Table 1.

Table representing the principal hypotheses for the etiopathogenesis of KD.

	Response to a pathogen	Autoantibody or T cell driven autoimmune process	Autoinflammatory process
Pros	• Histological features suggesting an early innate immune response, followed by an adaptive immunity • Plasmablast response such as in children with infectious diseases • Intracytoplasmic inclusions and oligoclonal IgA antibodies • Protective effect of breastfeeding • Low rate of recurrence • Seasonal variation and clusters of illness • Virtual absence of KD in adulthood	• AECAs antibodies in acute KD (conflicting results)	• Overlapping clinical features with AIDs • Increased expression of genes related to the NLRP3 inflammasome, IL-1a and IL-1b, and caspase 1 in blood • IL-1β and IL-1α implicated in myocarditis and aneurysm formation in LCWE -induced mouse model of KD • Efficacy of IL-1 blockade
Cons	• Unique gene expression pattern, differentiating KD from viral or bacterial diseases • No evidence for person-to-person transmission • Geospatial clustering at scales of 10-100 km	• Self-limited nature of KD • Low rate of recurrence • No concomitant autoimmune disease • No familial aggregation with other autoimmune disease • Selection of Fc-specific Treg cells in KD	• Polygenic nature of KD rather than a monogenic disease • Monophasic course

For each hypothesis, data confirming or refuting are summarized. KD, Kawasaki disease; AIDs, autoinflammatory diseases; AECAs, anti-endothelial cell auto-antibodies; IL-1, interleukin 1; LCWE, Lactobacillus casei cell wall extract.