Protein S activity in sickle cell anaemia patients in steady state and crisis

Background: In sickle cell anaemia, there is an ever-present risk for haemostatic abnormalities which may result in reduced levels of naturally occurring coagulation inhibitors. Protein S is a Vitamin-K dependent, γ-carboxy glutamic acid-containing glycoprotein that potentiates the action of protein C when activated resulting in anticoagulation. This study measured serum Protein S activity in SCA patients during vaso-occlusive crisis and in steady-state, and this was compared with the activity in HbAA controls with a view to establishing if Protein S plays a role in VOC in SCA patients. Methods: This was an analytical prospective study comprised of 30 HbSS patients and 30 HbAA controls. Using ELISA method, Protein S levels were measured in the HbSS study group during crisis and in the HbAA control group; When the HbSS patients were in steady state, Protein S levels were also measured. Results: Protein S levels were highest in the HbAA control group (5.27+0.47 ng/ml) followed by the HbSS patients in steady state (5.08+0.56 ng/ml) and lowest in the HbSS patients in crisis (4.96+0.97 ng/ml). However, this difference was not statistically significant. Conclusions: Protein S levels are reduced in HbSS patients when compared with HbAA controls, and the levels are lower during a VOC compared with steady state.