title: Levels of interleukin-15-expressing blood mononuclear cells are elevated in multiple sclerosis.
abstract: Interleukin-15 (IL-15) is a novel IL-2-like cytokine expressed by cells of the monocyte/macrophage and epithelial lineages. Cytokines might be involved in the pathogenesis of multiple sclerosis (MS). Using immunocytochemistry, we analysed spontaneous expression of IL-15 by peripheral blood (PB) and cerebrospinal fluid (CSF) mononuclear cells (MNC) from patients with MS, other neurological diseases (OND) and healthy controls. IL-15- positive peripheral blood mononuclear cells (PBMNC) were elevated in patients with MS compared to healthy controls (P < 0.05). The elevation of IL-15- positive PBMNC was restricted to patients with chronic progressive MS and not observed in patients studied during the relapsing-remitting phase of MS. The numbers of IL-15- expressing PBMNC correlated with the duration and disability of MS (r = 0.45, P < 0.001, and r = 0.39, P < 0.01, respectively). IL-15 was undetectable in CSF MNC, and ELISA showed low CSF levels of IL-15 in occasional patients with MS and OND. IL-15 is a potent growth factor for gammadelta T cells, but there was no correlation between IL-15 expression by PBMNC and percentage of gammadelta T cells in blood from the MS patients. Together, these data demonstrate that IL-15 expression by PBMNC is upregulated in the chronic stage of MS.
authors.affiliation: Division of Neurology, Neuroimmunology Unit, Huddinge University Hospital, Karolinska Institutet, Stockholm, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Pashenkov
authors.forename: M
authors.initials: M
authors.lastname: Mustafa
authors.forename: P
authors.initials: P
authors.lastname: Kivisäkk
authors.forename: H
authors.initials: H
authors.lastname: Link
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D019409:Interleukin-15 / Q000096:biosynthesis* / Q000097:blood / Q000134:cerebrospinal fluid; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000097:blood / Q000134:cerebrospinal fluid / Q000276:immunology*; D016692:Receptors, Antigen, T-Cell, gamma-delta; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D019409:Interleukin-15; D016692:Receptors, Antigen, T-Cell, gamma-delta