Increased frequency and compromised function of T regulatory cells in systemic sclerosis (SSc) is related to a diminished CD69 and TGFbeta expression.
BACKGROUND
Regulatory T cells (Tregs) are essential in the control of tolerance. Evidence implicates Tregs in human autoimmune conditions. Here we investigated their role in systemic sclerosis (SSc).


RESULTS
Patients were subdivided as having limited cutaneous SSc (lcSSc, n = 20) or diffuse cutaneous SSc (dcSSc, n = 48). Further subdivision was made between early dcSSc (n = 24) and late dcSSc (n = 24) based upon the duration of disease. 26 controls were studied for comparison. CD3+ cells were isolated using FACS and subsequently studied for the expression of CD4, CD8, CD25, FoxP3, CD127, CD62L, GITR, CD69 using flow cytometry. T cell suppression assays were performed using sorted CD4CD25(high)CD127(-) and CD4CD25(low)CD127(high) and CD3(+) cells. Suppressive function was correlated with CD69 surface expression and TGFbeta secretion/expression. The frequency of CD4(+)CD25(+) and CD25(high)FoxP3(high)CD127(neg) T cells was highly increased in all SSc subgroups. Although the expression of CD25 and GITR was comparable between groups, expression of CD62L and CD69 was dramatically lower in SSc patients, which correlated with a diminished suppressive function. Co-incubation of Tregs from healthy donors with plasma from SSc patients fully abrogated suppressive activity. Activation of Tregs from healthy donors or SSc patients with PHA significantly up regulated CD69 expression that could be inhibited by SSc plasma.


CONCLUSIONS
These results indicate that soluble factors in SSc plasma inhibit Treg function specifically that is associated with altered Treg CD69 and TGFbeta expression. These data suggest that a defective Treg function may underlie the immune dysfunction in systemic sclerosis.
Radstake
Timothy R D J
TR
Department of Rheumatology, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands. T.Radstake@reuma.umcn.nl
van Bon
Lenny
L
Broen
Jasper
J
Wenink
Mark
M
Santegoets
Kim
K
Deng
Yanhui
Y
Hussaini
Anila
A
Simms
Robert
R
Cruikshank
William W
WW
Lafyatis
Robert
R
D000328:Adult; D000911:Antibodies, Monoclonal / Q000737:chemistry; D015703:Antigens, CD / Q000096:biosynthesis*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000096:biosynthesis*; D017252:CD3 Complex / Q000096:biosynthesis; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D053645:Interleukin-2 Receptor alpha Subunit / Q000096:biosynthesis; D053699:Interleukin-7 Receptor alpha Subunit / Q000096:biosynthesis; D037181:Lectins, C-Type; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D012595:Scleroderma, Systemic / Q000276:immunology* / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000096:biosynthesis*; D000099192:CD69 Antigens
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D053645:Interleukin-2 Receptor alpha Subunit; D053699:Interleukin-7 Receptor alpha Subunit; D037181:Lectins, C-Type; D016212:Transforming Growth Factor beta; D000099192:CD69 Antigens