Parameters of red blood cell aggregation as correlates of the inflammatorystate

To identify clinically relevant parameters of red blood cell (RBC) aggregat ion, we examined correlations of aggregation parameters with C-reactive pro tein and fibrinogen in unstable angina (UA), acute myocardial infarction (A MI), and bacterial infection (BI). Aggregation parameters were derived from the distribution of RBC population into aggregate sizes (cells per aggrega te) and changing of the distribution by flow-derived shear stress. Increase d aggregation was observed in the following order: UA, AMI, and BI. The bes t correlation was obtained by integration of large aggregate fraction as a function of shear stress. To differentiate plasmatic from cellular factors in RBC aggregation, we determined the aggregation in the presence and absen ce of plasma and formulated a "plasma factor" (PF) ranging from 0 to 1. In AMI the enhanced aggregation was entirely due to PF (PF = 1), whereas in UA and BI it was due to both plasmatic and cellular factors (0 less than or e qual to PF less than or equal to 1). It is proposed that clinically relevan t parameters of RBC aggregation should express both RBC aggregate size dist ribution and aggregate resistance to disaggregation and distinguish between plasmatic and cellular factors.