Lower circulating levels of IL-7 in rheumatoid arthritis (RA). IL-7 levels were measured in serum samples taken longitudinally from RA patients (n = 6 at baseline and 1 month, n = 4 subsequently; patients without relapse all from cohort 3) or patients with lymphoma, cancer or systemic vasculitis (n = 4 up to 3 month, n = 2 afterward), all of whom were lymphopenic for up to 3 months after lymphodepleting therapies. IL-7 circulating levels remained low in RA patients, compared with a substantial rise in the mixed cohort of non-RA patients.
Ponchel et al. Arthritis Res Ther 2005 7:R80-R92 doi:10.1186/ar1452