Cytokine flow cytometry differentiates the clinical status of multiple sclerosis (MS) patients

Abstract

In this study we have examined intracellular cytokines in peripheral blood mononuclear cells (PBMC) of MS patients by flow cytometry (cytokine flow cytometry). MS progressive patients showed an increased number of cells producing interferon-gamma (IFN-g) after activation with phorbol 12- myristate 13-acetate and ionomycin, compared with patients with clinically inactive forms (P < 0001) and with healthy controls (P¼0001). These cells belonged to the CD4þ and CD8þ subsets in similar proportions. Clinically inactive patients showed a lower level of cells producing IL-2 than controls (P¼0·03) and active MS patients (P¼0·03). Most IL-2-producing cells were CD4þ lymphocytes, although a small part of the IL-2 was also produced by CD8þ cells. The percentage of cells producing simultaneously IL-2 and IFN-g was increased in active MS and they were mainly CD4þ lymphocytes. No differences in the production of IL-4 were observed between groups. However, we found an increased IL-10 production in clinically active MS patients (P¼0·03). Treatment with IFN-b of active MS patients showed lower levels of cytokines when compared with untreated MS patients. This methodological approach could help in the follow up and therapeutic monitoring of MS patients.