Apoptosis of peripheral blood lymphocytes in patients with relapsing-remitting multiple sclerosis

Recent data indicate that the apoptotic process, mediated by the CD95/Fas cell surface receptor, may be impaired in activated lymphocytes of patients with relapsing-remitting multiple sclerosis (RRMS). The aim of this study was to analyse the expression of CD95/Fas on peripheral blood (PB) CD4+ and CD8+ T lymphocytes and apoptosis of PB lymphocytes in RRMS patients in the relapse of the disease, immediately before and after pulse corticosteroid therapy (PCT), and in healthy individuals. The study included 27 patients (23 F, 4 M) with RRMS diagnosed by McDonald's criteria and 31 healthy controls (25 F, 6 M). Mean age of the patients was 36.85 +/- 7.52 years, mean duration of the disease 4.14 +/- 4.89 years, and average EDSS scale 3.24 +/- 1.18. Mean age of the controls was 36.54 +/- 10.72 years. The proportions of CD95+ T lymphocyte subsets were analysed by the use of monoclonal antibodies (anti-CD4-PE/Cy5, anti-CD8-FITC and anti-CD95-PE, DAKO) and flow cytometry (FACSscan cytometer and CellQuest software, Becton Dickinson). Apoptosis of lymphocytes was analysed by the use of annexin-V-FITC and PI labeling (Becton Dickinson), as well as flow cytometry. For statistical analysis nonparametric Mann-Whitney test for independent samples and Wilcoxon test for dependent samples were used. Results were presented as median (M) and range. The p values < 0.05 were considered as statistically significant. The proportion of CD4+CD95+ T lymphocytes was significantly higher in patients before therapy (M= 47.90 ; range 32.50 - 61.50), as compared to patients after therapy (M= 40.60 ; range 30.60 - 51.80, p< 0.01), and to controls (M= 36 ; range 30.40 - 40.10, p< 0.01). The proportion of CD8+CD95+ T lymphocytes was significantly higher in patients before therapy (M= 26 ; range 16.80 - 39.10), as compared to patients after therapy (M= 19.30 ; range 11-30, p< 0.01), and to controls (M= 19 ; range 12.30 - 25.50, p< 0.01). Apoptosis of lymphocytes was significantly lower in patients before therapy (M= 1.30 ; range 1- 4.70), as compared to patients after therapy (M= 5.60 ; range 3.10 - 48.80, p< 0.01), and to controls (M= 6.10 ; range 3.10 - 11.40, p< 0.01). Our results indirectly show that the process of apoptosis mediated by the CD95/Fas receptor is impaired in activated lymphocytes of RRMS patients. They also show that in those patients PCT influences on CD95/Fas expression on PB T lymphocytes, as well as on the lymphocyte apoptosis.