Functional Immunoregulation by Heme Oxygenase 1 in Juvenile Autoimmune Diseases

An autoimmune disease is an inflammatory condition in which the human body’s immune system attacks normal cells, resulting in decreased and abnormal immune function, which eventually leads to tissue damage or organ dysfunction. In the field of medicine, especially in pediatrics, knowledge about autoimmune diseases is still inadequate. Some common juvenile autoimmune diseases such as Henoch–Schonlein purpura, systemic juvenile idiopathic arthritis, mucocutaneous lymph node syndrome, and autoimmune encephalitis cause considerable public concern. Recent studies revealed that heme oxygenase 1 (HO-1), an enzyme that participates in heme degradation, plays a critical role in the pathogenesis and may regulate autoimmunity. Firstly, it may promote the differentiation of T lymphocytes into CD4+CD25+ regulatory T cells and may be associated with changes in the ratios of cytokines (Th1/Th2 and Th17/Treg) as well. Secondly, HO-1 can regulate the immune system through the secretion of proteins such as transforming growth factors and interleukins. Moreover, increasing the expression of HO-1 can improve vascular function by increasing antioxidant levels. Thus, HO-1 may provide a theoretical basis and guidance for therapeutic management of juvenile autoimmune diseases.