Our study complemented previous studies that showed that caspase 1 level in CTD inclduing rheumatoid arthritis, SLE, Sjogren’s syndrome, dermatomyositis and so on, whether in tissues or in plasma, increased significantly (Cascao et al., 2012; Guo et al., 2018; Monteith et al., 2018; Vakrakou et al., 2018; Yin et al., 2016; Zhai et al., 2018). Here, CASP1 is linked to rheumatoid arthritis.