Abstracts (complete list) - Wissenschaft Online

Jan Leipe, Alla Skapenko, Hendrik Schulze-Koops
Characterization of human Interleukin 17 (IL-17)-producing T
helper cells (Th17 cells) in healthy individuals and in patients
with rheumatoid arthritis
Th17 cells have recently been described as a distinct pro-inflammatory CD4 T cell
population that contributes to the development of several autoimmune disorders in
murine disease models. Their role in human autoimmune diseases, however, is less
clear as their phenotype and effector functions in humans has not been thoroughly
delineated. We analyzed Th17 cells in healthy human individuals and in patients with
the prototype autoimmune disease, rheumatoid arthritis. CD4 T cell-derived IL-17 was
detected by ELISA in the culture supernatants of ex vivo activated freshly isolated
mononuclear cells from the peripheral circulation of healthy individuals and RA patients
indicating the presence of Th17 cells in the peripheral circulation of both, controls and
patients. IL-17 was also produced by CD4 T cells from the synovial fluid of patients with
RA. Expression of IL-17 could be induced from highly purified memory CD4 T cells by
TCR stimulation with mAbs to CD3 and further enhanced by costimulation via CD28. Of
interest, IL-17 production was not modulated by IL-6 or TGF-beta, both of which have
been implicated in Th17 differentiation in mice. In contrast to memory T cells, naive
cells did not produce IL-17, even in the presence of IL-23. Together, the data indicate
the presence of IL-17-producing CD4 T cells in patients with rheumatoid arthritis but
also in healthy individuals. The precise function of these cells in autoimmune diseases,
therefore, remains to be shown.