Despite the seriously undernourished state of patients with anorexia nervosa (AN) and bulimia nervosa (BN), controversial findings have been published regarding some aspects of the immune system that are otherwise impaired in more typical types of malnutrition, such as protein-energy malnutrition. In general, adaptation processes seem to occur enabling immune function to be preserved during long periods of the illness. However, cell-mediated immunity is usually altered in AN and BN as reflected by lymphocyte subset counts and the response to delayed hypersensitivity tests. Regarding the helper/cytotoxic T cell ratio (CD4:CD8), an immunological marker of the nutritional status, the results of our studies on AN and BN patients showed that the duration of the eating disorder and the time when appropriate treatment is achieved are likely contributors to the alteration of this ratio. Despite these findings, it has been repeatedly pointed out that anorexic patients seem to be free of common viral infections at least until the most advanced stages of debilitation. Some hypotheses that could explain the lack of infection symptoms are reviewed. Cytokines and the altered acute phase response to infection, as well as cortisol and leptin, are considered to be potential factors involved in the adaptation processes occurring in these syndromes. Further progress in the knowledge of the psychoneuroendocrine-immune interactions established in AN and BN will be relevant to the understanding of the aetiology and maintenance mechanisms of these pathologies.

中文翻译：

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免疫系统对饮食失调的特殊营养反应。

尽管神经性厌食症（AN）和神经性贪食症（BN）的患者营养严重不足，但有关免疫系统某些方面的争议性研究结果已发表，这些方面否则会在更典型的营养不良类型中受损，例如蛋白质能量营养不良。通常，适应过程似乎会发生，从而使疾病的长期维持免疫功能得以维持。然而，如淋巴细胞亚群计数和对迟发型超敏反应的反应所反映的，细胞介导的免疫通常在AN和BN中发生改变。关于辅助/细胞毒性T细胞比率（CD4：CD8），即营养状况的免疫学标记，我们对AN和BN患者的研究结果表明，进食障碍的持续时间和获得适当治疗的时间很可能是这一比例变化的原因。尽管有这些发现，但已经反复指出，厌食症患者至少在最严重的衰弱阶段似乎没有常见的病毒感染。审查了一些可以解释缺乏感染症状的假设。细胞因子和对感染的急性期反应改变，以及皮质醇和瘦素，被认为是这些综合征中发生的适应过程的潜在因素。