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‐1) and RANTES. However, it is unclear whether subjects with the Fy(a−b−) phenotype exhibit altered clearance and hence altered plasma levels of chemo‐kines, 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 chemo‐kine 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 Fya and/or Fyb. Unexpectedly, persons expressing either Fya and/or Fyb had significantly higher plasma levels of MCP‐1 than Fy(a−b−) volunteers (women: 154 vs. 110 ng/L, p