The aim of the present research was to verify the production of BDNF by peripheral blood mononuclear cells (PBMCs), unstimulated and stimulated with phytohemagglutinin (PHA), anti-OKT3 Ab and myelin basic protein (MBP), in 35 patients affected by multiple sclerosis (MS), 20 with relapsing-remitting (R-R) MS and 15 with secondary progressive (SP) MS. Seven R-R MS patients were assessed during the attack, in the subsequent recovery phase and also 3 months after relapse. The production of BDNF by PBMCs was also evaluated in 20 age- and sex-matched control subjects. Levels of BDNF were also determined in CSF of both patient groups and 20 control subjects.
Results: Levels of BDNF (pg/ml) in the supernatants of unstimulated and PHA-, anti-OKT3 Ab- and MBP-stimulated PBMCs in patients with R-R MS were significantly higher during relapse and in the recovery phase compared with values detected in the stable phase of the disease. Significantly lower BDNF values were found in unstimulated and stimulated PBMC supernatants of patients with SP MS compared to control subjects. This reduction was greater in patients with a 1-point increase in the EDSS score in the last 6 months compared with that in patients without a progression of the disability score. Reduction in the levels of BDNF was also confirmed in the CSF of SP MS patients compared with R-R MS patients assessed during a stable phase of the disease and control subjects.
Discussion: On the basis of recent experimental findings, a neuroprotective effect of BDNF produced by inflammatory cells can be hypothesized during relapses in MS. This can favor remyelination. The reduced production of BDNF by PBMCs of patients with SP MS can contribute to the progression of demyelinating disease and axonal loss in this form.