JCV Antibody Sero-Conversion Ratio of RRMS Patients during and Regardless Natalizumab Therapy: A Single Centered Retrospective Survey

Background: JCV can be activated in immuno-compromised patients because of disease or a medication that modulates (Natalizumab) or suppresses (chemotherapies) immunity. The virus can then be entered into the brain, infects white matter and attacks myelin producing cells leading to significantly disabling, even fatal infection called PML. The presence of JCV antibodies in serum or plasma is considered as a risk factor for PML development. Researchers conducted studies on JCV sero-conversion with NAT therapy but, the comparison of the sero-conversion with general Multiple Sclerosis (MS) population regardless NAT use has not yet been studied.

Objectives: To determine the ratio of the John Cunningham virus (JCV) antibody sero-conversion during and regardless Natalizumab (NAT) treatment and explore for factors which may anticipate this sero-conversion.

Methods: A survey took place among 203 RRMS patients who are either currently on NAT or discontinued NAT therapy in recent years. A comprehensive search was conducted on patients’ clinical evaluation reports reflecting impressions and recommendations. Periodic JCV antibody ELISA reports available in patients’ medical records were reviewed as well.

Results: 203 patient records were surveyed. Factors analyzed included age, gender, ethnicity, duration on NAT and blood CD4 level. Among 203 patents, 23 were (11.33%) found converted to JCV antibodies sero-positivity. While the findings were not compelling, the following trends were distinct: Male patients were 0.66 times less likely to be sero-converted compared to females. Patients > 45 years of age were 1.18 times more likely to be sero-converted compared to patients < 45 years of age. Patients on NAT for > 2 years were 0.35 times less likely to be sero-converted compared to patients on NAT for < 2 years. African American patients were 0.37 times less likely to be sero-converted compared to Caucasian patients. Patients with >500 cells/ul of CD4 level were 1.5 times more likely to be sero-converted compared to patients with undeterminable levels of CD4.

Conclusions: A majority of patients’ JCV antibodies remained unchanged during NAT’s use.  Factors such as sex, age, ethnicity, duration of NAT treatment and blood CD4 level may foresee the possibility of JCV antibody sero-conversion. An extension of this study will be carried out which will look at gender, ethnicity and JC virus antibody sero-conversion ratios in general MS patient population regardless NAT use.