Dröge W, Breitkreutz R
Department of Immunochemistry, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany.
Proc Nutr Soc. 2000 Nov;59(4):595-600. doi: 10.1017/s0029665100000847.
The immune system works best if the lymphoid cells have a delicately balanced intermediate level of glutathione. Even moderate changes in the intracellular glutathione level have profound effects on lymphocyte functions. Certain functions, such as the DNA synthetic response, are exquisitely sensitive to reactive oxygen intermediates and, therefore, are favoured by high levels of the antioxidant glutathione. Certain signal pathways, in contrast, are enhanced by oxidative conditions and favoured by low intracellular glutathione levels. The available evidence suggests that the lymphocytes from healthy human subjects have, on average, an optimal glutathione level. There is no indication that immunological functions such as resistance to infection or the response to vaccination may be enhanced in healthy human subjects by administration of glutathione or its precursor amino acid cysteine. However, immunological functions in diseases that are associated with a cysteine and glutathione deficiency may be significantly enhanced and potentially restored by cysteine supplementation. This factor has been studied most extensively in the case of human immunodeficiency virus (HIV)-infected patients who were found to experience, on average, a massive loss of S equivalent to a net loss of approximately 4 g cysteine/d. Two randomized placebo-controlled trials have shown that treatment of HIV-infected patients with N-acetyl-cysteine caused in both cases a significant increase in all immunological functions under test, including an almost complete restoration of natural killer cell activity. It remains to be tested whether cysteine supplementation may be useful also in other diseases and conditions that are associated with a low mean plasma cystine level and impaired immunological functions.
如果淋巴细胞中的谷胱甘肽水平处于微妙平衡的中等水平，免疫系统就能最佳地发挥作用。即使细胞内谷胱甘肽水平有适度变化，也会对淋巴细胞功能产生深远影响。某些功能，如DNA合成反应，对活性氧中间体极为敏感，因此，高水平的抗氧化剂谷胱甘肽有利于这些功能。相反，某些信号通路在氧化条件下会增强，且细胞内谷胱甘肽水平较低时更有利。现有证据表明，健康人类受试者的淋巴细胞平均具有最佳的谷胱甘肽水平。没有迹象表明，健康人类受试者通过服用谷胱甘肽或其前体氨基酸半胱氨酸可增强免疫功能，如抗感染能力或对疫苗接种的反应。然而，对于与半胱氨酸和谷胱甘肽缺乏相关的疾病，补充半胱氨酸可能会显著增强免疫功能，并有可能使其恢复。在人类免疫缺陷病毒（HIV）感染患者中对这一因素进行了最广泛的研究，发现这些患者平均大量丢失硫，相当于每天净丢失约4克半胱氨酸。两项随机安慰剂对照试验表明，用N-乙酰半胱氨酸治疗HIV感染患者，在两种情况下均使所有受试免疫功能显著增强，包括自然杀伤细胞活性几乎完全恢复。半胱氨酸补充剂在其他与平均血浆胱氨酸水平低和免疫功能受损相关的疾病和病症中是否也有用，仍有待测试。
