TNFR1 mRNA expression level and TNFR1 gene polymorphisms are predictive markers for susceptibility to develop invasive pulmonary aspergillosis.

Tumour necrosis factor (TNF) is primarily secreted by monocytes/macrophages and activated T lymphocytes in response to fungal infections. TNF acts through TNF receptor 1 (TNFR1) triggering a pro-inflammatory response, and therefore plays a pivotal role in immune regulation and host immune responses. We hypothesized that single nucleotide polymorphisms (SNPs) in TNFR1 gene may influence the innate immune response against Aspergillus. Three SNPs were genotyped in 275 individuals (144 immunocompromised haematological patients with high-risk of developing IPA and 131 healthy controls): TNFR1(-383(A/C)) (rs2234649) and TNFR1(-609(G/T)) (rs4149570) in the 5 prime UTR region, and TNFR1(+36(A/G)) SNP (rs767455) in the first exon of the gene. Of the 144 haematological patients, 77 patients developed Invasive Pulmonary Aspergillosis (IPA) infection and the remaining 67 patients were not infected. TNFR1(+36(A/G)) and TNFR1(-609(G/T)) were associated with IPA susceptibility (p=0.033 and p=0.018, respectively). A role of TNFR1 genetic variants in the susceptibility of patients to develop IPA was also supported by the significantly lower TNFR1 mRNA expression level in IPA than in IPA-resistant patients and the strong correlation between the TNFR1(-609) genetic variant and the expression levels of TNFR1. There was also a tendency for a higher frequency of galactomannan (GM) positivity in patients with TNFR1(-609G/G) genotype than in patients with TNFR1(-609G/T) (p=0.0909) or TNFR1(-609T/T) (p=0.0913) genotype. Predictive sequence analysis of the effects of TNFR1(-609) promoter polymorphism revealed that this SNP might play a critical role in modifying the affinity of ICSBP/IRF-8, a transcription factor that is involved in the TNFR1-mediated activation of NFkappaB signalling pathway. Taken together, these data suggest that TNFR1 polymorphisms influence the risk of IPA disease and might be useful for risk stratification strategies. These findings need to be confirmed in validation studies with larger samples of haematological patients.

IL1 gene cluster polymorphisms and its haplotypes may predict the risk to develop invasive pulmonary aspergillosis and modulate C-reactive protein level.

OBJECTIVE: The aim of this study was to determine whether interleukin-1 alpha (IL1alpha), interleukin-1 beta (IL1beta), and IL1 receptor antagonist (IL1Ra) polymorphisms are implicated in invasive pulmonary aspergillosis (IPA) pathogenesis. MATERIALS AND METHODS: Subjects comprised 110 hematological patients and 148 healthy controls. Genotypic and allelic frequencies were similar between hematological patients and controls. IPA was diagnosed in 59 of the 110 patients according to consensus criteria published by the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group (EORTC/IFICG). RESULTS AND DISCUSSIONS: Individual locus analysis showed that IL1alpha and IL1Ra polymorphisms were not associated with the presence of IPA (p = 0.560 and p = 0.680, respectively). However, a trend towards a higher presence of IL1beta( - ) (511TT) genotype (or IL1beta(-511T) allele) in the IPA group than in the non-IPA patient group (p = 0.092 and p = 0.095, respectively) was found. Haplotype analysis revealed that VNTR2/-889C/-511T haplotype was strongly associated with susceptibility to develop IPA infection (p = 0.020). Haplotype analysis also showed an association between VNTR2/-889C/-511C haplotype and resistance to IPA infection (p = 0.028). Furthermore, patients with IL1Ra VNTR2/2 and IL1beta(-511)T/T genotypes had a higher positive serum galactomannan percentage versus patients with other genotypes. Finally, C-reactive protein (CRP) production was significantly associated with IL1 gene cluster polymorphisms, although CRP values were similar between IPA and non-IPA groups. CONCLUSION: These findings indicate a critical role of IL1 gene cluster polymorphisms in the susceptibility to IPA infection and CRP production.

Genetic variants of IL6 gene promoter influence on C-reactive protein levels but are not associated with susceptibility to invasive pulmonary aspergillosis in haematological patients.

Several lines of evidence indicate that IL6 plays a major role in the pathogenesis of a number of infectious diseases. The purpose of this study was to determine whether IL6 promoter polymorphisms were genetic markers of susceptibility to invasive pulmonary aspergillosis (IPA). To clarify the relationship between IL6 variants and IPA susceptibility, the IL6-174(G/C) and IL6-634(G/C) promoter single nucleotide polymorphisms (SNPs) were defined and plasma concentrations of IL6 and C-reactive protein (CRP) were measured. The study included 130 patients with haematological malignancies and 145 unrelated healthy individuals. No significant genotypic and allelic differences were found between patients and healthy controls. IPA was diagnosed in 71 of 130 patients according to the consensus criteria. CRP values were significantly associated with both IL6-174(G/C) and IL6-634(G/C) polymorphisms. However, IL6 and CRP values were similar between IPA and non-IPA groups. Neither IL6-174(G/C) nor IL6-634(G/C) polymorphisms were associated with IPA infection (p=0.414 and p=0.184, respectively). No evidence of association was found between allelic frequencies of IL6 promoter polymorphisms and IPA infection (p=0.864 and p=0.104, respectively). Further, no association was detected between IL6 genotypes and clinical profiles in IPA patients. Haplotype analysis also revealed that IL6 gene was not associated with IPA susceptibility in a Spanish population (Global haplotype association p value: 0.31). These findings suggest that IL6 polymorphisms influence on CRP circulating levels but are not associated with IPA susceptibility. Because the sample size is relatively small in our series, larger investigations of IL6-174(G/C)/IL6-634(G/C) genotypes and haplotypes are needed to clarify the potential role of this gene in the pathophysiology of IPA infection.

Synthesis and characterization of poly(ethyl-2-cyanoacrylate) nanoparticles with a magnetic core.

A method is described to prepare composite colloidal nanoparticles, consisting of a magnetic core (magnetite) and a biodegradable polymeric shell (poly(ethyl-2-cyanoacrylate) or PE-2-CA). The method is based on the so-called anionic polymerization procedure, often used in the synthesis of PE-2-CA nanospheres designed for drug delivery. In the present work, the heterogeneous structure of the particles can confer both magnetic-field responsiveness and potential applicability as a drug carrier. In order to investigate to what extent this target is achieved, we compare the structure, chemical composition, and surface properties of the core/shell particles with those of both the nucleus and the coating material. This preliminary study shows that the synthetic new material displays an intermediate behavior between that of magnetite and PE-2-CA spheres. Thus, electrophoresis measurements as a function of pH and as a function of KNO3 concentration, show great similarity between the core/shell and pure polymer nanoparticles. A similar conclusion is reached when a surface thermodynamic study is performed on the three types of particles: the electron-donor component of the surface free energy of the solids is the quantity that appears to be most sensitive to the surface composition. The fact that PE-2-CA is close to being a non-polar material gives rise to a measurable decrease in the electron-donor component of the surface free energy of core/shell particles as compared to magnetite.

Synthesis and Characterization of Spherical Magnetite/Biodegradable Polymer Composite Particles.

A method for preparing colloidal particles formed by a magnetite nucleus and a biodegradable poly(DL-lactide) polymer coating is first described. The method is based on the so-called double-emulsion technique, employed to obtain polymeric spheres loaded with therapeutic drugs, to be used as drug delivery vectors. The aim of this work was to obtain, in a reproducible and rather simple way, colloidal particles that were both magnetic field responsive, and useful as drug delivery systems. In order to investigate to what extent is this target achieved, we compare the structure, chemical composition, and surface properties of the composite particles with those of the nucleus and the coating material. Although the surface properties of the magnetite core are not completely masked, this preliminary study shows that the synthetic new material displays a behavior intermediate between that of magnetite and poly(DL-lactide) spheres. Thus, electrophoresis measurements as a function of pH shows that the isoelectric point (pH(iep)=5.2) of core/shell colloids is in between those of magnetite (pH(iep)=7) and polymer (pH(iep)<2). A similar conclusion is reached when a surface thermodynamic study is performed on the three types of particles: the electron-donor component of the surface free energy of the solids is the quantity that appears to be most sensitive to the surface composition. The fact that poly(DL-lactide) is close to being a nonpolar material gives rise to a measurable decrease in the electron-donor component of the surface free energy, although the effect of coating is also observable in the electron-acceptor and the apolar van der Waals component. Copyright 2001 Academic Press.

Magnetic Properties of Composite Hematite/Yttrium Oxide Colloidal Particles.

The effect of the shell thickness and density on the magnetic properties of composite colloidal particles consisting of a hematite (alpha-Fe(2)O(3)) core and an yttrium oxide (Y(2)O(3)) layer is described. Pure iron oxide colloidal spheres show two clearly different trends of variation of their magnetic susceptibility, chi(m), with temperature. Below T(M) approximately 220 K, chi(m) shows a slight increase when the particles are heated; a sharp transition is observed at such a critical temperature, whereby chi(m) increases almost 3 times in a very narrow temperature interval, decreasing slowly afterward. This is the result of a well-known transition from perfect to imperfect antiferromagnetism (canted antiferromagnetism). Three types of core/shell particles have been prepared, and a gradual change is observed in chi(m) from that of hematite to that of pure Y(2)O(3). Even the most efficiently covered particles still show a change in their chi(m)-T trends around T(M), and are clearly distinct from Y(2)O(3) particles. Magnetization curves show that coating of hematite particles induces significant changes in the coercivity of the samples. The latter is always larger for composite than for core particles. Copyright 2001 Academic Press.