JC virus in multiple sclerosis patients treated with natalizumab

• Published in: Multiple sclerosis Vol. 14; p. S39
• Main Authors: Dominguez-Mozo, MI, Alvarez-Lafuente, R, Garcia-Montojo, M, De las Heras, V, Bartolome, F M, Arroyo, R
• Format: Journal Article
• Language: English
• Published: 01.09.2008
• Subjects: JC virus; Polyomavirus
• ISSN: 1352-4585

Background: JC virus (JCV) is a human polyomavirus that establishes life-long latency in kidney and in other organs. JCV is known for its capability of inducing progressive multifocal leucoen-cephalopaty (PML). In a recent clinical trial with beta-1a interferon and natalizumab, two multiple sclerosis (MS) patients developed PML as a consequence of an opportunistic JCV infection of the CNS. Objective: We analyzed the effect of natalizumab treatment on the active replication of JCV in relapsing-remitting MS (RRMS) patients. Methods: We have analyzed 45 peripheral blood mononudear cells (PBMCs), serum and urine samples obtained from the 21 RRMS patients who are being currently treated with natalizumab (between 2 and 7 months) in the Hospital Clinico San Carlos of Madrid. The patients (mean age 33.9 years; range 26-46; and 71.4% women) were treated previously with beta-interferon. The samples were extracted monthly, and the DNA was extracted and finally analyzed by a quantitative real time polymerase chain reaction assay to detect JCV genomes. Results: We found that 7.7% of the MS patients had viral DNA in the serum (mean viral load: 1510 JCV copies/ml serum), and the 71.4% of MS patients had JCV in their urine samples (mean viral load: 64.2x105 JCV copies/ml urine; range 8.6-8560x 105 copies/ml). We did not find any difference between the prevalence or the viral load of JCV in the urine samples extracted before and after the treatment; there was no relation between the viral load and the duration of the treatment. Regarding the serum samples, the positive was found in one patient after the beginning of the treatment. Conclusions: We have found presence of JCV in the serum of MS patients treated with natalizumab; therefore, we should be aware of a possible spread to the brain and the risk of the development of PML.