% CI: 1.44-7.46], P=0.004, P(c)=0.04), but not to tuberculosis. We observed no significant associations with the other polymorphisms of the Th1-related genes. We further typed another IFNA polymorphism ( IFNA10 60T-->A) and confirmed two major haplotypes of the IFNA gene, viz., allele 1: IFNA10 [60T]- IFNA17 [551T] and allele 2: IFNA10 [60A]- IFNA17 [551G], in the Japanese population. In healthy subjects, IFNA allele 2, which is over-represented in patients with sarcoidosis, was significantly associated with increased IFN-alpha and IL-12p70 production induced by Sendai virus in vitro. This study suggests that possession of the IFNA allele with higher levels of IFN-alpha significantly increases the risk of sarcoidosis.

Modeling viral and drug kinetics: hepatitis C virus treatment with pegylated interferon alfa-2b

Administration of peginterferon alfa-2b plus ribavirin results in an early hepatitis C virus (HCV) RNA decay followed by an increase as the drug concentration declines between doses. Upon administration of the next dose 1 week later, the same pattern is observed. We have incorporated pharmacokinetic/pharmacodynamic analysis into a model of viral dynamics to describe the effect that changes in drug concentration and effectiveness can have on viral levels. To illustrate the relationship between pharmacokinetics and viral dynamics, we fit the model to data from four HCV/human immunodeficiency virus co-infected patients, and obtained good agreement with the measured serum HCV RNA levels. We were able to account for the observed increases in HCV RNA, and estimate virion and drug half-lives that are in agreement with previous reports. Models incorporating pharmacokinetics are needed to correctly interpret viral load changes and estimate drug effectiveness in treatment protocols using peginterferon alfa-2b.

[Serum concentration and antiviral activity of interferon alpha in chronic hepatitis and liver cirrhosis]

Blood serum concentration and antiviral activity of IFN-alpha were studied in 121 patients with chronic hepatitis (CH) and in 115 patients with hepatocirrhosis (HC). The increase in IFN-alpha antiviral activity was revealed in 62% CH patients and in 46% HC patients. In CH patients both the mean indices of blood serum IFN-alpha concentration and its antiviral activity increased. The changes were more expressed in CH having viral etiology (HBV and HCV). For the most CH patients with disease positive dynamics the initially high indices of IFN-alpha antiviral activity were typical. In HC patients with portal hypertension syndrome progress and against the background of increased blood serum IFN-alpha concentration its antiviral activity decreases. With development hepatocellular insufficiency, increasing of disease stage (according to the Child-Pugh classification) the decrease in IFN-alpha concentration and its antiviral activity is noted.

Prevalence of viral infection markers by polymerase chain reaction amplification and interferon-alpha measurements among patients undergoing lumbar puncture in an emergency department

Aseptic meningitis is a frequent diagnosis in emergency departments. Nevertheless, viral investigations are not carried out currently and the viral etiology in adult population has not been studied extensively. We conducted a prospective study including all consecutive patients undergoing lumbar puncture during a 15 months period in an adult emergency department. Bloody and purulent cerebrospinal fluid (CSF) were excluded. The main tests undertaken were: CSF genomic amplification by the polymerase chain reaction (PCR) for neurotropic viruses and serum and CSF interferon-alpha (IFN-alpha) measurements. Among 194 patients included, 45 had and 149 did not have aseptic meningitis. Of 45 patients with aseptic meningitis, 10 had alternative non-virological final diagnosis, and 35/45 were presumed to have neurological disorders of viral origin. Patients (27/35) completed virological analysis: 21/27 (78%) had either positive viral PCR (enterovirus: 8 patients, Varicella zoster virus (VZV): 5, Epstein-Barr virus (EBV): 2, herpes simplex virus (HSV): 1, human herpes virus 6: 1) or only raised serum or CSF IFN-alpha (4 patients). Overall, 59% of patients with a positive viral PCR had either CSF or serum raised IFN-alpha. Twentyone patients without meningitis had either positive viral PCR (enterovirus: 3 patients) or only high serum IFN-alpha level (18 patients). In the setting of aseptic meningitis diagnosed in an adult emergency department, viruses are the most common agents encountered, with enterovirus and VZV as the two main etiological agents. Current CSF viral genome amplification and IFN-alpha measurement are informative and could be useful to confirm the viral origin of various neurological disorders, although the sensitivity and specificity of IFN-alpha measurement for the diagnosis of viral infection need further confirmation.

[The role of cytokines and interferon-alpha in the pathogenesis of chronic diffuse diseases of the liver]

The cytokine profiles were investigated in 171 patients with chronic hepatitis (CH) and in 173 patients with liver cirrhosis (LC). Increasing mean concentrations of IFN-alpha, TNF-alpha, IL-4 and IL-6 in blood serum as well as of the functional (antiviral and cytolytic) activity of IFN-alpha and TNF-alpha were found to be typical of a majority of CH and LC patients. Higher concentrations of IFN-alpha, IL-1, TNF-alpha and IL-6 in blood serum of CH patients are more typical of viral hepatitis versus alcoholic one. The replicative activity of hepatotropic viruses induces a powerful cytokine response. The LC etiology did not have any essential impact, in a majority of cases, on the blood-serum cytokine profile. A low function activity of TNF-alpha in blood serum signifies that the biological effects of the above cytokine are blocked. Finally, such analysis of the parameters of concentrations and functional activity of serum cytokines ensures a more objective evaluation of the pathogenetic disease mechanism and provides for prognosticating its outcome.

[Clinical and immunological changes in atopic dermatitis patients treated with purified staphylococcal toxoid]

32 patients with atopic dermatitis (AD), complicated by pyoderma, were treated with purified staphylococcal toxoid (PST). Changes in clinical and laboratory characteristics in the course of treatment were evaluated. PST was shown to produce a satisfactory therapeutic effect, arresting the symptoms of local staphylococcal infection. An increase in the levels of alpha- and gamma-interferons and decreased content of CD25+ lymphocytes were found. Thus prospects appear for using this preparation as an interferon inductor, as well a for the immunotherapy of AD patients sensitized to Staphylococcus aureus.

CD8+ cell depletion amplifies the acute retroviral syndrome

The duration and severity of the symptomatology present during the early phase of human immunodeficiency virus (HIV) infection (known as the acute retroviral syndrome) is associated with alterations in the clinical profile of infection, such as a shortening of duration between infection with HIV and the onset of neurocognitive impairment and acquired immunodeficiency syndrome (AIDS). Viral-specific CD8+ cytotoxic T lymphocytes (CTLs) and CD8+ natural killer (NK) cells play a key role in antiviral immunity. Loss of CD8+ cells or their functional impairment during the early period of infection is associated with a rapid progression to AIDS in nonhuman primate studies. However, no studies have determined whether CD8+ cell loss or impairment is associated with symptoms of acute retroviral illness such as fever. In this study, the authors compared the early phase of simian immunodeficiency virus (SIV) infection in animals that were treated with the anti-CD8 monoclonal antibody cM-T807 to deplete CD8+ cells during the early period of infection (SIV+ CD8- group) to those with intact CD8+ cells (SIV+ CD8+ group). The SIV+ CD8- group had an enhanced acute retroviral syndrome when compared to the SIV+ CD8+ group. The SIV+ CD8- group also had prolonged high viral loads and distinct alterations in the proinflammatory cytokines interleukin (IL)-6 and interferon (IFN)-alpha, as well as in monocyte chemoattractant protein (MCP)-1. CD8+ cell depletion, therefore, appears to enhance symptoms of the acute retroviral syndrome and alters several of the immunological factors associated with the early phase of infection.

[Concentration and antiviral activity of interferon-alpha in the sera of patient with hepatic pathology]

The normalization of the antiviral activity of interferon-alpha (IFN-alpha) in the process of the treatment of patients with acute viral hepatitis (VH), simultaneously with the results of other clinico-laboratory tests, reflects the positive dynamics of the process. The prolonged preservation of the elevated level of the antiviral activity of IFN-alpha (up to 6 months and longer) is a prognostically unfavorable sign. In patients with chronic VH the growth of both the average concentration of IFN-alpha in the blood serum and its average antiviral activity can be observed. With the progress of the disease and the formation of the cirrhosis of the liver, the concentration of IFN-alpha in the blood serum remains to be elevated, while its antiviral activity drops.

Intravenous immunoglobulin abrogates dendritic cell differentiation induced by interferon-? present in serum from patients with systemic lupus erythematosus

OBJECTIVE

Alterations in the function of dendritic cells (DCs) may explain the systemic autoimmune responses that characterize systemic lupus erythematosus (SLE). Even though several reports have documented the beneficial effect of intravenous immunoglobulin (IVIG) in SLE, the underlying mechanisms of action remain poorly understood. Considering the effect of serum factors, including interferon-alpha (IFNalpha), on the activity of DCs, we investigated the effects of IVIG on the differentiation of DCs mediated by serum from SLE patients.

METHODS

DCs were differentiated from peripheral blood monocytes obtained from SLE patients and from healthy blood donors, in the presence of SLE serum. IVIG was used at a concentration of 0.15 mM. A functional assay was performed to assess the inhibitory effect of IVIG on the uptake of nucleosomes by DCs.

RESULTS

IVIG interfered with the differentiation of DCs from SLE patients and healthy donors cultured in the presence of SLE serum. Treatment of DCs with IVIG inhibited the ingestion of nucleosomes by immature DCs, by up to 36%.

CONCLUSION

The present findings indicate that IVIG, by down-regulating the IFNalpha-mediated differentiation of DCs and by inhibiting uptake of nucleosomes, may exert an essential immunoregulatory effect in SLE patients at the onset of the immune response, at the DC level. Given the critical role of HLA molecules and the costimulatory signals delivered by CD80 and CD86 in optimal antigen presentation and T cell activation, inhibition of expression of HLA and CD80/CD86 on DCs by IVIG offers a plausible explanation for the efficacy of IVIG in SLE and other immune-mediated inflammatory conditions.

Genetic heterogeneity of the NS5A gene of hepatitis C virus and early response to interferon-alpha

The double-stranded RNA-activated protein kinase-binding domain (PKRbd) of the NS5A gene of hepatitis C virus (HCV) was studied by the cloning and sequencing method, in HCV-infected patients who had a primary resistance to treatment with interferon (IFN)-alpha (early nonresponders). Patients whose virus load decreased by >or=0.5 log (early responders) were similarly analyzed. In the 2 groups, the PKRbd evolved similarly over the first 24 h. Selection of resistant HCV variants is unlikely to explain primary resistance to IFN-alpha.

Microarray analysis of gene expression in lupus

Recent advances in the study of global patterns of gene expression with the use of microarray technology, coupled with data analysis using sophisticated statistical algorithms, have provided new insights into pathogenic mechanisms of disease. Complementary and reproducible data from multiple laboratories have documented the feasibility of analysis of heterogeneous populations of peripheral blood mononuclear cells from patients with rheumatic diseases through use of this powerful technology. Although some patterns of gene expression, including increased expression of immune system cell surface activation molecules, confirm previous data obtained with other techniques, some novel genes that are differentially expressed have been identified. Most interesting is the dominant pattern of interferon-induced gene expression detected among blood mononuclear cells from patients with systemic lupus erythematosus and juvenile dermatomyositis. These data are consistent with longstanding observations indicating increased circulating interferon-alpha in the blood of patients with active lupus, but draw attention to the dominance of the interferon pathway in the hierarchy of gene expression pathways implicated in systemic autoimmunity.