Immune Cell Profiling During Switching from Natalizumab to Fingolimod Reveals Differential Effects on Systemic Immune-Regulatory Networks and on Trafficking of Non-T Cell Populations into the Cerebrospinal Fluid—Results from the ToFingo Successor Study

Abstract

Leukocyte sequestration is an established therapeutic concept in multiple sclerosis (MS) as represented by the trafficking drugs natalizumab (NAT) and fingolimod (FTY). However, the precise consequences of targeting immune cell trafficking for immunoregulatory network functions are only incompletely understood. In the present study, we performed an in-depth longitudinal characterization of functional and phenotypic immune signatures in peripheral blood (PB) and cerebrospinal fluid (CSF) of 15 MS patients during switching from long-term NAT to FTY treatment after a defined 8-week washout period within a clinical trial (ToFingo successor study; : NCT02325440). Unbiased visualization and analysis of high-dimensional single cell flow-cytometry data revealed that switching resulted in a profound alteration of more than 80% of investigated innate and adaptive immune cell subpopulations in the PB, revealing an unexpectedly broad effect of trafficking drugs on peripheral immune signatures. Longitudinal CSF analysis demonstrated that NAT and FTY both reduced T cell subset counts and proportions in the CSF of MS patients with equal potency; NAT however was superior with regard to sequestering non-T cell populations out of the CSF, including B cells, natural killer cells and inflammatory monocytes, suggesting that disease exacerbation in the context of switching might be driven by non-T cell populations. Finally, correlation of our immunological data with signs of disease exacerbation in this small cohort suggested that both (i) CD49d expression levels under NAT at the time of treatment cessation and (ii) swiftness of FTY-mediated effects on immune cell subsets in the PB together may predict stability during switching later on.

Fingolimod alters intrathecal B cell maturation in multiple sclerosis patients

“…The high frequency of clonal groups shared between PB and CSF under fingolimod treatment suggests that despite the limited number of PB B cells CSF migration remains unaffected. This is consistent with previous observations demonstrating a relatively high fraction of B cells in the CSF of patients receiving fingolimod therapy [14,19]. In the current study, the increased overlap between the peripheral blood and CSF B cells in fingolimod-treated patients, may be magnified by the significant contraction of the circulating PB B cell population.…”

“…In addition, fingolimod appears to reduce B cell maturation and expansion of migratory B cells within the CSF compartment resulting in depletion of pre-existing clonal populations.While our analysis was limited by patient numbers and the limited number of recoverable CSF B cells in treated patients, our study provides detailed information on the differential treatment effects of two highly-effective MS therapies on B cell repertoires in the PB and CSF. In agreement with prior publications[14,19], CSF B cell numbers recovered from fingolimod patients remained generally stable but declined in natalizumab treated patients. As anticipated, fingolimod reduced the number of circulating B cells in the PB while natalizumab resulted in an increase in PB B cells[14, 31, 32].…”

Real-World Lab Data in Natalizumab Treated Multiple Sclerosis Patients Up to 6 Years Long-Term Follow Up

“…In our evaluation, no association between the distribution of peripheral immune cell subsets and clinical disease activity parameters during NAT treatment could be found. The immune cell phenotyping presented in our study is part of the routine lab testing in our treated MS patients and is characterized by limitations in comparison to more detailed immune cell profiling as presented in other immune profiling studies using e.g., high-dimensional cytometry (44). These studies are more complex in immune cell profiling techniques but may elucidate more details in immune cell patterns and clinical response.…”

Immune signatures of prodromal multiple sclerosis in monozygotic twins

“…We took advantage of a comprehensive deep functional immune-cell phenotyping platform by using multicolor flow cytometry on frozen peripheral blood mononuclear cell (PBMC) specimens. In this system immunology approach, 13 9-to 10-color immunophenotyping panels were used for the characterization of major immune cell subpopulations and their maturation and functional status (13,14). Longitudinal repeated measurements (n = 26) of PBMCs derived from a study-independent healthy individual during the total acquisition period of 4 wk (mean variability of traits r = 0.05) revealed robustness of data acquisition (Dataset S4).…”