Fig. 1

Principal component analysis (PCA) plot showing an overview of the relationship between the presence of PA by HRCT (Any pulmonary abnormalities), neutrophil activation status (CD11b and CD62L expression) and subtypes (% LDG and CD177 expression) on LDGs and NDGs, calprotectin, as well as disease activity measures and demographic data in ueRA patients(n = 30). Closely clustered variables to Any pulmonary abnormalities (black circle) indicate positive association (grey area), while diagonally opposite variables indicate inverse relationship. Flow cytometry variables are represented as MFI