Intracellular TTP levels were detected using the TTP antibody in conjunction with a fluorescein-labelled antirabbit Ig. Background levels were subtracted from these results and CD14-staining plus forward and side scatter gating permitted specific analysis of TTP expression in the leukocyte populations. Monocytes have a significantly higher constitutive TTP expression than other leukocytes. aMean (SE); n = 8. *P < 0.001. MESF = milliequivalents of soluble fluorescein.