Elevated number of recently activated T cells in bone marrow of patients with rheumatoid arthritis: a role for interleukin 15?. Issue 1 (26th October 2010)

• Record Type: Journal Article
• Authors: Kuca-Warnawin, Ewa; Burakowski, Tomasz; Kurowska, Weronika; Prochorec-Sobieszek, Monika; Radzikowska, Anna; Chorazy-Massalska, Magdalena; Maldyk, Pawel; Kontny, Ewa; Maslinski, Wlodzimierz
• Is Part Of: Annals of the rheumatic diseases. Volume 70:Issue 1(2011)
• Page Start: 227
• Page End: 233
• Publication Date: 2010-10-26
• Subjects: Rheumatism -- Periodicals; 616.723005
• DOI: 10.1136/ard.2009.124966
• Languages: English
• ISSNs: 0003-4967

Abstract

Abstract : Objectives: (1) To compare the absolute T-cell numbers in bone marrow (BM) isolated from patients with rheumatoid arthritis (RA) and osteoarthritis (OA); (2) to measure the levels of soluble interleukin 15 (IL-15) and IL-7; (3) to analyse the expression of activation markers on T cells; (4) to analyse influence of IL-15 stimulation on T-cell proliferation. Methods: BM samples were obtained from patients undergoing joint replacement surgery. Concentrations of IL-15 and IL-7 were measured using specific ELISAs. The absolute number of T lymphocytes, their activation status and proliferation were evaluated by flow cytometry. Results: BM from patients with RA contained double the number of CD3 T cells in comparison with OA (6.1 vs 2.7 × 10 6 cells/ml, p<0.008). Ratio CD3CD4:CD3CD8 was increased in RA BM, clearly indicating accumulation of CD3CD4 cells. T cells obtained from patients with RA expressed higher level of early activation markers than from OA. Elevated levels of IL-15 were found in BM plasma from patients with RA in comparison with patients with OA (1304.5±956.3 pg/ml and 760±238.7 pg/ml respectively, p<0.01). These data were confirmed by immunohistochemistry of RA BM from regions proximal and distal to the joint. Although both CD3CD4 and CD3CD8 cells proliferated after IL-15 stimulation in vitro, CD3CD4 cells from patients with RA proliferated more vigorously than those from patients with OA, reflecting the composition of T-cell subsets in BM. Conclusion: These results suggest that locally overproduced IL-15 may be responsible for the activation and proliferation of T cells in situ, reflected by significantly increased number of activated T cells in RA BM, possibly contributing to the pathogenesis of RA.