Jirapongsananuruk O, Melamed I, Leung D Y
Division of Pediatric Allergy-Immunology, National Jewish Medical and Research Center, Denver, and Department of Pediatrics, University of Colorado Health Science Center, Denver.
J Allergy Clin Immunol. 2000 Nov;106(5):981-5. doi: 10.1067/mai.2000.110101.
The biologic role of the vitamin D analogue 1, 25-dihydroxyvitamin D(3), such as antiinflammatory functions, reduction of cytokine production by T cells, and immunoglobulin production by B cells, has been reported. Such immunomodulatory effects may be potentially useful in dealing with autoimmunity and transplantation. However, whether this hormone has an additive immunosuppressive effect when it is used with corticosteroids has not been investigated, although these agents are commonly used together.
Our purpose was to investigate the additive immunomodulatory effects of 1,25-dihydroxyvitamin D(3) on lymphocyte proliferation and cytokine production when used with corticosteroids.
To investigate the additive effects of 1, 25-dihydroxyvitamin D(3) and dexamethasone on suppression of lymphocyte proliferation, normal PBMCs were cultured in anti-CD3 with or without different concentrations of dexamethasone (0-10(-7) mol/L) plus or minus different concentrations of 1, 25-dihydroxyvitamin D(3) (0-10(-6) mol/L). After 3 days, lymphocyte proliferation was assessed by [(3)H]-thymidine incorporation. To investigate the additive effects of 1,25-dihydroxyvitamin D(3) and dexamethasone on cytokine production, PBMCs were cultured for 3 days in the presence of anti-CD3 with or without 10(-6) mol/L dexamethasone plus or minus 10(-6) mol/L 1,25-dihydroxyvitamin D(3). IFN-gamma, IL-5, and IL-13 production in supernatants were measured by ELISA.
Our study demonstrated that, at concentrations of 10(-8), 10(-7), and 10(-6) mol/L, 1,25-dihydroxyvitamin D(3) significantly decreased lymphocyte proliferation compared with an ethanol control (P <.05). The IC(50) for dexamethasone was 4 x 10(-9) mol/L in culture without 1,25-dihydroxyvitamin D(3.) When 10(-9) mol/L of 1,25-dihydroxyvitamin D(3) was added to cultures with dexamethasone, IC(50) became 2 x 10(-9) mol/L. Moreover, when 10(-6), 10(-7), and 10(-8) mol/L of 1,25-dihydroxyvitamin D(3) were added in culture with dexamethasone, IC(50) became less than 1 x 10(-9) mol/L. IFN-gamma production in culture with either dexamethasone or 1,25-dihydroxyvitamin D(3) was significantly decreased compared with media or ethanol control (P <.0001). Moreover, when both agents were added in the same culture, IFN-gamma production was further decreased compared with either agent alone (P <.05). In contrast, 1,25-dihydroxyvitamin D(3) significantly (P <. 0001) increased IL-5 and IL-13, whereas dexamethasone significantly decreased these 2 cytokines (P <.0005). When 1,25-dihydroxyvitamin D(3) was combined with dexamethasone, IL-5 and IL-13 production was increased compared with dexamethasone alone (P <.001).
Our results demonstrate that 1,25-dihydroxyvitamin D(3) has significant additive effects on dexamethasone-mediated inhibition of lymphocyte proliferation. This hormone also has additive effects on inhibition of T(H)1 cytokine production when combined with dexamethasone. However, this hormone upregulates T(H)2 cytokines and inhibits steroid-mediated suppression of cytokines. These findings demonstrate the potential use of 1,25-dihydroxyvitamin D(3) as an immunosuppressive agent when combined with corticosteroids in T(H)1, but not T(H)2, immune responses.
维生素D类似物1,25 - 二羟基维生素D(3)的生物学作用，如抗炎功能、减少T细胞产生细胞因子以及B细胞产生免疫球蛋白等，已有报道。这种免疫调节作用在处理自身免疫和移植方面可能具有潜在用途。然而，尽管这两种药物常联合使用，但该激素与皮质类固醇联合使用时是否具有附加免疫抑制作用尚未得到研究。
我们的目的是研究1,25 - 二羟基维生素D(3)与皮质类固醇联合使用时对淋巴细胞增殖和细胞因子产生的附加免疫调节作用。
为研究1,25 - 二羟基维生素D(3)和地塞米松对淋巴细胞增殖抑制的附加作用，将正常外周血单个核细胞（PBMCs）在有或无不同浓度地塞米松（0 - 10(-7) mol/L）加或不加不同浓度1,25 - 二羟基维生素D(3)（0 - 10(-6) mol/L）的抗CD3环境中培养。3天后，通过[3H] - 胸腺嘧啶核苷掺入法评估淋巴细胞增殖。为研究1,25 - 二羟基维生素D(3)和地塞米松对细胞因子产生的附加作用，将PBMCs在有或无10(-6) mol/L地塞米松加或不加10(-6) mol/L 1,25 - 二羟基维生素D(3)的抗CD3环境中培养3天。通过酶联免疫吸附测定（ELISA）法测量上清液中干扰素 - γ（IFN - γ）、白细胞介素 - 5（IL - 5）和白细胞介素 - 13（IL - 13）的产生。
我们的研究表明，在浓度为10(-8)、10(-7)和10(-6) mol/L时，与乙醇对照相比，1,25 - 二羟基维生素D(3)显著降低淋巴细胞增殖（P <.05）。在地塞米松单独培养（无1,25 - 二羟基维生素D(3)）时，地塞米松的半数抑制浓度（IC50）为4×10(-9) mol/L。当向地塞米松培养物中添加10(-9) mol/L的1,25 - 二羟基维生素D(3)时，IC50变为2×10(-9) mol/L。此外，当向地塞米松培养物中添加10(-6)、10(-7)和10(-8) mol/L的1,25 - 二羟基维生素D(3)时，IC50小于1×10(-9) mol/L。与培养基或乙醇对照相比，地塞米松或单独使用1,25 - 二羟基维生素D(3)培养时，IFN - γ的产生显著降低（P <.0001）。此外，当两种药物添加到同一培养物中时，与单独使用任何一种药物相比，IFN - γ的产生进一步降低（P <.05）。相反，1,25 - 二羟基维生素D(3)显著（P <.0001）增加IL - 5和IL - 13，而地塞米松显著降低这两种细胞因子（P <. [此处原文可能有误，推测应为P <.0005]）。当1,25 - 二羟基维生素D(3)与地塞米松联合使用时，与单独使用地塞米松相比，IL - 5和IL - 13的产生增加（P <.001）。
我们的结果表明，1,25 - 二羟基维生素D(3)在地塞米松介导的淋巴细胞增殖抑制方面具有显著的附加作用。该激素与地塞米松联合使用时，对抑制辅助性T细胞1（Th1）细胞因子产生也具有附加作用。然而，该激素上调辅助性T细胞2（Th2）细胞因子，并抑制类固醇介导的细胞因子抑制作用。这些发现表明，在Th1免疫反应中，1,25 - 二羟基维生素D(3)与皮质类固醇联合使用时具有作为免疫抑制剂的潜在用途，但在Th2免疫反应中并非如此。
