Immunotherapy suppresses the production of monocyte chemotactic and activating factor and augments the production of IL-8 in children with asthma

lnc-BAZ2B promotes M2 macrophage activation and inflammation in children with asthma through stabilizing BAZ2B pre-mRNA

BACKGROUND

Dysregulation of long noncoding RNAs (lncRNAs) is associated with a variety of human diseases; however, whether they have a role in childhood asthma is unknown.

OBJECTIVE

We sought to determine the differential expression profiles of lncRNAs in PBMCs of children with asthma and the mechanisms underlying the effects of lncRNAs on the pathogenesis of asthma.

METHODS

The differential expression profiles of lncRNAs were analyzed by transcriptome microarray. The effects and mechanisms by which lncRNAs influence macrophage activation were detected by real-time quantitative PCR, Western blot, RNase protection assay, and chromatin immunoprecipitation assay. The roles played by lncRNAs in asthma were tested in a cockroach allergen extract (CRE)-induced mouse model.

RESULTS

We identified 719 lncRNAs that were differentially expressed in PBMCs of children with asthma, 502 of which were upregulated and 217 were downregulated. An lncRNA of unknown function, lnc-BAZ2B, was dominantly expressed in monocytes and significantly upregulated in children with asthma. lnc-BAZ2B promotes M2 macrophage activation by enhancing BAZ2B expression and exacerbated lung inflammation in an M2 macrophage-associated CRE-induced asthma model. Mechanistically, lnc-BAZ2B promoted the expression of its cis target gene BAZ2B by stabilizing its pre-mRNA. BAZ2B, a reader of H3K14ac modification, enhanced the transcription of IRF4 and promoted M2 macrophage activation. lnc-BAZ2B expression was correlated with that of BAZ2B in PBMCs from children with asthma. Baz2b knockdown could alleviate asthma severity in a CRE-induced asthma model.

CONCLUSION

lnc-BAZ2B promotes M2 macrophage activation and inflammation in children with asthma and may serve as a potential therapeutic and diagnostic target in children with asthma.

Proteolytic processing and inactivation of CCL2/MCP-1 by meprins

Monocyte chemotactic protein 1 (CCL2/MCP-1) is a small chemokine involved in the recruitment and trafficking of mononuclear immune cells to inflammation sites. Our studies demonstrate that the metalloendopeptidases meprin A (purified from kidney cortex), recombinant meprin α, and recombinant meprin β can all process CCL2/MCP-1. The cleavage sites were determined by amino acid sequencing and mass spectrometry analysis of the generated products, and the biological activity of the products was evaluated by chemotactic migration assay using THP-1 cells. The cleavage sites generated by the meprin isoforms revealed that meprin A and meprin α cleaved the N-terminal domain of mouse CCL2/MCP-1 at the Asn⁶ and Ala⁷ bond, resulting in significant reduction in the chemotactic activity of the cleaved CCL2/MCP-1. Meprin β was unable to cleave the N-terminus of mouse CCL2/MCP-1 but cleaved the C-terminal region between Ser⁷⁴ and Glu⁷⁵. Human CCL2/MCP-1 that lacks the murine C-terminal region was also cleaved by meprin α at the N-terminus resulting in significant loss of CCL2/MCP-1 biological activity, whereas meprin β did not affect the biological activity. These studies suggest that meprin α and meprin β may play important roles in regulating the CCL2/MCP-1 chemokine activity during inflammation.

Selected CC and CXC chemokines in children with atopic asthma

INTRODUCTION

There are only limited data on CC and CXC chemokines regulation in children with asthma.

AIM

We compared the serum profile of selected CC and CXC chemokines in patients with atopic asthma and healthy children.

MATERIAL AND METHODS

Serum concentration of CC chemokines RANTES, MCP-1, and CXC chemokines IP-10, MIG, IL-8, RANTES was measured using cytometric bead array in 44 children with atopic asthma and 17 healthy subjects.

RESULTS

The concentration of RANTES was significantly higher and the MIG level was lower in all children with asthma as compared to their control counterparts. We observed increased RANTES and decreased MIG levels also in patients with stable asthma when compared with children in the control group. The IP-10 concentration was similar between the whole asthma group and healthy controls, while significantly increased levels of this chemokine in acute asthma have been observed when compared to stable asthma. For MCP-1 and IL-8, the serum concentration was similar in all compared groups. The MIG concentration correlated positively with IP-10, IL-8, and CRP levels and negatively with the eosinophil count. A negative correlation between the IP-10 and eosinophil count and a negative correlation between FEV1 and IP-10 were found.

CONCLUSIONS

An increased serum RANTES level in children with asthma may result in enhancement of Th2 lymphocyte recruitment into the airway. A decreased expression of Th1 chemokine MIG in children with stable asthma may contribute to a diminished antagonizing effect on Th2 cytokine production and hence intensify Th2 predominance. An increased IP-10 level in children during an asthma attack suggest that this chemokine is a serological marker of disease exacerbation.

Allergen immunotherapy decreases LPS-induced NF-κB activation in neutrophils from allergic patients

BACKGROUND

Allergen-specific immunotherapy (IT) is widely used to treat allergic diseases. The molecular mechanisms have not been clarified yet completely. The present work was undertaken to analyze the effect of IT in the activation of NF-κB.

METHODS

Neutrophils from 15 pollen-allergic IT-treated patients, 10 untreated pollen-allergic patients, and 10 healthy donors were in vitro stimulated with LPS. NF-κB activation (p65/p52) was measured in their nuclear extracts by enzyme-linked immunosorbent assay (ELISA). IκBα phosphorylation, NF-κB-repressing factor (NRF) activation, and thromboxane A2 (TXA2 ) and Interleukin-8 (IL-8) release were measured by ELISA.

RESULTS

There was a positive correlation between the score of symptoms and NF-κB activation in human neutrophils. IT significantly decreased NF-κB activation levels in neutrophils compared with neutrophils from untreated patients. IκBα phosphorylation and NRF activation levels were, respectively, significantly lower and higher in neutrophils from IT-treated patients than from untreated patients. IL-8 and TXA2 release were significantly lower in neutrophils from IT-treated patients than from untreated patients.

CONCLUSIONS

IT positive effects are at least in part mediated by the negative regulation of NF-κB activation in human neutrophils. These observations represent a novel view of neutrophils as possible cell target to treat IgE-dependent diseases through NF-κB downmodulation.

Differential roles of CXCL2 and CXCL3 and their receptors in regulating normal and asthmatic airway smooth muscle cell migration

Structural cell migration plays a central role in the pathophysiology of several diseases, including asthma. Previously, we established that IL-17-induced (CXCL1, CXCL2, and CXCL3) production promoted airway smooth muscle cell (ASMC) migration, and consequently we sought to investigate the molecular mechanism of CXC-induced ASMC migration. Recombinant human CXCL1, CXCL2, and CXCL3 were used to assess migration of human primary ASMCs from normal and asthmatic subjects using a modified Boyden chamber. Neutralizing Abs or small interfering RNA (siRNA) knockdown and pharmacological inhibitors of PI3K, ERK1/2, and p38 MAPK pathways were used to investigate the receptors and the signaling pathways involved in CXC-induced ASMC migration, respectively. We established the ability of CXCL2 and CXCL3, but not CXCL1, to induce ASMC migration at the tested concentrations using normal ASMCs. We found CXCL2-induced ASMC migration to be dependent on p38 MAPK and CXCR2, whereas CXCL3-induced migration was dependent on p38 and ERK1/2 MAPK pathways via CXCR1 and CXCR2. While investigating the effect of CXCL2 and CXCL3 on asthmatic ASMC migration, we found that they induced greater migration of asthmatic ASMCs compared with normal ones. Interestingly, unlike normal ASMCs, CXCL2- and CXCL3-induced asthmatic ASMC migration was mainly mediated by the PI3K pathway through CXCR1. In conclusion, our results establish a new role of CXCR1 in ASMC migration and demonstrate the diverse mechanisms by which CXCL2 and CXCL3 mediate normal and asthmatic ASMC migration, suggesting that they may play a role in the pathogenesis of airway remodeling in asthma.

3D-QSAR studies on CCR2B receptor antagonists: Insight into the structural requirements of (R)-3-aminopyrrolidine series of molecules based on CoMFA/CoMSIA models

Objective:

Monocyte chemo attractant protein-1 (MCP-1) is a member of the CC-chemokine family and it selectively recruits leukocytes from the circulation to the site of inflammation through binding with the chemotactic cytokine receptor 2B (CCR2B). The recruitment and activation of selected populations of leukocytes is a key feature in a variety of inflammatory conditions. Thus MCP-1 receptor antagonist represents an attractive target for drug discovery. To understand the structural requirements that will lead to enhanced inhibitory potencies, we have carried out 3D-QSAR (quantitative structure–activity relationship) studies on (R)-3-aminopyrrolidine series of molecules as CCR2B receptor antagonists.

Materials and Methods:

Comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were performed on a series of (R)-3-aminopyrrolidine derivatives as antagonists of CCR2B receptor with Sybyl 6.7v.

Results:

We have derived statistically significant model from 37 molecules and validated it against an external test set of 13 compounds. The CoMFA model yielded a leave one out r² (r²_loo) of 0.847, non-cross-validated r² (r²_ncv) of 0.977, F value of 267.930, and bootstrapped r² (r²_bs) of 0.988. We have derived the standard error of prediction value of 0.367, standard error of estimate 0.141, and a reliable external predictivity, with a predictive r² (r²_pred) of 0.673. While the CoMSIA model yielded an r²_loo of 0.719, r²_ncv of 0.964,F value of 135.666, r²_bs of 0.975, standard error of prediction of 0.512, standard error of estimate of 0.180, and an external predictivity with an r²_pred of 0.611. These validation tests not only revealed the robustness of the models but also demonstrated that for our models r²_pred, based on the mean activity of test set compounds can accurately estimate external predictivity.

Conclusion:

The QSAR model gave satisfactory statistical results in terms of q² and r² values. We analyzed the contour maps obtained, to study the activity trends of the molecules. We have tried to demonstrate structural features of compounds to account for the activity in terms of positively contributing physicochemical properties such as steric, electrostatic, hydrophobic, hydrogen bond donor, and acceptor fields. These contour plots identified several key features, which explain the wide range of activities. The results obtained from models offer important structural insight into designing novel CCR2B antagonists before their synthesis.

Properties of 7ND-CCL2 are modulated upon fusion to Fc

7ND, a truncated version of the chemokine MCP-1/CCL2 lacking amino acids 2-8, is a potent antagonist of CCR2. In contrast to CCL2, 7ND is an obligate monomer. Similar to other chemokines, the in vivo half-life of 7ND is very short and its use as an antagonist in disease models is thus limited. We therefore constructed a 7ND-Fc fusion protein to extend the half-life of 7ND and overcome its limitations as a potential therapeutic antagonist. When we tested the properties of the fusion molecule in vitro, we found to our surprise that 7ND-Fc, in contrast to 7ND, produced a distinct, albeit small, chemotactic response in THP-1 cells, and a robust chemotactic response in L1.2 cells stably transfected with CCR2. To test whether this unexpected observation might be due to the bivalency of 7ND-Fc stemming from the dimeric nature of Fc fusions, we produced a heterodimeric Fc fusion which displays only one 7ND moiety, using a technology called strand exchange of engineered CH3 domains (SEED). The monovalent construct had properties equivalent to the parent 7ND. Furthermore, partial agonist activity appears to depend on receptor density as well as the signaling pathway examined. However, we were able to show that 7ND-Fc, but not 7ND alone, has antagonistic activity in experimental autoimmune encephalomyelitis, a murine model of multiple sclerosis.

Sequential evaluation of serum monocyte chemotactic protein 1 among asymptomatic state and acute exacerbation and remission of asthma in children

BACKGROUND

Monocyte chemotactic protein 1 (MCP-1) plays an important role in various immune and allergic disorders since it is a potent chemo-attractant for inflammatory cells, such as eosinophils, memory T cells, and monocytes.

OBJECTIVE

To investigate serum MCP-1 during asymptomatic state and acute attacks of bronchial asthma.

METHODS

In this longitudinal cohort design study, sequential serum levels of MCP-1 were measured by a sandwich enzyme-linked immunosorbent assay (ELISA). Twenty-four asthma patients' MCP-1 levels were examined at 5 time points: during the asymptomatic phase, in an acute wheezing episode, and at 1 week, 1 month, and 2 months after acute asthma attack. Fifteen children without asthma were enrolled as control.

RESULTS

During the asymptomatic phase of asthma, serum MCP-1 levels were significantly higher than that of normal controls (329.57 +/- 99.20 pg/ml vs. 213.63 +/- 77.29 pg/ml, p = 0.001). In comparison with the asymptomatic phase, the serum MCP-1 levels during the acute asthma attack were significantly higher (682.88 +/- 88.45 pg/ml vs. 329.57 +/- 99.20 pg/ml, p < 0.001). After treatment of acute asthma exacerbation, all of the serum MCP-1 levels declined within 1 week, but were still higher than control 2 months later.

CONCLUSION

In asthma patients, the consistently elevated serum levels of MCP-1 suggest its role in the pathogenesis of bronchial asthma - not only in the chronic inflammatory processes, but also in acute asthma attack exacerbation. These findings suggest a possible role for MCP-1 in the pathogenesis of asthma and a potential role for its use in anti-asthma treatment in the future.

Potent and selective CC-chemokine receptor-2 (CCR2) antagonists as a potential treatment for asthma

A number of compounds bearing a quaternary ammonium moiety were found to be antagonists with nanomolar binding affinity for the chemokine receptor-2. The structure-activity relationships in the series are described herein along with some detailed characterization of the interesting compounds.

N-Benzylindole-2-carboxylic acids: potent functional antagonists of the CCR2b chemokine receptor

Screening of the corporate database led to the discovery of a novel series of N-benzylindole-2-carboxylic acid CCR2b chemokine receptor antagonists. These compounds demonstrate high affinity and functional inhibition of the CCR2b receptor. A discussion of the structure-activity relationships is presented, together with evidence for a highly selective receptor binding profile.

Both allergen-specific CD4 and CD8 Type 2 T cells decreased in asthmatic children with immunotherapy

Allergen-specific immunotherapy (IT) has been used for the treatment of atopic diseases since the turn of this century. The precise working mechanisms, however, remain to be clarified. The aim of this study was to investigate the role of particular subsets of allergen-specific T cells in the non-atopic individuals, untreated asthmatic children and the asthmatic children receiving immunotherapy. We collected peripheral blood from 16 untreated asthmatic children and 17 asthmatic children receiving immunotherapy over one and half years. All the patients were sensitive to mite allergen. Peripheral blood mononuclear cells (PBMC) were isolated and, in vitro, stimulated with crude mite extract to enrich the mite-specific T-cell population. After 14 days, the enriched mite-specific T cells were stimulated with phorbol-12-myristate-13-acetate (PMA) and ionomycin for intracellular detection of cytokines such as IFN-gamma, IL-4 in CD4+ and CD8+ T lymphocytes. The data here demonstrated that the levels of mite-specific IgG4 and IgA increased significantly in asthmatic children after immunotherapy. In addition, both IL-4 expressing CD4+ and CD8+ T cells were significantly lower in asthmatic children after immunotherapy compared with those of before treatment and the normal control (p < 0.05). In contrast, the frequency of IFN-gamma expressing CD4+ and CD8+ T cells did not significantly differ between untreated and SIT-treated groups. All these data suggested that decreased Type 2 CD4+ and CD8+ T cells might be closely correlated with the regulatory mechanisms of immunotherapy.

Reduced expression of CD69 and adhesion molecules of T lymphocytes in asthmatic children receiving immunotherapy

T lymphocytes play a fundamental role in the initiation and regulation of chronic inflammatory responses in patients with asthma. CD69 is an early marker of T-cell activation. The levels of intercellular adhesion molecule-1 (ICAM-1, CD54) and L-selectin have been reported to increase in patients with allergic diseases and asthma. The present study was therefore undertaken to investigate the expression of CD69, CD54, and L-selectin by T lymphocytes of children with asthma, before and after immunotherapy. Eighteen children newly diagnosed with asthma, 11 good and nine poor responders to immunotherapy, and 16 normal subjects, were enrolled in this study. The percentages of CD69+, CD54+, and CD62L+ cells in T lymphocytes were measured by using flow cytometry. The levels of CD69, CD54, and CD62L in serum and culture supernatants were determined by using enzyme-linked immunosorbent assay (ELISA). The expression of CD69 and CD54 on CD3+ T lymphocytes was significantly higher in children with asthma than in control patients. All the patient groups expressed (spontaneously and following stimulation with phorbol myristate acetate and ionomycin together with mite-extract proteins) greater amounts of CD69 and CD54 than did control subjects. With long-term immunotherapy, the percentages of CD69+ and CD54+ T lymphocytes were significantly lower in patients with a good response to immunotherapy. Our results also showed significantly lower serum L-selectin levels following immunotherapy. In conclusion, successful immunotherapy resulted in decreased expression and production of CD69 and CD54. These results may explain, in part, the clinical efficacy of immunotherapy.

The generation and characterisation of antagonist RNA aptamers to MCP-1

Monocyte chemoattractant protein-1 (MCP-1) has been implicated as a powerful pro-inflammatory mediator and may represent a potentially important, therapeutic opportunity for treatment of inflammatory disease and atherosclerosis. To further investigate the role of MCP-1 in inflammatory disorders we have isolated a series of RNA aptamers that bind specifically to mouse MCP-1. The highest affinity aptamers, designated ADR7 and ADR22, have been functionally characterised in vitro and in cell based assays. ADR7 and ADR22 have an affinity of 180 pM and 370 pM respectively for mouse MCP-1, they can antagonise MCP-1 binding to heparin and specifically antagonise MCP-1 induced chemotaxis in a cell based assay. An interesting feature of ADR22 but not ADR7 is that it is capable of antagonising the function of human MCP-1, demonstrating the high level of specificity of these aptamers and that the aptamers recognise MCP-1 in different ways. The aptamers may be used as a tool to further investigate the role of MCP-1 in inflammatory disorders and may also have a role as a therapeutic agent.

Identification of the binding site for a novel class of CCR2b chemokine receptor antagonists: binding to a common chemokine receptor motif within the helical bundle

Monocyte chemoattracant-1 (MCP-1) stimulates leukocyte chemotaxis to inflammatory sites, such as rheumatoid arthritis, atherosclerosis, and asthma, by use of the MCP-1 receptor, CCR2, a member of the G-protein-coupled seven-transmembrane receptor superfamily. These studies identified a family of antagonists, spiropiperidines. One of the more potent compounds blocks MCP-1 binding to CCR2 with a K(d) of 60 nm, but it is unable to block binding to CXCR1, CCR1, or CCR3. These compounds were effective inhibitors of chemotaxis toward MCP-1 but were very poor inhibitors of CCR1-mediated chemotaxis. The compounds are effective blockers of MCP-1-driven inhibition of adenylate cyclase and MCP-1- and MCP-3-driven cytosolic calcium influx; the compounds are not agonists for these pathways. We showed that glutamate 291 (Glu(291)) of CCR2 is a critical residue for high affinity binding and that this residue contributes little to MCP-1 binding to CCR2. The basic nitrogen present in the spiropiperidine compounds may be the interaction partner for Glu(291), because the basicity of this nitrogen was essential for affinity; furthermore, a different class of antagonists, a class that does not have a basic nitrogen (2-carboxypyrroles), were not affected by mutations of Glu(291). In addition to the CCR2 receptor, spiropiperidine compounds have affinity for several biogenic amine receptors. Receptor models indicate that the acidic residue, Glu(291), from transmembrane-7 of CCR2 is in a position similar to the acidic residue contributed from transmembrane-3 of biogenic amine receptors, which may account for the shared affinity of spiropiperidines for these two receptor classes. The models suggest that the acid-base pair, Glu(291) to piperidine nitrogen, anchors the spiropiperidine compound within the transmembrane ovoid bundle. This binding site may overlap with the space required by MCP-1 during binding and signaling; thus the small molecule ligands act as antagonists. An acidic residue in transmembrane region 7 is found in most chemokine receptors and is rare in other serpentine receptors. The model of the binding site may suggest ways to make new small molecule chemokine receptor antagonists, and it may rationalize the design of more potent and selective antagonists.

Identification of surface residues of the monocyte chemotactic protein 1 that affect signaling through the receptor CCR2

The CC chemokine, monocyte chemotactic protein, 1 (MCP-1) functions as a major chemoattractant for T-cells and monocytes by interacting with the seven-transmembrane G protein-coupled receptor CCR2. To identify which residues of MCP-1 contribute to signaling though CCR2, we mutated all the surface-exposed residues to alanine and other amino acids and made some selective large changes at the amino terminus. We then characterized the impact of these mutations on three postreceptor pathways involving inhibition of cAMP synthesis, stimulation of cytosolic calcium influx, and chemotaxis. The results highlight several important features of the signaling process and the correlation between binding and signaling: The amino terminus of MCP-1 is essential as truncation of residues 2-8 ([1+9-76]hMCP-1) results in a protein that cannot stimulate chemotaxis. However, the exact peptide sequence may be unimportant as individual alanine mutations or simultaneous replacement of residues 3-6 with alanine had little effect. Y13 is also important and must be a large nonpolar residue for chemotaxis to occur. Interestingly, both Y13 and [1+9-76]hMCP-1 are high-affinity binders and thus affinity of these mutants is not correlated with ability to promote chemotaxis. For the other surface residues there is a strong correlation between binding affinity and agonist potency in all three signaling pathways. Perhaps the most interesting observation is that although Y13A and [1+9-76]hMCP are antagonists of chemotaxis, they are agonists of pathways involving inhibition of cAMP synthesis and, in the case of Y13A, calcium influx. These results demonstrate that these two well-known signaling events are not sufficient to drive chemotaxis. Furthermore, it suggests that specific molecular features of MCP-1 induce different conformations in CCR2 that are coupled to separate postreceptor pathways. Therefore, by judicious design of antagonists, it should be possible to trap CCR2 in conformational states that are unable to stimulate all of the pathways required for chemotaxis.

Identification of residues in the monocyte chemotactic protein-1 that contact the MCP-1 receptor, CCR2

The CC chemokine, MCP-1, has been identified as a major chemoattractant for T cells and monocytes, and plays a significant role in the pathology of inflammatory diseases. To identify the regions of MCP-1 that contact its receptor, CCR2, we substituted all surface-exposed residues with alanine. Some residues were also mutated to other amino acids to identify the importance of charge, hydrophobicity, or aromaticity at specific positions. The binding affinity of each mutant for CCR2 was assayed with THP-1 and CCR2-transfected CHL cells. The majority of point mutations had no effect. Residues at the N-terminus of the protein, known to be crucial for signaling, contribute less than a factor of 10 to the binding affinity. However, two clusters of primarily basic residues (R24, K35, K38, K49, and Y13), separated by a 35 A hydrophobic groove, reduced the level of binding by 15-100-fold. A peptide fragment encompassing residues 13-35 recapitulated some of the mutational data derived from the intact protein. It exhibited modest binding as a linear peptide and dramatically improved affinity when the region which adopts a single turn of a 3(10)-helix in the protein, which includes R24, was constrained by a disulfide bond. Additional constraints at the ends of the peptide, corresponding to the disulfide between the first and third cysteines in MCP-1, yielded further improvements in affinity. Together, these data suggest a model in which a large surface area of MCP-1 contacts the receptor, and the accumulation of a number of weak interactions results in the 35 pM affinity observed for the wild-type (WT) protein. The receptor binding site of MCP-1 also is significantly different from the binding sites of RANTES and IL-8, providing insight into the issue of receptor specificity. It was previously shown that the N-terminus of CCR2 is critical for binding MCP-1 [Monteclaro, F. S., and Charo, I. F. (1996) J. Biol. Chem. 271, 19084-92; Monteclaro, F. S., and Charo, I. F. (1997) J. Biol. Chem. 272, 23186-90]. Point mutations of six acidic residues in this region of the receptor were made to test their role in ligand binding. This identified D25 and D27 of the DYDY motif as being important. On the basis of our data, we propose a model in which the receptor N-terminus lies along the hydrophobic groove in an extended fashion, placing the DYDY motif near the basic cluster involving R24 and K49 of MCP-1. This in turn orients the signaling residues (Y13 and the N-terminus) for productive interaction with the receptor.

Increased levels in vivo of mRNAs for IL-8 and macrophage inflammatory protein-1 alpha (MIP-1 alpha), but not of RANTES mRNA in peripheral blood mononuclear cells of patients with atopic dermatitis (AD)

Chemokines play an important role in the selective movement of leucocytes into inflammatory areas and they also activate various cells in inflamed tissues. However, it is unclear which cells are the main sources of chemokines in actual inflammatory diseases, even though both mononuclear cells and non-inflammatory resident cells are able to produce chemokines in vitro and the former cells are also the main target of chemokines. To clarify the roles of chemokines that are produced by mononuclear cells in AD, we measured levels in vivo of mRNA for IL-8 and MIP-1 alpha, as well as the level of regulated upon activation normal T cell expressed and secreted (RANTES) mRNA in freshly isolated peripheral blood mononuclear cells from patients with AD. We compared the results with those from psoriatic patients, and patients without AD who were suffering from other cutaneous diseases and eosinophilia. Levels of mRNAs were determined by semiquantitative reverse transcriptase-polymerase chain reactions. Levels of IL-8 and MIP-1 alpha mRNA were elevated not only in atopic patients but also in non-atopic patients with inflammatory skin disease associated with eosinophilia, compared with levels in psoriatic patients and healthy controls. Levels of RANTES mRNA were similar in atopic patients but they were lower in the other two groups of patients when compared with levels in healthy controls. In atopic patients, the levels of both IL-8 and MIP-1 alpha mRNAs but not of RANTES mRNA decreased with improvements in symptom scores after therapy. These findings suggest that mononuclear cells are not only the target of chemokines but might also play an important role in the pathogenesis of AD by producing IL-8 and MIP-1 alpha.

Comparison between the in vitro cytokine production of mononuclear cells of young asthmatics with and without immunotherapy (IT)

BACKGROUND

The underlying mechanisms of immunotherapy (IT) are still unknown but may be related to modifications of cytokine production of T lymphocytes.

OBJECTIVE

In this study we determined the in vitro allergen-induced production of IL-2, IL-4, IL-5, IL-12 and IFNgamma of peripheral blood mononuclear cells (PBMC) of eight young asthmatics, aged 15+/-2 years, receiving IT (IT group) and of eight comparable asthmatics, aged 13+/-3.5 years, who never received IT (non-IT group).

METHODS

All patients suffered from perennial asthma and were allergic to house dust mite (HDM). They were selected if they showed a positive stimulation index (SI) of PBMC after in vitro incubation with HDM (i.e. SI > 2). Cells were incubated with and without HDM (10 microg/mL) during 24 h, 48 h and 7 days. Cytokines were determined in the supernatant at the three time points and are expressed as median values in pg/mL.

RESULTS

In the IT group the secretion of IL-2 was lower compared with the non-IT group after 7 days incubation of PBMC with HDM (0 vs 33.2, P = 0.008). In both groups maximal secretion of IL-2 was observed after 48 h. In the non-IT group a high value of IL-2 persisted after 7 days, whereas in the IT group a significant decline of IL-2 occurred after 7 days. Although IL-4 secretion was low in all subjects, more patients of the non-IT group showed detectable IL-4 in the HDM cultures after 24 h and 48 h, although the difference was not statistically significant (P = 0.08 and P = 0.28, respectively). Furthermore, IL-4 secretion was lower in the HDM cultures after 24 h in the IT group (1.75 vs 4.1, P = 0.011) and 48 h (2.2 vs 4.1, P=0.035). IL-5 secretion was lower in the HDM cultures after 24h (12.4 vs 47.6, P = 0.035) and 48 h (26.8 vs 135, P = 0.046) in the IT group than in the non-IT group. After 7 days of incubation with HDM there was no difference between the groups. There was no difference between both groups in secretion of IFNgamma and IL-12.

CONCLUSIONS

These results show a difference in vitro cytokine secretion of PBMC of asthmatics receiving IT compared with asthmatics who never received IT. PBMC of patients receiving IT secrete less IL-2 and IL-5 after in vitro incubation with HDM and show a tendency to secrete less IL-4. The efficacy of IT may be attributed to a modified cytokine secretion of PBMC.

Immunologic changes during immunotherapy in asthmatic children: increased IL-13 and allergen-specific IgG4 antibody levels

BACKGROUND

The prevalence of allergic diseases such as asthma, allergic rhinitis, and atopic diseases has increased in recent years. Immunotherapy with allergens is a treatment documented to have an effect on regulating cytokine production and allergen-specific antibody production.

OBJECTIVE

The aim of this study was to further investigate immunologic changes during immunotherapy and to explore the possible more efficient approach of immunotherapy.

METHODS

Asthmatic children receiving house dust mite immunotherapy were followed to learn immunologic parameters such as allergen-specific antibody levels, proliferative response of peripheral blood mononuclear cells, and cytokine change during immunotherapy.

RESULTS

The data suggested (1) IgG4 anti-mite antibody increased 8 months after immunotherapy while IgE antibody level remained the same; (2) allergen-induced, in vitro production of certain cytokines such as IL-4 and IL-10 decreased after immunotherapy; (3) IL-13 (which can induce IgG4 and IgE antibody production by B cells) increased after immunotherapy.

CONCLUSION

Although this needs more study, IL-13 might play an important role in the generation of IgG4-blocking antibody during immunotherapy.