Fig. 4.

BTK protein levels of B cells of GPA patients correlate with B cell activation and decreased pro-inflammatory T cell subsets in the circulation

(A) CD86 expression on total peripheral B cells of HCs, active and remission GPA patients. Histogram shows an overlay of a representative HC and active GPA patient. (B–D) Correlation of BTK protein with CD86 expression on total B cells of patients and HCs (B), proportions of circulating pro-inflammatory (C) or regulatory (D) CD4⁺ T cell subsets in active GPA patients (circles) and remission GPA patients (squares). act: active; B: B cells; BCR: B cell receptor; BTK: Bruton’s tyrosine kinase; GPA: granulomatosis with polyangiitis; HC: healthy control; MFI: mean fluorescence intensity; T: T cells; Tfh-like: T follicular helper-like cell; Tfr-like: T follicular helper regulatory cell.