Decreased serum TIMP4 levels in patients with rheumatoid arthritis.

The current study was designed to explore the clinical significance of serum tissue inhibitor of metalloproteinase 4 (TIMP4) levels in rheumatoid arthritis (RA). The GSE1919 chip was analyzed, differentially expressed genes (DEGs) were identified, and gene ontology as well as Kyoto Encyclopedia of Genes and Genomes analyses of the identified DEGs were conducted. Patients with RA (n = 96) and healthy individuals (n = 96) were enrolled in this study. Serum from the participants was collected, and RT-qPCR as well as WB have been conducted to examine TIMP4 levels; additionally, interleukin (IL)-6 and IL-1β levels were determined using the ELISA method. Pearson's correlation analysis was conducted for evaluating relationships between the expression levels of TIMP4 and those of IL-6 or IL-1β. A receiver operating characteristic (ROC) curve was drawn to determine the potential diagnostic value of serum TIMP4 for RA. TIMP4 was identified as a markedly downregulated gene involved in RA development. TIMP4 levels were significantly decreased in patients with RA, and the results of the ROC analysis showed that TIMP4 may be a potential diagnostic marker. Furthermore, the concentrations of IL-6 and IL-1β were markedly elevated in patients with RA. Finally, TIMP4 levels showed negative correlation with the levels of either IL-6 or IL-1β. TIMP4 is downregulated in RA and is a reliable serum marker for RA diagnosis.