The effects of cytokines on suppression of lymphocyte proliferation by dexamethasone.

Treatment failure occurs in up to 30% of patients treated with steroids for inflammatory diseases. The aim of this study was to explore the potential role of 21 cytokines in steroid-resistant inflammatory disease and to develop methods to restore steroid sensitivity through cytokine manipulation. The dexamethasone inhibition of lymphocyte proliferation assay correlates with the outcome of steroid therapy in ulcerative colitis (UC) and other inflammatory diseases. Using this assay, PBMC production of 21 cytokines, assayed by cytokine bead array, was correlated with percentage of suppression of proliferation by 10(-6) M dexamethasone (Imax) in 26 healthy volunteers. Effects of the addition of exogenous cytokines to induce steroid resistance in PBMCs from healthy volunteers and cytokine blockade to improve steroid sensitivity in PBMCs from patients with steroid-resistant UC were then explored. Production of IL-1alpha, IL-10, IL-17, IFN-gamma, G-CSF, GM-CSF, TNF-alpha, and IFN-inducible protein 10 (IP-10) correlated significantly with in vitro steroid sensitivity; however, only IL-2 and TNF-alpha reduced steroid sensitivity when added exogenously. Addition of IL-10 enhanced steroid suppression. Immunoneutralization or receptor blockade of IL-2, but not TNF-alpha, IFN-gamma, IL-4, IL-17, or IP-10 increased steroid sensitivity in cells from steroid-resistant UC patients. Neutralization of IL-10 reduced steroid sensitivity. Of the large panel of cytokines studied, IL-2 appears to have the greatest antagonistic effect on the antiproliferative effect of steroids. These data suggest that IL-2 inhibition in vivo may improve the response to steroids in steroid-resistant individuals.

CD4+CD25(int) T cells in inflammatory diseases refractory to treatment with glucocorticoids.

Up to 30% of patients with autoimmune, allergic, and lymphoproliferative diseases are refractory to glucocorticoid therapy. The present study was undertaken to investigate whether such steroid resistance (SR) is limited to a subpopulation of CD4(+) T cells and, as IL-2 is a putative driver of SR, whether T cell SR is associated with CD25 expression. We show that SR patients have a characteristic subgroup of activated CD4(+) T cells that continue to proliferate despite exposure to high-dose Dexamethasone (Dex), demonstrate that CD4(+)CD25(-) cells are exquisitely sensitive to Dex whereas CD4(+)CD25(int) cells are highly SR, and further find that the combination of an anti-CD25 mAb with Dex enhances suppression of T cell proliferation compared with each agent alone. We therefore conclude that SR is not a general property of all lymphocytes but resides in T cell subpopulations, which are prevalent in SR patients and express intermediary levels of CD25. As a result, we propose a new paradigm for SR disease in which glucocorticoid therapy positively selects SR cells, generating a population of drug-resistant lymphocytes that perpetuate on-going inflammation.

Insulin-like growth factor binding protein-3: relationship to the development of gastric pre-malignancy and gastric adenocarcinoma (United Kingdom).

IGF family proteins play a pivotal role in regulating cell growth and apoptosis in normal and tumour tissues. IGFBP-3 is the major binding protein of IGFs and modulates the bioactivity of IGFs. To examine the role of IGFBP-3 in gastric cancer, an IGFBP3 promoter polymorphism, and serum and gastric mucosal levels of IGFBP-3 were assessed in two independent groups of patients (396 and 117 patients, respectively) with gastroduodenal diseases. There was no significant association between IGFBP-3 polymorphism and different gastroduodenal diseases ( p = 0.6), but a significantly higher frequency of CC, a genotype related to lower levels of serum IGFBP-3 previously, were observed in patients with antral intestinal metaplasia when compared with those without this pre-malignancy ( p = 0.04). Similarly, data from another independent group of patients further showed that patients with antral or corpus intestinal metaplasia had significantly lower serum levels of IGFBP-3 than those without these changes ( p = 0.03 and 0.04, respectively). Furthermore, the percentage of positive IGFBP-3 staining in tumour tissue was significantly higher in patients with well or moderately differentiated tumours than those with poorly differentiated tumours ( p = 0.04), indicating that IGFBP-3 may be associated with a better prognosis. In conclusion, our study suggests that IGFBP-3 may be protective against the development of gastric adenocarcinoma by preventing the formation of intestinal metaplasia and improve the prognosis of gastric cancer.