Relationship between hypercoagulable state and erythrocyte phosphatidylserine exposure in splenectomized haemoglobin E/beta-thalassaemic patients.
Small pulmonary arterial thromboses can occur following splenectomy of patients with haemoglobin E/beta-thalassaemia (Hb E/beta-thal). We compared plasma markers of coagulation activation in vivo and red blood cell (RBC) markers of procoagulant activity in 15 Hb E/beta-thal patients who were not splenectomized (NS), 15 who had been splenectomized (S), and 15 normal controls (NC). Levels of plasma thrombin-antithrombin III complex (TAT) were significantly higher in the S group than in either the NS or the NC groups, and levels of prothrombin fragment 1.2 (F 1.2) were significantly higher in the S than in the NC group. Diluted Russell's viper venom clotting times were significantly shorter when RBCs from group S patients were added to the assay compared with RBCs from the NC group. Phosphatidylserine (PS) expression (% of annexin V-positive RBCs) on the outer leaflet of RBC membrane of both 'larger'- and 'smaller'-sized RBCs was significantly higher for the S than the NC group. The RBC PS expression of the S and the NS groups, respectively, accounted for 25 x 3% (P = 0 x 174) and 6.3% (P = 0 x 675) of the variation in plasma TAT levels. Our findings indicated that, when compared with NC, splenectomized patients with Hb E/beta-thal were in a chronic low-grade hypercoagulable state associated with increased numbers of circulating PS exposed RBCs. This condition may have a role in the risk of these patients for pulmonary arterial thromboses.
Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand. ravtc@mucc.mahidol.ac.th
Vichai
V
Atichartakarn
Pantep
P
Angchaisuksiri
Katcharin
K
Aryurachai
Supornchai
S
Onpun
Suporn
S
Chuncharunee
Ammarin
A
Thakkinstian
Kanlayanee
K
Atamasirikul
D000328:Adult; D000990:Antithrombin III; D002908:Chronic Disease; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D006446:Hemoglobin E / Q000032:analysis*; D006801:Humans; D008297:Male; D010446:Peptide Fragments / Q000097:blood; D010447:Peptide Hydrolases / Q000097:blood; D010718:Phosphatidylserines / Q000097:blood*; D011516:Prothrombin; D013156:Splenectomy / Q000009:adverse effects*; D019851:Thrombophilia / Q000097:blood / Q000209:etiology*; D017086:beta-Thalassemia / Q000097:blood / Q000601:surgery*
D010446:Peptide Fragments; D010718:Phosphatidylserines; C046193:antithrombin III-protease complex; C045879:prothrombin fragment 1.2; D000990:Antithrombin III; D011516:Prothrombin; D006446:Hemoglobin E; D010447:Peptide Hydrolases