Fy phenotype and gender determine plasma levels of monocyte chemotactic protein

BACKGROUND: In vitro studies indicate that the Fy blood group system antigens serve as receptors for chemokines such as monocyte chemotactic protein-1 (MCP-I) and RANTES. However, it is unclear whether subjects with the Fy(a-b-) phenotype exhibit altered clearance and hence altered plasma levels of chemokines, because they still express Fy on endothelial cells. STUDY DESIGN AND METHODS: To clarify a possible in vivo role of Fy on RBCs in the regulation of chemokine levels, healthy young volunteers of common Fy phenotypes were compared in a cross-sectional study. RESULTS: More than 90 percent of the 34 subjects of African origin were Fy(a-b-), one black volunteer was Fy(a+b-), and two were Fy(a-b+). As expected, all 65 white volunteers were positive for either Fy(a) and/or Fy(b). Unexpectedly, persons expressing either Fy(a) and/or Fy(b) had significantly higher plasma levels of MCP-1 than Fy(a-b-) volunteers (women: 154 vs. 110 ng/L, p