Model diseases for studies of autoimmunity.

The events triggering autoimmune diseases are to large extent unknown and model diseases are an important tool in studies aiming to elucidate molecular mechanisms in autoimmunity. Autoimmune Addison’s disease (AAD) is a rare disease characterized by autoimmune destruction of adrenal glands and most patients with AAD have autoantibodies against the enzyme 21‑hydroxylase in the adrenal cortex. The autoimmune destruction in AAD is however suspected to be initiated by T cells. One of the most important investigations in this thesis was to characterize the T cell response in AAD. It could be concluded the T cells in AAD patients respond to three immunodominant epitopes on the 21-hydroxylase. In addition, this thesis aims to gain updated data on comorbidities, replacement therapy, autoantibody profiles, and metabolic factors in AAD. A cohort of 660 AAD patients was studied and it was found that AAD patients are prone to develop other autoimmune conditions. AAD is one of three main disease components Autoimmune Polyendocrine Syndrome type 1 (APS-1), a rare disorder caused by mutations in the AutoImmune REgulator gene (AIRE) that can be potentially fatal without timely diagnosis. Screening for autoantibodies against interferon-ω, interferon-α4, and interleukin-22 revealed four new APS-1 patients among the AAD cohort, confirmed by the presence of disease causing mutations in the AIRE gene. Cancer Associated Retinopathy (CAR) is a paraneoplastic phenomenon arising as a consequence to an autoimmune response triggered by a malignant neoplasm present in the body. This disease is devastating and it is valuable to identify new biomarkers associated with CAR, not least from a tumor diagnostic perspective. In this thesis, a patient with osteosarcoma and CAR was studied and by screening of a proteom array, and the novel CAR autoantigen Aryl hydrocarbon receptor interacting protein-like 1 (AIPL1) was identified. In conclusion, this thesis covers studies on T cell and B cell responses in AAD. Moreover, it includes an update on clinical and immunological characterisation of AAD patients. Finally, a novel autoantigen in CAR was identified and proposed as a diagnostic marker for the paraneoplastic syndrome