JCHAIN and cholesteryl ester measurement: Whereas 11 out of 13 genes (84.6%) upregulated in the CE endometria were immunoglobulin-related genes in the proliferative phase (Figure 6A), only two out of eight genes (25%) upregulated in CE endometria were immunoglobulin-related genes (IGHG4 and JCHAIN) in the secretory phase (Figure 6B).