IgA plasma cell infiltration of proximal respiratory tract, pancreas, kidney, and coronary artery in acute Kawasaki disease

The etiology and pathogenesis of Kawasaki disease (KD) remain unknown. As p reviously reported, in US patients with acute KD, IgA plasma cells (PCs) in filtrate the vascular wall, To determine whether IgA PCs are increased at m ucosal sites in KD and to determine whether other nonvascular KD tissues ar e infiltrated by IgA PCs, the cells were immunolocalized and quantitated in tissue sections taken from 18 US and Japanese patients who died of acute K D and from 10 age-matched controls. IgA PCs were significantly increased in the trachea of patients who died of acute KD, compared with controls (P < .01), a finding that was similar to findings in children with fatal respira tory viral infection. IgA PCs also infiltrated coronary artery, pancreas, a nd kidney in all KD patients. These findings strongly support entry of the KD etiologic agent through the upper respiratory tract, resulting in an IgA immune response, with systemic spread to vascular tissue, pancreas, and ki dney.