Platelet-Derived Microparticles: A New Index of Monitoring Platelet Activation and Inflammation in Kawasaki Disease

MRI Diagnosis of Coronary Artery Lesions in Children With Kawasaki Disease and Their Correlation With Inflammatory Factors

BACKGROUND

Ultrasonography (US), as a routine examination for evaluating coronary artery lesions (CAL) in children with Kawasaki disease (KD), has strong subjectivity and limitations. Non-contrast enhanced coronary magnetic resonance angiography (NCE-CMRA) is sensitive and reliable in displaying the segments of coronary arteries (CA).

PURPOSE

To evaluate the CA using NCE-CMRA, to compare NCE-CMRA with US, and to assess the correlation between KD-related inflammatory factors and the occurrence of CAL.

STUDY TYPE

Retrospective.

POPULATION

61 children with KD who had undergone NCE-CMRA. Ultimately, 52 cases were included (32 males and 20 females), with an average of 5.9 ± 0.3 years old.

FIELD STRENGTH/SEQUENCE

3-T, 3D balanced turbo field echo sequence.

ASSESSMENT

NCE-CMRA and US coronary visualization rates were compared in 41 children who were imaged with both techniques. Inflammatory factors were compared between CAL and normal coronary artery (NCA) subgroups. In the CAL group, correlations of these inflammatory factors with CAL parameters were investigated.

STATISTICAL TESTS

Comparison between groups was performed by the two independent samples t-test; the comparison of enumeration data between groups was performed by chi-square test. Receiver operating characteristic (ROC) curve analysis was performed to determine the sensitivity of inflammatory factors for detecting CAL. The correlation between CAL and inflammatory indexes was analyzed by multiple linear regression. A P value <0.05 was considered statistically significant.

RESULTS

NCE-CMRA visualized significantly more segments than US (76% vs. 46%). There were significant differences in PLT, CRP, ESR, and D-dimer between the CAL and NCA groups. ROC curve analysis showed that the sensitivities of these four indicators in diagnosing CAL were 39%, 44%, 72%, and 61%, respectively, at cut-off points of 562.5 × 109 /L, 48.93 mg/L, 45.5 mm/h, and 0.5 mg/L, respectively.

DATA CONCLUSION

The combination of NCE-CMRA and inflammatory factors is helpful for the early diagnosis and disease severity of CAL in children with KD.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 2.

The Systemic Immune-Inflammation Index (SII) and coronary artery lesions in Kawasaki disease

Coronary artery lesions (CALs) are the most common complications of Kawasaki disease (KD) and play a crucial role in determining the prognosis of the disease. Consequently, the early identification of children with KD who are at risk of developing coronary artery damage is vitally important. We sought to investigate the relationship between the Systemic Immune-Inflammation Index (SII) and CALs in patients with KD and to assess its predictive value. We carried out a retrospective review and analysis of medical records for KD patients treated at the First Affiliated Hospital of Anhui Medical University between January 2017 and January 2023. We utilized single-variable tests, binary logistic regression analysis, ROC curve analysis, restricted cubic spline tests, and curve fitting to evaluate the association between SII and CALs. In our study, 364 patients were included, with 63 (17.3%) presenting with CALs at the time of admission. The binary logistic regression analysis indicated that SII was a significant risk factor for CALs at admission, evident in both unadjusted and models adjusted for confounders. The ROC curve analysis revealed an AUC (Area Under the Curve) value of 0.789 (95%CI 0.723-0.855, P < 0.001) for SII's predictive ability regarding CALs at admission. A consistent positive linear relationship between SII and the risk of CALs at admission was observed in both the raw and adjusted models. Our research findings suggest that SII serves as a risk factor for CALs and can be used as an auxiliary laboratory biomarker for predicting CALs.

Early Clinical Evaluation of Coronary Artery Lesions in Kawasaki Disease

The purpose of this study is to analyze the early clinical features of coronary artery lesion (CAL) in Kawasaki disease (KD), evaluate systemic inflammation indicators, and enhance early recognition of CAL in the acute phase of KD. A total of 314 children with KD were divided into those with CAL (CAL group) and without CAL (NCAL group) using echocardiographic results, and their clinical data were retrospectively analyzed. For KD patients, male, children aged 3 to 9 years, and those with fever longer than 6 days before intravenous immunoglobulin (IVIG) use were more likely to have CAL. There were significant differences in sex, age, and fever time (P < .05). Moreover, some laboratory indicator test results revealed there was a significant difference between N-terminal pro-brain natriuretic peptide (NT-pro-BNP) and interleukin-6 (IL-6), and the CAL (P < .05). This study has certain guiding significance for early clinical evaluation.

[Platelet-to-lymphocyte ratio as a biomarker for predicting coronary artery lesions in Chinese children with Kawasaki disease: a Meta analysis]

OBJECTIVES

To systematically evaluate the value of the platelet-to-lymphocyte ratio (PLR) in predicting coronary artery lesions (CAL) in Chinese children with Kawasaki Disease (KD).

METHODS

A comprehensive search was conducted in databases including PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, Wanfang Data, China Biomedical Literature Database, and China Science and Technology Journal Database from inception to December 2022. The quality of the included literature was assessed using the Newcastle-Ottawa Scale, and a Meta analysis was performed using Stata 15.1.

RESULTS

A total of ten published reports, involving 3 664 Chinese children with KD, were included in this Meta analysis, of whom 1 328 developed CAL. The Meta analysis revealed a sensitivity of 0.78 (95%CI: 0.71-0.83), specificity of 0.71 (95%CI: 0.61-0.80), overall diagnostic odds ratio of 8.69 (95%CI: 5.02-15.06), and an area under the curve of the summary receiver operating characteristic of 0.82 (95%CI: 0.78-0.85) for PLR in predicting CAL in the children with KD. The sensitivity, specificity, and area under the curve of summary receiver operating characteristic were lower for PLR alone compared to PLR in combination with other indicators. Sensitivity analysis demonstrated the stability of the Meta analysis results with no significant changes upon excluding individual studies. However, a significant publication bias was observed (P<0.001).

CONCLUSIONS

PLR demonstrates certain predictive value for CAL in Chinese children with KD.

Inhibition of PDGFRβ alleviates endothelial cell apoptotic injury caused by DRP-1 overexpression and mitochondria fusion failure after mitophagy

Kawasaki disease (KD), described as "mucocutaneous lymph node syndrome", affects infants and toddlers. Patients with KD suffer from an inflammatory cascade leading to vasculitis with a predilection for coronary arteries. While the symptoms and pathogenesis of KD have received more and more attention, the precise mechanisms are still debated. Researches show that endothelial dysfunction process in KD leads to arterial damage and affect clinical outcome. In this study, we constructed a Candida albicans water soluble fraction (CAWS)-induced KD murine model and penetrated investigating the mechanisms behind endothelial dysfunction. CAWS-induced mice presented remarkably elevated vascular endothelial cell growth factor (VEGF) levels. Abundant expression of VEGF was documented in all vessels that showed edema from acute KD. It has been reported that Platelet-derived growth factor (PDGF) co-expression normalizes VEGF-induced aberrant angiogenesis. Hyperexpression of PDGFRβ was induced in the thickened medial layer and vascular endothelium of KD mice. Masitinib (Mas) is an oral tyrosine kinase inhibitor of numerous targets, which can selectively target PDGFR signaling. We set out to explore whether Mas could regulate coronary pathology in KD. Mas administration significantly reduced the VEGF-induced endothelial cells migration. NOX4 was activated in vascular endothelial cells to produce more ROS. Mitochondrial dysregulated fission and mitophagy caused by DRP-1 overexpression precipitated the arterial endothelial cells injury. Here, mitophagy seemed to work as the driving force of DRP-1/Bak/BNIP3-dependent endothelial cells apoptosis. In summary, how mitophagy is regulated by DRP-1 under pathologic status is critical and complex, which may contribute to the development of specific therapeutic interventions in cardiovascular diseases patients, for example Masatinib, the inhibitor of PDGFRβ. FACTS AND QUESTIONS: Kawasaki disease causing systemic vasculitis, affects infants and toddlers. Coronary artery injury remains the major causes of morbidity and mortality. DRP-1 overexpression induces DRP-1/Bak/BNIP3-dependent endothelial cells apoptosis. PDGFRβ was high-expressed in the thickened medial layer of CAWS-induced KD mice. Inhibition of PDGFRβ signaling alleviates arterial endothelial cells injury.

Novel Score to Predict Immunoglobulin Resistance in Kawasaki Disease

To evaluate existing scoring systems and develop a new model to predict intravenous immunoglobulin (IVIG) resistance in patients with Kawasaki disease (KD). A retrospective cohort study performed between 2004 and 2017 identified 115 patients treated with IVIG for classic or incomplete KD. In our practice, IVIG resistance was defined as fever for > 24 h and patients were divided into responders and non-responders. A univariate analysis was performed to identify independent predictors of IVIG resistance. The predictors were combined into a new scoring system and compared with existing scoring systems. Sixty-five patients had classic KD and 50 had incomplete KD. Among the 115 patients, 80 (69.6%) responded and the remaining 35 were resistant (30.4%) to IVIG. Of the 35 resistant patients, 16 patients had incomplete KD. Hispanic children comprised 43% of our sample population. Coronary artery abnormalities developed in 14 of the 35 IVIG-resistant patients (39%). Univariate analysis showed that IVIG-resistant patients were older and present with lower platelets, potassium, and creatinine (P < 0.05). Multivariate logistic regression analysis used platelets, potassium, body surface area (BSA), and creatinine to devise the Las Vegas Scoring System (LVSS), which demonstrated a sensitivity of 76.2% and a specificity of 68.6%. Compared to published data, we observed a higher rate of IVIG resistance and coronary artery abnormalities in our patient population. The LVSS (using platelets, potassium, BSA, and creatinine) showed higher specificity and comparable sensitivity to other scoring systems devised to predict IVIG resistance.

Platelets exacerbate cardiovascular inflammation in a murine model of Kawasaki disease vasculitis

Kawasaki disease (KD) is the leading cause of acquired heart disease among children. Increased platelet counts and activation are observed during the course of KD, and elevated platelet counts are associated with higher risks of developing intravenous immunoglobulin resistance and coronary artery aneurysms. However, the role of platelets in KD pathogenesis remains unclear. Here, we analyzed transcriptomics data generated from the whole blood of patients with KD and discovered changes in the expression of platelet-related genes during acute KD. In the Lactobacillus casei cell wall extract (LCWE) murine model of KD vasculitis, LCWE injection increased platelet counts and the formation of monocyte-platelet aggregates (MPAs), upregulated the concentration of soluble P-selectin, and increased circulating thrombopoietin and interleukin 6 (IL-6). Furthermore, platelet counts correlated with the severity of cardiovascular inflammation. Genetic depletion of platelets (Mpl-/- mice) or treatment with an anti-CD42b antibody significantly reduced LCWE-induced cardiovascular lesions. Furthermore, in the mouse model, platelets promoted vascular inflammation via the formation of MPAs, which likely amplified IL-1B production. Altogether, our results indicate that platelet activation exacerbates the development of cardiovascular lesions in a murine model of KD vasculitis. These findings enhance our understanding of KD vasculitis pathogenesis and highlight MPAs, which are known to enhance IL-1B production, as a potential therapeutic target for this disorder.

Platelet-Derived Microparticles and Autoimmune Diseases

Extracellular microparticles provide a means of cell-to-cell communication and can promote information exchanges between adjacent or distant cells. Platelets are cell fragments that are derived from megakaryocytes. Their main functions are to stop bleeding, regulate inflammation, and maintain the integrity of blood vessels. When platelets are activated, they can perform related tasks by secreting platelet-derived microparticles that contain lipids, proteins, nucleic acids, and even organelles. There are differences in the circulating platelet levels in many autoimmune diseases, including rheumatoid arthritis, systemic lupus erythematosus, antiphospholipid antibody syndrome, and Sjogren's syndrome. In this paper, the latest findings in the research field of platelet-derived microparticles are reviewed, including the potential pathogenesis of platelet-derived microparticles in various types of immune diseases, their potential as related markers, and for monitoring the progress and prognosis of disease treatment are expounded.

Thymic stromal lymphopoietin induces platelet mitophagy and promotes thrombosis in Kawasaki disease

Kawasaki disease (KD) is an acute systemic vasculitis primarily affecting infants and children. Activated platelets predispose patients to coronary artery structural lesions that may lead to thrombotic cardiovascular events. To discover potential proteins underlying platelet activation in KD, we conducted a protein chip assay of 34 cytokines and discovered thymic stromal lymphopoietin (TSLP) was aberrantly expressed, which remained elevated after intravenous immunoglobulin G (IVIG) treatment and during convalescence in KD patients in comparison to healthy controls. Enzyme-linked immunosorbent assay (ELISA) corroborated the upregulation of TSLP in KD patients, which was exacerbated in convalescent patients complicated with thrombosis. TSLP receptors on platelets were also significantly upregulated in KD patients complicated with thrombosis. Platelet activation, apoptosis, and mitochondrial autophagy (mitophagy) were increased in convalescence KD patients complicated with thrombosis. In vitro, TSLP induced platelet activation and platelet mitophagy in healthy blood donors, as observed in KD patients. TSLP, similar to mitophagy agonist carbonyl cyanide 3-chlorophenyl hydrazone (CCCP), promoted thrombosis, which was attenuated by the mitophagy inhibitor Mdivi-1. Co-immunoprecipitation in TSLP-treated platelets revealed TSLP receptor (TSLPR) bound to mitophagy regulators, Parkin and Voltage Dependent Anion Channel Protein 1 (VDAC1).Thus, our results demonstrated that TSLP induced platelet mitophagy via a novel TSLPR/Parkin/VDAC1 pathway that promoted thrombosis in KD. These results suggest TSLP as a novel therapeutic target against KD-associated thrombosis.

[Proteomics of serum exosomes in children in the acute stage of Kawasaki disease: a prospective study]

OBJECTIVES

To study the biological processes and functions of serum exosomes in children in the acute stage of Kawasaki disease (KD), so as to provide new biomarkers for the early diagnosis of KD.

METHODS

In this prospective study, 13 children with KD who were treated in Children's Hospital of Soochow University from June 2019 to August 2020 were enrolled as the KD group, and 13 children who were hospitalized due to bacterial infection during the same period were enrolled as the control group. Whole blood was collected on the next morning after admission, serum samples were obtained by centrifugation, and exosomes were extracted through ultracentrifugation. Serum exosomes were analyzed by label-free quantitative proteomics, and differentially expressed proteins (DEPs) were screened out for functional enrichment analysis. A protein-protein interaction (PPI) network was plotted, and unique proteins were validated by targeted proteomics.

RESULTS

A total of 131 DEPs were screened out for the two groups, among which 27 proteins were detected in both groups. There were 48 unique DEPs in the KD group, among which 23 were upregulated and 25 were downregulated, and these proteins acted on "complement and coagulation cascades" and "the MAPK signaling pathway". Validation by targeted proteomics showed that FGG, SERPING1, C1R, C1QA, IGHG4, and C1QC proteins were quantifiable in the KD group. A total of 29 proteins were only expressed in the control group, among which 12 were upregulated and 17 were downregulated. Four proteins were quantifiable based on targeted proteomics, i.e., VWF, ECM1, F13A1, and TTR. A PPI network was plotted for each group. In the KD group, FGG and C1QC had close interaction with other proteins, while in the control group, VWF had close interaction with other proteins.

CONCLUSIONS

The serum exosomes FGG and C1QC in children in the acute stage of KD are expected to become the biomarkers for the early diagnosis of KD. For children with unexplained fever, detection of FGG, C1QC1, and VWF may help with etiological screening.

Recent advances in Extracellular Vesicles and their involvements in vasculitis

Systemic vasculitis is a heterogeneous group of multisystem autoimmune disorders characterized by inflammation of blood vessels. Although many progresses in diagnosis and immunotherapies have been achieved over the past decades, there are still many unanswered questions about vasculitis from pathological understanding to more advanced therapies. Extracellular vesicles (EVs) are double-layer phospholipid membrane vesicles harboring various cargoes. EVs can be classified into exosomes, microvesicles (MVs), and apoptotic bodies depending on their size and origin of cellular compartment. EVs can be released by almost all cell types and may be involved in physical and pathological processes including inflammation and autoimmune responses. In systemic vasculitis, EVs may have pathogenic involvement in inflammation, autoimmune responses, thrombosis, endothelium injury, angiogenesis and intimal hyperplasia. EV-associated redox reaction may also be involved in vasculitis pathogenesis by inducing inflammation, endothelial injury and thrombosis. Additionally, EVs may serve as specific biomarkers for diagnosis or monitoring of disease activity and therapeutic efficacy, i.e. AAV-associated renal involvement. In this review, we have discussed the recent advances of EVs, especially their roles in pathogenesis and clinical involvements in vasculitis.

Clinical implications of thrombocytosis in acute phase Kawasaki disease

In Kawasaki disease (KD), thrombocytosis is commonly found in the subacute phase. However, the exact significance of thrombocytosis in the acute phase of KD is unclear. To evaluate serum platelet counts in patients during the acute phase of KD and assess the clinical outcomes according to the degree of thrombocytosis, we collected data of KD patients between 2009 and 2017. A total of 505 patients with KD were enrolled, and 249 (49.3%) patients had thrombocytosis, including mild (69.5%), moderate (21.7%), severe (4.8%), and extreme (4.0%) thrombocytosis. Correlation analysis revealed a positive correlation between the maximum platelet count and admission duration (r = 0.359, p < 0.001) and fever duration (r = 0.204, p < 0.001). The maximum platelet count was significantly higher in IVIG non-responders than that in IVIG responders (629 ± 201 × 10⁹/L vs. 499 ± 154 × 10⁹/L, p < 0.001), and in patients with coronary artery dilatation (CAD) than in those without CAD (602 ± 201 × 10⁹/L vs. 512 ± 164 × 10⁹/L, p < 0.001).Conclusion: Thrombocytosis in acute phase KD was associated with poor clinical outcomes such as IVIG non-responsiveness, CAD, and prolonged admission and fever durations. What is Known: • Thrombocytopenia in the acute phase of KD is related to non-responsiveness to IVIG and the risk of coronary artery dilatation. • The exact significance of thrombocytosis in the acute phase of KD as a benign phenomenon or a signal of poor outcome of KD is unclear. What is New: • Thrombocytosis in acute phase KD was associated with poor clinical outcomes such as IVIG non-responsiveness, CAD, and prolonged admission and fever durations.

Differentially expressed genes, lncRNAs, and competing endogenous RNAs in Kawasaki disease

BACKGROUND

Kawasaki disease (KD) is an acute and febrile systemic vasculitis of unknown etiology. This study aimed to identify the competing endogenous RNA (ceRNA) networks of lncRNAs, miRNAs, and genes in KD and explore the molecular mechanisms underlying KD.

METHODS

GSE68004 and GSE73464 datasets were downloaded from the Gene Expression Omnibus. Differentially expressed lncRNAs (DElncRNAs) and genes (DEGs) in KD were identified using the criteria of p < 0.05 and | log2 (fold change) | ≥ 1. MicroRNAs (miRNAs) related to KD were searched from databases. The lncRNA-miRNA-mRNA networks involving the DElncRNAs and DEGs were constructed.

RESULTS

A total of 769 common upregulated, 406 common downregulated DEGs, and six DElncRNAs were identified in the KD samples. The lncRNA-miRNA-mRNA network consisted of four miRNAs, three lncRNAs (including the upregulated PSORS1C3, LINC00999, and the downregulated SNHG5) and four DEGs (including the downregulated GATA3 and the upregulated SOD2, MAPK14, and PPARG). Validation in the GSE18606 dataset showed that intravenous immunoglobulin treatment significantly alleviated the deregulated profiles of the above RNAs in KD patients. Three ceRNA networks of LINC00999-hsa-miR-6780-SOD2, PSORS1C3-hsa-miR-216a-PPARG/MAPK14, and SNHG5-hsa-miR-132/hsa-miR-92-GATA3 were identified. Four genes were associated with functional categories, such as inflammatory response and vascular endothelial cell.

CONCLUSIONS

The ceRNA networks involve genes, such as SOD2, MAPK14, and PPARG, and lncRNAs, including PSORS1C3, LINC00999, and SNHG5, which might play a key role in the pathogenesis and development of KD by regulating inflammation.

Changes in and significance of platelet function and parameters in Kawasaki disease

Kawasaki disease (KD) is a systemic febrile, inflammatory vascular disease of unknown etiology. The coronary artery abnormality (CAA) caused by KD has become the most commonly acquired heart disease in children. Initial treatment of intravenous immunoglobulin (IVIG) can reduce the incidence of CAA. Thrombocytosis is common during the course of KD, but changes in and significances of platelet function and parameters are unclear. In this study, we enrolled 120 patients, including 40 patients with KD, 40 febrile controls, and 40 afebrile controls. The platelet function was assessed using the platelet function analyzer (PFA)-200. Platelet parameters, including platelet count (PLT), mean platelet volume (MPV), platelet distribution width (PDW), and platelet hematocrit (PCT) were measured. In the febrile period, the PDW and MPV were lower in KD patients (P < 0.05). The platelet function did not change significantly during the febrile period of KD but weakened in the defervescence phase. No significant differences between the CAA and normal groups, and between IVIG resistance and response groups. The diagnostic cutoff value of the PDW level for predicting KD was 10.85 fL with a sensitivity of 55% and a specificity of 77.5% (area under curve (AUC) = 0.690, 95% confidence interval (CI): 0.574–0.806, P < 0.01). Besides, the MPV level was 9.55 fL with sensitivity of 75% and specificity of 70% (AUC = 0.733, 95%CI: 0.620–0.846, P < 0.001). This is the first longitudinal study of platelet function changes in KD patients using PFA-200. Besides, lower PDW and MPV may be available markers for early diagnosis of KD.

Platelets in Kawasaki disease: Is this only a numbers game or something beyond?

Kawasaki disease (KD) is a medium vessel vasculitis with predilection to cause coronary artery abnormalities. KD is now the most common cause of acquired heart disease in developed countries. Thrombocytosis is consistently found in patients with KD, usually in 2nd to 3rd week of illness. Thrombocytopenia has occasionally been reported in the acute phase of KD. An increase or decrease in platelet number in patients with KD was initially considered to be a benign phenomenon. However, recent literature on platelet biology in KD has suggested that platelets are not only increasing but are rather activated. This phenomenon has been found to increase the risk of thrombosis in these patients. Similarly a fall in platelet counts during acute stage of KD has also been found to be associated with increased severity of disease. In this review, we update on the current best understanding about pathogenic role of platelets in patients with KD.

Maternal peripheral blood platelet-to-white blood cell ratio and platelet count as potential diagnostic markers of histological chorioamnionitis-related spontaneous preterm birth

Background

Histological chorioamnionitis (HCA) is one of the leading causes of spontaneous preterm birth, thus, to identify novel biomarkers for the early diagnosis of HCA is in a great need.

Objective

To investigate the diagnostic value of maternal peripheral blood platelet‐to‐white blood cell ratio (PLT/WBC) and platelet (PLT) counts in HCA‐related preterm birth.

Methods

A total of 400 patients with preterm birth were enrolled in this study: non‐HCA group (n = 193) and HCA group (n = 207), and 87 full‐term pregnancies were enrolled as the control. The peripheral blood of the participators was collected, and the neutrophil count, WBC count, platelet count, and levels of C‐reactive protein (CRP) and procalcitonin were recorded, and the platelet‐to‐white blood cell ratio (PLT/WBC) of the participators was calculated. Receiver operating characteristic (ROC) curve has been drawn to show the sensitivity and specificity of PLT/WBC and PLT count for the diagnosis of HCA‐related spontaneous preterm birth patients.

Results

The neutrophil count, WBC count, and procalcitonin show no significant differences among the three groups, and the PLT count, PLT/WBC, and CRP (P < 0.05) were significantly increased in HCA group compared with non‐HCA group; moreover, the area under the curve (AUC) of PLT/WBC, PLT, and CRP was 0.744 (95% confidence interval [CI], 0.6966‐0.7922), 0.8095 (95% CI, 0.7676‐0.8514), and 0.5730 (95% CI, 0.5173‐0.6287), respectively.

Conclusion

Platelet count and PLT/WBC may become a potential biomarker of HCA‐related spontaneous preterm birth.

Biomarkers for Kawasaki Disease: Clinical Utility and the Challenges Ahead

Kawasaki disease (KD) has replaced acute rheumatic fever as the most common cause of acquired heart disease in children in the developed world and is increasingly being recognized from several developing countries. It is a systemic vasculitis with a predilection for coronary arteries. The diagnosis is based on a constellation of clinical findings that appear in a temporal sequence. Quite understandably, this can become a problem in situations wherein the clinical features are not typical. In such situations, it can be very difficult, if not impossible, to arrive at a diagnosis. Several biomarkers have been recognized in children with acute KD but none of these has reasonably high sensitivity and specificity in predicting the course of the illness. A line up of inflammatory, proteomic, gene expression and micro-RNA based biomarkers has been studied in association with KD. The commonly used inflammatory markers e.g. erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and total leucocyte counts (TLC) lack specificity for KD. Proteomic studies are based on the identification of specific proteins in serum, plasma and urine by gel electrophoresis. A host of genetic studies have identified genes associated with KD and some of these genes can predict the course and coronary outcomes in the affected individuals. Most of these tests are in the early stages of their development and some of these can predict the course, propensity to develop coronary artery sequelae, intravenous immunoglobulin (IVIg) resistance and the severity of the illness in a patient. Development of clinical criteria based on these tests will improve our diagnostic acumen and aid in early identification and prevention of cardiovascular complications.