Fig. 1

Peripheral immune cell proportion in AD. A The distribution of cellular proportion of six peripheral blood immune cells in MCI, AD individuals, and controls. Boxplot shows the median and interquartile range, with the outer violin plot showing the full distribution of data. ns, not significant; •, P < 0.1; *, P ≤ 0.05; **, P ≤ 0.01; ***, P ≤ 0.001; Wilcoxon test. B Comparison of the neutrophil-to-lymphocyte ratio (NLR) between AD and NC across different datasets under different deconvolution tools. The one-tailed Wilcoxon test was applied to test whether NLR in AD was higher than in NC. C Principal component analysis (PCA) of cellular proportions in AD and NC participants. Each point represents one participant’s scores on the first 2 principal components (PC1 and PC2), where grey and red points correspond to NC and AD, respectively. The blue arrows show the loadings of cell types on the first 2 principal components. Ellipses show the 80% confidence ellipse for each group. The bottom bar plot shows the contribution of each cell type to PC1. The dashed red line represents the expected value if the contribution were uniform. D Spearman correlations between immune cell proportion, diagnosis, cognitive measurements, brain-area volumes, and demographic variables. Only significant correlations with P < 0.05 are shown. Color represents the correlation coefficient. Blue and red colors indicate positive and negative correlations, respectively. MoCA-B, Montreal Cognitive Assessment Basic; MMSE, Mini-Mental State Examination