We recruited 20 children of classical Kawasaki disease (KD) in follow up of atleast six months since diagnosis, from the pediatric rheumatology clinic at our hospital in August and September 2007. Twenty healthy age and sex matched children served as controls. Venous blood for the measurement of serum high sensitivity C-reactive protein (hs-CRP) concentrations was collected after an overnight fast and measured with a particle enhanced immuno-turbidometric assay consisting of an anti-mono-clonal antibody coupled to latex microparticles (Quantia CRP-US). The presence of hs-CRP resulted in an insoluble complex formation giving rise to turbidity, which was measured at wavelength between 505-578 nm and had a functional sensitivity of 0.015 mg/dL. The institutional ethics committee approved the study. Written informed consent was taken from either of the parent.

There were 13 boys with mean age of 4.5 years (range 1-12) and 7 girls with mean age of 2 years (range 0.5-3). Cardiac involvement (coronary dilatation-2, coronary aneurysm-3) was seen in 25% children in the acute phase which resolved on follow up. Intravenous immunoglobulin was received by 75% of the children and all received aspirin. Mean CRP values during acute phase of disease were 90.85 (range 7.4- 384 mg/dL; SD - 80.20); hs-CRP in patients ranged from 0.019- 0.510; SD- 0.226. After 6 months of disease onset, mean hs-CRP value in patients was significantly higher than controls (0.275 mg/dL and 0.085 mg/dL, respectively, P=0.002). There was no significant difference comparing the hs-CRP in boys and girls; children with and without history of cardiac involvement; and with and without immunoglobulin therapy in the acute phase of illness.

Increased CRP is characteristic during the acute phase of KD. Persistent elevation after the convalescent phase of KD validates the possibility of smouldering vasculitis playing a part in altering arterial function [1,2]. Mitani, et al. [3] observed that levels of CRP was elevated in KD patients with coronary artery lesions (CAL) compared to controls and other KD groups with normal coronary arteries or with regressed aneurysms. In our limited study, hs-CRP values were not different in the small number of patients with cardiac involvement in the acute phase as compared to those without. We did not have a case with residual CAL. There was no correlation between the CRP in the acute phase and hs-CRP in the follow up. Suppression of this chronic inflammatory process may be a new target for intervention, to improve arterial function. Significant reduction in serum hs-CRP levels after short-term statin treatment has been demonstrated [4].

Contributors: NK: conceived and designed the study, diagnosed and treated the involved subjects; and supervised the manuscript for important intellectual content and will act as guarantor of the study; AA: collected data, analyzed and drafted the paper; SB: performed the hs-CRP test and helped in the design and conduct of the study. The final manuscript was approved by all the authors.

Funding: Indian Council of Medical Research as short term student grant 2008 (No.21/127/ 08-BMS).

Competing interests: None stated.

1. Cheung YF, Ho MH, Tam SC, Yung TC. Increased high sensitivity C reactive protein concentrations and increased arterial stiffness in children with a history of Kawasaki disease. Heart.  2004;90:1281-5.

2. Kato H, Sugimura T, Akagi T, Sato N, Hashino K, Maeno Y, et al. Long term consequences of Kawasaki disease: a 10 to 21 year follow up study of 594 patients. Circulation. 1996;94:1379-85.

3. Mitani Y, Sawada H, Hayakawa H, Aoki K, Ohashi H, Matsumura M, et al.  Elevated levels of high-sensitivity C-reactive protein and serum amyloid-a late after Kawasaki disease-association between inflammation and late coronary sequelae in Kawasaki disease. Circulation. 2005;111;38-43.