The effect of paraprotein on platelet aggregation.

Background: Some patients with paraproteinemia have platelet aggregation disorders and the aim of this study was to examine disturbance of platelet aggregation in healthy blood donors by isolated paraprotein in vitro.

Methods: Using Rivanol, paraprotein was separated from the serum of ten patients with paraproteinemia, who had decreased platelet aggregation with several inducers. Platelet aggregation in ten healthy donors was measured with and without addition of the isolated induced paraprotein. The test was repeated with added human immunoglobulins for intravenous use.

Results: Average of maximal levels of platelet aggregation has been significantly decreased in plasma rich in platelets (PRP) of healthy donors after addition of paraprotein when inducers are used: adenosine diphosphate (ADP) (P = 0.007), collagen (COL) (P = 0.008), ristocetin (RIS) (P = 0.001), and epinephrine (EPI) (P = 0.002). Average of latent time of platelet aggregation was significantly prolonged in healthy donors after addition of paraprotein with inducers: COL (P = 0.008), RIS (P = 0.008) and EPI (P = 0.006) while addition of human immunoglobulins caused no change in platelet aggregation. In comparison, when human immunoglobulins were added, maximal platelet aggregation and latent time did not change significantly. Paraprotein isolated from patients with paraproteinamia, who had decrease platelet aggregation, had significantly decreased platelet aggregation when added to PRP of healthy donors, in vitro.

Conclusion: Platelet aggregation was not significantly changed was confirmed with addition of human immunoglobulins.