Selenium Supplementation Alter the Frequency of Th17 but not Th1/Th2 Lymphocytes in Diffuse Large B Cell Lymphoma Patients.

BACKGROUND: Selenium (Se) is a micronutrient, which has recently been proven to have a positive effect on the immune system of cancer patients, but the underlying mechanism is not clearly defined. In this randomized controlled trial, we evaluated the effect of three-month Se supplementation on the profile of CD4+ T-helper subsets including IFN-γ+/IL-4- Th1, IFN-γ-/IL-4+ Th2, and CD4+IL-17+ Th17 cells in sixteen diffuse large B cell lymphoma (DLBCL) patients at stable remission phase who consumed Se (Se+) compared to the fourteen control patients who did not receive Se (Se-). METHODS: The frequency of IFN-γ+/IL-4- Th1, IFN-γ-/IL-4+ Th2, and CD4+IL-17+ Th17 lymphocytes was determined using a four-color flow cytometry method. RESULTS: The results revealed that three-month Se supplementation significantly decreased the proportion of CD4+IL-17+ Th17 lymphocytes but not IFN-γ+/IL-4- Th1 and IFN-γ-/IL-4+ Th2 subtypes in DLBCL patients at stable remission. Change in the percentage of IFN-γ+/IL-4- Th1, IFN-γ-/IL-4+ Th2, and CD4+IL-17+ Th17 cells did not significantly differ between Se+ and Se- groups. No positive correlation was observed between changes in different Th subpopulations in both Se+ and Se- groups. CONCLUSIONS: Taken together, three-month Se supplementation can reduce the proportion of CD4+IL-17+ Th17 cells in DLBCL patients at stable remission phase. Larger population and longer follow-up of patients is necessary to specify the clinical significance of Se supplementation on the popularity of T-helper cells in DLBCL patients.

The impact of selenium on regulatory T cell frequency and immune checkpoint receptor expression in patients with diffuse large B cell lymphoma (DLBCL).

For many decades, selenium (Se) has been known as a potential anti-cancer agent that can also improve the function of immune cells in a variety of solid tumors. However, there is no report on the role of Se on CD4+ T cell subsets like CD4+CD25+FOXP3+ regulatory T cells (Tregs) in lymphoma patients. In this randomized clinical trial, we investigated the effect of 3-month Se consumption on the frequency of CD4+CD25+FOXP3+ Tregs and the expression of immune checkpoint receptors in thirty-two non-Hodgkin lymphoma (NHL) patients (16 patients with Se (Se+) and 16 without Se (Se-) consumption) with diffuse large B-cell lymphoma (DLBCL) subtype at stable remission. The change in the frequency of Tregs and expression of immune checkpoint receptors including CTLA-4, LAG-3, TIM-3, and PD-L1 genes were evaluated after 3 months in both groups using flow cytometry and SYBR Green Real-time PCR method, respectively. The results showed that the frequency of CD4+CD25+FOXP3+ Tregs and expression of immune checkpoint receptors did not significantly change after 3-month Se consumption in DLBCL patients. However, alteration in the frequency of CD4+CD25-FOXP3+ Treg subsets was positively correlated with change in CTLA-4, LAG-3, and TIM-3 expression in the Se+ group. Three-month Se supplementation did not prevent relapse in Se+ group. Taken together, Se supplementation alone did not affect the frequency of CD4+CD25+FOXP3+ Tregs, expression of checkpoint receptors, and prevention of relapse in DLBCL patients at stable remission phase but might influence the functional properties of other Treg subsets like CD4+CD25-FOXP3+ Tregs.

Inhibition of nitric oxide production and proinflammatory cytokines by several medicinal plants.

BACKGROUND: A number of medicinal plants have been used to treat various immunological diseases. Nitric oxide (NO) has an important regulatory role in the various types of inflammatory processes. OBJECTIVE: To investigate the NO modulatory activity of the extracts of several medicinal plants native to Iran including Dracocephalum kotschyi, Linum persicum, Dionysia termeana, Salvia mirzayanii, Ferulago angulata and Euphorbia cheiradenia. METHODS: The methanolic extracts of the plants were prepared and examined for their effects on the NO production by lipopolysaccharide-stimulated mouse macrophages. The level of TNF-α and IL-1ß pro-inflammatory cytokines in the macrophage culture were detected using enzyme-linked immunosorbent assay. RESULTS: All the extracts at concentration of 50 µg/ml demonstrated a significant decrease in NO production (p<0.001) after a 24-hour treatment. This inhibitory effect was also seen after 48 hours. Among the extracts, L. persicum was the strongest extract in reducing the NO production at 1 µg/ml after both 24 and 48-hours (nearly 100% inhibition, p<0.001). S. mirzayanii extract with 66.2 ± 8% inhibition at 50 µg/ml, showed the mildest effects in 48 hour culture. In cytokine release determination, the extract of L. persicum significantly inhibited both TNF-α and IL-1ß cytokines production by stimulated macrophages (p<0.001). D. kotschyi, D. termeana and F. angulata decreased secretion of IL-1ß from the cells. CONCLUSION: These results indicate the presence of anti-inflammatory and macrophage inhibitory substances in these plants.

In vitro immunomodulatory effects of extracts from three plants of the Labiatae family and isolation of the active compound(s).

Plants may have the ability to modulate immune responses. In the present study, the effects of three plants belonging to Labiatae family, each traditionally used for the treatments of infections and inflammatory diseases, as well as the role of thymol (as one the major components of these plants), were investigated for their potential to affect the activation of lymphocytes. Four organic extracts of Thymus vulgaris and two other plants (i.e., T. daenensis and Zataria multiflora) were prepared. The effect of the extracts on mitogen (PHA)-stimulated peripheral blood lymphocytes was determined using a cell proliferation assay. The hexane extracts obtained from the three plants showed the strongest inhibitory effects on PHA-induced proliferation. Use of preparative thin layer and gas chromatographies in conjunction with the proliferation assay confirmed that thymol was the major component responsible for the observed effects from the three plants. Thymol inhibited inducible lymphocyte proliferation in a concentration-dependent manner, with reductions ranging from 62.8% at 50 µg/ml to 89.8% at 200 µg/ml (> 0.1 µg/ml (p < 0.01). Flow cytometric analysis using propidium iodide staining showed that the inhibitory effect of thymol at 200 µg/ml was due to a cytotoxic activity. In conclusion, the three Labiatae plants studied here each showed immunosuppressive effects against lymphocytes and it was most likely that thymol was the compound in these plants responsible for this effect.