Which among the following body secretions does NOT contain ABO antigens?

The ABO(H) antigens are found not only on red cells, but also on other blood cells, in most body fluids such as saliva, gastric juice, semen, plasma and sweat (except cerebrospinal fluid), and on the cell membranes of tissues such as intestine, urothelium, and vascular endothelium. Ref: Wintrobe's clinical hematology, edited by John P. Greer, M.d., Volume 1, 2009, Page 636.