Fig. 3.

CD56^dim but not CD56^bright natural killer (NK) cells are reduced in active (non-remission) granulomatosis with polyangiitis (GPA). Peripheral blood mononuclear cells from patients with GPA (total = 19, in remission = 11 and non-remission = 8 patients) and 9 healthy controls (HC) were isolated by density gradient centrifugation and analyzed by multicolor flow cytometry (panel III). a Gating strategy. Peripheral blood lymphocytes were determined using forward scatter (FSC) and side scatter (SSC). Cell viability was assured by negative Zombie aqua staining. NK cells were determined by co-staining of CD3 (negative) and CD56 (positive). b Percentages of CD56^dim (left) and CD56^bright (right) NK cells among total NK cells were plotted according to activity states. The Kruskal-Wallis test was significant in both graphs (p = 0.0084 and p = 0.0081), Dunn's post hoc test was significant where indicated in the graphs; bars represent medians. c Absolute numbers of CD56^dim (left) and CD56^bright (right) NK cells were calculated on the basis of the absolute NK cell counts shown in Fig. 1. The Mann-Whitney test was significant only for CD56^dim NK cells (p = 0.0149); bars indicate medians. ns not significant