Wu Q, Wang Q, Mao G, Dowling CA, Lundy SK, Mao-Draayer Y. Dimethyl Fumarate Selectively Reduces Memory T Cells and Shifts the Balance between Th1/Th17 and Th2 in Multiple Sclerosis Patients. J Immunol. 2017. pii: 1601532
Dimethyl fumarate is an oral formulation of the fumaric acid ester that is Food and Drug Administration approved for treatment of relapsing-remitting multiple sclerosis. To better understand the therapeutic effects of Tecfidera and its rare side effect of progressive multifocal leukoencephalopathy, we conducted cross-sectional and longitudinal studies by immunophenotyping cells from peripheral blood (particularly T lymphocytes) derived from untreated and 4-6 and 18-26 mo Tecfidera-treated stable relapsing-remitting multiple sclerosis patients using multiparametric flow cytometry. The absolute numbers of CD4 and CD8 T cells were significantly decreased and the CD4/CD8 ratio was increased with DMF treatment. The proportions of both effector memory T cells and central memory T cells were reduced, whereas naive T cells increased in treated patients. T cell activation was reduced with DMF treatment, especially among effector memory T cells and effector memory RA T cells. Th subsets Th1 (CXCR3+), Th17 (CCR6+), and particularly those expressing both CXCR3 and CD161 were reduced most significantly, whereas the anti-inflammatory Th2 subset (CCR3+) was increased after DMF treatment. A corresponding increase in IL-4 and decrease in IFN-γ and IL-17-expressing CD4+ T cells were observed in DMF-treated patients. DMF in vitro treatment also led to increased T cell apoptosis and decreased activation, proliferation, reactive oxygen species, and CCR7 expression. Our results suggest that DMF acts on specific memory and effector T cell subsets by limiting their survival, proliferation, activation, and cytokine production. Monitoring these subsets could help to evaluate the efficacy and safety of DMF treatment.
We have been reporting on the potential for B cells as an important target,
but as we have said there are two sides to an argument and today we report on the other side. The results give the immunologists dream on what it does and blocks Th1/Th17 and increases Th2 and it all sounds great.
However why is the activity of DMF not better at inhibiting relapsing disease? However, doing this work and functional assesment does not give us the definative answer of how agents work. So it allows you to pick your favourite mechanism.
It has been seem before
Gross CC, Schulte-Mecklenbeck A, Klinsing S, Posevitz-Fejfár A, Wiendl H, Klotz L.Dimethyl fumarate treatment alters circulating T helper cell subsets in multiple sclerosis. Neurol Neuroimmunol Neuroinflamm. 2015 Dec 10;3(1):e183.
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