IMMUNOHISTOCHEMICAL STUDIES ON SMALL-INTESTINAL MUCOSA IN KAWASAKI-DISEASE

To investigate the etiology of Kawasaki disease (KD), the cell surface phenotypes of mononuclear cells and enterocytes in the jejunal mucosa of KD were investigated in a case-control study. Sixteen Japanese patients with KD were enrolled in the study. As disease controls, jejunal tissues from 10 patients with diarrhea due to cow's milk protein intolerance were used. The numbers of cells stained by an immunofluorescent technique were counted and analyzed statistically by t test. Both HLA-DR+ CD3+ and DR+CD4+ cells were significantly increased in the lamina propria of KD patients in the acute phase compared with numbers in controls and patients with cows milk protein intolerance (p less-than-or-equal-to 0.01). CD8+ cells were significantly reduced in both the epithelium and the lamina propria of KD patients in the acute phase in comparison with numbers in both controls (p less-than-or-equal-to 0.05) and patients with cow's milk protein intolerance (p less-than-or-equal-to 0.01). HLA-DR+ cells were significantly increased in both the enterocytes and the lamina propria of KD patients in the acute phase compared with numbers in controls (p less-than-or-equal-to 0.01). These cell patterns returned to normal in the convalescent phase of KD. Differences between these cell patterns in KD patients with and without diarrhea were not significant, although these immunohistochemical features tended to be more marked in patients with diarrhea than in those who lacked diarrhea. These results are consistent with what one would expect to find if a delayed-type hypersensitivity reaction had occurred in the small intestinal mucosa of KD patients. Although other explanations cannot be ruled out, it is conceivable that causative antigens may have invaded the body by breaching the barrier of the intestinal mucosa.