José Vaz Patto

Association study of IL10 and IL23R-IL12RB2 in Iranian patients with Behçet's disease.

OBJECTIVE Independent replication of the findings from genome-wide association studies (GWAS) remains the gold standard for results validation. Our aim was to test the association of Behçets disease (BD) with the interleukin-10 gene (IL10) and the IL-23 receptor-IL-12 receptor β2 (IL23R-IL12RB2) locus, each of which has been previously identified as a risk factor for BD in 2 different GWAS. METHODS Six haplotype-tagging single-nucleotide polymorphisms (SNPs) in IL10 and 42 in IL23R-IL12RB2 were genotyped in 973 Iranian patients with BD and 637 non-BD controls. Population stratification was assessed using a panel of 86 ancestry-informative markers. RESULTS Subtle evidence of population stratification was found in our data set. In IL10, rs1518111 was nominally associated with BD before and after adjustment for population stratification (odds ratio [OR] for T allele 1.20, 95% confidence interval [95% CI] 1.02-1.40, unadjusted P [P(unadj) ] = 2.53 × 10(-2) ; adjusted P [P(adj) ] = 1.43 × 10(-2) ), and rs1554286 demonstrated a trend toward association (P(unadj) = 6.14 × 10(-2) ; P(adj) = 3.21 × 10(-2) ). Six SNPs in IL23R-IL12RB2 were found to be associated with BD after Bonferroni correction for multiple testing, the most significant of which were rs17375018 (OR for G allele 1.51, 95% CI 1.27-1.78, P(unadj) = 1.93 × 10(-6) ), rs7517847 (OR for T allele 1.48, 95% CI 1.26-1.74, P(unadj) = 1.23 × 10(-6) ), and rs924080 (OR for T allele 1.29, 95% CI 1.20-1.39, P = 1.78 × 10(-5) ). SNPs rs10489629, rs1343151, and rs1495965 were also significantly associated with BD in all tests performed. Results of meta-analyses of our data combined with data from other populations further confirmed the role of rs1518111, rs17375018, rs7517847, and rs924080 in the risk of BD, but no epistatic interactions between IL10 and IL23R-IL12RB2 were detected. Results of imputation analysis highlighted the importance of IL23R regulatory regions in the susceptibility to BD. CONCLUSION These findings independently confirm, extend, and refine the association of BD with IL10 and IL23R-IL12RB2. These associations warrant further validation and investigation in patients with BD, as they may have implications for the development of novel therapies (e.g., immunosuppressive therapy targeted at IL-23p19).

Effects of gustatory stimulants of salivary secretion on salivary pH and flow in patients with Sjögren's syndrome: a randomized controlled trial.

OBJECTIVES To compare salivary pH changes and stimulation efficacy of two different gustatory stimulants of salivary secretion (GSSS) in patients with primary Sjögren syndrome. SETTING Portuguese Institute for Rheumatological Diseases. DESIGN Double-blind randomized controlled trial. SUBJECTS Eighty patients were randomized to two intervention groups. Sample size was calculated using an alpha error of 0.05 and a beta of 0.20. MATERIALS AND METHODS Participants were randomly assigned to receive a new GSSS containing a weaker malic acid, fluoride and xylitol or a traditionally citric acid-based one. Saliva collection was obtained by established methods at different times. The salivary pH of the samples was determined with a pH meter and a microelectrode. MAIN OUTCOME MEASURES Salivary pH variations and counts of subjects with pH below 4.5 for over 1 min and stimulated salivary flow were the main outcome measures. RESULTS Both GSSS significantly stimulated salivary output without significant differences between the two groups. The new gustatory stimulant of salivary secretion presented an absolute risk reduction of 52.78% [33.42-72.13 (95% CI)] when compared with the traditional one. CONCLUSIONS In Xerostomic Primary Sjögren syndrome patients, gustatory stimulants of salivary secretion based on acid mail only with fluoride and xylitol present similar salivary stimulation capacity when compared to citric acid-based ones, besides significantly reducing the number of salivary pH drops below 4.5. This could be related to a diminished risk for dental erosion and should be confirmed with further studies.

Gene expression profiling and association studies implicate the neuregulin signaling pathway in Behçet's disease susceptibility

Behçets disease (BD) is a complex disease with genetic and environmental risk factors implicated in its etiology; however, its pathophysiology is poorly understood. To decipher BDs genetic underpinnings, we combined gene expression profiling with pathway analysis and association studies. We compared the gene expression profiles in peripheral blood mononuclear cells (PBMCs) of 15 patients and 14 matched controls using Affymetrix microarrays and found that the neuregulin signaling pathway was over-represented among the differentially expressed genes. The Epiregulin (EREG), Amphiregulin (AREG), and Neuregulin-1 (NRG1) genes of this pathway stand out as they are also among the top differentially expressed genes. Twelve haplotype tagging SNPs at the EREG-AREG locus and 15 SNPs in NRG1 found associated in at least one published BD genome-wide association study were tested for association with BD in a dataset of 976 Iranian patients and 839 controls. We found a novel association with BD for the rs6845297 SNP located downstream of EREG, and replicated three associations at NRG1 (rs4489285, rs383632, and rs1462891). Multifactor dimensionality reduction analysis indicated the existence of epistatic interactions between EREG and NRG1 variants. EREG-AREG and NRG1, which are members of the epidermal growth factor (EGF) family, seem to modulate BD susceptibility through main effects and gene–gene interactions. These association findings support a role for the EGF/ErbB signaling pathway in BD pathogenesis that warrants further investigation and highlight the importance of combining genetic and genomic approaches to dissect the genetic architecture of complex diseases.

Crosstalk between inflammation, iron metabolism and endothelial function in Behçet’s disease

Behçets disease (BD) is a rare chronic vasculitis of unclear etiology. It has been suggested that inflammatory response has an important role in BD pathophysiology. Herein, we aimed to study the interplay between inflammation, iron metabolism and endothelial function in BD and search for its putative association with disease activity. Twenty five patients clinically diagnosed with BD were selected and twenty four healthy age-sex matched individuals participated as controls. Results showed an increase of total number of circulating white blood cells and neutrophils, serum transferrin, total iron binding capacity, mieloperoxidase (MPO), ceruloplasmin (Cp), C reactive protein, β2 microglobulin and Cp surface expression in peripheral blood monocytes in BD patients comparatively to healthy individuals (p < 0,05). Of notice, the alterations observed were associated to disease activity status. No significant differences between the two groups were found in serum nitric oxide concentration. The results obtained suggest an important contribution from innate immunity in the pathogenesis of this disease. In particular, surface expression of leukocyte-derived Cp may constitute a new and relevant biomarker to understand BD etiology.

IL10 low-frequency variants in Behçet's disease patients

To explain the missing heritability after the genome‐wide association studies era, sequencing studies allow the identification of low‐frequency variants with a stronger effect on disease risk. Common variants in the interleukin 10 gene (IL10) have been consistently associated with Behçets disease (BD) and the goal of this study is to investigate the role of low‐frequency IL10 variants in BD susceptibility.