Intravenous immunoglobulin inhibits NF-kappaB activation and affects Fcgamma receptor expression in monocytes/macrophages

Guidelines for the diagnosis and treatment of acute encephalopathy in childhood

The cardinal symptom of acute encephalopathy is impairment of consciousness of acute onset during the course of an infectious disease, with duration and severity meeting defined criteria. Acute encephalopathy consists of multiple syndromes such as acute necrotizing encephalopathy, acute encephalopathy with biphasic seizures and late reduced diffusion and clinically mild encephalitis/encephalopathy with reversible splenial lesion. Among these syndromes, there are both similarities and differences. In 2016, the Japanese Society of Child Neurology published 'Guidelines for the Diagnosis and Treatment of Acute Encephalopathy in Childhood', which made recommendations and comments on the general aspects of acute encephalopathy in the first half, and on individual syndromes in the latter half. Since the guidelines were written in Japanese, this review article describes extracts from the recommendations and comments in English, in order to introduce the essence of the guidelines to international clinicians and researchers.

Intravenous Immunoglobulin G Suppresses Heat Shock Protein (HSP)-70 Expression and Enhances the Activity of HSP90 and Proteasome Inhibitors

Intravenous immunoglobulin G (IVIgG) is approved for primary immunodeficiency syndromes but may induce anti-cancer effects, and while this has been attributed to its anti-inflammatory properties, IgG against specific tumor targets may play a role. We evaluated IVIgG alone, and with a Heat shock protein (HSP)-90 or proteasome inhibitor, using multiple myeloma and mantle cell lymphoma (MCL) cells in vitro, and with the proteasome inhibitor bortezomib in vivo. IVIgG inhibited the growth of all cell lines tested, induced G₁ cell cycle arrest, and suppressed pro-tumor cytokines including Interleukin (IL)-6, IL-8, and IL-10. Genomic and proteomic studies showed that IVIgG reduced tumor cell HSP70-1 levels by suppressing the ability of extracellular HSP70-1 to stimulate endogenous HSP70-1 promoter activity, and reduced extracellular vesicle uptake. Preparations of IVIgG were found to contain high titers of anti-HSP70-1 IgG, and recombinant HSP70-1 reduced the efficacy of IVIgG to suppress HSP70-1 levels. Combining IVIgG with the HSP90 inhibitor AUY922 produced superior cell growth inhibition and correlated with HSP70-1 suppression. Also, IVIgG with bortezomib or carfilzomib was superior to each single agent, and enhanced bortezomib's activity in bortezomib-resistant myeloma cells. Moreover, IVIgG reduced transfer of extracellular vesicles (EVs) to cells, and blocked transfer of bortezomib resistance through EVs. Finally, IVIgG with bortezomib were superior to the single agents in an in vivo myeloma model. These studies support the possibility that anti-HSP70-1 IgG contained in IVIgG can inhibit myeloma and MCL growth by interfering with a novel mechanism involving uptake of exogenous HSP70-1 which then induces its own promoter.

Risiken und Chancen von Immuntherapien in Zeiten der Coronavirus-2019-Pandemie

Immuntherapien stellen die essenzielle Grundlage der Behandlung von neuroinflammatorischen Erkrankungen dar. In Zeiten der Coronavirus-2019 (COVID-19)-Pandemie ergibt sich im klinischen Alltag jedoch zunehmend die Frage, ob eine Immuntherapie bei neurologischen Patienten aufgrund des potenziellen Infektionsrisikos eingeleitet, intensiviert, pausiert oder gar beendet werden sollte. Unsicherheit besteht v. a. deshalb, weil verschiedene nationale und internationale Fachgesellschaften diesbezüglich unterschiedliche Empfehlungen veröffentlichten. In diesem Artikel soll ein Überblick über die Wirkmechanismen von Immuntherapien und den daraus abzuleitenden Infektionsrisiken in Bezug auf COVID-19 (durch den Coronavirus verursachte Erkrankung) gegeben werden. Potenzielle Chancen und vorteilhafte Effekte einzelner Substrate in der Akuttherapie von COVID-19 werden diskutiert.

Merits and culprits of immunotherapies for neurological diseases in times of COVID-19

Immunosuppression and immunomodulation are valuable therapeutic approaches for managing neuroimmunological diseases. In times of the Coronavirus disease 2019 (COVID-19) pandemic, clinicians must deal with the question of whether immunotherapy should currently be initiated or discontinued in neurological patients. Uncertainty exists especially because different national medical associations publish different recommendations on the extent to which immunotherapies must be continued, monitored, or possibly switched during the current pandemic. Based on the most recently available data both about the novel coronavirus and the approved immunotherapies for neurological diseases, we provide an updated overview that includes current treatment strategies and the associated COVID-19 risk, but also the potential of immunotherapies to treat COVID-19.

Utility of Soluble CD163 in the Clinical Management of Patients With Kawasaki Disease

Objective: Intravenous immunoglobulin (IVIG) therapy is a useful first-line treatment for Kawasaki disease (KD); however, 10-20% of patients fail to respond and require additional IVIG. Soluble CD163 (sCD163) is considered a biomarker for macrophage activation. There are no reports measuring serum sCD163 in KD patients. This study aimed to explore its possible utility in the clinical management of patients with KD. Methods: Eighty-seven patients with well-defined KD were retrospectively enrolled together with 19 healthy individuals with comparable ages. KD patients were classified into three groups, Group A (initial IVIG responders), Group B (additional IVIG responders), and Group C (additional IVIG non-responders). Serum sCD163 together with complete blood counts, C-reactive protein, d-dimer, albumin, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were measured before the initial IVIG treatment in all cases, and afterward in a fraction of cases. Results: Serum sCD163 in KD patients before initial IVIG was generally much higher than the control group. The median (interquartile range) of sCD163 was as follows: Control 446 (385-521) ng/mL; Group A, 699 (478-1,072); Group B, 1,349 (1,116-1,390); and Group C, 665 (544-1,094). In general, sCD163 showed close positive correlation with ALT and AST, but none with other markers. Among the KD groups, Group B showed the highest sCD163: Group B vs. A: p = 0.0003; B vs. C: p = 0.035). Serum sCD163 was significantly increased after IVIG in Group A, while no change occurred in others. Conclusion: The serum sCD163 levels could be a useful biomarker in the clinical management of KD, especially for predicting responsiveness to IVIG.

Etanercept With IVIg for Acute Kawasaki Disease: A Randomized Controlled Trial

OBJECTIVES

Patients with Kawasaki disease can develop life-altering coronary arterial abnormalities, particularly in those resistant to intravenous immunoglobulin (IVIg) therapy. We tested the tumor necrosis factor α receptor antagonist etanercept for reducing both IVIg resistance and coronary artery (CA) disease progression.

METHODS

In a double-blind multicenter trial, patients with Kawasaki disease received either etanercept (0.8 mg/kg; n = 100) or placebo (n = 101) subcutaneously starting immediately after IVIg infusion. IVIg resistance was the primary outcome with prespecified subgroup analyses according to age, sex, and race. Secondary outcomes included echocardiographic CA measures within subgroups defined by coronary dilation (z score >2.5) at baseline. We used generalized estimating equations to analyze z score change and a prespecified algorithm for change in absolute diameters.

RESULTS

IVIg resistance occurred in 22% (placebo) and 13% (etanercept) of patients (P = .10). Etanercept reduced IVIg resistance in patients >1 year of age (P = .03). In the entire population, 46 (23%) had a coronary z score >2.5 at baseline. Etanercept reduced coronary z score change in those with and without baseline dilation (P = .04 and P = .001); no improvement occurred in the analogous placebo groups. Etanercept (n = 22) reduced dilation progression compared with placebo (n = 24) by algorithm in those with baseline dilation (P = .03). No difference in the safety profile occurred between etanercept and placebo.

CONCLUSIONS

Etanercept showed no significant benefit in IVIg resistance in the entire population. However, preplanned analyses showed benefit in patients >1 year. Importantly, etanercept appeared to ameliorate CA dilation, particularly in patients with baseline abnormalities.

MicroRNA-93 may control vascular endothelial growth factor A in circulating peripheral blood mononuclear cells in acute Kawasaki disease

BACKGROUND

Kawasaki disease (KD) is the most common systemic vasculitis syndrome primarily affecting medium-sized arteries, particularly the coronary arteries. Though KD may be associated with immunological problems, the involvement of microRNAs (miRs) has not been fully described.

METHODS

We enrolled 23 KD patients and 12 controls. We performed miR and mRNA microarray analysis of peripheral blood mononuclear cells (PBMCs) isolated from acute KD patients and controls. Continuously, we measured specific miRs, mRNA and the expression of proteins by using reverse-transcriptase PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA).

RESULTS

We identified strikingly high levels of miR-182 and miR-296-5p during the acute febrile phase, and of miR-93, miR-145-5p, miR-145-3p, and miR-150-3p in the defervescence stage, especially in refractory KD patients. The expression of vascular endothelial growth factor A (VEGFA) mRNA, previously reported to be controlled by miR-93, was significantly elevated during the febrile phase and normalized upon treatment, negatively correlating with the expression of miR-93. Further, plasma levels of VEGF-A correlated with PBMC VEGFA mRNA expression.

CONCLUSION

Several miRs are highly specific to the acute phase of KD, and may participate in regulating the expression of genes in pathways associated with KD. In particular, miR-93 may participate in regulating expression of VEGF-A and contribute to the pathogenesis of arteritis in acute KD.

Predisposing factors, pathogenesis and therapeutic intervention of Kawasaki disease

Kawasaki disease (KD) is an acute febrile childhood inflammatory disease, associated with coronary artery abnormalities. The disease is believed to result from an aberrant inflammatory response to an infectious trigger in a genetically predisposed individual. KD is associated with an endothelial cell injury as a consequence of T cell activation and cytotoxic effects of various proinflammatory cytokines. Intravenous immunoglobulin (IVIG) infusion and aspirin are the standard treatment of acute KD. However, 10-20% of patients show resistance to IVIG therapy and present higher risk of coronary vasculitis. The relative roles of second IVIG infusion, corticosteroids, calcineurin inhibitors, interleukin-1 antagonists and anti-tumor necrosis factor agents remain uncertain. In this review, we highlight the predisposing factors, pathogenesis and therapeutic intervention of KD, particularly new therapeutics for IVIG-resistant patients.

Effect of CD16a, the surface receptor of Kupffer cells, on the growth of hepatocellular carcinoma cells

FcγRIIIa (CD16) is a low-affinity Fc receptor of IgG. As the idio-binding receptor of IgG Fc, it plays an important role in the antibody-dependent cellular cytotoxicity of natural killer cells. The aim of the present study was to investigate the distribution of Kupffer cells (KCs) and the expression of their surface receptor FcγRIIIa in hepatocellular carcinoma. Furthermore, we also aimed to observe the functional mechanism of FcγRIIIa. Immunohistochemical analysis was employed to study KCs and FcγRIIIa. In order to explore the role of FcγRIIIa in the growth of cancer cells, KCs and H22 tumor cells were co-cultured in different serum. The mRNA expression levels of tumor necrosis factor (TNF)-α and FcγRIIIa were analyzed by RT-qPCR; the TNF-α and FcγRIIIa protein expression levels were examined by enzyme-linked immunosorbent assay and western blot analysis, respectively. Our results showed that the number of Kuppfer cells in cancerous tissues (21.6±7.8) was lower than those in para-cancerous (68.8±9.1) tissues and adjacent normal hepatic tissues (62.0±1.9) (P<0.01); this decreased with the reduction in the differentiation degree of cancer (P<0.05). FcγRIIIa-positive cells were similar in morphology to KCs, and their distributive tendency was coincident (P<0.05). The increase in CD16a mRNA levels in the group treated with immune serum was 3.9-, 4.9- and 3.9-fold greater than that in the ordinary serum group at different time points, and CD16a protein expression also markedly increased (P<0.05). However, these effects were inhibited by the addition of anti-IgG Fc serum (P<0.05). The results of the present study suggested that FcγRIIIa resided in KCs, and it contributed to the inhibition of the growth of liver tumor cells.

Relationship between T-cell HLA-DR expression and intravenous immunoglobulin treatment response in Kawasaki disease

BACKGROUND

Kawasaki disease (KD) is an acute febrile illness associated with the development of vasculitis. Administration of intravenous immunoglobulin (IVIG) is the standard treatment for KD. However, IVIG treatment is not effective in approximately 15% of children with KD. Some reports have presented evidence of immunological responses in IVIG-resistant KD patients. We assessed the possibility that T-cell activation is a contributing mechanism underlying this phenomenon.

METHODS

We analyzed human leukocyte antigen-DR (HLA-DR) expression on peripheral blood CD4+ and CD8+ T cells in 82 children with KD who were admitted to the hospital between October 2007 and February 2012. We compared the percentages of HLA-DR+ T cells among the CD4+ T-cell and CD8+ T-cell populations for the IVIG-effective and IVIG-resistant groups.

RESULTS

Among the 82 subjects, 51 had IVIG-effective KD and 31 children had IVIG-resistant KD. The percentages of HLA-DR+ T cells among the CD4+ T-cell and CD8+ T-cell populations in the IVIG-effective group were significantly lower than those in the IVIG-resistant group.

CONCLUSION

Our results suggest that increased T-cell HLA-DR expression is associated with IVIG resistance in KD patients, indicating that HLA-DR expression would be a useful tool for predicting IVIG responsiveness during KD pathogenesis.

Intravenous immunoglobulin preparation attenuates neurological signs in rat experimental autoimmune neuritis with the suppression of macrophage inflammatory protein -1α expression

To clarify the mechanism of action of an intravenous immunoglobulin (IVIG) preparation in chronic inflammatory demyelinating polyneuropathy, the effects of IVIG were investigated using an experimental autoimmune neuropathy model in the rat. IVIG significantly suppressed the progression of neurologic signs and sciatic nerve conduction velocity with the inhibition of inflammatory cell infiltration, mainly of macrophages, to the peripheral nerves. A significant suppressive effect on the expression of macrophage inflammatory protein 1-α (MIP-1α) was simultaneously observed in the nerves. These results suggest that IVIG is effective for inflammatory demyelinating polyneuropathy by inhibiting the chemotactic factor of macrophages.

Intravenous immunoglobulin inhibits BAFF production in chronic inflammatory demyelinating polyneuropathy - a new mechanism of action?

Chronic-inflammatory demyelinating polyneuropathy (CIDP) is an immune-mediated disease treated with intravenous immunoglobulin (IVIg). The underlying mechanism of action remains incompletely understood. The B-cell activating factor BAFF contributes to B-cell homeostasis and (auto-)antibody production. BAFF was recently identified as one key molecule in the development of autoimmune diseases. Herein, we demonstrate that BAFF serum levels are elevated in CIDP patients. IVIg treatment resulted in a significant decrease of BAFF serum level. In vitro, IVIg inhibited BAFF in monocytes. Consequently, we identified BAFF as a new target for IVIg in CIDP treatment and provide a new, Fcγ-receptor independent, mechanism of action for IVIg.

Bench-to-bedside review: Immunoglobulin therapy for sepsis - biological plausibility from a critical care perspective

Sepsis represents a dysregulated host response to infection, the extent of which determines the severity of organ dysfunction and subsequent outcome. All trialled immunomodulatory strategies to date have resulted in either outright failure or inconsistent degrees of success. Intravenous immunoglobulin (IVIg) therapy falls into the latter category with opinion still divided as to its utility. This article provides a narrative review of the biological rationale for using IVIg in sepsis. A literature search was conducted using the PubMed database (1966 to February 2011). The strategy included the following text terms and combinations of these: IVIg, intravenous immune globulin, intravenous immunoglobulin, immunoglobulin, immunoglobulin therapy, pentaglobin, sepsis, inflammation, immune modulation, apoptosis. Preclinical and extrapolated clinical data of IVIg therapy in sepsis suggests improved bacterial clearance, inhibitory effects upon upstream mediators of the host response (for example, the nuclear factor kappa B (NF-κB) transcription factor), scavenging of downstream inflammatory mediators (for example, cytokines), direct anti-inflammatory effects mediated via Fcγ receptors, and a potential ability to attenuate lymphocyte apoptosis and thus sepsis-related immunosuppression. Characterizing the trajectory of change in immunoglobulin levels during sepsis, understanding mechanisms contributing to these changes, and undertaking IVIg dose-finding studies should be performed prior to further large-scale interventional trials to enhance the likelihood of a successful outcome.

Intravenous immunoglobulin preparation attenuates LPS-induced production of pro-inflammatory cytokines in human monocytic cells by modulating TLR4-mediated signaling pathways

Intravenous immunoglobulin (IVIG) has been used for the treatment of inflammatory and autoimmune diseases. The ability to modulate cytokine production has been formerly described as one of the mechanisms of its action. This study aimed to investigate the effect of IVIG on the production of pro-inflammatory cytokines in lipopolysaccharide (LPS)-stimulated monocytic cells. Peripheral blood mononuclear cells (PBMCs) or THP-1 cells treated with phorbol myristate acetate (PMA) were stimulated with LPS. The protein levels of pro-inflammatory cytokines [tumor necrosis factor (TNF)-α, interleukin (IL)-6, and high-mobility group box 1 (HMGB1)] in the culture supernatants were determined using appropriate enzyme-linked immunosorbent assay kits. The mRNA of TNF-α was determined by reverse transcription-polymerase chain reaction. The phosphorylation of nuclear factor kappa B (NF-κB) and the mitogen-activated protein kinases was examined by Western blot analyses. IVIG suppressed the production of pro-inflammatory cytokines such as TNF-α and IL-6 in LPS-stimulated PBMCs. Furthermore, IVIG inhibited TNF-α, IL-6, and HMGB1 production from LPS-stimulated THP-1 cells treated with PMA. In addition, Fc fragment prepared from the IVIG inhibited production of these cytokines from the cells to the same degree as IVIG, whereas Fab and F(ab')(2) fragments inhibited this only partially. We showed that IVIG and Fc fragments suppressed LPS-induced signal transduction pathways involving phosphorylation of NF-κB, p38, and c-Jun N-terminal kinase (JNK). Taken together, our results suggest that IVIG attenuates LPS-induced cytokine production predominantly mediated by its Fc region. The activity might be regulated by inhibiting NF-κB, p38, and JNK pathways in human monocytic cells.

DC-SIGN (CD209) promoter -336 A/G (rs4804803) polymorphism associated with susceptibility of Kawasaki disease

Kawasaki disease (KD) is characterized by systemic vasculitis of unknown etiology. High-dose intravenous immunoglobulin (IVIG) is the most effective therapy for KD to reduce the prevalence of coronary artery lesion (CAL) formation. Recently, the α2, 6 sialylated IgG was reported to interact with a lectin receptor, specific intracellular adhesion molecule-3 grabbing nonintegrin homolog-related 1 (SIGN-R1) in mice and dendritic cell-specific intercellular adhesion molecule-3 grabbing nonintegrin (DC-SIGN) in human, and to trigger an anti-inflammatory cascade. This study was conducted to investigate whether the polymorphism of DC-SIGN (CD209) promoter −336 A/G (rs4804803) is responsible for susceptibility and CAL formation in KD patients using Custom TaqMan SNP Genotyping Assays. A total of 521 subjects (278 KD patients and 243 controls) were investigated to identify an SNP of rs4804803, and they were studied and showed a significant association between the genotypes and allele frequency of rs4804803 in control subjects and KD patients (P = 0.004 under the dominant model). However, the promoter variant of DC-SIGN gene was not associated with the occurrence of IVIG resistance, CAL formation in KD. The G allele of DC-SIGN promoter −336 (rs4804803) is a risk allele in the development of KD.

Cysteine, histidine and glycine exhibit anti-inflammatory effects in human coronary arterial endothelial cells

The activation of nuclear factor-kappa B (NF-κB) in vascular endothelial cells may be involved in vascular pathogeneses such as vasculitis or atherosclerosis. Recently, it has been reported that some amino acids exhibit anti-inflammatory effects. We investigated the inhibitory effects of a panel of amino acids on cytokine production or expression of adhesion molecules that are involved in inflammatory diseases in various cell types. The activation of NF-κB was determined in human coronary arterial endothelial cells (HCAECs) because NF-κB modulates the production of many cytokines and the expression of adhesion molecules. We examined the inhibitory effects of the amino acids cysteine, histidine and glycine on the induction of NF-κB activation, expression of CD62E (E-selectin) and the production of interleukin (IL)-6 in HCAECs stimulated with tumour necrosis factor (TNF)-α. Cysteine, histidine and glycine significantly reduced NF-κB activation and inhibitor κBα (IκBα) degradation in HCAECs stimulated with TNF-α. Additionally, all the amino acids inhibited the expression of E-selectin and the production of IL-6 in HCAECs, and the effects of cysteine were the most significant. Our results show that glycine, histidine and cysteine can inhibit NF-κB activation, IκBα degradation, CD62E expression and IL-6 production in HCAECs, suggesting that these amino acids may exhibit anti-inflammatory effects during endothelial inflammation.

Amino acids exhibit anti-inflammatory effects in human monocytic leukemia cell line, THP-1 cells

OBJECTIVE

The elemental diet is one of the effective therapies for inflammatory bowel disease. However, the mechanism remains unclear, and there have never been reports about the inhibitory effects of amino acids in human monocytes/macrophages. We investigated the inhibitory effects of amino acids on cytokine production or expression of adhesion molecules that are involved in inflammatory diseases, in human monocytes/macrophages.

METHODS

We examined the inhibitory effects of cysteine, histidine or glycine on the induction of nuclear factor-κB (NF-κB) activation, expression of intracellular adhesion molecule-1 (ICAM-1, CD54) and production of interleukin-8 (IL-8) in THP-1 cells, a human monocytic leukemia cell line, and peripheral blood mononuclear cells (PBMCs) stimulated with tumor necrosis factor-α (TNF-α).

RESULTS

Cysteine, histidine and glycine significantly reduced the activation of NF-κB in THP-1 cells stimulated with TNF-α. In addition, cysteine and histidine significantly inhibited the expression of ICAM-1 and production of IL-8 in THP-1 cells and PBMCs.

CONCLUSIONS

Our results suggest that cysteine and histidine exhibit anti-inflammatory effects in THP-1 cells, and may be responsible for the efficacy of treatment in inflammatory bowel diseases.

Preparations of intravenous immunoglobulins diminish the number and proinflammatory response of CD14+CD16++ monocytes in common variable immunodeficiency (CVID) patients

We have studied the effect of intravenous immunoglobulins (IVIG) on monocyte subpopulations and cytokine production in patients with CVID. The absolute number of CD14(+)CD16(++) monocytes decreased on average 2.5-fold 4h after IVIG and after 20h returned to the baseline. The cytokine level in the supernatants of peripheral blood mononuclear cells (PBMC) after ex vivo LPS stimulation demonstrated the >2-fold decrease in TNF production 4h after IVIG. The TNF expression, which is higher in the CD14(+)CD16(++) monocytes, was decreased in these cells by IVIG in 4/7 CVID cases. In vitro exposure of the healthy individuals' monocytes to the IVIG preparation resulted in reduced TNF production, which was overcome by blockade of the FcγRIIB in the CD14(+)CD16(++) CD32B(high) monocytes. Our data suggest that reduction in the number of CD14(+)CD16(++) monocytes and the blockade of their cytokine production via triggering CD32B can contribute to the anti-inflammatory action of IVIG.

Serum resistin concentrations in children with Kawasaki disease

OBJECTIVE

Human resistin is expressed strongly in monocytes or macrophages rather than in adipocytes and may play a pivotal role in inflammation. We hypothesize that resistin levels are elevated in patients with Kawasaki disease (KD) in the acute phase and may be associated with the disease severity.

DESIGN AND SUBJECTS

Serum resistin concentrations were measured in 44 Japanese children with KD and 17 age-matched healthy children. All the KD patients were given both aspirin and a single dose of intravenous immunoglobulin (IVIG).

RESULTS

The serum resistin levels at baseline in KD children were significantly higher than those in controls [33.0 (21.6-45.3) vs. 14.8 (12.4-18.6) ng/mL, P < 0.001]. After IVIG therapy, serum resistin levels were significantly decreased to normal control levels. No significant difference in baseline resistin levels was found between the high-risk group and the low-risk group of coronary artery aneurysms.

CONCLUSIONS

We confirmed that resistin was an acute inflammatory protein, but its concentrations were unlikely to predict the prognosis of disease in acute KD patients.

Designed surface with tunable IgG density as an in vitro model for immune complex mediated stimulation of leukocytes

We present the design of an in vitro model for immune-complex-mediated stimulation of leukocytes and its functional characteristics with respect to monocyte adhesion. The model was based on the orientation-controlled immobilization of a humanized IgG1 monoclonal antibody (rituximab) via its interaction with a biotinylated peptide epitope derived from the CD20 marker. The peptide was linked to neutravidin covalently attached to a mixed self-assembled monolayer of carboxyl- and methoxy-terminated oligo(ethylene glycol) alkane thiolates on gold. The surface adhesion propensity of human monocytes (cell line U937) was highly dependent on the lateral IgG density and indicated that there exists a distance between IgG-Fc on the surface where interactions with Fc gamma receptors are optimal. This well-defined platform allows for a careful control of the size and orientation of artificial IgG immune complexes, it is easily made compatible with, for example, cellular imaging, and it will become useful for in vitro studies on the importance of Fc gamma receptor interactions in chronic immune-mediated diseases.

Kawasaki disease: aetiopathogenesis and therapeutic utility of intravenous immunoglobulin

Kawasaki disease (KD) is an acute febrile childhood vasculitis, associated with the development of coronary artery abnormalities in 25–30% of untreated patients. The aetiopathogenesis is not well known but it is accepted that an undefined infectious trigger in genetically predisposed individuals results in the disease. KD is characterized by an endothelial cell injury, which could be due to abnormal cytokine production and to generation of cytotoxic antibodies against the endothelial cells. Intravenous immunoglobulin IVIG is an effective treatment in preventing the occurrence of coronary artery abnormalities in KD. Several mechanisms may explain the anti-inflammatory effects of IVIG in this disease. They include modification of the cytokine balance, and alteration on both the differentiation and the function of monocytes/macrophages, neutrophils and lymphocytes.

Fcgamma receptors mediate internalization of anti-Ro and anti-La autoantibodies from Sjögren's syndrome and apoptosis in human salivary gland cell line A-253

BACKGROUND

The presence of serum anti-Ro and anti-La autoantibodies directed against the ribonucleoproteins Ro and La has been associated with Sjögren's syndrome (SS), an autoimmune rheumatic disease that targets salivary and lachrymal glands. There is increasing evidence of the direct involvement of autoantibodies in the pathogenesis of tissue injury and correlation of their presence with clinical manifestations in SS. The focus of this work was to explore the cellular apoptotic pathway triggered by binding and penetration of anti-Ro and anti-La autoantibodies in human salivary gland cell line A-253 and to identify the membrane receptors through which anti-Ro and anti-La could exert their effect.

METHODS

Anti-Ro and anti-La autoantibodies were purified from IgG fractions, obtained from eleven healthy volunteers and patients with primary Sjögren's syndrome, using Sepharose 4B-Ro and Sepharose 4B-La affinity columns. Flow cytometry, RT-PCR, western blot and confocal microscopy analysis were used to visualize the FCgammaRI, FCgammaRII and FCgammaRIII receptors on the A-253 cell membrane. DNA laddering and western blot analysis of caspases activation were studied to evaluate in A-253 cells treated with anti-Ro and anti-La autoantibodies.

RESULTS

The results yeilded the evidence of the presence of members of the Fcgamma receptors (FcgammaRs) family on the cell membrane of the human salivary gland cell line A-253. Furthermore, we demonstrated that, in the A-253 cell line, anti-Ro and anti-La autoantibodies can access the cells probably through Fcgamma receptors, and trigger apoptotis.

CONCLUSIONS

We conclude that anti-Ro and anti-La autoantibodies have pathogenic effects that could depend on binding to Fcgamma receptors.

Anti-inflammatory effect of intravenous immunoglobulin in comparison with dexamethasone in vitro: implication for treatment of Kawasaki disease

High-dose intravenous immunoglobulin (IVIG) is a well-established standard therapy for Kawasaki disease (KD) that reduces the risk of developing coronary artery aneurysms. On the other hand, some reports have recommended an alternative therapy with steroids for KD patients. In this study we investigated the anti-inflammatory effect of IVIG in comparison with dexamethasone at clinical doses in vitro. High-dose IVIG inhibited tumor necrosis factor-alpha (TNF-alpha)-induced activation of nuclear factor-kappaB (NF-kappaB) to a greater degree than dexamethasone in human monocytic U937 cells and human coronary arterial endothelial cells (HCAEC), but not in human T lymphocytic Jurkat cells. IVIG was more potent than dexamethasone in reducing the expression of CD16 (FcgammaRIII) in human monocytic THP-1 cells stimulated with lipopolysaccharide and in Jurkat cells stimulated with dimethyl sulfoxide. In HCAEC exposed to TNF-alpha, IVIG and dexamethasone inhibited interleukin-6 production to a similar degree, whereas the expression of E-selectin was inhibited more strongly by IVIG. Our results show that high-dose IVIG inhibits the activation of monocytes/macrophages and coronary arterial endothelial cells more strongly than that of T cells, whereas dexamethasone inhibits the activation of all three cell types. These findings suggest that IVIG or dexamethasone therapy should be chosen to match the types of cells that are activated during acute KD.

Brain inflammation in epilepsy: experimental and clinical evidence

Inflammatory reactions occur in the brain in various CNS diseases, including autoimmune, neurodegenerative, and epileptic disorders. Proinflammatory and antiinflammatory cytokines and related molecules have been described in CNS and plasma, in experimental models of seizures and in clinical cases of epilepsy. Inflammation involves both the innate and the adaptive immune systems and shares molecules and pathways also activated by systemic infection. Experimental studies in rodents show that inflammatory reactions in the brain can enhance neuronal excitability, impair cell survival, and increase the permeability of the blood-brain barrier to blood-borne molecules and cells. Moreover, some antiinflammatory treatments reduce seizures in experimental models and, in some instances, in clinical cases of epilepsy. However, inflammatory reactions in brain also can be beneficial, depending on the tissue microenvironment, the inflammatory mediators produced in injured tissue, the functional status of the target cells, and the length of time the tissue is exposed to inflammation. We provide an overview of the current knowledge in this field and attempt to bridge experimental and clinical evidence to discuss critically the possibility that inflammation may be a common factor contributing, or predisposing, to the occurrence of seizures and cell death, in various forms of epilepsy of different etiologies. The elucidation of this aspect may open new perspectives for the pharmacologic treatment of seizures.

Association of selected phenotypic markers of lymphocyte activation and differentiation with perinatal human immunodeficiency virus transmission and infant infection

This study of a subset of women and infants participating in National Institutes of Health Pediatric AIDS Clinical Trials Group protocol 185 evaluated lymphocyte phenotypic markers of immune activation and differentiation to determine their association with the likelihood of human immunodeficiency virus (HIV) transmission from the women to their infants and the potential for early identification and/or prognosis of infection in the infants. Lymphocytes from 215 human immunodeficiency virus type 1 (HIV)-infected women and 192 of their infants were analyzed by flow cytometry with an extended three-color panel of monoclonal antibodies. Women who did not transmit to their infants tended to have higher CD4+ T cells. Most notably, levels of total CD8+ T cells and CD8+ CD38+ cells made significant independent contributions to predicting the risk of mother-to-child transmission. Adjusting for HIV-1 RNA level at entry, a one percentage-point increase in these marker combinations was associated with a nine percent increase in the likelihood of maternal transmission. Total as well as naive CD4+ T cells were significantly higher in uninfected than infected infants. Total CD8+ cells, as well as CD8+ cells positive for HLA-DR+, CD45 RA+ HLA-DR+, and CD28+ HLA-DR+ were elevated in infected infants. Detailed immunophenotyping may be helpful in predicting which pregnant HIV-infected women are at increased risk of transmitting HIV to their infants. Increasing differences in lymphocyte subsets between infected and uninfected infants became apparent as early as six weeks of age. Detailed immunophenotyping may be useful in supporting the diagnosis of HIV infection in infants with perinatal HIV exposure.

Immunological profile of peripheral blood lymphocytes and monocytes/macrophages in Kawasaki disease

Kawasaki disease (KD) is an acute illness of early childhood characterized by prolonged fever, diffuse mucosal inflammation, indurative oedema of the hands and feet, a polymorphous skin rash and nonsuppurative lymphadenopathy. The histopathological findings in KD comprise panvasculitis with endothelial necrosis, and the infiltration of mononuclear cells into small and medium-sized blood vessels. The levels of many proinflammatory cytokines, chemokines and adhesion molecules can be elevated in sera from children with KD at the acute stage. Although many immunological studies on KD involving peripheral blood have been reported, the data obtained remain controversial. This review focuses on the immune response of peripheral blood lymphocytes and monocytes/macrophages during acute KD.

Gene expression profiling of the effect of high-dose intravenous Ig in patients with Kawasaki disease

Kawasaki disease (KD) is an acute vasculitis of infants and young children, preferentially affecting the coronary arteries. Intravenous infusion of high dose Ig (IVIG) effectively reduces systemic inflammation and prevents coronary artery lesions in KD. To investigate the mechanisms underlying the therapeutic effects of IVIG, we examined gene expression profiles of PBMC and purified monocytes obtained from acute patients before and after IVIG therapy. The results suggest that IVIG suppresses activated monocytes and macrophages by altering various functional aspects of the genes of KD patients. Among the 18 commonly decreased transcripts in both PBMC and purified monocytes, we selected six genes, FCGR1A, FCGR3A, CCR2, ADM, S100A9, and S100A12, and confirmed the microarray results by real-time RT-PCR. Moreover, the expressions of FcgammaRI and FcgammaRIII on monocytes were reduced after IVIG. Plasma S100A8/A9 heterocomplex, but not S100A9, levels were elevated in patients with acute KD compared with those in febrile controls. Furthermore, S100A8/A9 was rapidly down-regulated in response to IVIG therapy. Persistent elevation of S100A8/A9 after IVIG was found in patients who later developed coronary aneurysms. These results indicate that the effects of IVIG in KD may be mediated by suppression of an array of immune activation genes in monocytes, including those activating FcgammaRs and the S100A8/A9 heterocomplex.

Biological effects of induction immunosuppression

The concept of induction immunosuppression is evolving. Once used to buttress the inadequacies of past maintenance immunosuppressive regimens, it is now being used to permit effective maintenance immunosuppression using ever decreasing amounts of modern agents. In addition to lymphocyte depletion, with which it was once synonymous, it is now recognized that induction immunosuppression is associated with a host of non-depletional effects such as receptor modulation and blockade, which profoundly alter the lymphocyte's capacity to mount an effective response. Additionally, the recent focus on the effect of induction agents on antigen presenting cells and on regulatory factors controlling homeostatic repopulation may ultimately permit a safer, more refined and more effective approach to induction immunosuppression.