Science, medicine, and the future: Tolerance and autoimmunity

Immune tolerance and autoimmunity are important clinically. Firstly, there are at least 40 known or suspected autoimmune diseases, and many are common (see box). Overall, 1 person in 31 is affected.1 Moreover, autoimmune type 1 diabetes is the most common of all chronic diseases of children. Secondly, autoimmune disease is poorly diagnosed because the onset can be stealthy, and initial symptoms are often non-specific—tiredness, fatigue, or fever. Thirdly, patients with autoimmune disease will expect an interpretation of their illness from their doctor. Fourthly, new insights are set to revolutionise management, by replacement of blanket immunosuppression with new selective immunotherapies #### Prevalence of autoimmune diseases Figure 1 illustrates how tolerance is established and maintained and how it fails with ensuing autoimmunity. Specific immune and autoimmune responses involve the same elements. These include ( a ) an antigen (or autoantigen); ( b ) a response by interacting families and subsets of cells that include antigen presenting cells, T lymphocytes, and B lymphocytes; ( c ) messenger molecules, cytokines, chemokines, and their receptors; and ( d ) signalling and costimulatory molecules on cell surfaces (fig 2). Many of the functionally important cell surface molecules and their receptors are described by the cluster of differentiation (CD) nomenclature, based on their identification by characterised monoclonal antibodies. #### Predicted developments Closer insights into generation of natural immune tolerance to self Clarification of importance of apoptosis for loss of tolerance and development of autoimmunity Enhanced understanding of how the “wrong …