[Changes in lymphocyte subsets s and treatment with beta interferon in active multiple sclerosis]

We report that interferon beta decreases CD8 T cells percentage and increases CD4/CD8 cell's rate in vivo in Multiple Sclerosis (MS) patients.

We studied 40 patients (22 women and 18 men) with clinically definite active MS who received IFN beta. Twenty-six were treated with nIFN (9 MU/week) and 14 with rIFN (28 MU/week). All patients except two with secondary progressive forms presented relapsing remitting courses. Mean age and mean age at onset were 36.5 +/- 9 and 27.8 +/- 7 years respectively. Mean EDSS score was 2.96 +/- 1.8. Patients were reviewed at four weeks and every eight weeks and periodical studies of immunity were performed. T cell subpopulations (CD3, CD4, CD8 and NK) were studied byflow cytometry.

The evolution of CD8 T cell percentage showed a statistically significant decrease in all blood samples after 20 weeks of treatment with rIFN (24.3 +/- 8 vs 34.7 +/- 5 in the control group) and after 36 weeks for nIFN beta group (25.7 +/- 6 vs 33.0 +/- 4 in the control group). No changes were detected in CD4 T cell subset. The evolution of CD4/CD8 T cell rate showed an increase over the cut-off (2.200) in all blood samples after 20 weeks of treatment with rIFN (2.302 +/- 1.12, 2.332 +/- 0.99 and 2.488 +/- 1.61 for 20, 28 and 36 weeks respectively) and after 52 weeks for nIFN beta group (2.128 +/- 1.07, 2.346 +/- 1.09 and 3.168 +/- 3.87 for 52, 60 and 68 weeks respectively).

Both nIFN and rIFN beta are able in vivo to decrease CD8 percentage of T cells and increase CD4/CD8+ T cell rate. The increase in the rate is produced earlier in the rIFN treated group.