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ABSTRACT. Objective. To investigate whether frequency of rheumatoid arthritis (RA) and/or other autoimmune (AI) disorders was increased in RA French Caucasian families among the first-(FDR) and seconddegree relatives (SDR), and to test whether the presence of AI disease family history identified a specific RA subset. Methods. We conducted telephone interviews to obtain histories of AI diseases among the FDR and SDR of 368 RA probands, belonging either to trio or affected sib-pair (ASP) families. All the AI diagnoses were confirmed by the physician of the affected relative

Rheumatoid arthritis seropositive for the rheumatoid factor is linked to the protein tyrosine phosphatase nonreceptor 22-620W allele

The protein tyrosine phosphatase nonreceptor type 22 (PTPN22) gene encodes for lymphoid tyrosine phosphatase LYP, involved in the negative regulation of early T-cell activation. An association has recently been reported between the PTPN22-620W functional allele and rheumatoid factor-positive (RF(+)) rheumatoid arthritis (RA), among other autoimmune diseases. Expected linkage proof for consistency cannot be definitely produced by an affected sib-pair (ASP) analysis. Our aim was therefore to search for linkage evidence with the transmission disequilibrium test. DNA from the French Caucasian population was available for two samples of 100 families with one RA patient and both parents, and for 88 RA index cases from RA ASP families. Genotyping was carried out by PCR-restriction fragment length polymorphism. The analysis was performed using the transmission disequilibrium test, genotype relative risk and ASP-based analysis. The transmission disequilibrium test of the PTPN22-620W allele revealed linkage and association for RF(+ )RA (61% of transmission, P = 0.037). The genotype relative risk showed the risk allele in 34% of RF(+ )RA patients and in 24% of controls derived from nontransmitted parental chromosomes (P = 0.047, odds ratio = 1.69, 95% confidence interval = 1.03–2.78). The ASP investigation showed no enriched risk allele in RA multiplex families, resulting in a lack of power of ASP analysis, explaining the published negative results. This study is the first to show linkage of PTPN22 to RF(+ )RA, consistent with PTPN22 as a new RA gene

An improved whole life cycle culture protocol for the hydrozoan genetic model Clytia hemisphaerica

The jellyfish species Clytia hemisphaerica (Cnidaria, Hydrozoa) has emerged as a new experimental model animal in the last decade. Favorable characteristics include a fully transparent body suitable for microscopy, daily gamete production and a relatively short life cycle. Furthermore, whole genome sequence assembly and efficient gene editing techniques using CRISPR/Cas9 have opened new possibilities for genetic studies. The quasi-immortal vegetatively-growing polyp colony stage provides a practical means to maintain mutant strains. In the context of developing Clytia as a genetic model, we report here an improved whole life cycle culture method including an aquarium tank system designed for culture of the tiny jellyfish form. We have compared different feeding regimes using Artemia larvae as food and demonstrate that the stage-dependent feeding control is the key for rapid and reliable medusa and polyp rearing. Metamorphosis of the planula larvae into a polyp colony can be induced efficiently using a new synthetic peptide. The optimized procedures detailed here make it practical to generate genetically modified Clytia strains and to maintain their whole life cycle in the laboratory

Validation of the reshaped shared epitope HLA-DRB1 classification in rheumatoid arthritis

Recently, we proposed a classification of HLA-DRB1 alleles that reshapes the shared epitope hypothesis in rheumatoid arthritis (RA); according to this model, RA is associated with the RAA shared epitope sequence (72–74 positions) and the association is modulated by the amino acids at positions 70 and 71, resulting in six genotypes with different RA risks. This was the first model to take into account the association between the HLA-DRB1 gene and RA, and linkage data for that gene. In the present study we tested this classification for validity in an independent sample. A new sample of the same size and population (100 RA French Caucasian families) was genotyped for the HLA-DRB1 gene. The alleles were grouped as proposed in the new classification: S(1 )alleles for the sequences A-RAA or E-RAA; S(2 )for Q or D-K-RAA; S(3D )for D-R-RAA; S(3P )for Q or R-R-RAA; and X alleles for no RAA sequence. Transmission of the alleles was investigated. Genotype odds ratio (OR) calculations were performed through conditional logistic regression, and we tested the homogeneity of these ORs with those of the 100 first trio families (one case and both parents) previously reported. As previously observed, the S(2 )and S(3P )alleles were significantly over-transmitted and the S(1), S(3D )and X alleles were under-transmitted. The latter were grouped as L alleles, resulting in the same three-allele classification. The risk hierarchy of the six derived genotypes was the same: (by decreasing OR and with L/L being the reference genotype) S(2)/S(3P), S(2)/S(2), S(3P)/S(3P), S(2)/L and S(3P)/L. The homogeneity test between the ORs of the initial and the replication samples revealed no significant differences. The new classification was therefore considered validated, and both samples were pooled to provide improved estimates of RA risk genotypes from the highest (S(2)/S(3P )[OR 22.2, 95% confidence interval 9.9–49.7]) to the lowest (S(3P)/L [OR 4.4, 95% confidence interval 2.3–8.4])

Transcriptome Analysis Describing New Immunity and Defense Genes in Peripheral Blood Mononuclear Cells of Rheumatoid Arthritis Patients

Background: Large-scale gene expression profiling of peripheral blood mononuclear cells from Rheumatoid Arthritis (RA) patients could provide a molecular description that reflects the contribution of diverse cellular responses associated with this disease. The aim of our study was to identify peripheral blood gene expression profiles for RA patients, using Illumina technology, to gain insights into RA molecular mechanisms. Methodology/Principal Findings: The Illumina Human-6v2 Expression BeadChips were used for a complete genome-wide transcript profiling of peripheral blood mononuclear cells (PBMCs) from 18 RA patients and 15 controls. Differential analysis per gene was performed with one-way analysis of variance (ANOVA) and P values were adjusted to control the False Discovery Rate (FDR < 5%). Genes differentially expressed at significant level between patients and controls were analyzed using Gene Ontology (GO) in the PANTHER database to identify biological processes. A differentially expression of 339 Reference Sequence genes (238 down-regulated and 101 up-regulated) between the two groups was observed. We identified a remarkably elevated expression of a spectrum of genes involved in Immunity and Defense in PBMCs of RA patients compared to controls. This result is confirmed by GO analysis, suggesting that these genes could be activated systemically in RA. No significant down-regulated ontology groups were found. Microarray data were validated by real time PCR in a set of nine genes showing a high degree of correlation. Conclusions/Significance: Our study highlighted several new genes that could contribute in the identification of innovative clinical biomarkers for diagnostic procedures and therapeutic interventions

Prevalence and distribution of autoimmune diseases in 368 rheumatoid arthritis families.

International audienceTo investigate whether frequency of rheumatoid arthritis (RA) and/or other autoimmune (AI) disorders was increased in RA French Caucasian families among the first- (FDR) and second-degree relatives (SDR), and to test whether the presence of AI disease family history identified a specific RA subset

Prevalence and distribution of autoimmune diseases in 368 rheumatoid arthritis families.

To investigate whether frequency of rheumatoid arthritis (RA) and/or other autoimmune (AI) disorders was increased in RA French Caucasian families among the first- (FDR) and second-degree relatives (SDR), and to test whether the presence of AI disease family history identified a specific RA subset

Prevalence and distribution of autoimmune diseases in 368 rheumatoid arthritis families.

International audienceTo investigate whether frequency of rheumatoid arthritis (RA) and/or other autoimmune (AI) disorders was increased in RA French Caucasian families among the first- (FDR) and second-degree relatives (SDR), and to test whether the presence of AI disease family history identified a specific RA subset

IRF5 rs2004640‐T allele, the new genetic factor for systemic lupus erythematosus, is not associated with rheumatoid arthritis

International audienceBackground: Recently, a new genetic factor within the interferon regulatory factor 5 (IRF5) gene was demonstrated for systemic lupus erythematosus (SLE) through linkage and association: the rs2004640-T allele. IRF5 is involved in the production of rheumatoid arthritis (RA) cytokines, and SLE already shares with RA one genetic factor within the tyrosine phosphatase PTPN22 gene. Aim: To test the hypothesis that the SLE IRF5 genetic factor could also be shared with RA. Patients and methods: 100 French Caucasian trio families with RA were genotyped and analysed with the transmission disequilibrium test, the frequency comparison of the transmitted and untransmitted alleles, and the genotype relative risk. 97% power was available to detect at least a trend in favour of a factor similar to that reported for SLE. Results: The analysis showed the absence of linkage and association globally and in "autoimmune" RA subsets, with a weak non-significant trend against the IRF5 rs20046470-T allele. Given the robustness of familial-based analysis, this slight negative trend provided strong evidence against even a weaker factor than that reported for SLE. Conclusion: Our results exclude the IRF5 rs2004640-T allele as a major genetic factor for RA in this French Caucasian population

Genetic and Expression Analysis of CASP7 Gene in a European Caucasian Population with Rheumatoid Arthritis

International audienceObjective. To study the possible role of the caspase 7 (CASP7) gene in susceptibility to rheumatoid arthritis (RA) in a European Caucasian population.Methods. CASP7 rs2227309 single nucleotide polymorphism (SNP) was genotyped in 197 French RA trio families and in 252 European RA families available for replication using Taqman allelic discrimination assay. Relative quantification of caspase 7 isoforms α and β mRNA expression was performed from whole blood in 25 unrelated patients with RA and in 15 healthy controls by real-time quantitative reverse transcription-polymerase chain reaction. The genetic analyses for association and linkage were performed using the comparison of allelic frequencies, the transmission disequilibrium test, and the genotype relative risk.Results. We observed, in the first sample, a significant association of rs2227309-AA genotype with RA [p = 0.03, odds ratio (OR) 2.11 (95% CI 1.0-4.6)]. The second sample did not show any significant association of the AA genotype with RA [p = 0.6, OR 0.87 (95% CI 0.4-1.8)]. When the 2 samples were combined, no significant association of the AA genotype [p = 0.3, OR 1.32 (95% CI 0.8-2.2)] was observed. CASP7 isoforms α and β mRNA were expressed in patients with RA at lower level than in healthy controls (-89%, p = 0.003 and -47%, p = 0.01; respectively). Conclusion. CASP7 rs2227309 SNP was not associated with RA in a European Caucasian population. Nevertheless, CASP7 isoforms α and β could have an involvement in the apoptosis process in RA