CD40LG and endometriosis: Although there seemed to be a trend toward slightly higher levels of both proteins in the proliferative phase compared to the secretory phase of the menstrual cycle in endometriosis patients and in controls (Figure 3), we did not see statistically significant differences associated with the cycle phase (sCD40L, p = 0.340 and CXCL1, p = 0.626, resp).