Protein S deficiency in sickle cell anemia.
To investigate the status of the protein C-protein S anticoagulant pathway in sickle cell disease, we measured protein C, total and free protein S, and C4b-binding protein levels in 20 subjects with sickle cell disease (Hb SS or SC). Mean total and free protein S levels were both significantly lower in subjects with sickle cell disease than in normal individuals, but greater reductions were observed for free S. The free protein S level was below the mean -2 SD for normal subjects in 12 subjects with sickle cell disease; the total protein S level was below this level in three subjects. Mean C4b-binding protein levels were normal in subjects with sickle cell disease, both during painful crisis and in the steady state, and no correlation was observed between the levels of C4b-binding protein and free protein S, suggesting that the low free protein S level was not caused by increased levels of C4b-binding protein. Crossed immunoelectrophoresis of plasma samples from eight subjects with sickle cell disease showed marked reductions in free protein S, with normal levels of protein S bound to C4b-binding protein. In contrast to the protein S level, mean protein C activity was normal in subjects with sickle cell disease, both during painful crisis and in the steady state. However, the protein C level was below the mean -2 SD for normal subjects on at least one occasion in four subjects with sickle cell disease.(ABSTRACT TRUNCATED AT 250 WORDS)
Francis
R B
RB
Department of Medicine, University of Southern California School of Medicine, Los Angeles.
D000755:Anemia, Sickle Cell / Q000150:complications*; D002352:Carrier Proteins / Q000032:analysis; D003169:Complement Inactivator Proteins; D006023:Glycoproteins / Q000097:blood / Q000172:deficiency*; D006450:Hemoglobin SC Disease / Q000097:blood / Q000150:complications / Q000503:physiopathology; D006451:Hemoglobin, Sickle / Q000032:analysis; D006706:Homeostasis; D006801:Humans; D007122:Immunoelectrophoresis; D010146:Pain; D017293:Protein S; D012709:Serum Albumin / Q000032:analysis; D012805:Sickle Cell Trait / Q000097:blood / Q000150:complications* / Q000503:physiopathology
D002352:Carrier Proteins; D003169:Complement Inactivator Proteins; D006023:Glycoproteins; D006451:Hemoglobin, Sickle; D017293:Protein S; D012709:Serum Albumin