JC Virus in CD34⁺and CD19⁺Cells in Patients With Multiple Sclerosis Treated With Natalizumab

Abstract

IMPORTANCE Infection with JC virus (JCV) may lead to development of demyelinating progressive multifocal leukoencephalopathy in patients with multiple sclerosis (MS) who are treated with natalizumab.OBJECTIVE To determine whether mononuclear cells in circulation from MS patients treated with natalizumab harbor JCV DNA. DESIGN, SETTING, AND PARTICIPANTSIn this prospective investigation, we enrolled 49 MS patients from the Clinical Center for Multiple Sclerosis at The University of Texas Southwestern Medical Center and 18 healthy volunteers. We drew 120-mL blood samples from 26 MS patients at baseline and at approximately 3-month intervals to 10 months during the course of natalizumab infusions. One blood sample was drawn from 23 MS patients receiving natalizumab for more than 24 months and from 18 healthy volunteers. INTERVENTIONS Natalizumab treatment of MS. MAIN OUTCOMES AND MEASURESThe blood samples were separated using flow cytometry into CD34 + , CD19 + , and CD3 + cell subsets; DNA templates were prepared using quantitative polymerase chain reaction for JCV DNA identification. Plasma samples were tested for anti-JCV antibodies by enzyme-linked immunosorbent assays performed at the Laboratory of Molecular Medicine and Neuroscience, National Institute of Neurological and Communicative Diseases and Stroke.RESULTS Thirteen of the 26 patients (50%) with baseline and follow-up blood samples had detectable viral DNA in at least 1 cell compartment at 1 or more points. Ten of the 23 patients (44%) receiving treatment for more than 24 months and 3 of the 18 healthy volunteers (17%) also had detectable viral DNA in 1 or more cell compartment. Fifteen of the 49 MS patients (31%) were confirmed to harbor JCV in CD34 + cells and 12 of 49 (24%) in CD19 + cells. Only 1 of 18 healthy volunteers were viremic in CD34 + cells and none in CD19 + cells. Nine patients and 1 healthy volunteer were viremic but had seronegative test results for JCV antibodies.CONCLUSIONS AND RELEVANCE JC virus DNA was detectable within cell compartments of natalizumab-treated MS patients after treatment inception and longer. JC virus DNA may harbor in CD34 + cells in bone marrow that mobilize into the peripheral circulation at high concentrations. Latently infected cells initiate differentiation to CD19 + cells that favors growth of JCV. These data link the mechanism of natalizumab treatment with progressive multifocal leukoencephalopathy.

Immunology of progressive multifocal leukoencephalopathy

“…Natalizumab reduces not only the migration of CD19 + B cells and CD138 + plasma cells through the blood-brain-barrier (Stuve et al, 2006b), but also perturbs B cell homing by increasing the number of memory-and marginal zone-like B cells in the peripheral blood . The latter conditions and the fact that natalizumab induces the migration of CD34 + progenitor cells to the peripheral blood may influence the shaping and reactivation of neurotropic JCV variants (Frohman et al, 2014;Marshall et al, 2014).…”

“…Archetypic JCV strains infect the majority of healthy humans, primarily persist in the kidney, urinary tract, but also hematopoietic progenitor cells and niches including B cells (Egli et al, 2009;Frohman et al, 2014;Major, 2010). As long as the individual's immune function remains intact, JCV infection will not cause disease.…”

“…Under conditions of immunocompromise or -modulation the virus mobilizes from the bone marrow to the peripheral blood via CD34 + progenitor cells, B cells and/or other peripheral blood leukocyte subsets (Brew et al, 2010;Frohman et al, 2014;Houff et al, 1988). Whether JCV is attached to peripheral blood leukocytes or whether these cells are infected and active viral replication or transcription occurs remains to be elucidated.…”

Immunological biomarkers identifying natalizumab-treated multiple sclerosis patients at risk of progressive multifocal leukoencephalopathy

“…A portion of these latently infected cells initiates its differentiation into CD19 + B lymphocytes, which can harbor the virus as well (Frohman et al, 2014). Starting from these findings, we investigated whether the drug also increases the release of newly produced T and B lymphocytes from thymus and bone marrow; to this end, we quantified T-cell receptor excision circles (TRECs) and K-deleting recombination excision circles (KRECs), which have been described as markers of new T-and B-cell release from their production sites .…”

“…In this context, a long lasting decrease of the thymic output, on one hand, depletes the peripheral T-cell compartment of the repertoire diversity necessary for an effective antigen recognition; on the other hand it increases repertoire restrictions in the CSF . This would likely cause an impaired identification of JCV displaying mutated antigens carried by CD34 + progenitor cells and B lymphocytes mobilized by natalizumab (Zohren et al, 2008;Frohman et al, 2014).…”