Fig. 4

Protein–protein interaction and correlation analysis of the selected proteins. A Protein–protein interaction network visualized by STRING. In this network, nodes are proteins, edges indicate the number of interactions and the thickness of lines represents the strength of predicted functional interactions between proteins. The number of average interactions per node is indicated by the node degree. The clustering coefficient specifies the average node density of the map. Confidence parameter = 0.4. Three clusters (red, blue and green are shown (clusters k-means 3). B Correlation matrix depicts the Spearman’s correlation coefficient observed between differentially expressed proteins (Fold Change values). The intensity of the colors as well as the diameter of the circles give an indication of the degree of correlation between two cytokines and reflect the strength of spearman’s rho correlation coefficient, ranging from red (positive correlations) to blue (negative correlations). Only significant correlations are shown (p < 0.05). The white squares represent correlation coefficients that were not statistically significant. C Scatterplots depicting values of the different biomarker pairs