Genetic basis of tobacco smoking: strong association of a specific major histocompatibility complex haplotype on chromosome 6 with smoking behavior

The genetic basis for addiction to tobacco smoking--particularly that of the perception of olfactory stimuli that may be important in reinforcing smoking addiction--is largely unknown. A cluster of genes for olfactory receptors is in close proximity to the MHC region on chromosome 6. Polymorphisms of MHC class III genes (RCCX modules, TNFA promoter polymorphisms) were determined in 101 healthy subjects and 232 coronary artery disease (CAD) patients from Hungary with defined tobacco smoking habits. A highly significant association between ever smoking (past + current smokers) and a specific MHC haplotype was observed (odds ratios = 2.14-4.13; P-values = 0.012 to <0.001). This haplotype is characterized by the presence of C4A null alleles and a solitary short C4B gene linked to the TNF2 allele of the promoter for TNFA gene. This haplotype occurred more frequently in the ever smokers than in the never smokers [odds ratio: 4.97 (1.96-12.62); P = 0.001], and such associations were stronger in women (odds ratio = 13.6) than in men (odds ratio = 2.79). An independent study of complement C4 protein polymorphism and smoking habits in Icelandic subjects (n = 351) yielded similar and confirmative results. Considering the documented link between olfactory stimuli and smoking in females, and the presence of a cluster of odorant receptor genes close to the MHC class I region, our findings implicate a potential role of the MHC-linked olfactory receptor genes in the initiation of smoking.     

Follicular lymphoma cell lines,an in vitro model for antigenic selection and cytokine-mediated growth regulation of germinal centre B cells

In the periphery, B cells differentiate in germinal centres (GCs) of secondary lymphoid organs. Isolated GC cells die quickly in vitro by apoptosis. Therefore, cell lines originating from follicular lymphomas, which are the malignant counterparts of GC B cells, would provide a stable in vitro model to study the immunobiology of GC B cells. We have established three novel human follicular lymphoma cell lines that were characterized with special reference to immunophenotypic features, response to B-cell receptor (BCR) triggering, response to cytokines and cytokine mRNA expression. One of the cell lines, HF-1A3, has a phenotype of a centrocyte. It expresses surface immunoglobulin G (sIgG) and dies by apoptosis following BCR cross-linking. Co-stimulation with interleukin-6 (IL-6), IL-15 or interferon-gamma (IFN-gamma) rescues HF-1A3 cells from BCR-induced apoptosis. The second cell line, HF-28, also represents phenotypically an IgG+ centrocyte. Ligation of its BCR leads to the cell-cycle arrest at G1 instead of apoptosis. HF-28 cells express both CD45RA and RO isoforms, which is unusual in B lymphocytes apart from plasma cells, thus suggesting a transition to plasma cell phenotype. The third cell line, HF-4.9, which phenotypically represents an sIgM+ centroblast, responds by proliferation to BCR cross-linking. These cell lines offer a unique in vitro model to study antigenic selection and cytokine-mediated growth regulation of human GC B cells.     

Quantitative comparison between two phase contrast techniques: diffraction enhanced imaging and phase propagation imaging

Two x-ray phase contrast imaging techniques are compared in a quantitative way for future mammographic applications: diffraction enhanced imaging (DEI) and phase propagation imaging (PPI). DEI involves, downstream of the sample, an analyser crystal acting as an angular filter for x-rays refracted by the sample. PPI simply uses the propagation (Fresnel diffraction) of the monochromatic and partially coherent x-ray beam over large distances. The information given by the two techniques is assessed by theoretical simulations and compared at the level of the experimental results for different kinds of samples (phantoms and real tissues). The imaging parameters such as the energy, the angular position of the analyser crystal in the DEI case or the sample to detector distance in the PPI case were varied in order to optimize the image quality in terms of contrast, visibility and figure of merit.     

Synthetic env gp41 peptide as a sensitive and specific diagnostic reagent in different stages of human immunodeficiency virus type 1 infection

An enzyme immunoassay (EIA) for serum antibodies to human immunodeficiency virus type 1 (HIV-1), based on the synthetic pentadecapeptide SGKLICT-TAVPWNAS, a segment of the transmembrane glycoprotein (gp41) of the virus, was developed and tested for sensitivity and specificity. Sera of 152 individuals at various stages of HIV-1 infection, including two prospectively and six retrospectively studied patients exposed to HIV-1 but seronegative on initial testing in whole-virus EIA and immunoblotting, were screened with the gp41 peptide antibody EIA. The reference population consisted of 1,000 healthy HIV-1 antibody-negative blood donors. In addition, five individuals with antibodies to HIV-2 were studied. Antibodies to the synthetic peptide were detected in 100% of those with asymptomatic infection. Only one patient with LAS failed to react in the peptide EIA. Patients with HIV-2 infection did not react in this test. The peptide antibodies appeared rapidly after infection, were detectable at the time when seroconversion was observed by immunoblotting, and preceded reactivity in whole-virus EIA. Sera of seven patients with verified HIV-1 infection did not react with gp41 in immunoblotting, although antibodies were readily detectable in the gp41 peptide EIA.     

Proinflammatory HLA-DRB1*01-haplotype predisposes to ST-elevation myocardial infarction

BackgroundMajor histocompatibility complex (MHC) gene region harbours haplotypes that associate with coronary artery disease (CAD). Their role in ST-elevation infarction (STEMI) or on the inflammatory level is not known.MethodsFour candidate MHC markers were analyzed by real-time quantitative PCR and constructed into haplotypes from patients with STEMI (n = 162), matched controls with no CAD (n = 319) and general population sample (n = 149). High sensitivity C-reactive protein (hsCRP) was assessed in a follow-up visit from patients (n = 86) and at inclusion from other study subjects.ResultsThe haplotype with one copy of HLA-DRB1*01, C4A, C4B but no HLA-B*35 doubled the risk of STEMI (OR = 2.15, 95%CI = 1.11–4.15, p = 0.020 for patients vs. controls, and OR = 2.26, 95%CI = 0.97–5.24, p = 0.052 for patients vs. population sample). The association between patients and controls persisted in multivariate analyses. The frequency of the haplotype was 5.86% (n = 19/324) in patients, 2.82% (n = 18/638) in controls and 2.68% (n = 8/298) in population sample. None of the individual MHC markers alone showed significant association with STEMI.In multivariate analyses, the haplotype carriers had higher hsCRP levels in patients (median 3.37 mg/L in carriers vs. 1.14 mg/L in non-carriers, p = 0.019) and in controls (median 2.90 mg/L vs. 1.21 mg/L, p = 0.009, respectively).ConclusionThe MHC haplotype associates with STEMI and elevated baseline hsCRP levels. The results are in concordance with previous data on non-STEMI patients, implying that a HLA-DRB1*01 – related haplotype increases the risk of CAD, possibly though increased inflammation.     

Psychotropic drug use in non-psychiatric departments of three European university hospitals

The use of psychotropic drugs in the university hospitals in Tartu, Estonia; Huddinge, Sweden; and Badajoz, Spain, were studied, using the defined daily doses per 100 bed-days (DDD/100 bed-days) method. The total amount of drugs used in the surgical and medical departments was 50 DDD/100 bed-days in Huddinge, versus 33 and 14 DDD/100 bed-days in Tartu and Badajoz, respectively. Barbiturates accounted for 35% of all psychotropics in Tartu but were practically not used in Huddinge. In contrast, antidepressants were practically not used in Tartu. The use of psychotropic drugs in the intensive care units was highest in Huddinge (320 DDD/100 bed-days), compared with Tartu and Badajoz (177 and 96 DDD/100 bed-days, respectively). The frequency of psychotropic drug use were strikingly different in the three hospitals studied.     

The human GIMAP5 gene has a common polyadenylation polymorphism increasing risk to systemic lupus erythematosus

Background

Several members of the GIMAP gene family have been suggested as being involved in different aspects of the immune system in different species. Recently, a mutation in the GIMAP5 gene was shown to cause lymphopenia in a rat model of autoimmune insulin‐dependent diabetes. Thus it was hypothesised that genetic variation in GIMAP5 may be involved in susceptibility to other autoimmune disorders where lymphopenia is a key feature, such as systemic lupus erythematosus (SLE).

Material and methods

To investigate this, seven single nucleotide polymorphisms in GIMAP5 were analysed in five independent sets of family‐based SLE collections, containing more than 2000 samples.

Result

A significant increase in SLE risk associated with the most common GIMAP5 haplotype was found (OR 1.26, 95% CI 1.02 to 1.54, p = 0.0033). In families with probands diagnosed with trombocytopenia, the risk was increased (OR 2.11, 95% CI 1.09 to 4.09, p = 0.0153). The risk haplotype bears a polymorphic polyadenylation signal which alters the 3′ part of GIMAP5 mRNA by producing an inefficient polyadenylation signal. This results in higher proportion of non‐terminated mRNA for homozygous individuals (p<0.005), a mechanism shown to be causal in thalassaemias. To further assess the functional effect of the polymorphic polyadenylation signal in the risk haplotype, monocytes were treated with several cytokines affecting apoptosis. All the apoptotic cytokines induced GIMAP5 expression in two monocyte cell lines (1.5–6 times, p<0.0001 for all tests).

Conclusion

Taken together, the data suggest the role of GIMAP5 in the pathogenesis of SLE.     

High-resolution CT by diffraction-enhanced x-ray imaging: mapping of breast tissue samples and comparison with their histo-pathology

The aim of this study was to introduce high-resolution computed tomography (CT) of breast tumours using the diffraction-enhanced x-ray imaging (DEI) technique and to compare results with radiological and histo-pathological examinations. X-ray CT images of tumour-bearing breast tissue samples were acquired by monochromatic synchrotron radiation (SR). Due to the narrow beam and a large sample-to-detector distance scattering is rejected in the absorption contrast images (SR-CT). Large contrast enhancement is achieved by the use of the DEI-CT method, where the effects of refraction and scatter rejection are analysed by crystal optics. Clinical mammograms and CT images were recorded as reference material for a radiological examination. Three malignant and benign samples were studied in detail. Their radiographs were compared with optical images of stained histological sections. The DEI-CT images map accurately the morphology of the samples, including collagen strands and micro-calcifications of dimensions less than 0.1 mm. Histo-pathological examination and reading of the radiographs were done independently, and the conclusions were in general agreement. High-resolution DEI-CT images show strong contrast and permit visualization of details invisible in clinical radiographs. The radiation dose may be reduced by an order of magnitude without compromising image quality, which would make possible clinical in vivo DEI-CT with future compact SR sources.