Fig. 2: Comparative distribution and immune phenotypic analysis of innate immune NK cells in HDs, ECs, and non-ECs.

a Comparative analysis of NK cell subsets distribution in HDs, ECs, and non-ECs. a1 SPADE tree with the distribution of the three main NK cell subsets in HDs (black), ECs (green), and non-ECs (red), based on CD56 and CD16 expression levels. Nodes are colored by count. aII Representative flow cytometry plots of NK cell subsets gated on CD19⁻CD14⁻TCRγδ⁻CD3⁻HLA-DR⁻ cells from the three studied groups: early NK (CD56^bright/CD16⁻), mature NK (CD56^dim/CD16⁺), and terminal NK (CD56⁻CD16⁺). aIII Frequency of early, mature, and terminal NK cells in each studied group (HDs n = 22, ECs n = 12, and non-ECs n = 8). b Differential expression of checkpoint molecules on mature NK cells among HDs, ECs, and non-ECs. Profiles display the expression level of Helios, natural cytotoxicity receptors (NKp30, NKp44, and NKp46), granzyme/perforin (GrzB/perf) (bI), and CD26, CD39, inhibitory killer Ig-like receptors (iKIR) (bIII) on mature NK cells from HDs (black), ECs (green), and non-ECs (red). (bII and bIV). Boxplots displaying the frequency of the indicated markers in mature NK cells in each studied group. Analysis was done in 22 HDs, 12 ECs, and 8 non-ECs for all markers except for Helios and NCR (11 HDs, 16 ECs, 18 non-ECs) and GrzB/perf (3 HDs, 9 ECs, 10 non-ECs). c Scatterplots of the relationships between IFNα serum level and the frequencies of selected NK cell subsets. Correlations were evaluated using Spearman’s rank correlation test. d Comparison of NKG2D et CD95 level between HDs and non-ECs in early and mature NK cells. Histograms show the expression level (measured by median fluorescence intensity [MFI]) of NKGD2 in early NK cells (dI) and CD95 in mature NK cells (dII) in non-ECs (n = 6) and HDs (n = 5). e IFNα effects on NK cell viability, proliferation and phenotype. Percentage of viable NK cells (n = 3) (eI) and frequency of CFD^low NK cells (n = 3) (eII) after 7 days of culture in the presence of increasing doses of IFNα. Histograms show the expression level of CD56 in CD56^dim/neg NK cells (n = 6) (eIII), distribution of mature (gray) and terminal NK cells (white) (n = 6) (eIV), expression levels of NKG2D in early NK cells (n = 3) (eV), and CD95 in mature NK cells (n = 3) (eVI) after 3 days of culture in the presence of IFNα. Comparisons between the two groups were performed using the Mann–Whitney U-test. Multiple group comparisons were made using the Kruskal–Wallis test with Dunn’s multiple comparison testing. *p < 0.05, **p < 0.01, ***p < 0.001, and ****p < 0.0001. Error bars on graphs represent interquartile ranges.