Neurol. praxi. 2011;12(5):364-365

Antibodies against JC virus and stratification of the progressive multifocal leukoencephalopathy risk in patients

MUDr.Dana Horáková, Ph.D., prof.MUDr.Eva Havrdová, CSc.

Neurologická klinika a Centrum klinických neurověd

Univerzita Karlova v Praze, 1. lékařská fakulta a Všeobecná fakultní nemocnice v Praze

with multiple sclerosis. Recommendations for a new diagnostic test – STRATIFY JCVTM

Tysabri (natalizumab) is a monoclonal antibody proved to be very effective in a treatment of multiple sclerosis (MS). The drug has shown

a very good tolerability, except in a rare viral infection, progressive multifocal leukoencephalopathy (PML). The common JCvirus is a causative

agent of PML. Its seroprevalence in human population ranges between 50 and 60 %. It was reported for the first time in the year

2005 in two patients with MS. Until June 1, 2011, 133 cases of PML have been reported from the cohort of approximately 84 thousand

patients treated with Tysabri all over the world. The paper summarizes current knowledge of the risk factors related to PML – significantly

higher risks seem to be in a subgroup of patients with 1) persistence of JC virus in the patient’s body (ELISA diagnostic set for JCV with

high sensitivity and specificity has been available in all MS centers since May 2011) in combination with 2) previous immunosuppressive

therapy and 3) duration of the therapeutic exposition to Tysabri exceeding 24 months.

The increased clinical supervision as well as other current PML-related safety recommendations still remain essentially significant for

all patients treated with Tysabri.

stratification.

Keywords: multiple sclerosis, Tysabri (natalizumab), progressive multifocal leukoencephalopathy (PML), JC virus antibodies, PML risk

Published: November 1, 2011  Show citation