LRG1, LBP, AGT, RBP4 potential biomarkers for Kawasaki disease diagnosis
Levels of serum proteins, particularly the leucine-rich alpha-2-glycoprotein 1 (LRG1), can be used as biomarkers for the diagnosis of Kawasaki disease (KD) and accurate identification of its phases, a new proteomic study reveals.
The study included 64 patients between the ages of 0 and 12 years and diagnosed with KD. This population yielded 55 serum samples obtained during the acute phase and 51 during the recovery phase. An additional 151 patients with other diseases and 13 healthy individuals were recruited as controls.
Mass spectrometry was used to identify proteins associated with KD that were differentially expressed between the phases. These were then verified against a further 270 samples using enzyme-linked immunosorbent assay (ELISA) and Western blotting.
Initial mass spectrometry analysis revealed that 65,514 peptides were differentially expressed between the two phases. From this, 102 peptides corresponding to 40 proteins were downregulated while 391 peptides corresponding to 56 proteins were upregulated during the acute phase of KD.
A further 20 and 6 proteins upregulated and downregulated, respectively, during the acute phase were determined to be related to KD. Some of these proteins were plasminogen, ceruloplasmin and alpha-1-antichymotrypsin.
Western blotting showed that the levels of LRG1, along with lipopolysaccharide-binding protein (LBP) and angiotensin (AGT), were significantly higher in serum samples collected during the acute phase than in those collected during the recovery phase. On the other hand, levels of retinol-binding protein 4 (RBP4) were significantly lower during the acute phase.
Further validation using ELISA showed that levels of LBP, AGT and LRG1 remained significantly greater during the acute phase (p<0.001), while RBP4 had significantly lower levels (p<0.001).