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Background: Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by autoantibody production and diverse tissue and organ inflammatory affections. Interleukin 21 (IL-21) is implicated in B cell survival, proliferation, differentiation, class switching, and immunoglobulin production; therefore, it is considered a key cytokine in the pathogenesis of SLE. However, its association with disease activity and clinical phenotypes remains unclear. We aimed to evaluate the association of IL-21 levels with the disease activity and clinical phenotypes in patients with SLE. Also, we analyzed the IL21 polymorphisms associated with increased IL-21 levels. Methods: The IL-21 serum levels were determined using the enzyme-linked immunosorbent assay (ELISA) method. The rs2221903 and rs2055979 polymorphisms were assessed in 300 healthy controls (HCs) and 300 patients with SLE by the polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) technique. The levels of IL-21 were monitored during follow-up visits in 59 patients with SLE. Results: The patients with SLE showed higher IL-21 levels compared to the HCs. The IL-21 levels did not correlate with Mex-SLEDAI and were not different in patients with inactive, mild–moderate, and severe disease. The IL-21 levels were increased in patients with hematological affection. The ROC curve analysis revealed that the IL-21 levels had good predictive power in discriminating among patients with SLE and HCs. In a follow-up analysis, the levels of IL-21 remained higher in the patients with SLE even when the patients were in remission. Also, the rs2221903 polymorphism was associated with increased IL-21 levels. Conclusions: This study highlights the importance of IL-21 as a key cytokine in SLE. IL-21 levels are higher in patients with SLE and remain increased regardless of disease activity. According to the ROC analysis, IL-21 is a potential biomarker of SLE. Further longitudinal studies are needed to explore the relationship between IL-21 and the clinical phenotypes of SLE. [ABSTRACT FROM AUTHOR]

Aim: The aim of this case‐control study was to evaluate the association between the TNFSF13B rs9514828 (−871 C > T) polymorphism and soluble BAFF (sBAFF) in apical periodontitis (AP) patients. Methodology: Two hundred and sixty one healthy subjects (HS) and 158 patients with AP classified as: 46 acute apical abscess (AAA), 81 primary AP (pAP) and 31 secondary AP (sAP) patients were included. Genomic DNA (gDNA) was extracted from peripheral blood cells according to the salting out method. The TNFSF13B rs9514828 (NC_000013.11:g.108269025C > T) were identified using polymerase chain reaction (PCR) followed by restriction fragment length polymorphisms (RFLP). Serum sBAFF levels were measured by ELISA test. The chi‐squared or Fisher's exact test was performed. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated to evaluate the risk of AP associated with the rs9514828. The Mann–Whitney U test and Kruskal–Wallis analysis were used for non‐normally distributed data. Differences were considered significant with a p‐value <.05. Results: No differences in the genotype/allele frequencies were shown between HS and patients with AAA. However, the TT genotype (OR = 2.68, 95% CI: 1.10–6.53; p =.025) and T allele (OR = 1.46, 95% CI: 1.00–2.12; p =.045) were associated with increased risk of pAP. In contrast, the minor allele T significantly decreased the risk of sAP (OR = 0.49, 95% CI: 0.024–0.99; p =.043). sBAFF serum levels were increased in AAA and pAP compared with HS (p <.01 and p =.021, respectively). The AAA patients had higher sBAFF serum levels than pAP (p =.034) and sAP (p <.01). Conclusions: These results suggest that the TNFSF13B rs9514828 (−871 C > T) polymorphism is associated with pAP susceptibility and that BAFF is a cytokine that might be involved in acute and chronic AP. The future exploration of the rs9514828 polymorphism in other AP cohorts is recommended. [ABSTRACT FROM AUTHOR]

Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune inflammatory disease characterized by loss of self-tolerance with hyperactivation of autoreactive T and B cells. Protein tyrosine phosphatase non- receptor type 22 ( PTPN22) encodes for lymphoid-specific phosphatase (Lyp), which is a key negative regulator of T lymphocyte activation. The aim of this study was to evaluate the genetic contribution of PTPN22 −1123G>C and +1858C>T polymorphisms and their haplotypes in SLE patients, as well as mRNA expression according to −1123G>C promoter polymorphism and disease activity. One hundred and fifty SLE patients and 150 unrelated healthy controls (HC), both Mexican mestizos, were genotyped by PCR-RFLP technique for the PTPN22 −1123G>C and +1858C>T polymorphisms. PTPN22 mRNA expression levels were determined by real-time PCR from PBMCs of thirty patients with SLE and fifteen HC carrying different genotypes. Distributions of genotype and allelic frequencies were similar between SLE and HC. The most frequent alleles were −1123 G and +1858 C in both groups (69 vs. 66 % and 97 vs. 98 %, in SLE and HC, respectively). However, the recessive model of inheritance analysis showed a lower frequency of −1123 CC genotype in SLE patients (7 vs. 15 %), suggesting a protection effect to develop SLE (OR 0.41, CI 1.10-5.28, p = 0.02). Haplotype analysis showed strong linkage disequilibrium D′ = 0.98 for PTPN22 −1123G>C and +1858C>T polymorphisms, but haplotypes were not associated with SLE. The PTPN22 mRNA expression did not show differences among −1123G>C genotypes; nevertheless, a significant negative correlation with disease activity was found ( r = −0.64, p < 0.01). SLE inactive patients showed similar PTPN22 mRNA expression levels to healthy controls, whereas in patients with severe flare, the expression was nearly depleted. In conclusion, we found a lack of association of PTPN22 −1123G>C and +1858C>T polymorphisms with the risk of developing SLE in a Mexican population. Moreover, decreased or absent PTPN22 mRNA expression in SLE patients with severe flare suggests that Lyp plays an important regulatory role, and its absence contributes to the inflammatory response and disease activity in SLE. However, further analysis in a prospective study could help us determine its usefulness as a genetic marker of disease activity in SLE. [ABSTRACT FROM AUTHOR]

The influence of genetic factors in rheumatoid arthritis (RA) has been described, including several cytokine genes such as transforming growth factor β (TGF-β) with regulatory effects on lymphocytes, dendritic cells, macrophages, chondrocytes, and osteoblasts, which are important in the RA pathogenesis. The G915C TGF- β1 polymorphism has been associated with soluble TGF-β1 (sTGF-β) serum levels. Thus, we studied the association of G915C (Arg25Pro) TGF- β1 polymorphism with sTGF-β1 serum levels in RA. We enrolled 120 RA patients and 120 control subjects (CS). The G915C TGF- β1 polymorphism was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method, and sTGF-β1 serum levels were quantified using an ELISA kit. The genotype frequency of G915C TGF- β1 polymorphism in RA and CS was G/G (91.7%), G/C (8.3%), C/C (0%) and G/G (85.8%), G/C (14.2%), C/C (0%), respectively, without significant differences. Moreover, the G/G TGF- β1 genotype carriers presented the highest disability index evaluated for the Spanish HAQ-DI score ( P < 0.001). In addition, the sTGF-β1 serum levels were higher in RA (182.2 ng/mL) than CS (160.2 ng/mL), there was not significant difference. However, we found a positive correlation between the sTGF-β1 serum levels and the functional class ( r = 0.472, P = 0.023). In conclusion, the G915C (Arg25Pro) TGF- β1 polymorphism is not associated with RA, but the sTGF-β1 serum levels are related with the functional class in RA. [ABSTRACT FROM AUTHOR]

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by the presence of autoantibodies against nuclear autoantigens as well as cytoplasmic and circulating proteins. Recent studies have demonstrated mechanisms responsible for modulation of the immune response by the plasminogen activator inhibitor-1 (PAI-1). Furthermore, the endogenous PAI-1 has shown to promote a Th2 immune response. We assessed the −844 G>A and HindIII C>G PAI- 1 polymorphisms in SLE. In a case-control study of 71 SLE patients classified according to ACR criteria and 71 healthy subjects (HS). The A allele of −844 PAI- 1 polymorphism showed a significant difference in SLE patients (41%) when compared with HS (27%) [ P = 0.01; OR = 1.8, 95%, CI = 1.1-3.0]. In addition, the −844 G>A PAI- 1 polymorphism was associated with increased risk for SLE in a dominant genetic model (G/G vs. G/A + A/A; OR = 2.3, 95% CI = 1.14-4.44). Also, anti-RNP positive antibodies in SLE were associated with G/G −844 PAI- 1 genotype. The HindIII polymorphism did not show any differences. The haplotype analysis showed that the AC haplotype confers susceptibility to SLE (OR = 3.1, 95% CI, 1.45-6.52; P = 0.003). The AC haplotype of the −844 and HindIII PAI- 1 polymorphism might be an additional susceptibility factor to SLE in Mexicans. [ABSTRACT FROM AUTHOR]

Plasminogen activator inhibitor type 1 (PAI-1) is an inhibitor of plasmin production. Plasmin can directly or indirectly to degrade cartilage and bone matrix. The PAI-1 HindIII polymorphism has been associated with high PAI-1 plasma levels in myocardial infarction patients and control populations. Furthermore, it has been associated with the angiographic extent of coronary artery disease, but their involvement in other diseases is still uncertain. Here, we assessed the relationship between PAI-1 HindIII polymorphism and PAI-1 plasma levels in rheumatoid arthritis (RA). One hundred and twenty-five RA patients and 132 control subjects (CS) were included. Genotypes were identified by the polymerase chain reaction-restriction fragment length polymorphism technique and PAI-1 plasma levels were quantified using an ELISA kit. Not significant differences in genotype and allele frequencies between both studied groups were observed ( P > 0.05). RA patients showed lower PAI-1 plasma levels (18.92 ± 12.94 ng/ml) than CS (23.68 ± 23.38 ng/ml), without significant difference ( P = 0.299). However, in RA patients the C/G genotype carriers showed higher PAI-1 plasma levels (23.00 ± 13.81 ng/ml) with respect to C/C (16.77 ± 11.97 ng/ml) and G/G (10.47 ± 7.07 ng/ml) genotype carriers ( P = 0.036). The PAI-1 HindIII polymorphism was not associated with RA susceptibility. However, the C/G genotype is associated with high PAI-1 plasma levels in RA patients. [ABSTRACT FROM AUTHOR]

Background: CD40 is a transmembrane protein mainly expressed on the antigen‐presenting cells surface. CD40 plays a crucial role in immunoglobulin class switching and antibodies production. Genetic polymorphisms in the CD40 gene have been associated with increased risk of systemic lupus erythematosus (SLE) in several populations. This study aimed to evaluate the association of CD40 polymorphisms (−1 C > T, rs1883832 and 6,048 G > T, rs4810485) with SLE susceptibility, as well as with mRNA expression and soluble CD40 (sCD40) levels. Methods: The study included 293 patients with SLE and 294 control subjects (CS). Genotyping was performed by PCR‐RFLP method. CD40 mRNA expression was determined by quantitative real‐time PCR, and ELISA quantified sCD40 levels. Results: The CD40 polymorphisms −1 C > T and 6,048 G > T were associated with SLE susceptibility. There was no difference between CD40 mRNA expression and CD40 polymorphisms. The sCD40 levels were lower in SLE patients with TT haplotype, whereas higher sCD40 levels were associated with damage and impaired renal function according to SLICC and KDIGO. The sCD40 levels were negatively correlated with eGFR. Conclusion: The CD40 gene polymorphisms increase the risk of SLE in the western Mexican population. The sCD40 levels are associated with −1 C > T polymorphism and chronic kidney disease. [ABSTRACT FROM AUTHOR]

Peptidyl arginine deiminase IV (PADI4) enzyme catalyzes the citrullination of proteins, which are recognized by anti-cyclic citrullinated peptide antibodies (anti-CCP) in rheumatoid arthritis (RA) patients. Here, we determined the association between PADI4 gene polymorphisms and haplotypes with RA susceptibility and clinical characteristics in a western Mexican population. The relationship of PADI4 polymorphisms with anti-CCP and PADI4 mRNA expression was also evaluated. PADI4_89, PADI4_90 and PADI4_92 polymorphisms were individually associated with RA susceptibility. The GTG haplotype was significantly associated with: RA susceptibility; disease onset at ≤40 years and anti-CCP antibodies. PADI4 expression was three fold higher in RA patients carrying the susceptibility haplotype (GTG) than in non-susceptibility haplotype carriers (ACC). In conclusion, polymorphisms and functional haplotype (GTG) in PADI4 are associated with RA susceptibility as well as anti-CCP antibodies in a Mexican population. This supports the role of PADI4 early in RA pathogenesis by promoting the generation of citrullinated autoantigens. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Rheumatoid arthritis (RA) is a common autoimmune disease with a complex genetic background. The PTPN22 gene encodes lymphoid tyrosine phosphatase LYP, a potent negative regulator of T cell activation. Polymorphic variants of this gene have previously been associated with various autoimmune disorders. The +1858C/T single-nucleotide polymorphism (SNP) (rs2476601), in the exon 14 of the PTPN22 gene has been associated with susceptibility to RA in several population. Objective: The aim of this work was to investigate whether the +1858C/T of the PTPN22 gene is associated with susceptibility to RA in Western Mexico population. Methods: A total of 309 unrelated RA patients, classified according to American College of Rheumatology (ACR) 1987 criteria, as well as 347 controls residents from Western Mexico were recruited for this study. The DNA samples were genotyped for +1858C/T PTPN22 gene SNP using the PCR-RFLP technique. Antibodies to cyclic citrullinated peptides (anti-CCP) were measured by enzyme-linked immunosorbent assay (ELISA). Results: The frequency of +1858T risk allele was significantly increased in patients with RA compared with controls (p =0.001, OR=2.83, 95%CI=1.50–5.32). To confirm this results we established a comparison between subjects carrying of CT+TT genotypes versus those carrying CC genotype, between both groups (p =0.004, OR=2.65, 95%CI=1.33–5.36). Nevertheless, we not observed association of the +1858C/T PTPN22 gene SNP with clinical activity and functional disability in RA patients. Likewise, the +1858T variant in RA patients seropositive for anti-CCP antibodies, increased the risk for RA (p =0.008, OR=2.5, 95%CI=1.3–5.0) when we compared with controls; however, in the group of seronegative patients, no was found significant difference (p =0.1, OR=2.5, 95%CI=0.9–7.2). Conclusions: Our results support the association of the +1858T risk allele of the +1858C/T PTPN22 polymorphism with susceptibility to RA and confirm that, in combination with anti-CCP antibodies, this SNP influence the autoimmune processes towards a development of RA in Mexican population. [Copyright &y& Elsevier]

To investigate the association of sICAM-1 and sVCAM-1 with ICAM1 721G>A and VCAM1 1238G>C polymorphisms and rheumatoid arthritis (RA) clinical activity, sixty RA patients and 60 healthy non-related subjects (HS) matched for age and sex were recruited. Soluble adhesion molecules were determined by ELISA technique. Rheumatoid factor (RF), C reactive protein (CRP) and the erythrocyte sedimentation rate (ESR) were measured by routine methods. Disability and clinical activity was measured with Spanish-HAQ-DI and DAS28 scores, respectively. The ICAM1 and VCAM1 polymorphism were identified using the PCR-RFLP procedure. Inter-group comparison showed increased levels of sICAM-1 and sVCAM-1 in RA patients (284 and 481 ng/mL) versus HS (132 and 280 ng/mL); in the RA group, significant correlations between sVCAM-1 and RF (r = 0.402), ESR (r = 0.426), Spanish-HAQ-DI (r = 0.276), and DAS28 (r = 0.342) were found, whereas sICAM-1 only correlated with RF (r = 0.445). In RA patients, a significant association with the 721A allele of ICAM1 polymorphism (p = 0.04), was found. In addition, the allele impact (G/A+A/A) of this polymorphism was confirmed, (p = 0.038, OR = 2.3, C.I. 1.1–5.0). sVCAM-1 and sICAM-1 serum levels reflected the clinical status in RA, independently of the ICAM1 and VCAM1 polymorphism. However, the ICAM1 721A allele could be a genetic marker to RA susceptibility. [ABSTRACT FROM AUTHOR]