Flow Cytometry-Based Assay to Detect Alpha Galactosidase Enzymatic Activity at the Cellular Level

BACKGROUND

Fabry disease is a progressive, X chromosome-linked lysosomal storage disorder with multiple organ dysfunction. Due to the absence or reduced activity of alpha-galactosidase A (AGAL), glycosphingolipids, primarily globotriaosyl-ceramide (Gb3), concentrate in cells. In heterozygous women, symptomatology is heterogenous and currently routinely used fluorometry-based assays measuring mean activity mostly fail to uncover AGAL dysfunction. The aim was the development of a flow cytometry assay to measure AGAL activity in individual cells.

METHODS

Conventional and multispectral imaging flow cytometry was used to detect AGAL activity. Specificity was validated using the GLA knockout (KO) Jurkat cell line and AGAL inhibitor 1-deoxygalactonojirimycin. The GLA KO cell line was generated via CRISPR-Cas9-based transfection, validated with exome sequencing, gene expression and substrate accumulation.

RESULTS

Flow cytometric detection of specific AGAL activity is feasible with fluorescently labelled Gb3. In the case of Jurkat cells, a substrate concentration of 2.83 nmol/mL and 6 h of incubation are required. Quenching of the aspecific exofacial binding of Gb3 with 20% trypan blue solution is necessary for the specific detection of lysosomal substrate accumulation.

CONCLUSION

A flow cytometry-based assay was developed for the quantitative detection of AGAL activity at the single-cell level, which may contribute to the diagnosis of Fabry patients.

mRNA-LNP COVID-19 Vaccine Lipids Induce Complement Activation and Production of Proinflammatory Cytokines: Mechanisms, Effects of Complement Inhibitors, and Relevance to Adverse Reactions

A small fraction of people vaccinated with mRNA-lipid nanoparticle (mRNA-LNP)-based COVID-19 vaccines display acute or subacute inflammatory symptoms whose mechanism has not been clarified to date. To better understand the molecular mechanism of these adverse events (AEs), here, we analyzed in vitro the vaccine-induced induction and interrelations of the following two major inflammatory processes: complement (C) activation and release of proinflammatory cytokines. Incubation of Pfizer-BioNTech's Comirnaty and Moderna's Spikevax with 75% human serum led to significant increases in C5a, sC5b-9, and Bb but not C4d, indicating C activation mainly via the alternative pathway. Control PEGylated liposomes (Doxebo) also induced C activation, but, on a weight basis, it was ~5 times less effective than that of Comirnaty. Viral or synthetic naked mRNAs had no C-activating effects. In peripheral blood mononuclear cell (PBMC) cultures supplemented with 20% autologous serum, besides C activation, Comirnaty induced the secretion of proinflammatory cytokines in the following order: IL-1α < IFN-γ < IL-1β < TNF-α < IL-6 < IL-8. Heat-inactivation of C in serum prevented a rise in IL-1α, IL-1β, and TNF-α, suggesting C-dependence of these cytokines' induction, although the C5 blocker Soliris and C1 inhibitor Berinert, which effectively inhibited C activation in both systems, did not suppress the release of any cytokines. These findings suggest that the inflammatory AEs of mRNA-LNP vaccines are due, at least in part, to stimulation of both arms of the innate immune system, whereupon C activation may be causally involved in the induction of some, but not all, inflammatory cytokines. Thus, the pharmacological attenuation of inflammatory AEs may not be achieved via monotherapy with the tested C inhibitors; efficacy may require combination therapy with different C inhibitors and/or other anti-inflammatory agents.

Role of anti-polyethylene glycol (PEG) antibodies in the allergic reactions to PEG-containing Covid-19 vaccines: Evidence for immunogenicity of PEG

A small fraction of recipients who receive polyethylene-glycol (PEG)-containing COVID-19 mRNA-LNP vaccines (Comirnaty and Spikevax) develop hypersensitivity reactions (HSRs) or anaphylaxis. A causal role of anti-PEG antibodies (Abs) has been proposed, but not yet been proven in humans.We used ELISA for serial measurements of SARS-CoV-2 neutralizing Ab (anti-S) and anti-PEG IgG/IgM Ab levels before and after the first and subsequent booster vaccinations with mRNA-LNP vaccines in a total of 291 blood donors. The HSRs in 15 subjects were graded and correlated with anti-PEG IgG/IgM, just as the anti-S and anti-PEG Ab levels with each other. The impacts of gender, allergy, mastocytosis and use of cosmetics were also analyzed. Serial testing of two or more plasma samples showed substantial individual variation of anti-S Ab levels after repeated vaccinations, just as the levels of anti-PEG IgG and IgM, which were over baseline in 98-99 % of unvaccinated individuals. About 3-4 % of subjects in the strongly left-skewed distribution had 15-45-fold higher values than the median, referred to as anti-PEG Ab supercarriers. Both vaccines caused significant rises of anti-PEG IgG/IgM with >10-fold rises in about ∼10 % of Comirnaty, and all Spikevax recipients. The anti-PEG IgG and/or IgM levels in the 15 vaccine reactors (3 anaphylaxis) were significantly higher compared to nonreactors. Serial testing of plasma showed significant correlation between the booster injection-induced rises of anti-S and anti-PEG IgGs, suggesting coupled anti-S and anti-PEG immunogenicity.Conclusions: The small percentage of people who have extremelevels of anti-PEG Ab in their blood may be at increased risk for HSRs/anaphylaxis to PEGylated vaccines and other PEGylated injectables. This risk might be further increased by the anti-PEG immunogenicity of these vaccines. Screening for anti-PEG Ab "supercarriers" may help predicting reactors and thus preventing these adverse phenomena.

Mini-Factor H Modulates Complement-Dependent IL-6 and IL-10 Release in an Immune Cell Culture (PBMC) Model: Potential Benefits Against Cytokine Storm

Cytokine storm (CS), an excessive release of proinflammatory cytokines upon overactivation of the innate immune system, came recently to the focus of interest because of its role in the life-threatening consequences of certain immune therapies and viral diseases, including CAR-T cell therapy and Covid-19. Because complement activation with subsequent anaphylatoxin release is in the core of innate immune stimulation, studying the relationship between complement activation and cytokine release in an in vitro CS model holds promise to better understand CS and identify new therapies against it. We used peripheral blood mononuclear cells (PBMCs) cultured in the presence of autologous serum to test the impact of complement activation and inhibition on cytokine release, testing the effects of liposomal amphotericin B (AmBisome), zymosan and bacterial lipopolysaccharide (LPS) as immune activators and heat inactivation of serum, EDTA and mini-factor H (mfH) as complement inhibitors. These activators induced significant rises of complement activation markers C3a, C4a, C5a, Ba, Bb, and sC5b-9 at 45 min of incubation, with or without ~5- to ~2,000-fold rises of IL-1α, IL-1β, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13 and TNFα at 6 and 18 h later. Inhibition of complement activation by the mentioned three methods had differential inhibition, or even stimulation of certain cytokines, among which effects a limited suppressive effect of mfH on IL-6 secretion and significant stimulation of IL-10 implies anti-CS and anti-inflammatory impacts. These findings suggest the utility of the model for in vitro studies on CS, and the potential clinical use of mfH against CS.

Anti-PEG antibodies: Properties, formation, testing and role in adverse immune reactions to PEGylated nano-biopharmaceuticals

Conjugation of polyethylene glycols (PEGs) to proteins or drug delivery nanosystems is a widely accepted method to increase the therapeutic index of complex nano-biopharmaceuticals. Nevertheless, these drugs and agents are often immunogenic, triggering the rise of anti-drug antibodies (ADAs). Among these ADAs, anti-PEG IgG and IgM were shown to account for efficacy loss due to accelerated blood clearance of the drug (ABC phenomenon) and hypersensitivity reactions (HSRs) entailing severe allergic symptoms with occasionally fatal anaphylaxis. In addition to recapitulating the basic information on PEG and its applications, this review expands on the physicochemical factors influencing its immunogenicity, the prevalence, features, mechanism of formation and detection of anti-PEG IgG and IgM and the mechanisms by which these antibodies (Abs) induce ABC and HSRs. In particular, we highlight the in vitro, animal and human data attesting to anti-PEG Ab-induced complement (C) activation as common underlying cause of both adverse effects. A main message is that correct measurement of anti-PEG Abs and individual proneness for C activation might predict the rise of adverse immune reactions to PEGylated drugs and thereby increase their efficacy and safety.

Pseudo-anaphylaxis to Polyethylene Glycol (PEG)-Coated Liposomes: Roles of Anti-PEG IgM and Complement Activation in a Porcine Model of Human Infusion Reactions

Polyethylene glycol (PEG)-coated nanopharmaceuticals can cause mild to severe hypersensitivity reactions (HSRs), which can occasionally be life threatening or even lethal. The phenomenon represents an unsolved immune barrier to the use of these drugs, yet its mechanism is poorly understood. This study showed that a single i.v. injection in pigs of a low dose of PEGylated liposomes (Doxebo) induced a massive rise of anti-PEG IgM in blood, peaking at days 7-9 and declining over 6 weeks. Bolus injections of PEG-liposomes during seroconversion resulted in anaphylactoid shock (pseudo-anaphylaxis) within 2-3 min, although similar treatments of naı̈ve animals led to only mild hemodynamic disturbance. Parallel measurement of pulmonary arterial pressure (PAP) and sC5b-9 in blood, taken as measures of HSR and complement activation, respectively, showed a concordant rise of the two variables within 3 min and a decline within 15 min, suggesting a causal relationship between complement activation and pulmonary hypertension. We also observed a rapid decline of anti-PEG IgM in the blood within minutes, increased binding of PEGylated liposomes to IgM⁺ B cells in the spleen of immunized animals compared to control, and increased C3 conversion by PEGylated liposomes in the serum of immunized pigs. These observations taken together suggest rapid binding of anti-PEG IgM to PEGylated liposomes, leading to complement activation via the classical pathway, entailing anaphylactoid shock and accelerated blood clearance of liposome-IgM complexes. These data suggest that complement activation plays a causal role in severe HSRs to PEGylated nanomedicines and that pigs can be used as a hazard identification model to assess the risk of HSRs in preclinical safety studies.

Involvement of complement activation in the pulmonary vasoactivity of polystyrene nanoparticles in pigs: unique surface properties underlying alternative pathway activation and instant opsonization

Background

It has been proposed that many hypersensitivity reactions to nanopharmaceuticals represent complement (C)-activation-related pseudoallergy (CARPA), and that pigs provide a sensitive animal model to study the phenomenon. However, a recent study suggested that pulmonary hypertension, the pivotal symptom of porcine CARPA, is not mediated by C in cases of polystyrene nanoparticle (PS-NP)-induced reactions.

Goals

To characterize PS-NPs and reexamine the contribution of CARPA to their pulmonary reactivity in pigs.

Study design

C activation by 200, 500, and 750 nm (diameter) PS-NPs and their opsonization were measured in human and pig sera, respectively, and correlated with hemodynamic effects of the same NPs in pigs in vivo.

Methods

Physicochemical characterization of PS-NPs included size, ζ-potential, cryo-transmission electron microscopy, and hydrophobicity analyses. C activation in human serum was measured by ELISA and opsonization of PS-NPs in pig serum by Western blot and flow cytometry. Pulmonary vasoactivity of PS-NPs was quantified in the porcine CARPA model.

Results

PS-NPs are monodisperse, highly hydrophobic spheres with strong negative surface charge. In human serum, they caused size-dependent, significant rises in C3a, Bb, and sC5b-9, but not C4d. Exposure to pig serum led within minutes to deposition of C5b-9 and opsonic iC3b on the NPs, and opsonic iC3b fragments (C3dg, C3d) also appeared in serum. PS-NPs caused major hemodynamic changes in pigs, primarily pulmonary hypertension, on the same time scale (minutes) as iC3b fragmentation and opsonization proceeded. There was significant correlation between C activation by different PS-NPs in human serum and pulmonary hypertension in pigs.

Conclusion

PS-NPs have extreme surface properties with no relevance to clinically used nanomedicines. They can activate C via the alternative pathway, entailing instantaneous opsonization of NPs in pig serum. Therefore, rather than being solely C-independent reactivity, the mechanism of PS-NP-induced hypersensitivity in pigs may involve C activation. These data are consistent with the “double-hit” concept of nanoparticle-induced hypersensitivity reactions involving both CARPA and C-independent pseudoallergy.

Immunocompatibility of Rad-PC-Rad liposomes in vitro, based on human complement activation and cytokine release

Liposomal drug delivery systems can protect pharmaceutical substances and control their release. Systemic administration of liposomes, however, often activate the innate immune system, resulting in hypersensitivity reactions. These pseudo-allergic reactions can be interpreted as activating the complement system. Complement activation destroys and eliminates foreign substances, either directly through opsonization and the formation of the membrane attack complex (MAC), or by activating leukocytes and initiating inflammatory responses via mediators, such as cytokines. In this study, we investigated the in vitro immune toxicity of the recently synthesized Rad-PC-Rad liposomes, analyzing the liposome-induced complement activation. In five human sera, Rad-PC-Rad liposomes did not induce activation, but in one serum high sensitivity via alternative pathway was detected. Such a behavior in adverse phenomena is characteristic for patient-to-patient variation and, thus, the number of donors should be in the order of hundreds rather than tens, hence the present study based on six donors is preliminary. In order to further prove the suitability of mechano-responsive Rad-PC-Rad liposomes for clinical trials, the production of pro-inflammatory cytokines was examined by human white blood cells. The concentrations of the pro-inflammatory cytokines, IL-6, IL-12p70, TNF-α, and IL-1β, induced by Rad-PC-Rad liposomal formulations, incubated with whole blood samples, were smaller or comparable to saline (negative control). Because of this favorable in vitro hemo-compatibility, in vivo investigations using these mechano-responsive liposomes should be designed.

Increased synthesis of vascular endothelial growth factor in allergic airway inflammation in histidine decarboxylase knockout (HDC(-/-)) mice

Histamine and vascular endothelial growth factor (VEGF) have been implicated in the pathogenesis of allergic asthma; they enhance inflammation, vascular permeability, and mucus secretion. Histamine was suggested to alter the level of VEGF via the H2 receptors. Here the authors have applied histidine decarboxylase gene-targeted (HDC(-/-)) mice, lacking histamine, to investigate the effect of histamine deficiency on VEGF expression in an animal model of asthma. HDC(-/-) and wild-type (WT) mice were sensitized and challenged with ovalbumin (OVA). VEGF mRNA expression and protein level were determined in the lung. Number of VEGF-positive immune cells of bronchoalveolar lavage (BAL) and their intracellular VEGF content were measured by flow cytometry. VEGF protein level in the lung and in the BAL cells was increased in OVA treated (HDC(-/-)(ova) as well as in WT(ova)) animals compared to their controls. However, there was no difference in the VEGF levels between HDC(-/-) or WT animals, either in the lung or in the BAL cells. In conclusion, increased VEGF production of the lung or BAL immune cells can be induced by allergen provocation independently from the genetic background of the animals. These data suggest that VEGF-mediated allergic processes can persist in the absence of histamine.

Galectin-9 in allergic airway inflammation and hyper-responsiveness in mice

BACKGROUND

Galectin-9 (Gal-9) is a member of the growing family of beta-galactoside-binding lectins. Gal-9 is an eosinophil chemoattractant and inducer of Th1 cell apoptosis. These effects suggest its potential role in the pathogenesis of asthma. Our aim was to study the expression of Gal-9 in an ovalbumin (OVA)-induced mouse model of allergic asthma.

METHODS

To investigate the significance of Gal-9 in allergic inflammation and airway hyperresponsiveness (AHR), a group of BALB/c mice was sensitized and challenged with OVA (G(OVA)). Another group of animals was allergized with OVA and also treated with dexamethasone (DEX) (G(OVA+DEX)). The control group (G(PBS)) received phosphate-buffered saline instead of OVA as placebo. Airway reactivity to intravenous methacholine was assessed.

RESULTS

The percentage of Gal-9-positive cells and their intracellular Gal-9 content and Th1/Th2 cytokine levels in the bronchoalveolar lavage (BAL) were determined by flow cytometry. Gal-9 mRNA expression and protein level were measured in the lung tissue by real-time RT-PCR and Western blot. In G(OVA )mice, airway inflammation and mucus hypersecretion developed. DEX treatment inhibited the main features of experimental asthma. The number of Gal-9-positive lymphocytes, eosinophil and neutrophil granulocytes and the levels of Th2 cytokines were higher in the BAL of G(OVA) compared to G(PBS) or G(OVA+DEX )mice. Moreover, Gal-9 protein level was elevated in the lungs of G(OVA) mice.

CONCLUSIONS

These results suggest that Gal-9 plays a role as a mediator contributing to the development of allergic airway inflammation. Gal-9 may serve as a recruiter of eosinophil granulocytes and promoter of Th2 dominance.

Seasonal changes of proapoptotic soluble Fas ligand level in allergic rhinitis combined with asthma

The function of apoptosis is to eliminate unnecessary or dangerous cells. The balance between production and death is important in the control of cell numbers within physiological ranges. Cells involved in allergic reactions may have altered apoptosis. The aim of this study was to examine the seasonal changes of programmed cell death in children with pollen allergy. We measured serum levels of soluble Fas (sFas) and soluble Fas ligand (sFasL), and examined whether there was any correlation between soluble apoptosis markers and development of asthma and or rhinitis in children with pollen allergy. We examined two groups of patients with ragweed pollen allergy. The first group consisted of 17 children with 'rhinitis only'. The second group consisted of 16 children with 'asthma + rhinitis'. For seasonal analysis we pooled the two groups and termed this the 'ragweed sensitive' group (n = 33, 5-18 yr, 25 boys, eight girls). Measurements (sFas and sFasL) were taken during the ragweed pollen allergy season, while control measurements were performed during the symptom-free period. There was no difference in sFas levels measured during and after [1941 +/- 68, 1963 +/- 83 pg/ml (mean+/-s.e.m, respectively)] the pollen season in the 'ragweed sensitive' group. The sFasL level showed seasonal change, which was significantly higher (p = 0.0086) in the symptomatic period compared to the symptom-free state (99 +/- 13 and 53 +/- 16 pg/ml, respectively). There was a difference between the 'rhinitis only' and the 'asthma + rhinitis' groups in the measured parameters of apoptosis. Children having allergic rhinitis combined with asthma had a significantly (p = 0.03) higher sFas level in the symptom-free state than the 'rhinitis only' group did (2115 +/- 156 and 1820 +/- 52 pg/ml, respectively). During the allergic symptom state the sFasL level of the 'asthma + rhinitis' group was significantly higher (p = 0.025) than that of the 'rhinitis only' group (125 +/- 20 and 75 +/- 14 pg/ml, respectively). In conclusion, the increased level of sFasL during the pollen season may signal its role in the pathogenesis of allergic airway diseases. There was no seasonal change in sFas levels in the examined ragweed allergic group, however in the symptomatic period we observed a diminished level of antiapoptotic factor (sFas) and an elevated level of proapoptotic factor (sFasL) if there was a combined disease with pollen allergic asthma. We suggest that there is a deviation in the apoptotic reaction in children that may increase the seasonal allergic inflammation.

Lipopolysaccharide exposure makes allergic airway inflammation and hyper-responsiveness less responsive to dexamethasone and inhibition of iNOS

Allergic airway disease can be refractory to anti-inflammatory treatment, whose cause is unclarified. Therefore, in the present experiment, we have tested the hypothesis that co-exposure to lipopolysacharide (Lps) and allergen results in glucocorticoid-resistant eosinophil airway inflammation and hyper-responsiveness (AHR). Ovalbumin (Ova)-sensitized BALB/c mice were primed with 10 microg intranasal Lps 24 h before the start of Ova challenges (20 min on 3 consecutive days). Dexamethasone (5 mg/kg/day) was given on the last 2 days of Ova challenges. AHR, cellular build-up, cytokine and nitrite concentrations of bronchoalveolar lavage fluid (BALF) and lung histology were examined. To assess the role of iNOS-derived NO in airway responsiveness, mice were treated with a selective inhibitor of this enzyme (1400W) 2 h before AHR measurements. More severe eosinophil inflammation and higher nitrite formation were found in Lps-primed than in non-primed allergized mice. After Lps priming, AHR and concentrations of T-helper type 2 cytokines in BALF were decreased, but still remained significantly higher than in controls. Eosinophil inflammation was partially, while nitrite production and AHR were observed to be largely dexamethasone resistant in Lps-primed allergized animals. 1400W effectively and rapidly diminished the AHR in Ova-sensitized and challenged mice, but failed to affect it after Lps priming plus allergization. In conclusion, Lps inhalation may exaggerate eosinophil inflammation and reduce responsiveness to anti-inflammatory treatment in allergic airway disease.

Polymorphism in the promoter region of the apolipoprotein A5 gene is associated with an increased susceptibility for coronary artery disease

Although triglycerides (TG) are a major risk factor for coronary artery disease (CAD), their exact role is still controversial. Recently, a T/C polymorphism in the promoter region of the apoA5 gene at position 1131 has been found that is associated with an increased plasma TG concentration. We investigated the role of this polymorphism in 308 Hungarian patients with CAD referred to coronary bypass surgery, and in 310 controls recruited from the same area. The prevalence of the apoA5-1131C allele was significantly higher among CAD patients than among controls (10.9% versus 5.7%; P < 0.001, Odds ratio (OR) = 1.99 (1.30-3.04)). Controls carrying the rare C allele had in average 23.0% (P < 0.001), subjects with CAD 13.8% (P < 0.001) higher TG levels compared to common allele homozygotes. The polymorphism was not associated with other conventional CAD risk factors or laboratory data of the patients. In logistic regression models adjusted for age, gender, presence of diabetes, BMI, smoking, LDL-C, HDL-C and hypertension a significantly increased risk of developing CAD was found in patients carrying the apoA5-1131C allele (P < 0.001; OR = 1.98 (1.14-3.48)), suggesting that this allele variant is an independent genetic risk factor for CAD.

No association between asthma or allergy and the CCR5Delta 32 mutation

AIMS

To investigate whether the presence of the CCR5Delta32 allele was associated with atopy or asthma.

METHODS

A total of 118 children with asthma, 145 children with non-asthmatic, but allergic phenotype, and 303 children without allergic or asthmatic disorders were studied.

RESULTS

There were no significant differences in the frequency of CCR5Delta32, or in the distributions of genotypes between the groups. The relative eosinophil blood count was slightly lower in patients with heterozygous genotype, than in patients with wild type genotype.

CONCLUSION

No association was found between the susceptibility of allergy or asthma and the functional deficient CCR5Delta32 allele.

[Genomic approach to allergic diseases: present and future perspectives]

The rapid advances in genomic research have a major impact on biomedical sciences. In this review the authors summarize the current results of the genomic investigation of allergic diseases. From a genetic point of view allergy is multifactorial, which means that the susceptibility to the disease is determined by interactions between multiple genes, and involve important nongenetic factors such as the environment for their expression. There are two widespread methods for searching for disease susceptibility genes in allergy: (1) genome-wide search and (2) candidate gene association studies. Until now five groups have completed genome-wide searches for asthma, and almost 500 genetic linkage and association studies have reported more than 500 atopy and asthma loci throughout the genome. In this review we selected those results, which were consistently confirmed by several independent studies, or appeared particularly important, or interesting. On the basis of this, 9 chromosome regions can be associated with the susceptibility to allergic diseases: 2q, 5q31-q33, 6p21.3, 7q31, 11q13, 12q14.3-q24.31, 14q11.2-q13, 16p21, 17q11.2. According to the results of the human genome programs, and association studies, the authors discuss the possible roles of candidate genes found in these loci in the pathomechanism of allergy. Besides, the authors summarize briefly the results of pharmacogenomics, and animal linkage and genetics studies related to allergy.

Lack of association between atopic eczema/dermatitis syndrome and polymorphisms in the promoter region of RANTES and regulatory region of MCP-1

BACKGROUND

Chemokines play an important role in the pathophysiology of atopic eczema/dermatitis syndrome (AEDS) and allergy. Recently polymorphisms in the promoter region of RANTES (regulated on activation normal T cell expressed and secreted) and in the gene regulatory region of MCP-1 (monocyte chemoattractant protein-1) have been found, which increase the expression of these chemokines. The - 403A allele of the RANTES promoter region was found associated with AEDS in German children. We investigated whether the presence of these polymorphisms was associated with AEDS or allergy in Hungarian children.

METHODS

One hundred and twenty-eight children with AEDS, 102 allergic children without AEDS and 303 children of comparable ages without allergic disorders were screened for genotype with a PCR-based assay.

RESULTS

There were no significant differences in the frequency of these polymorphisms, or in the distribution of genotypes between the groups. The total IgE concentration, the white blood cell count and the blood eosinophil cell count did not differ between the genotypes.

CONCLUSION

In this cohort of Hungarian children there was no association between - 28G, and - 403A alleles in the RANTES promoter, - 2518G polymorphism in the distal regulatory region of the MCP-1 and AEDS, or allergy.

Polymorphism in the gene regulatory region of MCP-1 is associated with asthma susceptibility and severity

BACKGROUND

Chemokines play an important role in the pathophysiology of asthma and allergy. Recently, polymorphisms in the gene regulatory region of monocyte chemoattractant protein 1 (MCP-1) and in the promoter region of RANTES have been found; these polymorphisms increase the expression of the chemokines.

OBJECTIVE

We investigated whether the presence of the polymorphisms was associated with atopy or asthma and whether these alleles influenced the severity of asthma in affected individuals.

METHODS

Three groups of subjects-160 children with asthma (disease severity being classified according to the Global Initiative for Asthma guidelines, modified for children), 151 children with nonasthmatic but allergic phenotype, and 303 children without allergic or asthmatic disorders-were screened with a PCR-based assay for genotyping.

RESULTS

The frequency of the -2518G polymorphism in the gene regulatory region of MCP-1 was significantly higher in asthmatic children than in controls (P <.001; odds ratio [OR] = 2.0 [1.4-2.6]) and nonasthmatic atopic children (P <.001; OR = 2.0 [1.4-2.9]). The MCP-1 G/G genotype correlated with asthma severity. In asthmatic children, the MCP-1 -2518G allele was also associated with an increased blood eosinophil level. The promoter polymorphisms in the RANTES gene did not have a detectable effect on the susceptibility to asthma or allergy or on the blood eosinophil count.

CONCLUSION

In this cohort of children, there are associations between carrying G at -2518 of the MCP-1 gene regulatory region and the presence of asthma as well as between asthma severity and homozygosity for the G allele. In asthmatic children, the MCP-1 -2518G polymorphism correlated with increased eosinophil levels. This variant of MCP-1 might belong to the predictor gene set for asthma.