Cytokines and autoantibodies to cytokines

Insights from a Case of Good's Syndrome (Immunodeficiency with Thymoma)

Immunodeficiency with thymoma was described by R.A. Good in 1954 and is also named after him. The syndrome is characterized by hypogammaglobulinemia associated with thymoma and recurrent infections, bacterial but also viral, fungal and parasitic. Autoimmune diseases, mainly pure red cell aplasia, other hematological disorders and erosive lichen planus are a common finding. We describe here a typical case exhibiting all these clinical features and report a detailed immunophenotypic assessment, as well as the positivity for autoantibodies against three cytokines (IFN-alpha, IL-6 and GM-CSF), which may add to known immune abnormalities. A review of the published literature, based on case series and immunological studies, offers some hints on the still unsolved issues of this rare condition.

The short-term predictive value of CD4+ cells for combination therapy with high-dose dexamethasone and immunoglobulin in newly diagnosed primary immune thrombocytopenia patients

INTRODUCTION

Dexamethasone (DXM) or immunoglobulin (IVIg) are first-line therapies for primary immune thrombocytopenia (ITP), with an effective rate of 80 %. Some patients with both severe bleeding symptoms and platelet counts of <30 × 10⁹/L received a combination of DXM and IVIg. Autoimmune disorders, especially involving CD4⁺ T-cells, play a key role in the pathogenesis of ITP. We assumed that variations in the immune status of CD4⁺ T-cells will lead to different treatment responses. Until now, there have been few relevant clinical studies on CD4⁺ T-cells and the outcome of first-line therapies.

METHODS

A prospective study enrolling 42 newly diagnosed ITP patients and 30 normal control volunteers was performed. The profiles of major CD4⁺ T-cells, including T helper (Th)1, Th2, Th17, and regulatory T (Treg) cells, and the related levels of interleukin (IL)-2, IL-17, and IL-23 were examined. The platelet number was recorded at the time point of day 0, day 14, and day 30.

RESULTS

Greater concentrations of Th1 and Th17 cells and lower relative numbers of Treg cells were found in the ITP group. As for the treatment outcome on day 14, the profiles of Th2 and IL-2 were significantly greater in the NR group, while the expression of IL-17 was elevated in the CR group. As for the treatment outcome on day 30, higher levels of Th2 cells were observed in those patients who needed 2× pulses of HD DXM compared to those who needed only 1× pulse of HD DXM and IVIg, and receiver operating characteristic curve analysis showed that lower Treg cell may predict favorable values. Meanwhile, the higher IL-23 value may predict a poor early response.

CONCLUSIONS

Our results indicate that Th1, Th17, and Treg cells and IL-2 and IL-23 participate in the onset of ITP. Higher profiles of Th2, IL-2 and IL-23 may predict poor treatment outcomes. Higher levels of IL-17 and lower profile of Treg may predict sensitivity to HD DXM and IVIg combination therapy.

IVIG ameliorate inflammation in collagen-induced arthritis: projection for IVIG therapy in rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic inflammatory autoimmune disease that leads to joint destruction and disability. Despite a significant progress in administration of biological agents for RA patients, there is still a need for improved therapy. Intravenous immunoglobulins (IVIG), a pooled polyspecific immunoglobulin (Ig)G extracted from 5000 to 20 000 healthy subjects, showed beneficial therapeutic effect in patients with immune deficiency, sepsis and autoimmune diseases. The current study aimed to investigate the beneficial effect of treatment with IVIG in established collagen-induced arthritis in DBA/1j mice. Murine arthritis was induced in DBA/1j mice. Treatment with IVIG began when the disease was established. The clinical score was followed twice a week until day 48. The mice were bled for plasma and the paws were hematoxylin and eosin (H&E)-stained. Cytokine profile in the plasma was analyzed by Luminex technology and titers of circulating anti-collagen antibodies in the plasma was tested by enzyme-linked immunosorbent assay. Our results show that treatment with IVIG in murine significantly reduced the clinical arthritis score (P < 0·001). Moreover, mode of action showed that IVIG significantly reduced circulating levels of inflammatory cytokines [interferon (IFN)-γ, interleukin (IL)-1β, IL-17, IL-6, tumor necrosis factor (TNF)-α, P < 0·001], inhibiting anti-collagen antibodies (P < 0·001) in the plasma of collagen-induced arthritis mice. Importantly, histopathological examination revealed that IVIG treatment prevented the migration of inflammatory immune cells into the cartilage and synovium, reduced the extent of joint damage and preserved joint architecture. Our results proved for the first time the valuable anti-inflammatory treatment of IVIG in experimental RA. We propose IVIG therapy for a subgroup of patients with rheumatologically related diseases.

Infectious Complications of Biological and Small Molecule Targeted Immunomodulatory Therapies

The past 2 decades have seen a revolution in our approach to therapeutic immunosuppression. We have moved from relying on broadly active traditional medications, such as prednisolone or methotrexate, toward more specific agents that often target a single receptor, cytokine, or cell type, using monoclonal antibodies, fusion proteins, or targeted small molecules. This change has transformed the treatment of many conditions, including rheumatoid arthritis, cancers, asthma, and inflammatory bowel disease, but along with the benefits have come risks. Contrary to the hope that these more specific agents would have minimal and predictable infectious sequelae, infectious complications have emerged as a major stumbling block for many of these agents. Furthermore, the growing number and complexity of available biologic agents makes it difficult for clinicians to maintain current knowledge, and most review articles focus on a particular target disease or class of agent. In this article, we review the current state of knowledge about infectious complications of biologic and small molecule immunomodulatory agents, aiming to create a single resource relevant to a broad range of clinicians and researchers. For each of 19 classes of agent, we discuss the mechanism of action, the risk and types of infectious complications, and recommendations for prevention of infection.

Autoantibodies against BAFF, APRIL or IL21 - an alternative pathogenesis for antibody-deficiencies?

BACKGROUND

The ability of anti-cytokine antibodies to play a disease-causing role in the pathogenesis of immunodeficiencies is widely accepted. The aim of this study was to investigate whether autoantibodies against BAFF (important B cell survival signal), APRIL (important plasma cell survival signal), or Interleukin-21 (important cytokine for immunoglobulin class switch) present an alternative mechanism for the development of the following primary antibody deficiencies (PADs): common variable immune deficiency (CVID) or selective IgA deficiency (sIgAD).

RESULTS

Two hundred thirty-two sera from patients with PADs were screened for autoantibodies against cytokines by ELISA. Statistical data analysis yielded a significant difference (p < 0.01) between the healthy donor sera and both PAD cohorts. The analysis was deepened by subdividing the patient collective into groups with distinct B cell phenotypes but no significant differences were found. For selected sera with notable high ELISA-read outs functional analysis ensued. Anti-BAFF and anti-APRIL antibodies were further examined by a B cell survival assay, whilst the functional relevance of putative anti-IL-21 autoantibodies was investigated by means of a STAT3 phosphorylation assay. However, the results of these experiments revealed no discernible functional effect.

CONCLUSION

Whilst statistical analysis of ELISA results showed significant differences between patients and healthy controls, in our set of patients functional tests yielded no evidence for an involvement of autoantibodies against BAFF, APRIL, or IL-21 in the pathogenesis of CVID or sIgAD.

Potentiation of cytokine-induced proliferation of human Natural Killer cells by intravenous immunoglobulin G

Intravenous IgG (IVIG) therapy can be used for immunomodulation. IL-2 is an immunoregulatory cytokine. We evaluated IVIG modulation of human blood lymphocyte response to IL-2 and other cytokines. Neither IVIG nor low concentrations of IL-2 (3-30U/ml) induced lymphocyte proliferation, but in combination they synergistically enhanced proliferation of NK cells. The CD56(bright) cells expanded more than CD56(dim) NK cells, with 90% of NK cells dividing up to 8 generations by day 6, while <8% of T cells divided. IVIG also potentiated NK cell proliferation with IL-12, IL-15 and IL-18. The IVIG+cytokine-expanded NK cells were less cytotoxic for K562 cells, than NK cells with cytokine alone. IVIG also enhanced interferon-γ production with IL-2, IL-12 and IL-18. In conclusion, IVIG selectively potentiates NK cell proliferation and interferon-γ secretion with IL-2, IL-12, IL-15 and IL-18 in vitro. These findings warrant evaluation in vivo in relation to NK cells and the immunoregulatory actions of IVIG.

Biologic therapies in rheumatology: lessons learned, future directions

During the past decade biologic therapies such as monoclonal antibodies and fusion proteins have revolutionized the management of rheumatic disease. By targeting key cytokines and immune cells biologics have provided more specific therapeutic interventions with less immunosuppression. Clinical use, however, has revealed that their theoretical simplicity hides a more complex reality. Efficacy, toxicity and even pharmacodynamic effects can deviate from those predicted, as poignantly illustrated by the catastrophic effects witnessed during the first-into-human administration of TGN1412. This review summarizes lessons gleaned from practical experience and discusses how these can inform future discovery and development of new biologic therapies for rheumatology.

IgM-enriched human intravenous immunoglobulin suppresses T lymphocyte functions in vitro and delays the activation of T lymphocytes in hu-SCID mice

Previous studies of an experimental human immunoglobulin preparation for intravenous use, containing normal pooled IgM (IVIgM), have shown its beneficial therapeutic effect in experimental autoimmune diseases. The mechanisms of its immunomodulatory activity remain however, poorly understood. In the experiments reported here, IVIgM inhibited the proliferation of various autonomously growing human lymphoid cell lines in vitro, as well as of MLR- and of PHA-stimulated human T-lymphocytes. These effects of IVIgM were observed at non-apoptotic concentrations and were stronger on a molar basis than those of normal pooled IgG for intravenous use (IVIg). Both preparations, when administered to SCID mice, repopulated with human peripheral blood mononuclear cells, delayed the expression of the early activation marker CD69 on both human CD4+ and CD8+ T-lymphocytes, activated by the mouse antigenic environment. The data obtained show that normal pooled human IgM exerts a powerful antiproliferative effect on T-cells that is qualitatively similar but quantitatively superior to that of therapeutic IVIg. Our results suggest that infusions with IVIgM might have a significant beneficial immunomodulating activity in patients with selected autoimmune diseases.

Caspase independence of radio-induced cell death

Colon carcinoma cells subjected to gamma-irradiation (4 Gy) manifest signs of apoptosis (caspase activation, chromatin condensation, phosphatidylserine (PS) exposure on the cell surface, sub-diploid DNA content), correlating with their radiosensitivity, which is increased in cells lacking the 14-3-3sigma protein as compared to wild-type controls. Inhibition of caspases by addition of Z-Val-Ala-DL-Asp (OMe)-fluoromethylketone, by stable transfection with the Baculovirus gene coding for p35, or by Bax knockout reduced all signs of apoptosis, yet failed to suppress radio-induced micro- and multinucleation. Moreover, pharmacological caspase inhibition, p35 expression or Bax knockout had no effect on the clonogenic survival that was reduced by gamma-irradiation and caspase inhibition failed to abolish the increased radiosensitivity of 14-3-3sigma-deficient cells. Micro- and multinucleation was detectable among non-apoptotic cells lacking PS exposure, as well as among cells undergoing apoptosis. Moreover, a fraction of micro- or multinucleated cells manifested caspase activation, and videomicroscopic analyses revealed that such cells could succumb to caspase-dependent apoptosis. Altogether, these results suggest that genomic instability induced by gamma-irradiation can trigger apoptosis, although apoptosis is dispensable for radio-induced clonogenic death.

The efficiency of intraperitoneal high-dose immunoglobulin in experimental nephrotic syndrome

Although it has been reported that high-dose immunoglobulin has beneficial effects in chronic glomerulonephritis, it is not known whether it is effective in the treatment of idiopathic nephrotic syndrome. We have investigated the effects of intraperitoneal immunoglobulin in adriamycin-induced nephrotic syndrome. Adriamycin (2 mg kg(-1) per dose) was given intravenously to sixteen Wistar albino rats (eight control and eight treatment rats) on day 1 and at week 3. At week 5 intraperitoneal immunoglobulin (1 g kg(-1) per dose) was given to the treatment group on two consecutive days whereas the control group received intraperitoneal saline solution. In both treatment and control groups urinary protein excretion was significantly elevated after administration of adriamycin (P=0.018). Urinary protein excretion, serum albumin, and triglyceride levels in the two groups were not significantly different after 5, 8, 12, and 16 weeks. Serum creatinine levels were higher and creatinine clearance was significantly lower in the control group in week 16 (P=0.001 and P=0.049, respectively). Glomerular sclerosis index was significantly lower in the treatment group (P=0.012). Although intraperitoneal high-dose immunoglobulin did not reverse biochemical results, it is encouraging that glomerular sclerosis index was significantly lower in the treatment group.

Anti-IFN-γ Autoantibodies in Disseminated Nontuberculous Mycobacterial Infections

Although many patients with disseminated nontuberculous mycobacterial disease have molecular defects in the IFN-gamma/IL-12 axis, recent case reports have shown autoantibodies against IFN-gamma associated with severe nontuberculous mycobacterial infections. To check this finding in an independent population, we screened 35 patients with either disseminated or pulmonary nontuberculous mycobacterial infections for whom no molecular defect was known. We identified high-titer-neutralizing anti-IFN-gamma IgG in the plasma of six patients. All six patients were female, parous, of East Asian descent, and had disseminated infection, predominantly with rapidly growing mycobacteria. The anti-IFN-gamma IgG had in vitro biological activity on the IFN-gamma-dependent phosphorylation of STAT-1 as well as on the IFN-gamma-dependent up-regulation of TNF-alpha and IL-12. In contrast, this anti-IFN-gamma Ab had no effect on IFN-alpha-dependent STAT-1 phosphorylation. These patients confirm a novel syndrome linking autoimmunity and immunodeficiency.

Effets immunomodulateurs des immunoglobulines intraveineuses

Intravenous immunoglobulins (IVIg) are therapeutic preparations of normal human IgG obtained from pools of more than 1000 healthy blood donors. They are currently used in the treatment of a wide range of auto-immune diseases, whether associated with auto-antibodies or auto-reactive T lymphocytes, as well as in the treatment of systemic inflammatory diseases. Several mechanisms of action have been identified during the last 20 years, including: (i) modulation of Fc receptors expression on leukocytes and endothelial cells; (ii) interaction with complement proteins; (iii) modulation of cytokines and chemokines synthesis and release; (iv) modulation of cell proliferation and apoptosis; (v) remyelinisation; (vi) neutralisation of circulating autoantibodies; (vii) selection of repertoires of B and T lymphocytes; (viii) interaction with other cell-surface molecules on lymphocytes and monocytes; (ix) corticosteroid sparing. These mechanisms of action are multiple and often intricate. However, they are still little known and further investigations are warranted.

Myelin basic protein epitopes secreted by human T cells encounter natural autoantibodies in the serum

A previously isolated and characterized IgM monoclonal antibody (mAb 1H6.2) specific to myelin basic protein (MBP) and to MBP epitopes expressed by nonneural cells was used to immunoprecipitate and investigate the expression of MBP epitopes by human T cells. Peripheral T lymphocytes secreted MBP epitopes, and secretion increased in time after mitogen stimulation. Conversely, thymocytes secreted these proteins independently on mitogen stimulation. Specific antibody reactivity (primarily due to IgG3) towards immunoprecipitated MBP epitopes was found in all tested sera from healthy donors and from multiple sclerosis patients as well as in sera from normal human cord blood. Collectively, these data provide insights into the immunological mechanisms leading to central and peripheral tolerance to MBP products.

Mechanisms of intravenous immunoglobulin action in the treatment of autoimmune disorders

Intravenous immunoglobulins (IVIg) are therapeutic preparations of normal human immunoglobulin (Ig) G obtained from pools of blood from more than 1000 healthy donors, and exert immunomodulatory effects in autoantibody-mediated and T-cell-mediated autoimmune disorders and systemic inflammatory diseases. IVIg mechanisms of action in autoimmune diseases have been extensively analysed during the last 15 years and include the following: (i) interaction of the IgG Fc fragment with Fc receptors on leucocytes and endothelial cells; (ii) interaction of infused IgG with complement proteins; (iii) monocyte and lymphocyte modulation of synthesis and release of cytokines and cytokine antagonists; (iv) modulation of cell proliferation and reparation; (v) neutralisation of circulating autoantibodies; (vi) selection of immune repertoires; and (vii) interaction with other cell-surface molecules on T and B lymphocytes.

Plasma cytokines in acute stroke

GOALS

The aim of this study was to test the relations between plasma cytokines and the clinical characteristics, course, and risk factors in acute stroke.

PATIENTS AND METHODS

The analysis was based on 179 patients with acute stroke included within 24 hours of stroke onset. On inclusion and 3 months later plasma levels of interleukin 1 beta (IL-1beta), tumor necrosis factor alpha (TNF-alpha), interleukin-1 receptor antagonist (IL-1RA), interleukin 6 (IL-6), interleukin 10 (IL-10), soluble tumor necrosis factor receptor 1 (sTNF-R1), and soluble tumor necrosis factor receptor 2 (sTNF-R2) were measured by enzyme-linked immunoassay (ELISA).

FINDINGS

The levels of most cytokines were significantly different in acute stroke from the levels 3 months later; but only IL-10 was positively associated with stroke severity. C-reactive protein and white blood cell count were positively associated with the cytokine response.

CONCLUSIONS

We found a substantial overall cytokine reaction that reflected the stroke incident. However, these results do not, at present, suggest a potential for clinical use, as they do not seem to add to the information obtained from the clinical workup of the individual patient.

Drug-induced and drug-dependent immune thrombocytopenias

Thrombocytopenia is a frequent comorbid condition in many in hospital patients. In some patients, drugs are the cause of low platelet counts. While cytotoxic effects of anti-tumor therapy are the most frequent cause, immune mechanisms should also be considered. This review addresses thrombocytopenias in four groups. Heparin-dependent thrombocytopenia (HIT), by far the most frequent drug-induced immune-mediated type of thrombocytopenia, has a unique pathogenesis and clinical consequences. HIT is a clinicopathological syndrome in which antibodies mostly directed against a multimolecular complex of platelet factor 4 and heparin cause paradoxical thromboembolic complications. The mechanisms through which heparin can enhance thrombin generation are discussed and treatment alternatives for affected patients are presented in detail. It is of primary importance to recognize these patients as early as possible and to substitute heparin with a compatible anticoagulatory drug, such as hirudin, danaparoid or argatroban. Patients seem to benefit from therapeutic doses of alternative treatment rather than from low-dose prophylactic doses. With the increasing use of glycoprotein (GP) IIb/IIIa inhibitors in patients with acute coronary syndromes, thrombocytopenias are increasingly recognized as an adverse effect of these drugs. Up to 4% of treated patients are affected. Most important, pseudothrombocytopenia, a laboratory artefact, is as frequent as real drug-induced thrombocytopenia and must be excluded before changes in treatment are considered. The pathogenesis of these thrombocytopenias is still debated; an immune mechanism involving preformed antibodies is likely. However, since these antibodies are also detectable in a high percentage of normal controls and of patients not developing thrombocytopenia, their impact is still unclear. Patients with real thrombocytopenia are at an increased risk of bleeding; treatment consists of cessation of the GP IIb/IIIa inhibitor and platelet transfusions in cases of severe hemorrhage. Classic immune thrombocytopenia can be induced by some drugs, e.g. gold, which trigger anti-platelet antibodies indistinguishable from platelet autoantibodies found in autoimmune thrombocytopenia. Drug-induced and drug-dependent immune thrombocytopenia is induced by antibodies recognizing an epitope on platelet GP formed after binding of a drug to a platelet glycoprotein. Still unresolved is whether antibody binding is the consequence of a conformational change of the antigen, the antibody, or both. These antibodies typically react with monomorphic epitopes on platelet GP, but only in the presence of the drug or a metabolite. Although several platelet GP have been identified as antibody target (GPIb/IX, GPV, GP IIb/IIIa), antibodies in an individual patient are highly specific for a single GP. Clinically, these patients present with very low platelet counts and acute, sometimes severe, hemorrhage. Treatment is restricted to withdrawal of the drug and symptomatic treatment of bleeding.

Interleukin 1 components in cicatricial pemphigoid. Role in intravenous immunoglobulin therapy

Interleukin (IL-)1 is an important mediator of inflammatory responses and plays an important role in the pathogenesis of various autoimmune diseases. Cicatricial pemphigoid (CP) is a multisystem autoimmune inflammatory disease. We have studied the role of IL-1 in its pathogenesis. We have investigated the serum levels of IL-1 components (IL-1alpha, IL-1beta, and IL-1Ra), and determined the role of intravenous immunoglobulin (IVIg) therapy in patients with CP. Serum levels of IL-1alpha and beta were significantly higher in untreated patients with active disease compared to levels in patients in prolonged clinical remission and normal human controls (P<0.0001). The serum levels of IL-1Ra were higher in patients in prolonged clinical remission compared to patients with active disease (P=0.002). Hence elevated levels of IL-1alpha and beta and low levels of IL-1Ra correlate with disease activity. The levels of IL-1alpha and beta were statistically significantly higher in sera of CP patients with active disease pre-IVIg therapy compared to post-IVIg therapy (P<0.0001). Statistically significantly higher levels of IL-1Ra were present in post-IVIg treatment serum samples when compared to levels in pre-IVIg treatment (P<0.0001). In the in vitro experiments, the levels of IL-1alpha and beta produced by the peripheral blood mononuclear cells (PBMC) isolated from patients before IVIg therapy were significantly higher when compared to the PBMC isolated from post-IVIg patients (P<0.0001). Significantly higher levels of IL-1Ra were observed in the supernatants of PBMC collected from pre-IVIg patients and cultured with exogenously added IVIg, when compared to the levels of PBMC to which IVIg was not added (P<0.0001). IL-1 may be an important cytokine involved in the pathogenesis of CP. The regulation of IL-1 could be one of the mechanisms, amongst others, by which IVIg may exert its beneficial effect in the treatment of CP.

Reduction of serum interleukin-5 levels reflect clinical improvement in patients with atopic dermatitis

Cytokines, in particular IL-4 and IL-5, regulate IgE synthesis and eosinophil activation in atopic dermatitis (AD). To elucidate whether the serum levels of IL-4 and IL-5 are related to the serum IgE level, eosinophilia, or clinical severity of the disease, 25 cases with AD were studied. Blood samples were isolated from two groups of donors: 1) patients with AD (n = 25); 2) non-allergic individuals (NA, n = 20) with serum IgE levels below 100 IU/ml and with blood eosinophil counts below 250/microliter. Each parameter was evaluated at least twice in AD patients at the beginning of the study and after 4, 8 or 12 weeks of treatment. IL-4 was hardly detected in AD and NA, but IL-5 was increased (> 10 pg/ml) in most cases (22/25) of AD group with 513.6 pg/ml as the mean. AD with normal serum IgE levels exhibited increased levels of IL-5, whereas AD with high serum IgE levels did not necessarily have elevated IL-5 levels. The IL-5 level tended to change in parallel with the clinical severity in each AD case, although the level itself was not correlated with the clinical severity per se. A significant decrease of IL-5 was observed in AD when the clinical severity decreased. Eosinophils also decreased along with the improvement of AD, whereas the serum level of IgE did not change during the observation period. Our results suggest that IL-5 is involved in the regulation of clinical courses of AD and that its kinetics at the serum level reflects the clinical activity of AD.

Detergents in the indoor environment - what is the evidence for an allergy promoting effect? Known and postulated mechanisms

IgE-mediated allergic diseases, such as asthma and rhinitis seem to be increasing in industrialised societies. One possible explanation for this could be the increased use of more effective and aggressive detergents. The surfactants from these could interfere with the sensitisation process in which specific IgE is formed to ubiquitously occurring environmental allergens. Only sparse data exist in relation to surfactants and allergic sensitization. However, it can be speculated that the strong surfactant properties of some of ingredients used in modem detergents may interfere with some of the intricate cellular interactions taking place along the immunological pathways. These include formation of IL-4 and IL-5 producing T helper lymphocytes type 2 and the B-lymphocyte isotype switch, which leads to production of specific IgE. Candidates for experimental studies of such phenomena on the cellular level are proposed.

Suppression of experimental autoimmune encephalomyelitis by intravenously administered polyclonal immunoglobulins

Experimental autoimmune encephalomyelitis (EAE) was induced in Lewis rats either by active immunization with myelin basic protein (MBP) or by adoptive transfer using anti-MBP specific CD4(+)T cells. Treatment with human polyclonal immunoglobulins (IgG) effectively suppressed active EAE. Time-dependent experiments demonstrated that the effect of IgG was manifested only when treatment was given immediately after immunization; administration from day 7 after disease induction did not suppress the disease. In the adoptive transfer model of EAE, IgG had no effect in vivo. However, pretreatment in vitro of the antigen-specific T-cells with IgG inhibited their ability to mediate adoptive EAE, as it did in active EAE. Similarly, in vitro IgG pretreatment of the antigen-specific T-cells suppressed the proliferative response to MBP. Fluorescent Activated Cell Sorter (FACS) analysis demonstrated the binding of IgG to activated T-cell lines that was inhibited by soluble Fc molecules. The differential effects of IgG on active EAE and on the adoptive transfer of EAE suggest that IgG in vivo can suppress disease by acting during the early phase of the immune response which involves naive T cells. The inhibition of T-cell proliferation and adoptive transfer of EAE by incubation of T cells in vitro appears to require higher concentrations of IgG than those obtained in vivo.

Antibodies binding granulocyte-macrophage colony stimulating factor produced by cord blood-derived B cell lines immortalized by Epstein-Barr virus in vitro

We detected natural antibodies (auto-Abs) binding human granulocyte-macrophage colony stimulating factor (GM-CSF) in umbilical cord blood (CB) (23 of 94 samples screened) and peripheral blood of women at the end of pregnancy (6 of 42 samples tested). To demonstrate that Abs detected in CB were produced by the fetus, CB mononuclear cells were infected with Epstein-Barr virus in vitro. Ten cell lines producing constitutively anti-recombinant human GM-CSF (rhGM-CSF) Abs were isolated and characterized. These cells displayed a male karyotype, an early activated B cell phenotype, coexpressed surface IgM and IgD, and secreted only IgM with prevailing lambda clonal restriction. Specific cell surface binding of biotinylated rhGM-CSF and high-level anti-rhGM-CSF IgM Ab production were typical features of early cell cultures. In late cell passages the frequency of more undifferentiated B cells increased. Serum Abs of either maternal or fetal origin or Abs produced in culture did not affect the granulocyte and macrophage colony stimulating activity of rhGM-CSF from bone marrow progenitors in soft agar, suggesting that the Abs produced were nonneutralizing.

Therapeutic strategies in multiple sclerosis. I. Immunotherapy

This review first addresses several general aspects of the immunotherapy of multiple sclerosis. Next, two approved immunomodulatory treatments, interferon-beta and copolymer-1 (glatiramer acetate), are reviewed in more detail. Finally, other immunosuppressive therapies and experimental strategies are briefly discussed.

Levels of gamma interferon and interleukin-4 are inversely related to the levels of their corresponding autoantibodies in patients with lower respiratory tract infection

To study the involvement of cytokines and their corresponding autoantibodies (Aabs) in inflammatory mechanisms in patients with lower respiratory tract infections, blood samples were taken from patients at the time of admission to the hospital and before treatment. Cell-released capturing enzyme-linked immunosorbent assay was used to measure the levels of gamma interferon (IFN-gamma) and interleukin-4 (IL-4) produced spontaneously by peripheral mononuclear cells (PMNC). ELISA was used to measure Aabs to these cytokines in sera. The levels of both cytokines were inversely related to the levels of their corresponding Aabs. While a high level of IFN-gamma was observed together with a low level of anti-IFN-gamma Aab, decreased IL-4 levels were observed with increased levels of Aabs to IL-4. Immunoglobulins were purified, digested to obtain Fab fragments, and tested for specificity and cross-reactivity. The Aabs and their Fab fragments were tested in cytokine biological assays and showed neutralizing effects. Our data demonstrated increased levels of the proinflammatory cytokine IFN-gamma and decreased release of the anti-inflammatory cytokine IL-4 during early presentation of lower respiratory tract infection. The levels of these cytokines were inversely related to the levels of their corresponding Aabs that exhibited regulatory effects on the cytokine biological function in vitro.

The influence of cryopreservation on cytokine production by human T lymphocytes

Human T lymphocytes isolated from peripheral blood were cryopreserved at -196 degreesC for different periods of 3, 14, 21, 35, and 50 days. Viability and cytokine-producing activity of T cells were examined before and after cryopreservation. A high recovery (90 +/- 1%) of viable T cells was obtained at each frozen period, indicating that a 10% loss of cells was due to the freezing process rather than the duration of cryopreservation. There was no difference in cell cycle distribution between PHA-treated fresh and frozen lymphocytes. Resting human T cells produced little or no cytokine. After stimulation of fresh T cells with PHA, an apparent increase in cytokine production was noted in IL-2 (35.5 +/- 8.3 pg/ml), IL-6 (1280.4 +/- 64.7 pg/ml), tumor necrosis factor-alpha (874.3 +/- 71.7 pg/ml), interferon-gamma (58.9 +/- 2.2 pg/ml), and granulocyte macrophage-colony-stimulating factor (59.5 +/- 4.4 colonies/5 x 10(4) bone marrow cells). Compared with PHA-activated fresh T cells, all the above cytokines did not diminish in their levels in conditioned medium from PHA-treated frozen T cells thawed at each storage period, suggesting that cryopreservation could well retain the cytokine-producing activity of human T lymphocytes. In addition, our results also revealed that cryopreservation rendered T lymphocytes more responsive to PHA in IL-2 production than fresh T cells.

Natural and therapeutically-induced antibodies to cytokines

Serum samples obtained from non-immunocompromised patients treated therapeutically with recombinant cytokines (e.g. Il-1alpha; Il-1beta; Il-2 to Il-18; IFNalpha; GM-CSF; G-CSF; etc.) often reveal the presence of high affinity anti-cytokine antibodies. Antibody Fab binding in a saturable manner by ELISA and RIA or western immunoblotting prove their specificity. Antibody level often increases in these patients with repeated cytokine administration, suggesting boosts of antigen stimulation. However, the appearance in circulation of auto-antibodies to exogenous cytokine is not always associated with a decreased clinical response to therapy. The demonstration that non-neutralizing auto-antibodies to several natural cytokines can be found even in sera of normal healthy individuals never treated before with cytokines and particularly during the last trimester of pregnancy and in cord-blood, suggests that these naturally- occurring and therapeutically-induced auto-antibodies may exert different functions, not only as inhibitors or antagonists but also as beneficial physiological cytokine carriers or regulators of their activity.

Natural and therapy-induced anti-GM-CSF and anti-G-CSF antibodies in human serum

Serum samples were obtained from patients with lymphoid and plasma cell malignancies who received after chemotherapy human recombinant GM-CSF or G-CSF. Sera from some patients revealed the presence of anti-cytokine antibodies, particularly after repetitive cytokine injections. Antibody Fab binding in a saturable manner by ELISA and Western immuno-blotting confirmed antibody specificity. Anti-cytokine antibodies were detected before the exogenous cytokine injections in some patients, but increasing antibody levels were found after one or subsequent treatments. Low levels of anti-GM-CSF and anti-G-CSF antibodies were also detected in a relatively large proportion (about 10-30%) of normal sera from different adult healthy volunteers who had never been treated before with exologous cytokines as well as from cord blood. EBV-immortalized cord blood derived B-cell cultures were also found to produce anti GM-CSF and/or anti-G-CSF antibodies with high frequency.

Naturally occurring and therapy-induced antibodies to human granulocyte colony-stimulating factor (G-CSF) in human serum

Sera were obtained from two groups of patients. Group A included 7 patients with low-grade non-Hodgkin's lymphoma treated with three or more cycles of standard-dose chemotherapy and recombinant human granulocyte-colony stimulating factor (rhG-CSF). The cytokine was administered to half the patients after the first chemotherapy cycle and to the other half after the second according to a randomized design and then to all patients from the third chemotherapy cycle on, until documented hemopoietic reconstitution. Group B included 3 patients with high-grade non-Hodgkin's lymphoma, 1 patient with resistant Hodgkin's disease, and 1 patient with multiple myeloma who received high-dose chemotherapy and rhG-CSF. Anti-G-CSF antibodies were detected in the sera of 4 patients. Both immunoglobulin IgM and IgG antibodies were detected at low levels in pretreatment sera from one group A patient. IgG antibody titers increased markedly during the first and second periods of G-CSF administration. IgG class antibodies developed in 3 groups B patients during the first course of rhG-CSF administration. Circulating anti-G-CSF antibodies did not seem to affect hematological recovery. Low levels of anti-G-CSF antibodies were also detected in sera (15/135) from different healthy adults and in sera (5/40) from umbilical cord blood. Saturable antibody binding and competition enzyme-linked immunosorbent assay (ELISA) and immunoblotting confirmed antibody specificity.

A primer on cytokines: sources, receptors, effects, and inducers

Protection against pathogens is a prerequisite for survival of most organisms. To cope with this continuous challenge, complex defense mechanisms have evolved. The construction, adaptation, and maintenance of these mechanisms are under control of an extensive network of regulatory proteins called cytokines. A great number of cytokines have been described over the last 2 decades. This review consists of an overview of cytokines that are involved in immune responses and describes some historical and general aspects as well as prospective clinical applications. Major biological effects together with information on cytokine receptors, producers, inducers, and biochemical and molecular characteristics are listed in tables. In addition, some basic information is given on cytokine receptor signal transduction. Finally, the recent discoveries of cytokine receptors functioning as coreceptors in the pathogenesis of human immunodeficiency virus are summarized.

Increased In Vivo Antibody Activity Against Interferon α, Interleukin-1α, and Interleukin-6 After High-Dose Ig Therapy

High-avidity antibodies against interferon α (IFNα), interleukin-1α (IL-1α), and IL-6 have been demonstrated in preparations of normal human IgG, and in vivo modulation of these cytokines may therefore account for immunomodulatory and anti-inflammatory effects of high-dose intravenous IgG therapy. We have investigated the in vivo recovery and the effect on serum cytokine levels of antibodies to IFNα, IL-1α, and IL-6 infused with IgG preparations. Fifteen treatment series of 0.4 g IgG/kg/d were administered over 3 days to eight patients with autoimmune diseases. All IgG preparations contained variable amounts of antibodies binding to 125I-labeled human IFNα2A, -IL-1α, and -IL-6, and the contents of these molecules correlated with increased levels in serum anticytokine activities after IgG infusion. The infused anti–IL-1α antibody activity was fully recovered, whereas the recovery of anti-IFNα2A antibodies was significantly reduced. Serum antiviral activities were significantly reduced after IgG therapy (before, 0 to 5.6 IU/mL; after, 0 to 0.6 IU/mL). In contrast, enzyme-linked immunosorbent assay (ELISA) showed no significant reduction in the serum levels of IL-6 (before, 1 to 70 pg/mL; after, 2 to 55 pg/mL), and the levels of IL-1α were consistently below the detection limit (<30 pg/mL). In conclusion, increased levels of antibodies to IFNα2A, IL-1α, and IL-6 occurred in patients receiving IgG and this reduced the serum antiviral activity.

Increased In Vivo Antibody Activity Against Interferon α, Interleukin-1α, and Interleukin-6 After High-Dose Ig Therapy

High-avidity antibodies against interferon α (IFNα), interleukin-1α (IL-1α), and IL-6 have been demonstrated in preparations of normal human IgG, and in vivo modulation of these cytokines may therefore account for immunomodulatory and anti-inflammatory effects of high-dose intravenous IgG therapy. We have investigated the in vivo recovery and the effect on serum cytokine levels of antibodies to IFNα, IL-1α, and IL-6 infused with IgG preparations. Fifteen treatment series of 0.4 g IgG/kg/d were administered over 3 days to eight patients with autoimmune diseases. All IgG preparations contained variable amounts of antibodies binding to 125I-labeled human IFNα2A, -IL-1α, and -IL-6, and the contents of these molecules correlated with increased levels in serum anticytokine activities after IgG infusion. The infused anti–IL-1α antibody activity was fully recovered, whereas the recovery of anti-IFNα2A antibodies was significantly reduced. Serum antiviral activities were significantly reduced after IgG therapy (before, 0 to 5.6 IU/mL; after, 0 to 0.6 IU/mL). In contrast, enzyme-linked immunosorbent assay (ELISA) showed no significant reduction in the serum levels of IL-6 (before, 1 to 70 pg/mL; after, 2 to 55 pg/mL), and the levels of IL-1α were consistently below the detection limit (<30 pg/mL). In conclusion, increased levels of antibodies to IFNα2A, IL-1α, and IL-6 occurred in patients receiving IgG and this reduced the serum antiviral activity.

Immunomodulation, autoimmunity and haemostatic dysfunctions

Many links exist between the two major host defence mechanisms, haemostasis and immunity. Blood cells and endothelium are involved in these systems and their dysfunctions. The dual function of these cells is discussed. Once activated, cell-cell interactions enhance the biological response and contribute to development of pathology. Furthermore, autoimmunity presents a special clinical relevance, and could be involved in many haemostatic disorders. A hypothesis is presented on how some auto-antibodies are generated and can trigger pathology, by targeting the immune response onto blood or endothelial cells, or to body's organs.

The anti-tumor effect of Ganoderma lucidum is mediated by cytokines released from activated macrophages and T lymphocytes

The present study was to ascertain the immunomodulating and anti-tumor effects of Ganoderma (G.) lucidum. Polysaccharides (PS) from fresh fruiting bodies of G. lucidum (PS-G) were isolated and used to potentiate cytokine production by human monocytes-macrophages and T lymphocytes. Our results had shown that the levels of interleukin (IL)-1 beta, tumor necrosis factor (TNF)- alpha, and IL-6 in macrophage cultures treated with PS-G (100 micrograms/ml) were 5.1-, 9.8- and 29-fold higher, respectively, than those of untreated controls. In addition, the release of interferon (IFN)- gamma from T lymphocytes was also greatly promoted in the presence of PS-G (25-100 micrograms/ml). Furthermore, these cytokine-containing mononuclear cell-conditioned media (PSG-MNC-CM) were found to suppress the proliferation and clonogenicity of both the HL-60 and the U937 leukemic cell lines. DNA labeling and gel electrophoresis showed that treatment with PSG-MNC-CM markedly induced leukemic-cell apoptosis. Flow-cytometric analysis revealed that few (2.3 +/- 0.8%) apoptotic cells were seen in the control cultures, while PSG-MNC-CM treatment resulted in a significant increase in the apoptotic population both in the HL-60 (38.3 +/- 4.5%) and in the U937 (44.5 +/- 3.8%) cells. In addition, 40 to 45% of the treated leukemic cells were triggered to differentiate into mature monocytic cells expressing CD14 and CD68 surface antigens. However, PS-G alone had no such effects even at a higher dose of 400 micrograms/ml. Since untreated macrophages and T lymphocytes produced little or no cytokine, and normal MNC-CM did not suppress leukemic cell growth, it was suggestive that the anti-tumor activity of PSG-MNC-CM was derived from the elevated levels of cytokines. Antibody-neutralization studies further revealed that the anti-tumor cytokines in the PSG-MNC-CM were mainly of TNF- alpha and IFN- gamma, and these 2 cytokines acted synergistically on the inhibition of leukemic-cell growth.

IgG for intravenous use, autologous serum and plasma induce comparable interleukin-1 receptor antagonist liberation from human mononuclear cells: an in vitro phenomenon depending upon plastic adherence

Immunoglobulin G (IgG) for intravenous use (IVIg) selectively stimulates production of interleukin-1 receptor antagonist protein (IL-1ra) by mononuclear cells in vitro and has been proposed to stimulate IL-1ra production in vivo as part of the therapeutic effect. We tested if IVIg differed from human IgG-containing media (i.e., autologous serum (HS) and plasma (HP)) in stimulating IL-1ra release by MNC in vitro and whether IVIg induced a delayed increase in serum levels of IL-1ra. IVIg, 0.01-0.5 mg/ml, increased the IL-1ra liberation from MNC 10-15 times over that of untreated controls. HP and HS (5% v/v) had comparable effects. However, the stimulated IL-1ra liberation was reduced to less than twice the background liberation when fetal calf serum (FCS)-precoated tubes were used. Three days of high-dose IgG infusion had no significant effect on the serum levels of IL-1ra. It is concluded that therapeutic effects of IVIg cannot be ascribed to significant stimulation of IL-1ra production in vivo, as previously suggested, and that the observed stimulation of IL-1ra production in vitro is an epiphenomenon strictly dependent upon adherence of human serum and plasma constituents.