Immune dysregulation in offspring of a bipolar parent. Altered serum levels of immune growth factors at adolescent age.

Immune dysregulation plays a role in the vulnerability for mood disorders. Immune growth factors, such as Stem Cell Factor (SCF), Insulin-like Growth Factor-Binding Protein-2 (IGF-BP2), Epidermal Growth Factor (EGF), IL-7 and sCD25 have repeatedly been reported altered in patients with mood disorders. The aim of this study was to investigate levels of these factors in serum of adolescent bipolar offspring, who have a heightened risk for mood disorder development and to also analyze the data combined with previously published data. Growth factors were assessed by CBA/ELISA in adolescent bipolar offspring (n=96, mean age=16years) and in age- and gender-matched healthy controls (n=50). EGF belonged to a mutually correlating cluster of mainly neurotrophic compounds including S100B and BDNF, which were in general decreased in serum. IL-7, SCF, IGF-BP2 and sCD25, belonged to a different mutually correlating cluster of immune growth factors, which were in general increased: IGF-BP2 significantly in serum of offspring without a mood disorder, IL-7 and SCF in serum of offspring who had experienced a mood episode. This pattern of de- and increases was not different between bipolar offspring that developed or did not develop a mood disorder over time, apart from the IGF-BP2 level, which was near significantly higher in offspring later developing a mood disorder. Correlations with the previously published immune-cellular abnormalities were not found. In conclusion non-affected adolescents at familial mood disorder development risk were characterized by a distinct pattern of a series of compounds operating in a network of hematopoiesis, neurogenesis and inflammation.