On 2015 May 02, Donald Forsdyke commented:

DIABETIC PLASMA IS MORE ROULEAUGENIC THAN NORMAL PLASMA This fine paper reports an impressive in vivo method for evaluating rouleaux formation. The authors correctly state that rouleaux formation is "attributed to some changes in the plasma concentration" of certain proteins, "which modify the interaction between RBC." However, they go on to conclude that "diabetic erythrocytes have a higher propensity to form aggregates." To show this they would have had to study both RBCs from diabetic patients in normal subjects’ plasma and the converse (normal RBCs in diabetic patients’ plasma). But they do not report such experiments.

Following their original premise, it would be predicted that, when suspended in plasma from diabetic patients, normal RBC (of the same blood group) would form rouleaux just as well as the RBC from diabetic patients. That the primary change is in the surrounding plasma has long been known. Indeed, normal plasma can be made rouleaugenic by either heating to generate polymeric albumin, or merely by slightly concentrating. In both circumstances, the plasma will aggregate autologous RBC (1).

It appears that the aggregation is entropy-driven, showing a degree of specificity (like-RBC aggregating with like-RBC) analogous to the homoaggregation of macromolecules that can be induced by increasing the concentrations of surrounding but dissimilar macromolecules (2). The early history and theoretical implications of rouleaux formation are reviewed elsewhere (3), and in my webpages: see Entropy-Driven Protein Self-Aggregation at http://post.queensu.ca/~forsdyke/mhc001.htm

(1) Forsdyke DR, Palfree RGE, Takeda A (1982) Formation of erythrocyte rouleaux in preheated normal serum: roles of albumin polymers and lysophosphatidylcholine, Canadian Journal of Biochemistry 60: 705-711.

(2) Forsdyke DR, Ford PM (1983) Segregation into separate rouleaux of erythrocytes from different species. Evidence against the agglomerin hypothesis of rouleaux formation. Biochemical Journal 214: 257-260.

(3) Forsdyke DR (1995) Entropy-driven protein self-aggregation as the basis for self/not-self discrimination in the crowded cytosol. Journal of Biological Systems 3: 273-287.

On 2015 May 02, Donald Forsdyke commented:

DIABETIC PLASMA IS MORE ROULEAUGENIC THAN NORMAL PLASMA This fine paper reports an impressive in vivo method for evaluating rouleaux formation. The authors correctly state that rouleaux formation is "attributed to some changes in the plasma concentration" of certain proteins, "which modify the interaction between RBC." However, they go on to conclude that "diabetic erythrocytes have a higher propensity to form aggregates." To show this they would have had to study both RBCs from diabetic patients in normal subjects’ plasma and the converse (normal RBCs in diabetic patients’ plasma). But they do not report such experiments.

Following their original premise, it would be predicted that, when suspended in plasma from diabetic patients, normal RBC (of the same blood group) would form rouleaux just as well as the RBC from diabetic patients. That the primary change is in the surrounding plasma has long been known. Indeed, normal plasma can be made rouleaugenic by either heating to generate polymeric albumin, or merely by slightly concentrating. In both circumstances, the plasma will aggregate autologous RBC (1).

It appears that the aggregation is entropy-driven, showing a degree of specificity (like-RBC aggregating with like-RBC) analogous to the homoaggregation of macromolecules that can be induced by increasing the concentrations of surrounding but dissimilar macromolecules (2). The early history and theoretical implications of rouleaux formation are reviewed elsewhere (3), and in my webpages: see Entropy-Driven Protein Self-Aggregation at http://post.queensu.ca/~forsdyke/mhc001.htm

(1) Forsdyke DR, Palfree RGE, Takeda A (1982) Formation of erythrocyte rouleaux in preheated normal serum: roles of albumin polymers and lysophosphatidylcholine, Canadian Journal of Biochemistry 60: 705-711.

(2) Forsdyke DR, Ford PM (1983) Segregation into separate rouleaux of erythrocytes from different species. Evidence against the agglomerin hypothesis of rouleaux formation. Biochemical Journal 214: 257-260.

(3) Forsdyke DR (1995) Entropy-driven protein self-aggregation as the basis for self/not-self discrimination in the crowded cytosol. Journal of Biological Systems 3: 273-287.