Details

Autor(en) / Beteiligte

• Hawke, Simon
• Zinger, Anna
• Juillard, Pierre-Georges
• Holdaway, Karen
• Byrne, Scott N.
• Grau, Georges E.

Titel

Selective modulation of trans-endothelial migration of lymphocyte subsets in multiple sclerosis patients under fingolimod treatment

Ist Teil von

• Journal of neuroimmunology, 2020-12, Vol.349, p.577392-577392, Article 577392

Ort / Verlag

Netherlands: Elsevier B.V

Erscheinungsjahr

2020

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• Multiple sclerosis (MS) is an autoimmune disorder where auto-aggressive T cells target the central nervous system (CNS), causing demyelination. The trans-endothelial migration of leucocytes across the blood-brain barrier (BBB) is one of the earliest CNS events in MS pathogenesis. We examined the effect of the disease state and treatment with fingolimod on the transmigration of peripheral blood mononuclear cells (PBMCs) in an in vitro BBB model. Patients' leucocyte numbers, subsets and phenotypes were assessed by flow cytometry. As expected, fingolimod treatment induced a significant reduction in T cell and B cell numbers compared to untreated MS patients and healthy controls. Interestingly fingolimod led to a marked reduction of CD4+ and a significant increase in CD8+ cell numbers. In migrated cells, only CD3+ cell numbers were reduced in fingolimod-treated, compared to untreated patients; it had no effect on B cell or monocyte transmigration. T cells were then differentiated into naïve, effector and memory subsets based on their expression of CCR7. This showed that MS patients had increased numbers of effector memory CD4+ cells re-expressing CD45RA (TEMRA) and a decrease in central memory (CM) CD8+ cells. The former was corrected by fingolimod, while the latter was not. CM CD4+ and CD8+ cells migrated across BBB more efficiently in fingolimod-treated patients. We found that while fingolimod reduced the proportions of naïve CD19+ B cells, it significantly increased the proportions of these cells which migrated. When B cells were further stratified based on CD24, CD27 and CD38 expression, the only effect of fingolimod was an enhancement of CD24hiCD27+ B cell migration, compared to untreated MS patients. The migratory capacities of CD8hi Natural Killer (NK), CD8dim NK and NK-T cells were also reduced by fingolimod. While the disease-modifying effects of fingolimod are currently explained by its effect on reducing circulating auto-aggressive lymphocytes, our data suggests that fingolimod may also have a direct though differential effect on the trans-endothelial migration of circulating lymphocyte populations. Diagrammatic representation of the changes in mononuclear cell subsets in fingolimod-treated versus untreated MS patients. Top panel represents the changes noted in circulating blood. Bottom panel shows changes in trans-endothelial migration in the in vitro BBB model. [Display omitted] •Fingolimod inhibited the migratory capacity of some lymphocyte sub-populations across an in vitro blood brain barrier.•CD4+ and CD8+ TCM cells migrated more efficiently in fingolimod-treated patients.•Fingolimod treatment reduced the proportions of naïve B cells, but significantly increased the proportions of these cells which migrated.•Fingolimod dramatically enhanced CD27−CD38hi B cell percentages, a population that includes BRegs.•Our results might explain the small increased risk of PML in fingolimod-treated patients.