Identification of a novel anti-heat shock cognate 71 kDa protein antibody in patients with Kawasaki disease

Kawasaki disease (KD) is an idiopathic form of acute systemic vasculitis, which clinically mimics febrile diseases. Although it has been hypothesized that immune system malfunction is associated with KD, its etiology remains unclear. The aim of the present study was to identify a KD-associated antibody. Immunoproteomic methods were used to identify KD-associated antigens that could be recognized in the sera of patients with KD. HeLa cells were used as an antigen source and KD sera were used as probe antibodies to determine the binding of the antibodies using an indirect immunofluorescence assay. Western blotting was performed to identify KD-associated antigens in HeLa whole cell lysates. Eight out of 12 serum samples obtained from patients with KD demonstrated immunoreactive bands at ~70 kDa, which was later determined to be heat shock cognate 71 kDa protein (HSP7C) by mass spectrometry. The diagnostic value of serum anti-HSP7C antibodies for KD was assessed using ELISA. Using a cut-off value of 0.267, anti-HSP7C antibodies were observed to be present in the sera of 60.00% (30/50) of patients with KD, in 21.05% (8/38) of non-KD febrile controls, and in 5.26% (2/38) of healthy controls. High serum levels of anti-HSP7C antibodies were detected in the peripheral circulation of patients with KD. To the best of our knowledge, the present study is the first to observe the high expression levels of anti-HSP7C antibodies in patients with KD. Therefore, anti-HSP7C antibodies may be used as a diagnostic marker to detect KD.