PTPN22 +788 G>A (R263Q) Polymorphism is Associated with mRNA Expression but it is not a Susceptibility Marker for Rheumatoid Arthritis Patients from Western Mexico.

PTPN22 represents an important non-HLA gene that has been strongly associated with rheumatoid arthritis (RA) pathogenesis. Several studies have reported a specific genetic variant for PTPN22 (+788 G>A; rs33996649) that might be associated with decreased RA risk in Caucasian population; nevertheless, its specific role in western Mexican population has not been yet described. A case-control study with 443 RA patients and 317 control subjects (CS) was conducted. The genotyping was performed by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) technique and the PTPN22 mRNA expression was determined by SYBR Green-based real-time quantitative-PCR assay. No association between the PTPN22 +788 G>A polymorphism and RA susceptibility in western Mexican population was found when comparing genotype and allelic frequencies between RA patients and CS (G/G vs. G/A: OR 0.55, p = 0.14, 95% CI 0.22-1.32; G vs. A: OR 0.56, p = 0.14, 95% CI 0.23-1.36). The PTPN22 mRNA expression increased 4.6-fold more in RA patients than in CS, and RA patients, carriers of PTPN22 +788 G/A genotype, expressed 15.6-fold more than RA patients carrying the homozygous G/G genotype. Overall, these results showed that the PTPN22 +788 G>A polymorphism is not associated with RA susceptibility in western Mexican population, whereas the presence of G/A genotype is associated with increased PTPN22 mRNA expression in RA patients.

CD40 functional gene polymorphisms and mRNA expression in rheumatoid arthritis patients from western Mexico.

The CD40 pathway is involved in the development and pathogenesis of autoimmune diseases, including rheumatoid arthritis (RA). Two single nucleotide polymorphisms (SNPs) in the CD40 gene, rs1883832 and rs4810485, are associated with susceptibility to inflammatory and autoimmune diseases and are thought to alter CD40 expression at the mRNA and protein level. This study assessed for the first time the association of these SNPs with RA and CD40 mRNA levels in a western Mexican population. A total of 278 RA patients and 318 control subjects were included. Genotyping was performed by polymerase chain reaction (PCR)-restriction fragment length polymorphism, and CD40 mRNA expression was determined by real-time quantitative PCR. No significant differences in genotype and allele frequencies were identified between the RA patients and controls. When stratified by genotype, these SNPs were not found to be associated with the presence of autoantibodies or the clinical activity of the disease. CD40 mRNA levels were elevated 1.5-fold in RA patients compared to control subjects; however, no clear tendencies were observed following stratification by genotype. These results suggest that the CD40 SNPs rs1883832 and rs4810485 are not RA susceptibility markers in the western Mexican population. Further studies are needed to clarify their roles in CD40 mRNA expression.

Comparative analysis of autoantibodies targeting peptidylarginine deiminase type 4, mutated citrullinated vimentin and cyclic citrullinated peptides in rheumatoid arthritis: associations with cytokine profiles, clinical and genetic features.

Antibodies against cyclic citrullinated peptides (anti-CCP) are widely used for diagnosis of rheumatoid arthritis (RA). We performed a comparative analysis of antibodies targeting the citrullinating enzyme peptidylarginine deiminase type 4 (anti-PAD4) and mutated citrullinated vimentin (anti-MCV) with anti-CCP autoantibodies in RA patients and examined their relationships with clinical parameters, cytokine profiles and the PADI4 gene. Autoantibodies were examined by enzyme-linked immunosorbent assay (ELISA) in sera of 170 RA patients and 103 controls. Cytokine profiles were measured using a multiplex system. PADI4 polymorphisms (89 G > A, 90 T > C and 92 G > C) were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Anti-PAD4, anti-MCV and anti-CCP autoantibodies were detected in 24, 61 and 74% of RA patients, respectively. Positive correlations were observed between anti-PAD4 and disease duration; anti-CCP and erythrocyte sedimentation rate (ESR); anti-MCV and ESR and C-reactive protein. Anti-MCV antibodies were associated with high disease activity score 28 (DAS-28) in early RA. Concentrations of T helper type 1 (Th1) [tumour necrosis factor (TNF)-α, interleukin (IL)-12, IL-2, IL-1ß], Th2 (IL-4, IL-6, IL-10, IL-13) and Th17 (IL-17) cytokines were higher in RA than in controls. Th2 and, to a lesser extent, Th1-related cytokines, showed positive correlations with anti-MCV and anti-CCP. The GTG haplotype in PADI4 was associated with anti-CCP and anti-MCV, but not anti-PAD4 antibodies. In conclusion, anti-PAD4 antibodies are detected mainly in established RA, which is in contrast to the early detection of antibodies against citrullinated peptide/proteins (ACPAs). Among autoantibodies, anti-MCV appear to perform better as markers of disease activity. Furthermore, anti-CCP and anti-MCV are associated genetically with the citrullinating enzyme PAD4 and are related strongly to Th1 and Th2 cytokines, suggesting a feed-forward loop between cytokines and ACPA production.

High BAFF expression associated with active disease in systemic lupus erythematosus and relationship with rs9514828C>T polymorphism in TNFSF13B gene.

B cell-activating factor (BAFF) promotes the survival, proliferation and maturation of B lymphocytes, which are key elements in the pathogenesis of systemic lupus erythematosus (SLE). This cytokine is encoded on TNFSF13B gene, and diverse single-nucleotide polymorphisms have been associated with susceptibility in different autoimmune disorders. In this study, the relationship of TNFSF13B gene rs9514827T>C, rs1041567T>A and rs9514828C>T polymorphisms, mRNA expression and soluble BAFF levels was investigated in 175 SLE patients and 208 healthy controls (HC). The TNFSF13B polymorphisms were evaluated by PCR-RFLP technique. The TNFSF13B gene expression was quantified through the RT-PCR assays. The soluble BAFF (sBAFF) levels were measured with ELISA test. There were no differences in genotype and allele frequencies for the three TNFSF13B polymorphisms, between SLE patients and HC. SLE patients showed 3.15-fold more TNFSF13B gene expression than HC. The patients who displayed most mRNA expression were those with active disease and the carriers of rs9514828 T variant allele. The sBAFF serum levels were higher in SLE patients compared to HC (2.083 vs. 0.742 ng/mL, p < 0.001). The SLE patients with active disease showed the higher sBAFF serum levels (2.403 ng/mL), mainly patients with lupus nephritis and hematological manifestations. In addition, a correlation of sBAFF with disease activity was found (r = 0.32, p < 0.001). In conclusion, the TNFSF13B gene polymorphisms were not found to be associated with SLE susceptibility in Mexican mestizos. Nevertheless, rs9514828C>T polymorphism seems to increase TNFSF13B gene expression. High BAFF expression is related to active disease, renal and hematological involvement; therefore, it could be considered as follow-up biomarker in SLE patients.

The 3'-UTR (CA)n microsatellite on CD40LG gene as a possible genetic marker for rheumatoid arthritis in Mexican population: impact on CD40LG mRNA expression.

The objective of this study was to determine the association of the CD40LG 3'-UTR (CA)n microsatellite with rheumatoid arthritis (RA) and CD40LG mRNA levels in females from western Mexico. A case-control study with 219 RA patients and 175 control subjects (CS) was conducted. Genotyping was performed by polymerase chain reaction (PCR), X 2 test was used to compare genotype and allele frequencies, and odds ratios and 95% confidence intervals were calculated to evaluate the association between RA and the microsatellite. CD40LG mRNA expression was assessed by real-time quantitative PCR. For comparisons between groups, Kruskal-Wallis or Mann-Whitney U tests for non-parametric data and ANOVA test for parametric data were performed. Among the 13 different alleles identified, CA25 was the most represented (45.4% RA and 46.3% CS). Stratification according to CA repeats as CA25 showed a tendency towards a higher frequency of >CA25 alleles in RA patients (29%) compared to CS (23.4%). There was no association between any genotype and the clinical parameters of RA patients. According to the 2-∆∆Cq method, CD40LG mRNA expression in RA patients was 4.5-fold higher compared to CS; this difference was significant when assessed by the 2-∆Cq method (p = 0.028). Compared to carriers of the CA25/CA25 genotype, CS carrying the CA25/>CA25 carriers. The 3'-UTR CD40LG (CA)n microsatellite is not a genetic marker for RA in western Mexican population; however, results suggest that it plays a role in the CD40LG mRNA expression.

Expression of MIF and TNFA in psoriatic arthritis: relationship with Th1/Th2/Th17 cytokine profiles and clinical variables.

Psoriatic arthritis (PsA) is an autoimmune inflammatory disease associated with psoriasis. The cause of this pathology is still unknown, but research suggests the diseases are caused by a deregulated cytokine production. MIF is a cytokine associated with immunomodulation of Th1, Th2, and Th17 cytokine profiles in inflammatory diseases. Based on this knowledge, the aim of this study was to determine the association of MIF and TNFA expression with Th1, Th2, and Th17 cytokine profiles in serum levels of PsA patients. A cross-sectional study was performed in 50 PsA patients and 30 control subjects (CS). The cytokine profiles were quantified by BioPlex MagPix system and the mRNA expression levels by real-time PCR. TNFA mRNA expression was 138.81-folds higher in PsA patients than CS (p < 0.001). Regarding MIF mRNA expression, no significant differences were observed; however, a positive correlation was identified between MIF mRNA expression and PsA time of evolution (r = - 0.53, p = 0.009). An increase of Th1 (IFNγ: PsA = 37.1 pg/mL vs. CS = 17 pg/mL, p < 0.05; TNFα: PsA = 24.6 pg/mL vs. CS = 9.8 pg/mL, p < 0.0001) and Th17 cytokine profiles (IL-17: PsA = 6.4 pg/mL vs. CS = 2.7 pg/mL, p < 0.05; IL-22: PsA = 8.4 pg/mL vs. CS = 1.8 pg/mL, p < 0.001), were found in PsA patients. Th2 cytokines were not significantly different in both groups. In conclusion, a high expression of TNFA mRNA, as well as an increase of Th1 and Th17 cytokine profiles evaluated by IFNγ, TNFα, IL-17, and IL-22 cytokines, was observed in PsA patients.

High expression of interleukine-1 receptor antagonist in rheumatoid arthritis: Association with IL1RN*2/2 genotype.

Rheumatoid arthritis (RA) is an autoimmune disease characterized by inflammation and pro-inflammatory cytokines production. IL-1Ra is an anti-inflammatory cytokine codified by IL1RN gene that blocks IL-1 signalling. A VNTR polymorphism of 86 bp in IL1RN gene has been associated with RA risk and regulation of IL-1Ra expression. In this study, we determined mRNA and protein expression of IL-1Ra in RA patients and control subjects (CS). This study included 85 RA patients classified according to the ACR/EULAR 2010 criteria and 67 CS. Polymerase chain reaction was used to identify IL1RN VNTR polymorphism, the expression of sIL-1Ra (secreted isoform) mRNA was determined by SYBR Green-based real time quantitave-PCR assay, and IL-1Ra soluble levels quantification was evaluated by ELISA test. RA patients had higher soluble levels of IL-1Ra than CS (p < .01), sIL-1Ra mRNA expression was higher in RA patients compared to CS (p < .01). Carriers of IL1RN*2/2 homozygous genotype show increased IL-1Ra soluble levels compared to IL1RN*long/long and IL1RN*2/long genotypes (p < .05) in the CS group, whereas mRNA expression in carriers of IL1RN*2/2 genotype was 1.2 times higher compared to IL1RN*long/long genotypes in the same group. Regarding RA patients, high expression of sIL-1Ra mRNA on carriers of IL1RN*long/long genotype was observed. Nevertheless, in RA patients IL-1Ra soluble levels among genotypes did not show significant differences. High expression of IL-1Ra in RA patients under treatment or not with antirheumatic drugs was detected. Additionally, carriers of IL1RN*2/2 genotype had higher IL-1Ra expression than carriers of other genotypes.

Associations of killer cell immunoglobulin- like receptor genes with rheumatoid arthritis.

OBJECTIVE: Rheumatoid Arthritis (RA) is an autoimmune and chronic inflammatory disease of unknown etiology. Killer cell immunoglobulin-like receptors are expressed on the surface of natural killer cells and CD28null T-cells, both present in synovial membrane of RA. Therefore we evaluated the associations of KIR genes with RA. METHODS: 16 KIR genes were genotyped in 100 healthy subjects (HS) and 100 RA patients from Western Mexico using PCR-SSP. Differences in KIR genotypes and gene frequencies were assessed using the X^{2} test. RESULTS: Gene frequency of KIR2DL3 was lower in RA than in HS (p= 0.0019), whereas KIR2DL2 and KIR2DS2 were higher in RA than HS (p =0.0004 and p = 0.0487, respectively). In addition were identified 38 genotypes (from G1-G38) in both studied groups, and the genotype frequencies of G1, G6 and G14 showed significant differences (p =0.0001, p =0.0208 and p =0.0300, respectively). CONCLUSIONS: The presence of KIR2DL2, KIR2DS2 and absence of KIR2DL3 are associated with RA. Moreover, two genotypes BX are associated with RA. These results suggest that KIRs can be involved in RA susceptibility.

Association of CD28 IVS3 +17T/C polymorphism with soluble CD28 in rheumatoid arthritis.

OBJECTIVE: Rheumatoid arthritis (RA) is an autoimmune disease of unknown etiology in which inflammatory pathology involves T cell activation and the CD28 costimulatory molecule involved in T cell presentation. The gene includes the CD28 IVS3 +17T/C polymorphism that could be associated with susceptibility to RA whereas the soluble concentrations of CD28 (sCD28) could be related to clinical activity. METHODS: We investigated the CD28 IVS3 +17T/C polymorphism in 200 RA patients and 200 healthy subjects (HS). Furthermore, we quantified the sCD28 concentrations in 77 samples of each group. We applied indexes focused to determine the activity and disability (DAS28 and Spanish HAQ-DI, respectively) in RA patients. RESULTS: RA patients had significantly higher frequencies of the CD28 T allele compared to HS (p = 0.032 OR = 1.59, C.I. 1.02-2.49). In addition, the IVS3 +17 T/T genotype frequency was also increased in RA vs. HS (p = 0.026). The RA patients showed higher sCD28 serum levels than HS (p = 0.001). Carriers of the T/T genotype in RA patients showed higher sCD28 levels than C/C carriers (p =0.047). In addition, a correlation between sCD28 and Spanish HAQ-DI (correlation, 0.272; p =0.016), was found. CONCLUSION: The T allele in CD28 IVS3 +17T/C polymorphism is associated with a susceptibility to RA in Western Mexico. In addition, increased sCD28 levels are related to T/T genotype in RA patients.

A novel Leu171Pro mutation in presenilin-1 gene in a Mexican family with early onset Alzheimer disease.

A search for mutations in exons 6, 7, 9 and 12 of the PS1 gene in four Mexican families with Early-Onset (36-40 years) Alzheimer Disease yielded the discovery in one family of a T-->C mismatch in exon 7 which correspond to nucleotide 760 of cDNA, leading to a Leu171Pro mutation. The pedigree analysis and the literature data strongly suggest an etiopathogenic relationship of the mutation with the disorder.