We then compared average gene expression of specific genes associated with M1 and M2 macrophages using heatmap and found that the main population of M cells in endometriosis highly expressed CD206 and CD163 (Additional file 1: Fig. S7I), which have been described as M2 genes, indicating impaired immune function and the pro-remodelling nature of endometriosis [30]. Here, CD163 is linked to endometriosis.