CD28 and bronchiectasis: Importantly, in addition to the upregulation of exhaustion markers, we defined a nine-gene signature in CD4+ T cells (S1PR1, IL4R, STAT5A, JAK1, CD28, SOCS5, IL10RA, GFI1 and BCL6) and a seven-gene signature in CD8+ T cells (JAK1, S1PR1, IFNγR1, STAT5A, PTGER2, CD27 and CXCR3) which could differentiate active NTM-PD infection from healthy individuals and bronchiectasis controls.