Chemokine receptor expression in human endometrium.

Chemokines play a role in endometrial physiology and pathology and may affect endometrial receptivity and menstrual shedding. Chemokines exert their effect by binding to their relevant receptors, the expression levels of which may modulate their action. In the present study, we examined the expression of chemokine receptors CXCR1 and CXCR2 (receptors for interleukin-8) and CCR5 (receptor for RANTES [regulated-on-activation, normal-T-cell-expressed and -secreted], macrophage inflammatory protein [MIP]-1alpha, and MIP-1beta) in human endometrium. Human endometria (n = 35) were grouped according to the menstrual cycle phase and examined by immunohistochemistry for CXCR1, CXCR2, and CCR5. In both epithelial and stromal cells, CXCR1 and CXCR2 immunoreactivity was detected. Staining was most prominent at the apical and basal aspects of epithelial cells. Intense CCR5 immunostaining was observed in epithelial and stromal compartments throughout the menstrual cycle. Epithelial and stromal staining for CXCR1 reached a peak at the midsecretory phase, during which it was significantly higher than the level of staining during the proliferative phase (P < 0.05). Immunostaining for CXCR2 and CCR5 showed no significant variation across the menstrual cycle. Expression of interleukin-8 and RANTES in endometrium, together with the presence of their receptors, suggests that autocrine and paracrine interactions involving these chemokines may participate in endometrial physiology.