Kawasaki Disease Associated With Reactive Hemophagocytic Lymphohistiocytosis

We report a case of Kawasaki disease with significant coronary artery aneurysms subsequently associated with reactive hemophagocytic lymphohistiocytosis in a young child with low T-cell perforin expression and NK-cell dysfunction. The patient was treated with a selective T-cell costimulation modulator in an effort to regulate T-cells. This case is unique for several reasons: (1) the severe degree of coronary artery aneurysms; (2) low T-cell perforin and NK-cell values; and (3) treatment with a selective T-cell costimulation modulator, none of which has been described in prior cases.