The coding SNP rs1801274 has been validated in a number of KD ancestry cohorts and was shown to cause a difference in the ability of FcRIIa to bind the human IgG2 immunoglobulin isotype. The discovery of rare patients with single-gene high-penetrance mutations informed our understanding of pathways driving systemic inflammation. Here, we review the advances in practicing PM in patients with primary systemic vasculitides (PSVs). We summarize recent genetic studies and discuss current knowledge around the contribution of epigenetic factors and extracellular vesicles (EVs) ABCC4 in disease progression and treatment response. Implementation of PM in PSVs is usually a developing field that will require analysis of a large cohort of patients to validate data from genomics, transcriptomics, metabolomics, proteomics, and epigenomics studies for accurate disease profiling. This multi-omics approach to study disease pathogeneses should ultimately provide a powerful tool for stratification of patients to receive tailored optimal therapies and for monitoring their disease activity. and (poor prognosis)Immunoglobulin A Vasculitis/Henoch-Sch?nlein Purpura (IgAV/HSP)Susceptibility locus for IgAV/HSP (42)HLA-DRB1Giant cell arteritis (GCA)Susceptibilty genes for GCA (43)HLA-DRB1*04, PLG, and P4HA2 Open in a separate windows Kawasaki Disease KD is an acute, self-limited vasculitis that typically affects infants and children under the NGD-4715 age of 5 years. Coronary artery aneurysms NGD-4715 (CAAs) occur in 25% of untreated patients and may lead to ischemic heart disease, myocardial infarction, and sudden death at a young age. The pathogenesis of KD remains unknown; however, it is thought that host genetics play an important role in susceptibility and disease outcome. Interestingly, the incidence of KD is usually up to 50-fold higher in children of Asian descent. Epidemiologic and clinical features of KD also strongly support an infectious etiology in genetically predisposed children NGD-4715 (47). GWAS in KD have identified a number of susceptibility SNPs/genes that contribute to the risk of KD (and gene to be associated with susceptibility to KD in Japanese and European cohorts (meta analysis = 0.0001). encodes NCX1 (a sodium/calcium exchanger) that functions as a bidirectional sodium/calcium channel. Patients homozygous for the risk allele (rs13017968) have higher rates of coronary artery abnormalities. Homozygosity for rs13017968 is usually associated with an increase in Ca2+ flux NGD-4715 in EBV-transformed B cells of healthy individuals. The NCX1 protein expression was detected in the postmortem coronary artery tissue of a young KD patient. Another study by Onouchi et al. (48) found a coding SNP (rs3741596) in the ORAI Calcium Release-Activated Calcium Modulator 1 (= 0.00041). Interestingly, frequency of the risk allele is more than 20 occasions higher in Japanese compared to Europeans, which may account for higher prevalence of KD in the Japanese population. Together, these genetic and functional data provide evidence for the role of Ca2+-mediated signaling pathways in the pathogenesis of KD and for the use of calcineurin inhibitors (49). Lv et al. (46) used statistically significant candidate variants from multiple GWAS and other gene association studies for pathways analysis. This investigation showed that KD susceptibility genes are enriched in functional networks for calcium ion homeostasis and immune responses and highlighted the role of nuclear transcription factor of activated T cells (NF-AT) and nuclear factor (NF) kappa light chain enhancer of activated B cells (NF-B) in the pathogenesis of KD. Another indication from GWAS for the use of new therapies in KD has come from the study by Chang et al. (44). The promoter variant, rs2736340, in the B lymphoid tyrosine kinase (= 4.74 10(?31)]. The transformed and primary B cells with the risk allele express significantly lower levels of BLK and have reduced signaling downstream of B cell receptors. These data suggest a role for humoral immunity in the pathogenesis of the acute stage of KD (44). Although B cells and autoantibodies have been found in blood samples of KD patients, their role, whether they are causal NGD-4715 or bystanders of an activated immune system or specific to an infectious agent in the etiology of KD, is currently unknown (50). Standard treatment for KD consists of a single infusion of high-dose IVIGs and high-dose.