Targeted proteomics profiling reveals valuable biomarkers in the diagnosis of primary immune thrombocytopaenia

Summary The lack of biomarkers for accurate diagnosis and prognosis is a major clinical challenge of primary immune thrombocytopaenia (ITP). Using an Olink proteomics platform with a 92 immune response‐related human protein panel, we analysed plasma samples from ITP patients (ITP, n = 40), patients with thrombocytopaenia secondary to other causes (Non‐ITP, n = 19) and healthy controls (NC, n = 18), of a discovery cohort as well as a validation cohort (ITP, n = 36; NC, n = 20). A total of 10 differentially expressed proteins (DEPs) were identified in the ITP group compared with the non‐ITP and NC groups of the discovery cohort. These include CXCL11, GZMH, ARG1, TGF‐β1, ANGPT1, CXCL12, CD40‐L, PDGF subunit B, IL4 and TNFSF14. Furthermore, least absolute shrinkage and selection operator regression analysis showed some of these DEPs, such as CXCL11, TGF‐β1, ARG1 and GZMH to be significant in differentiating between patients with ITP and healthy controls (validation area under the curve = 0.87). The analysis demonstrated that the ITP group has a specific proteomic profile relative to non‐ITP and NC groups. In summary, we report for the first time that Olink precision proteomics can specifically detect up‐regulated inflammatory proteins as potential diagnostic biomarkers for ITP.