Schizophrenia and the Immune System

The involvement of the immune system in schizophrenia is an even more complicated issue compared to involvement with depression. There have been suggestions for many decades that schizophrenia is associated with immune dysfunction (Vaughan etal., 1949). However, it is only recently that substantial evidence relating to this idea has begun to appear and this is even less 

Nevertheless, despite the difficulties, there are intriguing findings that have shengthened the hypothesis that neuro-immune interactions are altered in schizophrenia patients. One argument for an association between immune function and schizophrenia is that epidemiological data show a linkage between prenatal viral infections and subsequent appearance of schizophrenia. There have also been studies that show an acute exacerbation of schizophrenia can occur in response to immune system dysfunction. These have been reviewed (Rapaport and Muller, 2001). The most extensively examined idea is that schizophrenia is associated with autoimmune diseases or that schizophrenia may, in certain instances, be associated with a lack of normal autoimmune function (Gaughran, 2002 Jones et al., 2005 Kipnis et al., 2006). 

Name three of the four peptides for wliich proenkephahn 

The major physiological role of the enkephalins in regulating iimnune function appears to be 

Name the three products derived from proopiomelanocortin (POMC) for which evidence is the strongest supporting involvement in regulating immune system function. 

The studies reviewed in this chapter demonstrate that a strong and reciprocal relationship exists between the central nervous system and the immune system. Indeed, the term neuroim-mune system is clearly justified and appropriate to emphasize the fact that nervous and lymphoid tissues constitute a unified system that functions in the maintenance of homeostasis. The conventional division between the two systems has blurred, as well as the distinction between neuropeptides on the one hand, and immune cytokines on the other. Two lines of research have altered our perspective on neuroimmune interactions (a) the identification of conventional neuropeptides and then-receptors, especially those related to the HPA axis, in most lymphoid tissues, and (b) the large body of evidence that cytokines, historically associated with immune system communication, play vital roles in nervous function. 

The role of the HPA axis in coordinating responses to stressors, and the role of the immune system in mediating the sickness response, underscore this reciprocal relationship between the CNS and the immune system. However, the relationship is complex, and it should be clear that we are in the early stages of understanding how immune tissue can contribute to psychiatric disorders. In spite of this nascent state of knowledge, the evidence for hyper-reactivity of the HPA axis and the alterations in cytokine levels observed in both MDD and schizophrenia serve as a foundation for further research establishing a causative relationship between alterations in immune system function and these debilitating CNS disorders. 

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