A psoriasis vulgaris protective gene maps close to the HLA-C locus on the EH18.2-extended haplotype

We determined the molecular haplotypes of the HLA-A, HLA-C and HLA-B loci and the MHC class I-B-related (MIB) microsatellite in 179 unrelated psoriatic patients (72 familial cases) and in 120 controls. The HLA-A*3002-Cw*0501-B*1801-MIB1 haplotype showed a strong negative association with psoriasis vulgaris (PV) and in particular with familial PV, revealing the presence of a PV-protective gene. Analysis of association and linkage disequilibrium of the single alleles and the various two-three-four-locus segments of this haplotype indicated the presence of a protective gene telomeric to the HLA-C locus. This finding was confirmed in 13 informative multiplex PV families, in which at least one parent carried the EH18.2 haplotype. In two families, an affected sibling presented HLA-A/C recombination on the EH18.2 haplotype. A study of 12 polymorphic microsatellites in all members of the informative families, 145 PV patients, 120 controls and 32 EH18.2 homozygous healthy individuals demonstrated that the protection conferred by the EH18.2 haplotype lies within a 170 kb interval between the C143 and C244 loci, most probably in a 60 kb segment between the C132 and C244 loci.     

Biallelic somatic inactivation of the mismatch repair gene MLH1 in a primary skin melanoma

Inactivation of mismatch repair (MMR) genes has been linked to the hereditary nonpolyposis colon cancer syndrome and to a subset of sporadic cancers. A phenotypic characteristic of tumors with defective MMR is microsatellite instability (MSI). Although MSI has been reported in a proportion of cutaneous melanomas, inactivation of MMR genes in this tumor type has not been detected thus far. We recently described a human melanoma cell line, PR-Mel, and a cutaneous metastasis from the same patient, which displayed a MMR defect, and showed high MSI. Here we report that in the PR-Mel cell line both MLH1 alleles are somatically inactivated. One allele is lost through a chromosomal deletion of the region 3p21-24, whereas the remaining allele harbors a G --> A transition at position -1 of the acceptor splice site of intron 15, leading to the in-frame skipping of exon 16. The primary melanoma of the PR patient shows loss of heterozygosity at the BAT21 microsatellite marker, located in the MLH1 gene, and does not express the MLH1 and PMS2 proteins. Moreover, it harbors the same mutation detected in the PR-Mel cells. These results demonstrate that biallelic inactivation of MLH1 had occurred in the primary melanoma of the PR patient and suggest that disruption of MMR might have had a role in the development of the melanoma. This is the first report in which genetic defects leading to disruption of MMR function in a human melanoma have been identified.     

ABCA1 gene deletion protects against cerebral malaria: potential pathogenic role of microparticles in neuropathology

The ATP-binding cassette transporter A1 (ABCA1) modulates the transbilayer distribution of phosphatidylserine at the outer leaflet of the plasma membrane. This external exposure of phosphatidylserine is a hallmark of microparticle production and is impaired in ABCA1(-/-) mice. In this study, we report about the complete resistance to cerebral malaria of these mice. On analysis of histological and systemic parameters we evidenced an impairment of cellular responses to Plasmodium berghei ANKA infection in ABCA1(-/-) mice, as shown by lower plasma tumor necrosis factor levels, a weaker up-regulation of endothelial adhesion molecules in brain microvessels, a reduced leukocyte sequestration, as well as an ablated platelet accumulation. Besides, the number and the procoagulant activity of microparticles were dramatically reduced in the plasma of ABCA1(-/-) compared to ABCA1(+/+) mice. Moreover, microparticles derived from Plasmodium berghei ANKA-infected ABCA1(+/+) mice induced a significant increase of tumor necrosis factor release by noninfected macrophages. In ABCA1(-/-) mice platelet and macrophage responses to vesiculation agonists were ablated and reduced, respectively. Altogether, by pointing out the ABCA1 transporter as a major element controlling cerebral malaria susceptibility, these data provide a novel insight into its pathophysiological mechanisms and are consistent with a pathogenic role of microparticles in this neurological syndrome.     

The Trypanosoma lewisi immunofluorescence test: A new simple technique for simultaneous determination of total antinuclear antibodies and the detection of antibodies to double-stranded DNA

An indirect immunofluorescence technique was developed for the detection of antibodies to dsDNA and the simultaneous assessment of antinuclear antibodies ‘in toto’ (ANA). This assay was based upon the use as substrate of smears of peripheral blood derived from rats infected with Trypanosoma lewisi. T. lewisi possesses a giant kinetoplast posteriorly to the nucleus. Enzyme digestion and absorption experiments provided strong evidence that T. lewisi kinetoplast contains dsDNA uncontaminated by other nuclear antigens. The T. lewisi immunofluorescent test was evaluated on a total of 130 sera (30 from patients with SLE) and compared with radioimmunoassays for antibodies to dsDNA ([¹²⁵I]dsDNA-RIA) and antibodies to ssDNA ([¹²⁵I]ssDNA-RIA). Excellent correlation was found between kinetoplast immunofluorescence and [¹²⁵I]dsDNA-RIA, whereas no non-SLE sera showing significant ssDNA binding activity gave kinetoplast staining. With a single exception, only SLE sera reacted with T. lewisi kinetoplast. Sera containing auto-antibodies other than ANA did not induce fluorescene of any part of the parasite, including the flagellum and its base. These results indicated that the T. lewisi immunofluorescence test is specific and reliablem and combines the advantages of Crithidia luciliae with those of Trypanosoma gambiense. It may be used routinely for evaluating of total ANA and simultaneous detection of antibodies against dsDNA.     

Increased COVID-19 Lockdown Burden in Italian Adults with Gastrointestinal Diseases

Background: Coronavirus disease 2019 (COVID-19) causes not only severe illness but also detrimental effects associated with the lockdown measures. The present study aimed to evaluate reported lifestyle changes in a cohort of adults in Italy, including physical exercise, food choices, and psychological wellbeing, after two months of lockdown. Methods: A web survey on social media (Facebook and LinkedIn) of 32 multiple-choice questions aiming to evaluate the impact of the national COVID-19 lockdown in a sample of Italian adults. Results: We received 1378 complete responses (women 68.3%, mean age 39.5 ± 12.5 years). The percentage of participants reporting regular exercise decreased during lockdown (52 vs. 56.5%). The vast majority of people continued to consume the three traditional meals per day, but the consumption of meat, fish, and eggs significantly decreased. Women reported more frequent anxiety, sadness, fear, and feelings of insecurity than men. The factors predicting the worst outcome during the lockdown were being a woman, low education and income, gastrointestinal diseases. Conclusion: The lockdown has had a limited impact on food choices and physical exercise in Italian adults of our series, since most of them made an effort to improve their lifestyle. However, women with gastrointestinal diseases reported more frequent negative feelings and poor adaptation to the lockdown.     

Association of the Chronotype Score with Circulating Trimethylamine N-Oxide (TMAO) Concentrations

Individual differences in the chronotype, an attitude that best expresses the individual circadian preference in behavioral and biological rhythms, have been associated with cardiometabolic risk and gut dysbiosis. Up to now, there are no studies evaluating the association between chronotypes and circulating TMAO concentrations, a predictor of cardiometabolic risk and a useful marker of gut dysbiosis. In this study population (147 females and 100 males), subjects with the morning chronotype had the lowest BMI and waist circumference (p < 0.001), and a better metabolic profile compared to the other chronotypes. In addition, the morning chronotype had the highest adherence to the Mediterranean diet (p < 0.001) and the lowest circulating TMAO concentrations (p < 0.001). After adjusting for BMI and adherence to the Mediterranean diet, the correlation between circulating TMAO concentrations and chronotype score was still kept (r = −0.627, p < 0.001). Using a linear regression analysis, higher chronotype scores were mostly associated with lower circulating TMAO concentrations (β = −0.479, t = −12.08, and p < 0.001). Using a restricted cubic spline analysis, we found that a chronotype score ≥59 (p < 0.001, R² = −0.824) demonstrated a more significant inverse linear relationship with circulating TMAO concentrations compared with knots <59 (neither chronotype) and <41 (evening chronotype). The current study reported the first evidence that higher circulating TMAO concentrations were associated with the evening chronotype that, in turn, is usually linked to an unhealthy lifestyle mostly characterized by low adherence to the MD.