Late diagnosis of Kawasaki disease is associated with haptoglobin phenotype

Background. Kawasaki disease (KD) is an acute febrile illness characterized by multiple clinical and biochemical features of inflammation and the most common complications of coronary artery abnormality (CAA). Haptoglobin (Hp) is an acute-phase protein whose phenotype is known to be involved in coronary artery diseases. In this paper, we report the investigation of the association of Hp phenotype with the formation of CAA in KD. Patients and methods. Forty-seven consecutive patients with clinically diagnosed KD were admitted. Sera were taken before therapy of intravenous immunoglobulins (IVIG) plus aspirin, and levels of serum proteins were measured by a rate immunonephelometer. The echocardiographic criteria for coronary artery abnormality were evaluated during acute or subacute stages. Hp phenotyping was performed by Western immunoblotting. Results. Duration of fever at diagnosis of KD was significantly different between patients with Hp 2-2 (6.4 ± 1.2 days, n = 25) and with Hp¹ allele (Hp 2-1 plus Hp 1-1; 8.8 ± 3.5 days, n = 22). In contrast, serum levels of Hp between KD patients with Hp2-2 and with Hp¹ allele (297 ± 121 mg dL^-1 vs. 330 ± 101 mg dL^-1, respectively) was not significantly different. On the other hand, no patients with Hp 2-2 (0/25) were recognized as having KD in subacute stage. However, 5 out of 20 patients with Hp 2-1 were recognized in subacute stage, and their incidence of CAA was 80.0% (4/5). Conclusions. Patients with Hp 2-1 have patterns of delayed or incomplete presentation of clinical symptoms. Therefore, the late diagnosis of KD is associated with haptoglobin phenotype.