Increased expression of the membrane-bound CD40 ligand on peripheral CD4 + T cells in the acute phase of AQP4-IgG-seropositive neuromyelitis optica spectrum disorders.

Currently, no data are available regarding the expression levels of CD40L on CD4+ T cells in patients with neuromyelitis optica spectrum disorders (NMOSD). The percentage of circulating CD40L+CD4+ T cells was measured by flow cytometry in 23 NMOSD patients and 10 healthy controls. The ratio of CD40L+CD4+ to CD4+ T cells in patients at acute phase (18.28 ± 15.56%) was significantly higher than that in healthy controls (7.23 ± 5.94%, P = .032) and was positively correlated with disease severity (r = 0.532, P = .041). Thus, our results suggest an important role of this molecule in acute attacks of NMOSD.