RESUMO
Objective:To explore the expression level of interleukin-1 receptor-associated kinase-1 (IRAK1) in the peripheral blood of rheumatoid arthritis (RA) patients and analyze its relevance between disease activity and CD4 + T cell subsets. Methods:① The concentration of IRAK1 in the peripheral blood of 77 RA patients and 24 healthy controls were detected by enzyme linked immunosorbent assay (ELISA). ② The demo-graphic and clinical data of the RA group including disease activity score with 28 joints (DAS28), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), CD4 + T cell subsets in peripheral blood. ③Independent sample t test or Mann-Whitney U test were used to compare the differences between the two groups. Spearman rank correlation test and multiple linear regression were used to analyze the correlation between IRAK1 expression level and clinical data. Results:① The IRAK1 level of the peripheral blood of RA patients was significantly higher than in the normal controls ( P<0.001). ② Compared to normal controls, the peripheral blood of the RA group, the absolute numbers and proportion of regulatory T (Treg) cells were decreased ( P<0.001), the absolute numbers and proportion of helper T (Th) 17 and the ratio of Th17/Treg were increased. Moreover, the ratio of Th17/Treg was also increased. ③ With the increase of disease activity in RA patients, the expression of IRAK1 also increased. The expression of IRAK1 in the peripheral blood of RA group was positively correlated with ESR, number of joints involved and DAS28, and had statistically significant difference between the two groups ( r=0.23, P<0.05; r=0.24, P<0.05; r=0.27, P<0.05). Meanwhile, it was sign-ificantly negatively correlated with the percentage of Treg ( r=-0.27, P<0.05), and was significantly positively correlated with the ratio of Th17/Treg ( r=0.23, P<0.05) . However, there was no significant correlation with the ratio of Th1/Th2( P>0.05). Furthermore, multiple stepwise regression analysis showed that the expression of IRAK1 in the peripheral blood of RA group was positively correlated with ESR and the number of joints involved ( β=0.34, P=0.019; β=0.27, P=0.004), and it was inversely correlated with percentage of Treg ( β=-0.23, P=0.047, R2=0.219). Conclusion:IRAK1 expression in the peripheral blood of RA patients is up-regulated and correlated with disease activity. The decrease of Treg and the imbalance of Th17/Treg caused by high expression of IRAK1 may be one of the main factors for the occurrence and development of RA. Interfering the expression of IRAK1 may be a potential new target for RA treatment.
