Bone Abstracts

Rheumatoid arthritis (RA) is an immune-mediated disease characterized by T cells activation and bone erosions that severely reduces patients quality of life; however a clear role for different T helper (Th) cells has not been established yet.

This work aims to evaluate Th phenotypes, osteoclast (OCs) precursors cells and cytokines in peripheral blood of women affected by early RA (eRA) compared to healthy women matched for age. The study was approved by our Ethical Committee.

We enrolled in the study 36 women affected by eRA and 31 healthy controls. To quantify OCs precursors and Th subset in peripheral blood we used flow cytometry. We measured classical OCs precursors (CD14+/CD11b+/VNR+) and inflammatory OCs precursors (CD14+/CD11b+/VNR+/CD16+) and Th subset. We also measured TNFα, IFNγ, TGFβ, IL-4, IL-17, IL-23, IL-6, RANKL and OPG in the serum by ELISA.

Th were significantly altered in eRA: Th17 and Th17/IFNγ were increased, whereas Th1, Th2 and Tregs were not significantly affected. Classical OCs were reduced in eR patients whereas inflammatory OCs were increased and correlated with CRP (Rho 0.35, P=0.039).

RANKL/OPG was significantly increased in eRA due to increased RANKL and directly correlated with inflammatory OCs precursors. (R=0.31, P=0.017).

TNFα, TGF-β, IL-23 and IL-6 were significantly increased whereas IL-17 and IFNγ were not.

The increase in inflammatory OC precursors suggests a specific role for these cells in bone erosions and possibly in systemical bone loss in RA.

This is the first attempt to describe Th cells and OC precursors in early phase of RA.

We showed an impairment in Th cells subtypes that may be the first pathogenetic driver in early phase of RA whereas the increase in TGFβ may be due to deregulation in T regulatory cells function. Previous paper showed conflicting results on Th subsets in RA, this is mainly due to different models used.