IL-6: positive correlation with the four genes; IL-8 and COX-2: no correlation for any gene; VEGF: positive correlation with MGMT and RARβ, no correlation with RASSF1A and CDH13.
IL-6/Illumina HumanMethylation27K DNA Analysis BeadChip
Among patients with lifetime depression, there was a significant inverse correlation between methylation of IL-6 and serum levels of IL-6 and CRP (Pearson r=-0.54, p=0.001 and Pearson r=-0.48, p=0.006, respectively.
Hypomethylation of -145C was correlated with higher IL-10 mRNA expression (r=-0.746, p=0.001). The authors did not report the results for the other CpG sites.
IL-10: Susceptibility to HIV type 1, rheumatic conditions, cutaneous leishmaniasis.
No significant correlation was observed between the circulating levels of leptin and the methylation frequencies of the two selected CpG sites of LEP promoter (at − 51 and − 31 nt).
A positive trend between the levels of SOCS-1 methylation and CRP levels was observed (R2=0.1127, p=0.0278). Patients with serum IL-6 above median showed a significantly higher SOCS-1 methylation than the patients with serum IL-6 below median (p<0.001). Similar results were observed for TNF-α (p<0.001).
SOCS-1: Cancer, hepatic system diseases, ophthalmological diseases.
LY86 gene, 6 CpG sites / HumanMethylation 27 BeadChip and ThumanMethylation 450 BeadChip from Illumina
Age, sex, race, BMI and batch
They performed a principal component analysis to combine the six CpG sites into one score. The score of these CpG sites was significantly associated with fibrinogen (partial r=0.145, p<0.001) and CRP (partial r=0.114, p=0.005).
Plasma CRP levels were significantly associated with IL-6 promoter methylation (p=0.025). One interquartile range increase in plasma CRP was associated with a decrease in IL-6 methylation by 0.78% (95% CI: -1.47% to -0.1%).
Results showed correlations between LEPR methylation and concentration of LEP (r=-0.24, p=0.047). Also, between EEF2 methylation and concentration of TNF-α (r=0.24, p= 0.0408) and CRP (r=0.24, p=0.0457).
IPA: Inflammatory response, cardiovascular disease, reproductive system diseases.