Fig. 1.

T cell subset distribution between HC and r-GPA patients. a Gating strategy of CD4⁺ T_EM cell subsets using chemokine receptor expression patterns. The flow cytometry plots show sequential gating (dashed arrows) to identify different CD4⁺ T_EM cell subsets within the CD4⁺T_EM cell population. CD4⁺ T cell subsets from peripheral blood were identified based on the expression of CCR7 and CD45RO. Within CD4⁺T_EM cells CCR6^- and CCR6⁺ cells were identified based on the isotype (grey histogram with dashed line). Within CCR6^- CD4⁺T_EM cells expression of CXCR3 and CCR4 was analyzed to identify T_EM1 cells (CD4⁺CD45RO⁺CCR7^-CCR6^-CXCR3⁺CCR4^-). Expression of CRTh2 was used to identify lineage-committed T_EM2 cells (CD4⁺CD45RO⁺CCR7^-CCR6^-CXCR3^-CCR4⁺CRTh2⁺) derived from CCR6^-CXCR3^-CCR4⁺ CD4⁺T_EM cells. The CXCR3 and CCR4 expression was also analyzed on CCR6⁺ CD4⁺T_EM cells to identify T_EM17 cells (CD4⁺CD45RO⁺CCR7^-CCR6⁺CXCR3^-CCR4⁺), and T_EM17.1 cells (CD4⁺CD45RO⁺CCR7^-CCR6⁺CXCR3⁺CCR4^-). The unclassified populations within the CCR6^- and CCR6⁺ populations were identified, that were double-negative (DN) or double-positive (DP) for CXCR3 and CCR4. Representative flow cytometry plots from one r-GPA patient. b Percentages of CD45RO^-CCR7⁺ (T _NAIVE), CD45RO⁺CCR7⁺ (T _CM), CD45RO⁺CCR7^- (T _EM) and CD45RO^-CCR7^- (T _TD) subpopulations within the CD4⁺ T cell population in peripheral blood of HCs (open circles; n = 42) and r-GPA patients (filled squares; n = 63). c The percentage of CD4⁺ T_EM cell subsets in peripheral blood of HCs (open circles; n = 42) and r-GPA patients (filled squares; n = 63). Black squares indicate r-GPA patients on treatment (n = 29), grey squares indicate r-GPA patients off treatment (n = 34). Horizontal lines represent median percentages. ^* p < 0.05, ^** p < 0.01, and ^*** p < 0.001. CCR C-C chemokine receptor, CD cluster of differentiation, CXCR3 CXC chemokine receptor 3, HC healthy control, r-GPA GPA patient in remission, T _EM effector memory T cell