Expression of intracellular transforming growth factor-beta1 in CD4+CD25+ cells in patients with systemic lupus erythematosus.
ABSTRACT The CD4+CD25+ regulatory T (Treg) cells exert immunoregulatory functions in various autoimmune diseases, in part through transforming growth factor-beta1 (TGF-beta1), and can be expanded by TGF-beta1 stimulation in normal subjects. This study aimed to examine intrinsic TGF-beta1 expression and the response to TGF-beta1 stimulation of this CD4+CD25+ subset in patients with systemic lupus erythematosus (SLE).
Flow cytometry with multicolor staining of CD4+, CD25+, and TGF-beta1 was used to quantify the percentage of CD4+CD25+ T cells in fresh peripheral blood and TGF-beta1-stimulated peripheral blood mononuclear cell (PBMC) cultures, and their corresponding intracellular TGF-beta1 expression.
In fresh peripheral blood, we found that decreased percentages of CD4+CD25+/CD4+ in SLE patients were associated with disease activity and renal involvement. Intracellular TGF-beta1 expression of CD4+CD25+ cells was significantly elevated in SLE compared with matched controls (p<0.001). In addition, there was significant negative correlation between TGF-beta1 expression and percentage of CD4+CD25+ cells present (r = -0.432, p=0.004). Nevertheless, in ex vivo unstimulated PBMC cultures, the percentage and intracellular TGF-beta1 expression of CD4+CD25+ cells of SLE were normalized to the levels of the control group. In TGF-beta1-stimulated PBMC cultures, CD4+CD25+ cells and their intracellular TGF-beta1 expression were significantly increased (p<0.001), both in SLE and controls. Moreover, the increments in the percentage of CD4+CD25+ cells and intracellular TGF-beta1 expression by TGF-beta1 stimulation were comparable in SLE and controls, and were not significantly influenced by disease activity or renal involvement in SLE.
CD4+CD25+ cells were deficient in peripheral blood but not impaired either in intrinsic TGF-beta1 expression or in response to TGF-beta1 stimulation in patients with SLE. This study suggests that TGF-beta1, by inducing CD4+CD25+ cells, has potential clinical application in treating SLE.
Article: Low frequency of CD4+CD25+ Treg in SLE patients: a heritable trait associated with CTLA4 and TGFbeta gene variants.[show abstract] [hide abstract]
ABSTRACT: CD4+CD25+ regulatory T cells play an essential role in maintaining immune homeostasis and preventing autoimmunity. Therefore, defects in Treg development, maintenance or function have been associated with several human autoimmune diseases including Systemic Lupus Erythematosus (SLE), a systemic autoimmune disease characterized by loss of tolerance to nuclear components and significantly more frequent in females. To investigate the involvement of Treg in SLE pathogenesis, we determined the frequency of CD4+CD25+CD45RO+ T cells, which encompass the majority of Treg activity, in the PBMC of 148 SLE patients (76 patients were part of 54 families), 166 relatives and 117 controls. SLE patients and their relatives were recruited in several Portuguese hospitals and through the Portuguese Lupus Association. Control individuals were blood donors recruited from several regional blood donor centers. Treg frequency was significantly lower in SLE patients than healthy controls (z = -6.161, P < 0.00001) and intermediate in the relatives' group. Remarkably, this T cell subset was also lower in females, most strikingly in the control population (z = 4.121, P < 0.001). We further ascertained that the decreased frequency of Treg in SLE patients resulted from the specific reduction of bona fide FOXP3+CD4+CD25+ Treg. Treg frequency was negatively correlated with SLE activity index (SLEDAI) and titers of serum anti-dsDNA antibodies. Both Treg frequency and disease activity were modulated by IVIg treatment in a documented SLE case. The segregation of Treg frequency within the SLE families was indicative of a genetic trait. Candidate gene analysis revealed that specific variants of CTLA4 and TGFbeta were associated with the decreased frequency of Treg in PBMC, while FOXP3 gene variants were associated with affection status, but not with Treg frequency. SLE patients have impaired Treg production or maintenance, a trait strongly associated with SLE disease activity and autoantibody titers, and possibly resulting from the inability to convert FOXP3+CD25- into FOXP3+CD25+ T cells. Treg frequency is highly heritable within SLE families, with specific variants of the CTLA4 and TGFbeta genes contributing to this trait, while FOXP3 contributes to SLE through mechanisms not involving a modulation of Treg frequency. These findings establish that the genetic components in SLE pathogenesis include genes related to Treg generation or maintenance.BMC Immunology 02/2009; 10:5. · 2.53 Impact Factor