To investigate the associations of DNA methylation levels and mRNA expressions of DNA cytosine-5-methyltransferase 1 (DNMT1) and methyl CpG-binding domain 2 (MBD2) with systemic lupus erythematosus (SLE), 108 patients with SLE and 97 healthy controls were enrolled in this study. DNA and total RNA were extracted from the peripheral blood mononuclear cells of the SLE patients and the controls. The global methylation levels of DNA were measured in 63 patients with SLE and 68 healthy controls by the ELISA method. DNMT1 and MBD2 mRNA were also detected in 108 SLE patients and 97 controls using the quantitative real-time polymerase chain reaction method. The global methylation level of DNA was significantly decreased in the SLE patients in comparison with that in the controls (p < 0.001, 95% CI = 0.1573-0.5052). The patients with SLE have higher expressions of DNMT1 and MBD2 mRNA than the controls (p < 0.001, 95% CI = -0.0049 - -0.0019 and p = 0.001, 95% CI = -0.0119 - -0.0029, respectively). We also found that there were no significant differences in the methylation level and the expression of DNMT1 and MBD2 mRNA between the active and the inactive SLE patients. A positive correlation was also found between DNMT1 and MBD2 mRNA expressions in the SLE patients (p < 0.001). This study demonstrated that the patients with SLE had a significantly lower level of DNA methylation than the controls. The expression of both DNMT1 and MBD2 mRNA was significantly increased in the SLE patients compared with the controls. This study also showed a positive correlation between DNMT1 and MBD2 mRNA levels in the patients with SLE.

ABSTRACT. Epidemiological studies have indicated that folate metabolism is correlated with increased risk of gastric cancer. Since methylenetetrahydrofolate reductase (MTHFR) is an important enzyme involved in folate metabolism, in this study, we examined whether polymorphisms and haplotypes of MTHFR are correlated with the risk of gastric cancer. The polymorphisms MTHFR C677T and MTHFR A1298C were genotyped by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analysis in 285 patients and 570 healthy controls. Association analyses based on binary logistic regression were conducted to determine the odds ratio (OR) and its 95% confidence interval (95%CI) for each genotype. The MTHFR 677TT genotype was significantly related with a reduced risk of gastric cancer (OR = 0.60, 95%CI = 0.39-0.92) compared to the CC genotype. Similarly, the MTHFR 1298CC genotype was significantly MTHFR and risk of gastric cancer associated with a decreased risk of cancer (OR = 0.52, 95%CI = 0.32-0.81). Haplotype analysis showed that the TC haplotype was associated with a reduced risk of gastric cancer compared to the most common haplotype, CA (OR = 0.28, 95%CI = 0.12-0.60). Our results suggest that the MTHFR C677T and MTHFR A1298C polymorphisms are related to gastric cancer susceptibility in the Chinese population.

With the aim of investigating the role of suppressor of cytokine signaling 1 (SOCS1) in the pathogenesis of systemic lupus erythematosus, 107 patients with systemic lupus erythematosus, 101 healthy controls, and 151 patients with ankylosing spondylitis were enrolled in this study. SOCS1 mRNA level was measured by the method of quantitative real-time polymerase chain reaction. SOCS1 polymorphisms were detected by the polymerase chain reaction/restriction fragment length polymorphisms method. Systemic lupus erythematosus disease activity was evaluated with the SLEDAI. This study showed that the SOCS1 mRNA expression was significantly higher in the patients with systemic lupus erythematosus than in the healthy controls (p = 0.0014). Patients with active systemic lupus erythematosus had a higher expression of SOCS1 mRNA than the patients with inactive systemic lupus erythematosus (p = 0.035). There was no significant difference in the frequencies of the SOCS1-1478CA/del polymorphisms among the patients with systemic lupus erythematosus, healthy controls, and patients with ankylosing spondylitis. The genotype frequency of the SOCS1-1478 polymorphisms in the dominant model (CA/del+del/del versus CA/CA) was significantly decreased in the patients with thrombocytopenia compared with those without thrombocytopenia (p(c) = 0.035). Moreover, the allele frequency of SOCS1-1478del was also significantly lower in the patients with thrombocytopenia than in those without thrombocytopenia (p( c) = 0.02). In conclusion, this study demonstrated that the expression of SOCS1 mRNA was significantly increased in patients with systemic lupus erythematosus. Moreover, SOCS1 mRNA levels in patients with active systemic lupus erythematosus were significantly higher than those in the inactive patients. We also found that the systemic lupus erythematosus patients with thrombocytopenia have a lower frequency of SOCS1-1478del compared with patients without thrombocytopenia.

The bactericidal activity of monocytes in patients with ReA is lower than that in healthy controls. The SLC11A1 274C/T and 823C/T polymorphisms may be associated with the decreased bactericidal activity of the monocytes.