Cell-contact-dependent activation of CD4+ T cells by adhesion molecules on synovial fibroblasts

Objective: To determine how cell–cell contact with synovial fibroblasts (SF) influence on the proliferation and cytokine production of CD4^+?T cells.

Methods: Naïve CD4^+?T cells were cultured with SF from rheumatoid arthritis patients, stimulated by anti-CD3/28 antibody, and CD4^+?T cell proliferation and IFN-γ/IL-17 production were analyzed. To study the role of adhesion molecules, cell contact was blocked by transwell plate or anti-intracellular adhesion molecule-1 (ICAM-1)/vascular cell adhesion molecule-1(VCAM-1) antibody. To study the direct role of adhesion molecules for CD4^+?T cells, CD161^+?or CD161^- naïve CD4^+?T cells were stimulated on plastic plates coated by recombinant ICAM-1 or VCAM-1, and the source of IFN-γ/IL-17 were analyzed.

Results: SF enhanced naïve CD4^+?T cell proliferation and IFN-γ/IL-17 production in cell-contact and in part ICAM-1-/VCAM-1-dependent manner. Plate-coated ICAM-1 and VCAM-1 enhanced naïve CD4^+?T cell proliferation and IFN-γ production, while VCAM-1 efficiently promoting IL-17 production. CD161^+?naïve T cells upregulating LFA-1 and VLA-4 were the major source of IFN-γ/IL-17 upon interaction with ICAM-1/VCAM-1.

Conclusion: CD4^+?T cells rapidly expand and secrete IFN-γ/IL-17 upon cell-contact with SF via adhesion molecules. Interfering with ICAM-1-/VCAM-1 may be beneficial for inhibiting RA synovitis.     

Analysis of Th1 and Th2 cytokines expressing CD4+ and CD8+ T cells in rheumatoid arthritis by flow cytometry

OBJECTIVE: A Th1/Th2 cytokine imbalance with a predominance of Th1 cytokines has been suggested to be of pathogenetic importance in rheumatoid arthritis (RA). To evaluate the role of Th1/Th2 cytokines in RA, we used intracellular cytokine flow cytometry to determine cytokine profiles of CD4+ and CD8+ T cells in 34 peripheral blood (PB) and 10 synovial fluid (SF) samples from patients with RA. Results were compared with 10 PB samples from healthy controls (HC) and 5 SF samples from patients with non-RA synovitis. METHODS: After stimulating cells with PMA and ionomycin or alternatively with anti-CD3/CD28 in the presence of brefeldin A, intracellular levels of Th1 [interleukin 2 (IL-2), interferon-gamma (IFN-gamma)] and Th2 cytokines (IL-4, IL-5, IL-10, IL-13) were determined for CD3+CD8- (i.e., CD4+ Th1 and Th2 cells) and CD3+CD8+ (i.e., CD8+ Tc1 and Tc2 cells) T cells. RESULTS: The percentages of CD4+ and CD8+ Th1 and Th2 cytokines producing T cells (PB) were similar in patients with RA and healthy controls (HC), with a clear predominance of Th1 cytokines expressing, T cells. With regard to T cell subsets, IFN-gamma-producing T cells were significantly more frequently detected in the CD8+ subset [CD8+: median 45.1% (RA; p < 0.001), 38.2% (HC; p = 0.009) vs CD4+: 10.8%(RA), 17.0% (HC)]. Conversely, IL-2 was found in a higher percentage of CD4+ T cells [CD4+: median 33.4% (RA), 17.9% (HC) vs CD8+: 23.6% (RA), 12.3% (HC)]. Patients not in disease remission tended to have more IFN-gamma-producing CD8+ and IL-2-producing CD4+ T cells than patients in remission [CD8+: median 45.9% (IFN-gamma) vs 23.0% (IFN-gamma); CD4+: median 34.1% (IL-2) vs 18.2% (IL-2)1. In all PB samples, the proportion of T cells producing the Th2 cytokines IL-4, IL-5, IL-10, and IL-13 did not exceed 2%. Cytokine profiles did not differ between patients receiving immunosuppressive treatment and patients treated only with nonsteroidal antiinflammatory drugs. In comparison to PB, RA SF analysis revealed a significant increase in the percentage of IFN-gamma-producing CD4+ (p < 0.001) and CD8+ T cells (p < 0.001). In addition, the percentage of IL-10-producing CD4+ (p < 0.001) as well as CD8+ T cells (p = 0.001) was significantly elevated in SF. However, production of the other Th2 cytokines (IL-4, IL-5, IL-13) was similar in SF and PB. CONCLUSION: These data indicate similar cytokine profiles of T cells in PB of RA patients and healthy controls, with a strong predominance of Th1 cytokines producing T cells in the CD4+ and CD8+ T cell subset of both groups. PB cytokine profiles did not significantly differ in patients with active and non-active disease or between patients receiving and those not receiving immunosuppressive medication. In SF, the proportion of Th1 and Tcl cells was significantly elevated compared to PB, emphasizing the local importance of these cells for inflammation. CD8+ T cells (Tc1 cells) mainly contributed to the production of IFN-gamma, indicating an underestimated role of this cell subset for local cytokine production. The upregulation of IL-10-producing Th2 and Tc2 cells in SF may reflect an insufficient effort to down-regulate chronic inflammation in the joint. Modifying this cytokine imbalance in the joints may be a promising therapeutic approach in RA.     

Th17细胞/调节性T细胞偏倚在类风湿关节炎中的意义

目的 探讨白细胞介素(IL)-17+CD4+炎症性T细胞(Th17细胞)和Foxp3+CD4+调节性T细胞在类风湿关节炎(RA)的相互关系及可能机制.方法 采用前瞻性随机开放研究.测定RA患者外周血IL-17+CD4+T细胞及Foxp3+CD4+T细胞的比例变化及其相关细胞因子转化生长因子(TGF)-β、IL-6、IL-23和IL-17水平.结果 RA患者外周血IL-17+CD4+T细胞明显升高(P<0.01),而Foxp3+CD4+T细胞明显降低(P<0.01).同时,血清中IL-6、IL-23和IL-17水平明显升高(均P<0.01),而TGF-β水平无明显变化(P>0.05).结论 RA患者Th17细胞数量增高,而调节性T细胞数量减少,体内相关细胞因子的变化是引起上述改变的重要原因.     

Th17细胞/调节性T细胞偏倚在类风湿关节炎中的意义

目的 探讨白细胞介素(IL)-17+CD4+炎症性T细胞(Th17细胞)和Foxp3+CD4+调节性T细胞在类风湿关节炎(RA)的相互关系及可能机制.方法 采用前瞻性随机开放研究.测定RA患者外周血IL-17+CD4+T细胞及Foxp3+CD4+T细胞的比例变化及其相关细胞因子转化生长因子(TGF)-β、IL-6、IL-23和IL-17水平.结果 RA患者外周血IL-17+CD4+T细胞明显升高(P<0.01),而Foxp3+CD4+T细胞明显降低(P<0.01).同时,血清中IL-6、IL-23和IL-17水平明显升高(均P<0.01),而TGF-β水平无明显变化(P>0.05).结论 RA患者Th17细胞数量增高,而调节性T细胞数量减少,体内相关细胞因子的变化是引起上述改变的重要原因.     

Th17细胞/调节性T细胞偏倚在类风湿关节炎中的意义

目的 探讨白细胞介素(IL)-17+CD4+炎症性T细胞(Th17细胞)和Foxp3+CD4+调节性T细胞在类风湿关节炎(RA)的相互关系及可能机制.方法 采用前瞻性随机开放研究.测定RA患者外周血IL-17+CD4+T细胞及Foxp3+CD4+T细胞的比例变化及其相关细胞因子转化生长因子(TGF)-β、IL-6、IL-23和IL-17水平.结果 RA患者外周血IL-17+CD4+T细胞明显升高(P<0.01),而Foxp3+CD4+T细胞明显降低(P<0.01).同时,血清中IL-6、IL-23和IL-17水平明显升高(均P<0.01),而TGF-β水平无明显变化(P>0.05).结论 RA患者Th17细胞数量增高,而调节性T细胞数量减少,体内相关细胞因子的变化是引起上述改变的重要原因.     

Th17细胞/调节性T细胞偏倚在类风湿关节炎中的意义

目的 探讨白细胞介素(IL)-17+CD4+炎症性T细胞(Th17细胞)和Foxp3+CD4+调节性T细胞在类风湿关节炎(RA)的相互关系及可能机制.方法 采用前瞻性随机开放研究.测定RA患者外周血IL-17+CD4+T细胞及Foxp3+CD4+T细胞的比例变化及其相关细胞因子转化生长因子(TGF)-β、IL-6、IL-23和IL-17水平.结果 RA患者外周血IL-17+CD4+T细胞明显升高(P<0.01),而Foxp3+CD4+T细胞明显降低(P<0.01).同时,血清中IL-6、IL-23和IL-17水平明显升高(均P<0.01),而TGF-β水平无明显变化(P>0.05).结论 RA患者Th17细胞数量增高,而调节性T细胞数量减少,体内相关细胞因子的变化是引起上述改变的重要原因.     

Th17细胞/调节性T细胞偏倚在类风湿关节炎中的意义

目的 探讨白细胞介素(IL)-17+CD4+炎症性T细胞(Th17细胞)和Foxp3+CD4+调节性T细胞在类风湿关节炎(RA)的相互关系及可能机制.方法 采用前瞻性随机开放研究.测定RA患者外周血IL-17+CD4+T细胞及Foxp3+CD4+T细胞的比例变化及其相关细胞因子转化生长因子(TGF)-β、IL-6、IL-23和IL-17水平.结果 RA患者外周血IL-17+CD4+T细胞明显升高(P<0.01),而Foxp3+CD4+T细胞明显降低(P<0.01).同时,血清中IL-6、IL-23和IL-17水平明显升高(均P<0.01),而TGF-β水平无明显变化(P>0.05).结论 RA患者Th17细胞数量增高,而调节性T细胞数量减少,体内相关细胞因子的变化是引起上述改变的重要原因.     

Th17细胞/调节性T细胞偏倚在类风湿关节炎中的意义

目的 探讨白细胞介素(IL)-17+CD4+炎症性T细胞(Th17细胞)和Foxp3+CD4+调节性T细胞在类风湿关节炎(RA)的相互关系及可能机制.方法 采用前瞻性随机开放研究.测定RA患者外周血IL-17+CD4+T细胞及Foxp3+CD4+T细胞的比例变化及其相关细胞因子转化生长因子(TGF)-β、IL-6、IL-23和IL-17水平.结果 RA患者外周血IL-17+CD4+T细胞明显升高(P<0.01),而Foxp3+CD4+T细胞明显降低(P<0.01).同时,血清中IL-6、IL-23和IL-17水平明显升高(均P<0.01),而TGF-β水平无明显变化(P>0.05).结论 RA患者Th17细胞数量增高,而调节性T细胞数量减少,体内相关细胞因子的变化是引起上述改变的重要原因.     

Th17细胞/调节性T细胞偏倚在类风湿关节炎中的意义

目的 探讨白细胞介素(IL)-17+CD4+炎症性T细胞(Th17细胞)和Foxp3+CD4+调节性T细胞在类风湿关节炎(RA)的相互关系及可能机制.方法 采用前瞻性随机开放研究.测定RA患者外周血IL-17+CD4+T细胞及Foxp3+CD4+T细胞的比例变化及其相关细胞因子转化生长因子(TGF)-β、IL-6、IL-23和IL-17水平.结果 RA患者外周血IL-17+CD4+T细胞明显升高(P<0.01),而Foxp3+CD4+T细胞明显降低(P<0.01).同时,血清中IL-6、IL-23和IL-17水平明显升高(均P<0.01),而TGF-β水平无明显变化(P>0.05).结论 RA患者Th17细胞数量增高,而调节性T细胞数量减少,体内相关细胞因子的变化是引起上述改变的重要原因.     

Th17细胞/调节性T细胞偏倚在类风湿关节炎中的意义

目的 探讨白细胞介素(IL)-17+CD4+炎症性T细胞(Th17细胞)和Foxp3+CD4+调节性T细胞在类风湿关节炎(RA)的相互关系及可能机制.方法 采用前瞻性随机开放研究.测定RA患者外周血IL-17+CD4+T细胞及Foxp3+CD4+T细胞的比例变化及其相关细胞因子转化生长因子(TGF)-β、IL-6、IL-23和IL-17水平.结果 RA患者外周血IL-17+CD4+T细胞明显升高(P<0.01),而Foxp3+CD4+T细胞明显降低(P<0.01).同时,血清中IL-6、IL-23和IL-17水平明显升高(均P<0.01),而TGF-β水平无明显变化(P>0.05).结论 RA患者Th17细胞数量增高,而调节性T细胞数量减少,体内相关细胞因子的变化是引起上述改变的重要原因.     

Th17细胞/调节性T细胞偏倚在类风湿关节炎中的意义

目的 探讨白细胞介素(IL)-17+CD4+炎症性T细胞(Th17细胞)和Foxp3+CD4+调节性T细胞在类风湿关节炎(RA)的相互关系及可能机制.方法 采用前瞻性随机开放研究.测定RA患者外周血IL-17+CD4+T细胞及Foxp3+CD4+T细胞的比例变化及其相关细胞因子转化生长因子(TGF)-β、IL-6、IL-23和IL-17水平.结果 RA患者外周血IL-17+CD4+T细胞明显升高(P<0.01),而Foxp3+CD4+T细胞明显降低(P<0.01).同时,血清中IL-6、IL-23和IL-17水平明显升高(均P<0.01),而TGF-β水平无明显变化(P>0.05).结论 RA患者Th17细胞数量增高,而调节性T细胞数量减少,体内相关细胞因子的变化是引起上述改变的重要原因.     

Th17细胞/调节性T细胞偏倚在类风湿关节炎中的意义

目的 探讨白细胞介素(IL)-17+CD4+炎症性T细胞(Th17细胞)和Foxp3+CD4+调节性T细胞在类风湿关节炎(RA)的相互关系及可能机制.方法 采用前瞻性随机开放研究.测定RA患者外周血IL-17+CD4+T细胞及Foxp3+CD4+T细胞的比例变化及其相关细胞因子转化生长因子(TGF)-β、IL-6、IL-23和IL-17水平.结果 RA患者外周血IL-17+CD4+T细胞明显升高(P<0.01),而Foxp3+CD4+T细胞明显降低(P<0.01).同时,血清中IL-6、IL-23和IL-17水平明显升高(均P<0.01),而TGF-β水平无明显变化(P>0.05).结论 RA患者Th17细胞数量增高,而调节性T细胞数量减少,体内相关细胞因子的变化是引起上述改变的重要原因.     

Th17细胞/调节性T细胞偏倚在类风湿关节炎中的意义

目的 探讨白细胞介素(IL)-17+CD4+炎症性T细胞(Th17细胞)和Foxp3+CD4+调节性T细胞在类风湿关节炎(RA)的相互关系及可能机制.方法 采用前瞻性随机开放研究.测定RA患者外周血IL-17+CD4+T细胞及Foxp3+CD4+T细胞的比例变化及其相关细胞因子转化生长因子(TGF)-β、IL-6、IL-23和IL-17水平.结果 RA患者外周血IL-17+CD4+T细胞明显升高(P<0.01),而Foxp3+CD4+T细胞明显降低(P<0.01).同时,血清中IL-6、IL-23和IL-17水平明显升高(均P<0.01),而TGF-β水平无明显变化(P>0.05).结论 RA患者Th17细胞数量增高,而调节性T细胞数量减少,体内相关细胞因子的变化是引起上述改变的重要原因.     

Human Langerhans cells induce distinct IL-22-producing CD4+ T cells lacking IL-17 production

IL-22 is a cytokine that acts mainly on epithelial cells. In the skin, it mediates keratinocyte proliferation and epidermal hyperplasia and is thought to play a central role in inflammatory diseases with marked epidermal acanthosis, such as psoriasis. Although IL-22 was initially considered a Th17 cytokine, increasing evidence suggests that T helper cells can produce IL-22 even without IL-17 expression. In addition, we have shown the existence of this unique IL-22-producing T cell in normal skin and in the skin of psoriasis and atopic dermatitis patients. In the present study, we investigated the ability of cutaneous resident dendritic cells (DCs) to differentiate IL-22-producing cells. Using FACS, we isolated Langerhans cells (LCs; HLA-DR⁺CD207⁺ cells) and dermal DCs (HLA-DR^hiCD11c⁺BDCA-1⁺ cells) from normal human epidermis and dermis, respectively. Both LCs and dermal DCs significantly induced IL-22-producing CD4⁺ and CD8⁺ T cells from peripheral blood T cells and naive CD4⁺ T cells in mixed leukocyte reactions. LCs were more powerful in the induction of IL-22-producing cells than dermal DCs. Moreover, in vitro-generated LC-type DCs induced IL-22-producing cells more efficiently than monocyte-derived DCs. The induced IL-22 production was more correlated with IFN-γ than IL-17. Surprisingly, the majority of IL-22-producing cells induced by LCs and dermal DCs lacked the expression of IL-17, IFN-γ, and IL-4. Thus, LCs and dermal DCs preferentially induced helper T cells to produce only IL-22, possibly “Th22” cells. Our data indicate that cutaneous DCs, especially LCs, may control the generation of distinct IL-22 producing Th22 cells infiltrating into the skin.     

Expansion of unusual CD4+ T cells in severe rheumatoid arthritis

Objective. The repertoire of T cells in patients with rheumatoid arthritis (RA) is characterized by clonal expansion of selected CD4+ T cells, which are autoreactive and lack the expression of the functionally important CD28 molecule. The goal of this study was to determine the contribution of these unusual lymphocytes to the disease process. Methods. RA patients (n = 108) and normal controls (n = 53) were examined for the expression of CD4+CD28- T cells by 2-color fluorescence-activated cell sorter analysis. Clinical data were ascertained by retrospective chart review. Results. The frequencies of CD4+CD28- T cells displayed a bimodal distribution, defining carriers and noncarriers in normal subjects and RA patients. In longitudinal studies, the noncarrier and carrier phenotypes were stable over time. Carriers of CD4+CD28- T cells accumulated in the RA population (64% versus 45%; P = 0.02). The expansion of CD4+CD28- T cells correlated with extraarticular involvement, but not with disease duration, antirheumatic treatment, or severity of joint destruction. The patient subsets with nodular disease (P = 0.02) and rheumatoid organ disease (P = 0.04) had the highest proportion of CD4+CD28- T cell carriers. The size of the CD4+CD28- compartment correlated with extraarticular progression of RA (P = 0.001 in nodular RA, P = 0.003 in rheumatoid organ disease). Conclusion. The bimodality of distribution of CD4+CD28- T cell frequencies is compatible with genetic control of the generation of these unusual T cells. In RA patients, CD4+CD28- T cells are not an epiphenomenon of the disease process, but predispose patients to developing inflammatory lesions in extraarticular tissues.     

Increased frequency of intestinal CD4+ T cells reactive with mycobacteria in patients with Crohn's disease

Abstract

Objective. The aim of this study was to assess the frequency of mycobacteria and Escherichia coli reactive T cells in intestinal biopsies from patients with Crohn's disease (CD) and ulcerative colitis (UC). Materials and methods. The biopsies were obtained by colonoscopy from adult patients with active CD (n = 5) and active UC (n = 4). The number of CD4+ T cell clones expanded and screened from each patient varied from 383 to 3972 giving a total of 16639 individual clones. The T cell clones were tested for responses to Mycobacterium avium subspecies paratuberculosis (MAP) and E. coli. The cytokine profile of 42 individual T cell clones from four CD patients was assessed. Results. The frequency of mycobacteria reactive T cell clones in CD patients ranged from 0.17 to 1.63% and was higher (p = 0.038) than the frequency of E. coli reactive T cells ranging from 0 to 0.18%. No or very low numbers of mycobacteria reactive clones were detected in three UC patients while the fourth UC patient had a frequency similar to what was observed in CD patients. The frequencies of E. coli reactive T cell clones in UC patients ranged from 0 to 0.52%. T cell clones (n = 42) from CD patients all produced IL-17 and/or IFN-γ. Several clones were also able to produce IL-10. Conclusions. The high frequency of intestinal tissue resident T cells reactive to mycobacteria suggests that an adaptive immune response have taken place and argues that these bacteria may contribute to the chronic inflammation in CD.     

结核性胸膜炎患者胸液中CD4~+ CD25~+ FoxP3~+调节T细胞抑制抗结核免疫

目的研究结核性胸膜炎患者胸液中CD4+CD25+FoxP3+调节T细胞是否增多,这些调节T细胞是否抑制结核的特异细胞免疫反应。方法使用细胞分离、流式细胞分析及体外细胞培养作细胞增殖及增殖抑制等实验方法,对15例结核性胸膜炎患者及17例健康正常人群胸液及外周血白细胞中CD4+CD25+FoxP3+调节T细胞的量及特征作研究。结果结核性胸膜炎患者胸液中CD4+CD25+FoxP3+调节T细胞明显高于患者及健康人群外周血。在体外,结核性胸膜炎患者胸液中单核细胞对BCG刺激产生γ-干扰素(IFN-γ)的能力明显强于患者及健康人群外周血中单核细胞;把这些调节T细胞从胸液单核细胞中清除,增强了结核患者胸液单核细胞对BCG刺激产生IFN-γ;从结核患者胸液分离的这些调节T细胞能抑制结核患者Th1细胞产生IFN-γ。结论结核性胸膜炎患者胸液CD4+CD25+FoxP3+调节T细胞增多,抑制结核性胸膜炎患者Th1细胞免疫反应,从而参与了结核性胸膜炎的发病。     

CD4+CXCR5+ T cells activate CD27+IgG+ B cells via IL-21 in patients with hepatitis C virus infection

BACKGROUND: Chronic hepatitis C virus (HCV) infection causes the skewing and activation of B cell subsets, but the characteristics of IgG+ B cells in patients with chronic hepa-titis C (CHC) infection have not been thoroughly elucidated. CD4+CXCR5+ follicularhelperT(Tfh)cells,viainterleukin (IL)-21 secretion, activate B cells. However, the role of CD4+CXCR5+T cellsintheactivationof IgG+ BcellsinCHCpatientsis not clear.
METHODS: The frequency of IgG+ B cells, including CD27?IgG+B and CD27+IgG+ B cells,the expression of the activation markers (CD86 and CD95) in IgG+ B cells, and the percentage of circu-lating CD4+CXCR5+ T cells were detected by flow cytometry in CHC patients (n=70) and healthy controls (n=25). The con-centrations of serum IL-21 were analyzed using ELISA. The role of CD4+CXCR5+ T cells in the activation of IgG+ B cells was investigated using a co-culture system.
RESULTS: A significantly lower proportion of CD27+IgG+ B cells with increased expression of CD86 and CD95 was observed in CHC patients.The expression of CD95 was negatively correlated with the percentage of CD27+IgG+ B cells, and it contributed to CD27+IgG+ B cell apoptosis. Circulating CD4+CXCR5+ T cells and serum IL-21 were significantly increased in CHC patients. Moreover, circulating CD4+CXCR5+ T cells from CHC patients induced higher expressions of CD86 and CD95 in CD27+IgG+B cells in a co-culture system; the blockade of the IL-21 decreased the expression levels of CD86 and CD95 in CD27+IgG+ B cells.
CONCLUSIONS: HCV infection increased the frequency of CD4+CXCR5+ T cells and decreased the frequency of CD27+IgG+B cells. CD4+CXCR5+ T cells activated CD27+IgG+ B cells via the secretion of IL-21.     

IL-17-producing CD4+ T cells, pro-inflammatory cytokines and apoptosis are increased in low risk myelodysplastic syndrome

Immunological responses are increasingly recognised as being important in the initiation and progression of myelodysplastic syndrome (MDS). Indeed, autoimmune diseases commonly occur in association with MDS, particularly in subtypes with a low risk of leukaemic transformation. This study showed for the first time that the numbers of CD3⁺ CD4⁺ IL-17 producing T cells (Th17) were markedly increased in low risk MDS compared with high risk MDS ( P  < 0·01). An inverse relationship between the numbers of Th17 cells and naturally occurring CD4⁺CD25^high FoxP3⁺ regulatory T cells (Tregs) were also described. The Th17:Tregs ratio was significantly higher in low risk disease ( P  < 0·005) compared with high risk MDS and was correlated with increased bone marrow (BM) apoptosis ( P  < 0·01). Tregs from MDS patients suppressed interferon-γ (IFN-γ) secretion by effector CD4⁺ T cells but had no effect on interleukin (IL)-17 production. In addition, the serum levels of IL-7, IL-12, RANTES and IFN-γ are significantly elevated in low risk MDS, while inhibitory factors, such as IL-10 and soluble IL-2 receptor, are significantly higher in high risk disease. The 'unfavourable' Th17:Tregs ratio in low risk MDS may explain the higher risk of autoimmunity and the improved response to immune suppression in patients with low risk MDS compared to those with high risk disease.