Marta Barreto

Evidence for CTLA4 as a susceptibility gene for systemic lupus erythematosus.

Several lines of evidence implicate the Cytotoxic T Lymphocyte Antigen 4 (CTLA4) gene in susceptibility to autoimmune disease. We have examined the association of systemic lupus erythematosus (SLE) with polymorhisms within the CTLA4 gene that were previously proposed to regulate CTLA-4 function: a single nucleotide polymorphism (SNP) in position +49 of exon 1 and a dinucleotide repeat in the 3′ untranslated region (3’UTR). The 3′UTR repeat showed a significant association with SLE, with one allele conferring susceptibility and another conferring protection to the disease. The associated alleles do not support previous suggestions of an allele size-dependent effect of the 3’ UTR polymorphism in autoimmunity development and instead suggest that it is in linkage disequilibrium with a true causative locus. No association of the exon 1 SNP with SLE was found in our population. Given the conflicting results obtained in different studies on the association of SLE with this polymorphism, we performed a meta-analysis including seven previously published studies and the present one. Significantly increased and decreased risks for SLE were found for carriers of the G allele and the A allele, respectively. The functional characterization of disease-associated CTLA4 gene variants is now required to elucidate their role in the pathogenesis of SLE and other autoimmune diseases.

Compensatory T-Cell Regulation in Unaffected Relatives of SLE Patients, and Opposite IL-2/CD25-Mediated Effects Suggested by Coreferentiality Modeling

In human systemic lupus erythematosus (SLE), diverse autoantibodies accumulate over years before disease manifestation. Unaffected relatives of SLE patients frequently share a sustained production of autoantibodies with indiscriminable specificity, usually without ever acquiring the disease. We studied relations of IgG autoantibody profiles and peripheral blood activated regulatory T-cells (aTregs), represented by CD4+CD25bright T-cells that were regularly 70–90% Foxp3+. We found consistent positive correlations of broad-range as well as specific SLE-associated IgG with aTreg frequencies within unaffected relatives, but not patients or unrelated controls. Our interpretation: unaffected relatives with shared genetic factors compensated pathogenic effects by aTregs engaged in parallel with the individual autoantibody production. To study this further, we applied a novel analytic approach named coreferentiality that tests the indirect relatedness of parameters in respect to multivariate phenotype data. Results show that independently of their direct correlation, aTreg frequencies and specific SLE-associated IgG were likely functionally related in unaffected relatives: they significantly parallelled each other in their relations to broad-range immunoblot autoantibody profiles. In unaffected relatives, we also found coreferential effects of genetic variation in the loci encoding IL-2 and CD25. A model of CD25 functional genetic effects constructed by coreferentiality maximization suggests that IL-2-CD25 interaction, likely stimulating aTregs in unaffected relatives, had an opposed effect in SLE patients, presumably triggering primarily T-effector cells in this group. Coreferentiality modeling as we do it here could also be useful in other contexts, particularly to explore combined functional genetic effects.

A Remarkable Depletion of Both Naïve CD4+ and CD8+ with High Proportion of Memory T Cells in an IPEX Infant with a FOXP3 Mutation in the Forkhead Domain

IPEX is a rare X‐linked syndrome, with immune dysfunction, polyendocrinopathy and enteropathy. We describe an infant who died at the age of 11 months after developing eczema, severe diarrhoea, diabetes, hypothyroidism, thrombocytopenia and four episodes of septicaemia. Immunophenotyping of peripheral blood at 8 months revealed normal CD3+ T, CD4+ T and CD8+ T cell numbers, with low NK and B cells. CD4+ and CD8+ T lymphocytes showed remarkably low numbers and percentages of naïve cells and high numbers of memory CD4 and CD8 cells. At autopsy, an intense depletion of immune cells in thymus, spleen and lymph nodes was observed. No Hassall’s corpuscles were found in thymus. Lymphocytic pancreatitis and intense villous atrophy with mucosal lymphocytic infiltration in small bowel were also seen. FOXP3 gene studies revealed a: C→G substitution 3 bp upstream of exon 10, which prevents splicing between exons 9 and 10, likely resulting in a functionally altered or deficient protein. Florid clinical findings are usually observed in association of forkhead DNA‐binding domain mutations. The intense depletion of naïve T cells we report suggest that depletion of immune cells might take place due to uncontrolled activation due to the absence of regulatory T cells.

Hospitalization Risk Due to Respiratory Illness Associated with Genetic Variation at IFITM3 in Patients with Influenza A(H1N1)pdm09 Infection: A Case-Control Study

Background Recent studies suggest an association between the Interferon Inducible Transmembrane 3 (IFITM3) rs12252 variant and the course of influenza infection. However, it is not clear whether the reported association relates to influenza infection severity. The aim of this study was to estimate the hospitalization risk associated with this variant in Influenza Like Illness (ILI) patients during the H1N1 pandemic influenza. Methods A case-control genetic association study was performed, using nasopharyngeal/oropharyngeal swabs collected during the H1N1 pandemic influenza. Laboratory diagnosis of influenza infection was performed by RT-PCR, the IFITM3 rs12252 was genotyped by RFLP and tested for association with hospitalization. Conditional logistic regression was performed to calculate the confounder-adjusted odds ratio of hospitalization associated with IFITM3 rs12252. Results We selected 312 ILI cases and 624 matched non-hospitalized controls. Within ILI Influenza A(H1N1)pdm09 positive patients, no statistical significant association was found between the variant and the hospitalization risk (Adjusted OR: 0.73 (95%CI: 0.33–1.50)). Regarding ILI Influenza A(H1N1)pdm09 negative patients, CT/CC genotype carriers had a higher risk of being hospitalized than patients with TT genotype (Adjusted OR: 2.54 (95%CI: 1.54–4.19)). Conclusions The IFITM3 rs12252 variant was associated with respiratory infection hospitalization but not specifically in patients infected with Influenza A(H1N1)pdm09.

Factors associated to repeated influenza vaccination in the Portuguese adults with chronic conditions

Annual influenza vaccination is recommended to people with chronic conditions. This study aimed to estimate the proportion of chronically ill adults vaccinated against influenza in consecutive seasons and to identify associated factors. We used data from the first National Health Examination Survey (INSEF), a cross-sectional study conducted in 2015 on a probabilistic sample of individuals aged 25-74 years. The population was restricted to individuals who self-reported diabetes, a respiratory, cardiovascular, liver or kidney disease. Self-reported vaccination in 4 consecutive seasons was categorized in 3 levels: unvaccinated, occasionally (vaccinated 1-3 seasons) and repeatedly vaccinated (in all 4 seasons). A multinomial logistic regression was applied to estimate odds-ratio (OR) of influenza vaccination according to sociodemographic factors, chronic condition, health care use and status. In the target population, the 2014/15 influenza vaccine coverage was 33.8% (95% CI: 29.8-38.1). The higher coverage was found in individuals reporting renal disease (66.7%) and diabetes (43.8%). The coverage decreased to 32.6%, 26.0% and 20.8% for individuals with respiratory, cardiovascular and liver diseases, respectively. The probability of being repeatedly vaccinated, compared to unvaccinated, was higher in males (OR = 2.14: 95% CI: 1.31-3.52); aged 65 and 74 (OR = 4.39; 95% CI: 1.99-9.69); whom had an appointment with a general practitioner (OR = 2.77; 95% CI: 1.00-7.66) or other physician (OR = 3.95: 95% CI: 2.53-6.16); with no smoking habits (OR = 1.58; 95% I: 1.02-2.46) and reporting diabetes (OR = 2.13; 95% CI: 1.02-4.45). Finally, having a self-reported cardiovascular condition decreased the likelihood of being occasionally (OR = 0.38; 95% CI = 0.22-0.65) vaccinated against influenza. Younger individuals, females and the ones with a self-reported cardiovascular condition were identified as more likely of non-compliance to the vaccine uptake recommendation. Future vaccination strategies should focus on the previous identified population subgroups. Also, the medical recommendation of the influenza vaccine uptake should continue and be reinforced particularly in individuals with a cardiovascular condition.

Prevalence, awareness, treatment and control of diabetes in Portugal: Results from the first National Health examination Survey (INSEF 2015)

AIMS Diabetes Mellitus is a major public health threat worldwide and continues to increase in numbers and significance. Estimates of diabetes prevalence, awareness, treatment and control are essential to effectively monitor its trends, plan and evaluate interventions. METHODS We conducted a nationwide health examination survey in the population residing in Portugal aged between 25 and 74 years old in 2015. It consisted in a cross sectional prevalence study which included the measurement of HbA1c, a physical examination and a general health interview of a probabilistic sample of 4911 individuals (Authorization n°9348/2010 of the National Committee for Data Protection). RESULTS The overall prevalence of diabetes was 9.9% (95%CI: 8.4; 11.5). It was higher in males than in females (12.1% vs 7.8%). Diabetes was more prevalent among individuals of lower education and without any professional activity. The majority of persons with diabetes was aware of their condition (87.1%) and was taking antidiabetic medication (79.7%). Of these, 63.2% had glycated hemoglobin levels lower than 7.0% (53 mmol/mol), but the majority failed to comply with the LDL and blood pressure recommended clinical targets (71.9% and 59.0%). Similarly, the prevalence of prediabetes was 16%, higher among women than men (17.5% vs 14.4%). CONCLUSION The prevalence of diabetes and prediabetes remains higher than the global and European estimates, although there is increasing awareness of this disorder.

Socioeconomic inequalities in obesity prevalence: Portuguese Health Examination Survey results

The Portuguese National Health Examination Survey is developed as a part of the project “Improvement of epidemiological health information to support public health decision and management in Portugal. Towards reduced inequalities, improved health, and bilateral cooperation”, that benefits from a 1.500.000€ Grant from Iceland, Liechtenstein and Norway through the EEA Grants.

Prevalence of Elevated Cholesterol in Portugal: National Health Examination Survey (2015) results

The Portuguese National Health Examination Survey is developed as a part of the project “Improvement of epidemiological health information to support public health decision and management in Portugal. Towards reduced inequalities, improved health, and bilateral cooperation”, that benefits from a 1.500.000€ Grant from Iceland, Liechtenstein and Norway through the EEA Grants.