Is is increasingly clear that the CD40 and CD40 ligand (CD40L) receptor-lig
and pair mediates a crucial activation signal in both cell-mediated and hum
oral immune responses. Here, we detected mRNA levels of CD40 and CD40L in n
on-stimulated peripheral blood mononuclear cells in 46 patients with multip
le sclerosis (MS) and 46 healthy controls by a competitive RT-PCR procedure
allowing quantification without previous culture or antigenic stimulation.
The levels of CD40 and CD40L mRNA were markedly increased in MS patients (
P<0.0001) compared with healthy controls. There was no difference between c
linical MS subgroups or stage of disease. Our findings indicate that althou
gh MS is on organ specific disorder, an increased signaling via the CD40 an
d CD40L pathway may be present or the systemic level. The nature of this up
regulation, whether primary or secondary to the organ-specific autoimmune r
esponse, is yet to be determined. Since interference with CD40/CD40L is on
effective way to interfere with autoimmune model diseases such as experimen
tal autoimmune encephalomyelitis, it may be relevant to investigate further
the role of these molecules in the pathogenesis of MS.