[The risk of varicella zoster virus infection in multiple sclerosis patients treated with fingolimod].

Fingolimod, a sphingosine-1-phosphate receptor modulator, inhibits the egress of CCR7-positive lymphocytes, including encephalitogenic lymphocytes, from lymph nodes and may sometimes cause lymphopenia. A recent study reported that varicella zoster virus reactivation occurred in the saliva of 20% of multiple sclerosis (MS) patients treated with fingolimod. I compared the risk of developing herpes zoster between 32 MS patients treated with fingolimod (FTY-MS) and 45 patients, including those with neuromyelitis optica spectrum disorder, horizontal hemianopsia without anti-aquaporin-4 antibodies, and myelitis with anti-myelin oligodendrocyte glycoprotein antibodies, treated with tacrolimus (TCR-NMO). The risk of developing herpes zoster in FTY-MS (40/1,000 patient-years) was significantly higher than that in TCR-NMO (6/1,000 patient-years) (P < 0.0001, odds ratio: 6.90). The incidence of herpes zoster of patients with rheumatoid arthritis treated with Tofacitinib in Asian countries has been shown to be higher than those of patients in the United States or European countries. It may be better to pay more attention to develop herpes zoster in Japanese MS patients treated with fingolimod.