Erythrocyte aggregability and disaggregability in thalassemia trait carriers analyzed by a laser backscattering technique.

Erythrocyte aggregability was determined by a laser backscattering light technique in 23 beta minor thalassemia carriers and in 36 age and sex matched controls. The aggregation time (Ta) was statistically higher in cases than in controls (2.8 +/- 1.0 vs 2.3 +/- 0.4, p < 0.05) and the aggregation index at 10 sec (AI10) was statistically lower (25.1 +/- 5.7 vs 28.2 +/- 3.8, p < 0.05), suggesting both parameters a statistically lower erythrocyte aggregability tendency. However, the total disaggregation threshold (gammaD) was statistically higher in cases than in controls (134.4 +/- 34.1 vs 105.1 +/- 33.1, p < 0.05), indicating that once aggregates are formed a higher shear rate is needed to break them up. No differences were observed in plasmatic factors, i.e., fibrinogen, total cholesterol and triglycerides, that could have influenced erythrocyte aggregation. A negative statistically significant correlation was found between erythrocyte indexes and the total disaggregation threshold. The lower erythrocyte aggregation found in minor thalassemia carriers could be attributed in part to the morphological alterations, although others mechanisms such as modifications in the membrane structure of the RBC can not be ruled out.