Rosetting index (E rosettes/mouse rosettes): a simple diagnostic and prognostic value in CLL.
The rosetting index (E rosettes/mouse rosettes) was evaluated in 34 controls, 4 chronic benign lymphocytosis and 28 CLL patients, grouped according to the Rai classification: 6 asymptomatic stage 0 patients (lymphocytosis less than 10,000/mm3) with a rosetting index of 0.35 +/- 0.2; 11 asymptomatic stage 1-2 patients (lymphocytosis 10,000-40,000/mm3) with a rosetting index of 0.19 +/- 0.11; 9 symptomatic stage 3-4 patients (lymphocytosis greater than 40,000/mm3) with a rosetting index of 0.09 +/- 0.09 and 2 T-CLL patients post splenectomy and 4 chronic benign lymphocytosis patients with a rosetting index of 25 +/- 15. The average rosetting index for the controls was 10.0 (range 3.5-54). Student's t test was p less than 0.0001 for groups 1, 2 and 3 and p less than 0.02 for group 4. These results show that the rosetting index is helpful for the characterization of B-CLL in all stages, the rosetting index decreases with the proliferative activity of the disease and could be used as a prognostic factor, and the rosetting index is significantly increased in T-CLL and chronic benign T lymphocytosis thus being useful in differentiating these conditions from the early stage of CLL, when the SmIg is not conclusive of a monoclonal proliferation.