Studies of the capacity of plasma proteins to bind hemoglobin were made in patients with sickle cell anemia (SS), sickle cell trait (SA), hemoglobin C disease and in patients with hemolytic anemias. Hemoglobin binding was quantitatively normal in sickle cell trait, but was greatly reduced or absent in sickle cell anemia, hemoglobin C disease and in other hemolytic disorders. These alterations have been attributed to a reduction in the level of hemoglobin-binding proteins in circulating plasma. The mechanism of this reduction was not established, but the observed changes were correlated with the presence of increased hemolytic activity.
The binding of hemoglobin C and hemoglobin S by normal plasma was quantitatively normal.