Vasculitis diseases include Kawasaki Disease (KD), Kawasaki Disease Shock Syndrome (KDSS), Multisystem Inflammatory Syndromes (MIS), Henoch-Schönlein purpura (HS) or IgA Vasculitis, and additional vasculitis diseases. These diseases are often preceded by infections or immunizations. Disease incidence rates are higher in children than adults. These diseases have been extensively studied, but understanding of the disease etiology remains to be established. Many studies have failed to demonstrate an association between these vasculitis diseases and vaccination. Here, the Vaccine Adverse Event Reporting System (VAERS) is used to demonstrate that, in certain rare cases, the number of cases of KD, MIS, and HS is higher than background following vaccination. These rare cases are predicted to occur in individuals with genetic risk factors who produce antibody titer levels above primary immune response level. Herein, the model of humoral immune response antibodies bound to antigens (pathogen or vaccine) creating immune complexes is proposed. These immune complexes are proposed to bind Fc receptors on immune cells and platelets resulting in cell activation and release of inflammatory molecules including histamine and serotonin. Immune complexes and inflammatory molecules including serotonin and histamine likely trigger vasculitis. Elevated serotonin and likely histamine drive initial vasoconstrictions disrupting blood flow. Increased blood flow pressure from cardiac capillary vasoconstrictions is predicted to trigger coronary artery aneurysms in some patients. For KDSS and MIS patients, these cardiac capillary vasoconstrictions are predicted to result in ischemia followed by ventricular dysfunction. Ongoing ischemia can result in long-term cardiac damage. Cases associated with pathogens are likely to have persistent infections triggering disease onset.
