Immune surveillance in multiple sclerosis patients treated with natalizumab

Area of Science:

• Neuroimmunology
• Immunology
• Neurology

Background:

• Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS).
• Natalizumab is an antibody targeting very late activating antigen (VLA)-4, used to treat MS.
• The impact of natalizumab on CNS immune surveillance requires detailed investigation.

Purpose of the Study:

• To determine if natalizumab affects immune cell populations within the CNS.
• To assess the influence of natalizumab on cerebrospinal fluid (CSF) and peripheral blood immune cell phenotypes.
• To evaluate the potential impairment of CNS immune surveillance by natalizumab.

Main Methods:

• Analysis of leukocyte cell numbers and phenotypes in CSF and peripheral blood.
• Comparison between natalizumab-treated MS patients, untreated MS patients, and patients with other neurological diseases (OND).
• Quantification of JC virus DNA in CSF and peripheral blood using kinetic polymerase chain reaction.

Main Results:

• Natalizumab-treated MS patients showed significantly lower CSF leukocyte counts, including CD4(+) and CD8(+) T cells, CD19(+) B cells, and CD138(+) plasma cells, compared to OND and untreated MS patients.
• JC virus DNA was undetectable in the CSF and peripheral blood of natalizumab-treated patients.
• Reduced lymphocyte counts in the CSF persisted for at least six months after discontinuing natalizumab therapy.

Conclusions:

• Natalizumab treatment leads to a sustained reduction in CSF lymphocytes.
• These findings support the hypothesis that natalizumab compromises immune surveillance of the CNS.
• The persistent decrease in lymphocytes suggests long-term effects on CNS immunity.