Soluble adhesion molecules in serum throughout the menstrual cycle.

BACKGROUND The female reproductive and immune systems are integrally linked with respect to shared cellular and molecular mediators. Cell adhesion molecules (CAMs) involved in leukocyte-endothelial interactions, e.g. intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and E-selectin, are regulated by sex steroids when expressed by cultured endothelium, while uterine and ovarian CAM expression appears to be cyclically or gonadotrophin-regulated. METHODS AND RESULTS To determine if these effects translate into changes in soluble CAMs (sICAM-1, sVCAM-1 and sE-selectin) levels in peripheral blood, normally cycling women received regular venous sampling throughout a complete menstrual cycle. Soluble ICAM-1 levels were maximal in the early and mid-follicular stages, progressively decreased throughout the remainder of the cycle and were significantly reduced in the late luteal stage (P < 0.001). Levels of sVCAM-1 fluctuated during the follicular phase and mid-cycle, but also declined in the late luteal phase (P < 0.01), whereas sE-selectin concentration did not vary markedly across the menstrual cycle. Plasma hormone and urinary hormone metabolite levels confirmed precise cycle tracking and revealed an inverse relationship between sICAM-1 and estradiol (r = -0.38, P < 0.005). A negative correlation was also apparent between sVCAM-1 and circulating monocyte cell numbers (r = -0.47, P < 0.001). CONCLUSIONS The normal cyclic variation in peripheral sICAM-1 and sVCAM-1 levels reported here may reflect uterine and/or ovarian tissue remodelling events, and is of particular importance if soluble CAM levels are utilized as biological markers of certain disease states in women of reproductive age.