Innate lymphoid cells (ILCs) are emerging mediators of immunity, and accumulation of inflammatory ILC populations can occur in inflammatory-mediated conditions. Since early lymph node (LN) activation has been shown in rheumatoid arthritis (RA), we aimed to investigate the frequency and distribution of ILCs in LN biopsy specimens obtained during the earliest phases of RA.
Twelve patients with early RA, 12 individuals with IgM rheumatoid factor and/or anti-citrullinated protein antibodies without arthritis (RA risk group), and 7 healthy controls underwent ultrasound-guided inguinal LN biopsy. ILC subsets and the expression of vascular cell adhesion molecule (VCAM) and intercellular adhesion molecule (ICAM) by LN endothelial cells and fibroblasts were analyzed by flow cytometry.
Although no differences in the frequencies of total ILCs (Lin-CD45
Our findings indicate that during the at-risk and earliest phases of RA, the ILC distribution in LN changes from a homeostatic profile toward a more inflammatory profile, thereby providing evidence of a role for ILCs in RA pathogenesis.