To investigate whether β1-integrin and/or plexin C1 is implicated in the stimulatory effect of Sema7A observed in monocytes, we first evaluated the mRNA levels of β1-integrin and plexin C1 by quantitative RT-PCR in CD14+ monocytes derived from patients with RA and healthy subjects. Here, PLXNC1 is linked to rheumatoid arthritis.