Markers of Infection in Childhood Autoimmune Diabetes and Related Disorders

Sammanfattning: Popular Abstract in English The main aim of this thesis was to contribute to the knowledge about mechanisms involved in the development of type 1 diabetes (T1D) and other autoimmune diseases in children. Immune markers in relation to genetic propensity in children with autoimmune disease, mainly T1D and a small group of juvenile idiopathic arthritis (JIA) and thyroiditis (THYR), as well as healthy controls have been studied. The possible influence by environmental factors as viral infections is supported by several studies. This thesis includes studies of antibodies to virus in blood samples from healthy children and from children at T1D onset and other organ specific autoimmune diseases in geographically different parts of Sweden. The virus analyses focus on antibodies to Ljungan virus (LV), a fairly recently defined parechovirus, reported to cause diabetes in voles that are found to carry LV, but LV is yet not shown to be pathogenic to humans. The last aim also included analyses of Ljungan virus antibodies (LVA) in voles as possible source of infection to humans. To test the specificity and possible cross-reactivity of the radiobinding assay (RBA) method for LVA analysis samples from children in the third study were analyzed for antibodies to several human parechoviruses (HPeV) and related viruses by a multiplex suspension array (SMIA). Islet autoantibodies and HLA-type of the children in study were analyzed for possible association to antibodies to LV, risk for infection and/ or autoimmune disease. The major objective was to study possible mechanisms of the etiology and pathogenesis of T1D at the time of clinical onset. The aim was also to compare features of T1D at onset with JIA and THYR which are less common but distinct autoimmune disorders.