The cause of the disease is not yet clear. Kawasaki disease is somewhat epidemic and land-locked, with clinical manifestations such as fever and rash. It is thought to be caused by a variety of pathogens, including EBV, retrovirus, or streptococcal or propionibacterium infections. 1986 saw a report of increased retrotransposon activity in peripheral blood lymphocyte culture supernatants, suggesting that the disease may be caused by retrovirus. A Japanese study found that the frequency of HLA-BWzz was approximately 2-fold higher in patients with Kawasaki disease than in the general population; while the detection rate of HLA-BW51 was increased in the Boston area epidemic in the United States. Therefore, it is speculated that genetic susceptibility and infection may be the etiology of Kawasaki disease. Mycoplasma, rickettsiae, and dust mites have also been proposed as the cause of Kawasaki disease, but this has not been confirmed. Environmental pollution or chemical allergies have also been considered as possible causes of the disease, but most studies have not obtained consistent results.
Recent studies have shown that Kawasaki disease presents with significant immune dysregulation in the acute phase, which plays an important role in the pathogenesis.
Kawasaki disease has an imbalance of peripheral blood T-cell subsets in the acute phase, with increased CD4, decreased CD8, and increased CD4/CD8 ratio. This change is most pronounced at 3-5 weeks of disease and returns to normal by 8 weeks. increased CD4/CD8 ratio puts the body’s immune system in an activated state, increases lymphokines secreted by CD4, promotes B-cell polyclonal water activation, proliferation and differentiation into plasma cells, leading to elevated serum IgM, IgA, IgG, IgE, and high secretion of interleukins by activated T cells (1L-1, 4 5, 6), r-interferon (IFN-r), and tumor necrosis factor (TNF). These lymphokines and active interferons on the one hand can induce endothelial cells to express and produce neoantigens; on the other hand, they promote the secretion of autoantibodies by B cells, which leads to endothelial cell lysis cytotoxic effects and endothelial cell damage so vasculitis occurs.
The increase of 1L-11L-6 and TNF can also induce hepatocytes to synthesize acute reactive proteins, such as C-reactive protein, αr-antitrypsin, and binding bead protein, causing acute febrile reaction in Kawasaki disease. The mechanism of the role of CIC in Kawasaki disease is not clear, but the absence of immune complex deposition at the site of Kawasaki disease and the increase in serum C3 instead of decreasing are not consistent with general immune complex disease. The trigger cause of these immune dysregulation is unknown. Kawasaki disease is nowadays considered to be an immune-mediated systemic vasculitis triggered by a variety of infectious agents in a certain susceptible host. These immune dysregulations may be caused by lymphohistiophilic viral infections, and the affinity of the virus for endothelial cells may be the cause of polyangiitis.
In addition, autopsy revealed that the coronary artery was the most damaged site, and others included the aorta, abdominal aorta, carotid artery, subclavian artery, and pulmonary artery. The pathological changes are similar to those of infantile polyarteritis nodosa, showing arterial allodynia; intimal thickening with granulocyte and monocyte infiltration, disruption of the internal elastic lamina and mesentery, wall necrosis and aneurysm formation. The heart had endocarditis and myocarditis. There is thrombosis of the coronary arteries, which can lead to myocardial infarction, often resulting in death.