Lymphocyte Gene Expression and JC Virus Noncoding Control Region Sequences Are Linked with the Risk of Progressive Multifocal Leukoencephalopathy

Abstract

Progressive multifocal leukoencephalopathy (PML)-derived noncoding control region (NCCR) sequences permitted greater early viral gene expression than kidney-associated NCCR sequences. This was driven in part by binding of the transcription factor Spi-B to unique PML-associated Spi-B binding sites. Spi-B is upregulated in developing B cells in response to natalizumab therapy, a known risk factor for PML. Naturally occurring JCV sequence variation, together with drug treatment-induced cellular changes, may synergize to create an environment leading to an increased risk of PML. The incidence of progressive multifocal leukoencephalopathy (PML) has risen dramatically in recent years because of the AIDS pandemic and the increased use of immunomodulatory therapies (1). In particular, natalizumab (Tysabri; Biogen Idec), a very effective multiple sclerosis (MS) treatment, has been highly associated with PML (2).Natalizumab treatment alters the expression profiles of peripheral blood mononuclear cells (PBMCs), including the expression of the transcription factor Spi-B (3). Spi-B is required for normal B-cell receptor signaling and maturation (4-7). Spi-B levels are higher in cells permissive to JC virus (JCV) transcription and replication, and overexpression of Spi-B increases viral gene expression (8). Spi-B binds to target sites in the JCV noncoding control region (NCCR) isolated from PML brain tissue but not in the archetype NCCR commonly detected in the urine of asymptomatic healthy individuals (8-11). Importantly, mutation of these sites in PML-associated NCCRs decreases Spi-B protein binding and viral gene expression (8,12). Taken together, these results suggest that Spi-B binding to sequences in the JCV NCCR have functional effects on viral gene expression and may play a role in the activation of JCV in peripheral blood cells (13).JCV DNA has been detected in CD19 ϩ B cells and CD34 ϩ hematopoietic progenitor cells (14, 15) isolated from peripheral blood and bone marrow. These CD34 ϩ cells are strikingly increased in the peripheral blood of natalizumab-treated patients (16, 17). Immunomagnetic separation was used to isolate CD3 ϩ , CD19 ϩ , and CD34 ϩ cells from PBMCs of normal donors and MS patients treated with natalizumab. Total RNA was isolated from each cell subset, and Spi-B gene expression was measured by quantitative reverse transcription (qRT)-PCR using the endogenous control PUM1 for normalization. Spi-B gene expression was more variable in natalizumab patients. It was upregulated up to 2-fold in CD19 ϩ B cells in some patients treated with natalizumab (Fig. 1C). Spi-B expression was increased ϩ , CD19 ϩ , and CD34 ϩ cells were isolated by immunomagnetic separation from PBMC samples from patients treated with natalizumab or normal donors. The remaining cells from the separation are labeled the negative fraction. Total RNA was isolated from each fraction of cells, and the Spi-B gene expression level was measured by qRT-PCR. Spi-B mRNA levels were normalized between samples by using the endogenous control P...

Broadly neutralizing human monoclonal JC polyomavirus VP1–specific antibodies as candidate therapeutics for progressive multifocal leukoencephalopathy

“…NAT not only compromises CNS immune surveillance by reducing the migration of T cells, CD19 + B cells, and CD138 + plasma cells through the blood-brain barrier (42) but also perturbs peripheral B cell niches by increasing the number of memory- and marginal zone–like B cells (43). The release of CD34 + progenitor cells into the peripheral blood may favor the evolution and reactivation of neurotropic JCPyV variants (44, 45). Rituximab depletes CD20 + B cells and perturbs B cell homeostasis (5, 46); however, it is currently unknown whether the B cell depletion by rituximab results in PML because of reduced antibody responses against JCPyV, which is less likely, or perturbation of other B cell functions such as antigen presentation to T cells (47).…”

The Importance of Mouse Models to Define Immunovirologic Determinants of Progressive Multifocal Leukoencephalopathy

“…( 13 )]. Notably, gene expression of unfractionated blood, and sorted CD19 + B cells, and CD34 + HPCs from MS patients receiving natalizumab revealed upregulation of genes involved in B cell activation and differentiation, including Spi-B ( 106 , 107 ). These findings are in line with a proposal that upregulation of specific transcription factors that bind JCV NCCR underlie a resurgence of JCV replication in natalizumab-treated individuals ( 108 , 109 ).…”

Standard Issue: Copy number heterogeneity of JC virus standards discovered through next-generation sequencing

“…This variant allele frequency matched the copy number difference found in the BKV large T-antigen. No sequence alteration was found in the origin for either of the JC virus sequences isolated in this study, although a tatataGaaaa change (from tatataTaaaa) was found in the downstream TA-rich region that to date has only been recovered in one JC virus ever deposited in NCBI (KF788289) (27). This data would be consistent with the hypothesis that SV40 large T-antigen shows preference for its own origin relative to BKV but not JCV, as the BKV origin changed to the SV40 origin but the JCV origin did not change.…”