Leucocyte rheology at baseline and after activation in post-phlebitic syndrome

Objective: To evaluate leucocyte rheology, expressed as leucocyte filtratio n, polymorphonuclear leucocyte (PMN) membrane fluidity and cytosolic Ca2+ c oncentration in subjects with post-phlebitic leg syndrome (PPS). Methods: In 22 subjects with PPS we determined leucocyte filtration [unfrac tionated, mononuclear (MN) and PMN cells], employing the St George Filtrome ter, PMN membrane fluidity using the fluorescent probe 1-[4-(trimethylamino )phenyl]-6-phenyl-1,3,5-hexatriene (TMA-DPH) and PMN cytosolic Ca2+ concent ration using the fluorescent probe Fura 2-AM. Subsequently we determined th e same PMN parameters after in vitro activation with 4-phorbol 12-myristate 13-acetate (PMA) and N-formyl-methionyl-leucyl-phenylalanine (fMLP). Results: At baseline we observed a difference in the filtration parameters of unfractionated and MN cells and an increase in PMN cytosolic Ca2+ concen tration. After activation, a significant variation in Ph IN filtration para meters was evident both in normals and in PPS subjects, although in subject s with PPS this variation, especially with PMA, was significantly greater. We found a decrease in PMN membrane fluidity and an increase in PMN cytosol ic Ca2+ concentration only in subjects with PPS. Conclusion: These results suggest that there is a functional alteration of systemic leucocytes in PPS, in which the mechanisms are not yet clear.