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Fig. 6 | Arthritis Research & Therapy

Fig. 6

From: Active but not inactive granulomatosis with polyangiitis is associated with decreased and phenotypically and functionally altered CD56dim natural killer cells

Fig. 6

Natural cytotoxicity is not measurable in active (non-remission) granulomatosis with polyangiitis (GPA). Freshly isolated, thawed peripheral blood mononuclear cells (PBMCs) from 11 healthy controls (HC) and patients with GPA from cohort II (in remissionā€‰=ā€‰11 and non-remissionā€‰=ā€‰7 patients; totalā€‰=ā€‰18) were cultured overnight in medium. After washing PBMCs (effector cells) and 51Cr-labeled K562 (target) cells were co-cultured for 4Ā hours without further stimulation. The highest effector (PBMC)/target (E:T) ratio was 25:1, only viable PBMCs were counted. Percent specific lysis was determined by measuring 51Cr in the supernatant. The sensitivity threshold of this assay lies at about 5ā€“10Ā % specific lysis. a No natural cytotoxicity was detectable in PBMCs from 7/18 patients (left), whereas typical cytotoxicity curves were measured in PBMCs from the remaining 11/18 patients and all HC (right). b Analysis of the GPA activity states in patients revealed that PBMCs without natural cytotoxic response were all from patients in the non-remission group, except for the two patients with the lowest natural killer (NK)/target ratios within the remission group (0.96 and 1.1, respectively). Two patients from the non-remission group exhibited measurable minor natural cytotoxicity; both were clinically categorized as having "grumbling disease". c Statistical analysis at the highest E (viable PBMC):T ratio (25:1); Kruskal-Wallis test, pā€‰=ā€‰0.0016; Dunn's post hoc test was significant where indicated in the graph. d NK/target ratios of the highest E:T were calculated based on the percentages of NK cells in PBMCs and blotted against the percentage of lysed target cells (% specific lysis); linear equation, r 2, Spearman's r and statistical significance of the correlation as indicated in the graphs

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