Our results show that IL-25 levels increased in the supernatants of PBMC from CS and RA after stimulation with LPS, providing the first report on said response in CS and RA PBMC and supporting what was described by Liu et al. [7] on the effect of LPS on IL-25 production (studied in bronchial epithelial cells in vitro). This evidence concerns the gene IL25 and rheumatoid arthritis.