Significance of platelet activation in sickle cell anaemia.
BACKGROUND
There is increasing evidence suggesting the contribution of platelets in the vaso-occlusive phenomena found in sickle cell anaemia. This study is aimed at using simple, inexpensive parameters to determine the role of platelets in the steady state and vaso-occlusive crisis state of Nigerian sickle cell anaemia patients.


METHODS
The circulating platelet aggregate (CPA) ratio, platelet factor-3 availability (PF-3) and platelet counts of 60 adult Nigerian sickle cell anaemia patients were studied.


RESULTS
The CPA ratio in the sickle cell anaemia (SCA) patients in steady state (SS) was 0.93 +/- 0.05, 0.89 +/- 0.04 during vaso-occlusive crisis (VOC) and 0.98 +/- 0.02 in the control group (C). The values in the vaso-occlusive crisis and in steady state were significantly lower than in the control group (P < 0.05). PF3 availability in steady state and vaso-occlusive crisis were 29.7 +/- 4.0 secs and 28.4 +/- secs respectively. The times are significantly shorter when compared with the control group with a time of 36.2 +/- 4.3 secs (P < 0.05). There was however no significant difference between the two sickle cell groups. Platelet count was significantly raised in the steady state patients 224.3 +/- 46.3 x 10(9)/L when compared with controls of 196.6 +/- 39.3 x 10(9)/L (P < 0.05). There was a significant fall during VOC to 140.6 +/- 36.3 x 10(9)/L (P < 0.05). The difference between the two sickle cell groups is significant (P < 0.05).


CONCLUSIONS
This study indicates varying degrees of partial activation of platelets in vivo in the steady state and vaso-occlusive crisis state of sickle cell anaemia. It support's a contribution of platelet to the vascular occlusion that underlies much of the morbidity in the disease.
Ibanga
I A
IA
Department of Hematology, University of Calabar, Calabar, Nigeria.
D000328:Adult; D000755:Anemia, Sickle Cell / Q000150:complications / Q000503:physiopathology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D009549:Nigeria; D015539:Platelet Activation / Q000502:physiology*; D010974:Platelet Aggregation / Q000502:physiology; D010976:Platelet Count; D010977:Platelet Factor 3 / Q000502:physiology; D010979:Platelet Function Tests; D014652:Vascular Diseases / Q000209:etiology* / Q000503:physiopathology
D010977:Platelet Factor 3