Increased cytomegalovirus immune responses at disease onset are protective in the long-term prognosis of patients with multiple sclerosis.

OBJECTIVE: It remains unclear whether viral infections interfere with multiple sclerosis (MS) disease progression. We evaluated the prognostic role of antibody responses toward viruses determined at disease onset on long-term disease outcomes. METHODS: Humoral immune responses against Epstein-Barr virus (EBV)-encoded nuclear antigen EBNA1, viral capsid antigen (VCA) and early antigen, and toward cytomegalovirus (HCMV), human herpesvirus 6 and measles were investigated in a cohort of 143 patients with MS for their association with long-term disability and inflammation disease outcomes. RESULTS: Median (IQR) follow-up was 20 (17.2-22.8) years. In univariable analysis, increased HCMV levels were associated with a lower risk to Expanded Disability Status Scale 4.0 (HR 0.95; 95% CI 0.91 to 0.99; p=0.03), to develop a secondary progressive MS (HR 0.94; 95% CI 0.90 to 0.99; p=0.02) and to first-line treatment (HR 0.98; 95% CI 0.96 to 0.99; p=0.04). High HCMV IgG levels were associated with a longer time to first-line treatment (p=0.01). Increased immune responses against EBV-VCA were associated with higher risk for first-line (HR 1.45; 95% CI 1.12 to 1.88; p=0.005) and second-line treatments (HR 2.03; 95% CI 1.18 to 3.49; p=0.01), and high VCA IgG levels were associated with shorter time to first-line (p=0.004) and second-line (p=0.02) therapies. EBNA1-specific IgG levels correlated with disease severity (0.17; p=0.04) and with an increased relapse rate during follow-up (relapse rate 1.26; 95% CI 1.03 to 1.56; p=0.02) that remained stable in multivariable analysis. CONCLUSIONS: These results indicate that elevated immune responses against HCMV at disease onset have protective effects on long-term disability and inflammation disease outcomes. Our data also indicate that increased immune responses against EBV in early phases may influence long-term disease prognosis.

CSF chitinase 3-like 1 is associated with iron rims in patients with a first demyelinating event.

BACKGROUND: Chronic active lesions with iron rims have prognostic implications in patients with multiple sclerosis. OBJECTIVE: To assess the relationship between iron rims and levels of chitinase 3-like 1 (CHI3L1), neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) in patients with a first demyelinating event. METHODS: Iron rims were identified using 3T susceptibility-weighted imaging. Serum NfL and GFAP levels were measured by single-molecule array assays. CSF (cerebrospinal fluid) CHI3L1 levels were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: Sixty-one patients were included in the study. The presence of iron rims was associated with higher T2 lesion volume and higher number of gadolinium-enhancing lesions. In univariable analysis, having ⩾2 iron rims (vs 0) was associated with increased CSF CHI3L1 levels (ß = 1.41; 95% confidence interval (CI) = 1.10-1.79; p < 0.01) and serum NfL levels (ß = 2.30; 95% CI = 1.47-3.60; p < 0.01). In multivariable analysis, however, only CSF CHI3L1 levels remained significantly associated with the presence of iron rim lesions (ß = 1.45; 95% CI = 1.11-1.90; p < 0.01). The presence of ⩾2 iron rims was not associated with increased serum GFAP levels in univariable or multivariable analyses. CONCLUSION: These findings support an important contribution of activated microglia/macrophages to the pathophysiology of chronic active lesions with iron rims in patients with a first demyelinating event.

Serum Neurofilament Levels and PML Risk in Patients With Multiple Sclerosis Treated With Natalizumab.

OBJECTIVES: The study aimed to assess the potential for serum neurofilament light chain (NFL) levels to predict the risk of progressive multifocal leukoencephalopathy (PML) in natalizumab (NTZ)-treated patients with multiple sclerosis (MS) and to discriminate PML from MS relapses. METHODS: NFL levels were measured with single molecule array (Simoa) in 4 cohorts: (1) a prospective cohort of patients with MS who developed PML under NTZ therapy (pre-PML) and non-PML NTZ-treated patients (NTZ-ctr); (2) a cohort of patients whose blood was collected during PML; (3) an independent cohort of non-PML NTZ-treated patients with serum NFL determinations at 2 years (replication cohort); and (4) a cohort of patients whose blood was collected during exacerbations. RESULTS: Serum NFL levels were significantly increased after 2 years of NTZ treatment in pre-PML patients compared with NTZ-ctr. The prognostic performance of serum NFL levels to predict PML development at 2 years was similar in the NTZ-ctr group and replication cohort. Serum NFL levels also distinguished PML from MS relapses and were 8-fold higher during PML compared with relapses. CONCLUSIONS: These results support the use of serum NFL levels in clinical practice to identify patients with relapsing-remitting MS at higher PML risk and to differentiate PML from clinical relapses in NTZ-treated patients. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that serum NFL levels can identify NTZ-treated patients with MS who will develop PML with a sensitivity of 67% and specificity of 80%.

Circulating EZH2-positive T cells are decreased in multiple sclerosis patients.

BACKGROUND: Recent studies in experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis (MS), suggest an involvement of the histone methyltransferase enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2) in important processes such as cell adhesion and migration. METHODS: Here, we aimed to expand these initial observations by investigating the role of EZH2 in MS. mRNA expression levels for EZH2 were measured by real-time PCR in peripheral blood mononuclear cells (PBMC) from 121 MS patients (62 untreated and 59 receiving treatment) and 24 healthy controls. RESULTS: EZH2 expression levels were decreased in PBMC from untreated patients compared to that from controls, and treatment significantly upregulated EZH2 expression. Expression of miR-124 was increased in MS patients compared to controls. Blood immunophenotyping revealed EZH2 expression mostly restricted to CD4+ and CD8+ T cells, and circulating EZH2+ CD4+ and CD8+ T cells were decreased in untreated MS patients compared to controls. CD8+ T cells expressing EZH2 exhibited a predominant central memory phenotype, whereas EZH2+ CD4+ T cells were of effector memory nature, and both T cell subsets produced TNF-α. EZH2+ T cells were enriched in the cerebrospinal fluid compartment compared to blood and were found in chronic active lesions from MS patients. EZH2 inhibition and microarray analysis in PBMC was associated with significant downregulation of key T cell adhesion molecules. CONCLUSION: These findings suggest a role of EZH2 in the migration of T cells in MS patients. The observation of TNF-α expression by CD4+ and CD8+ T cells expressing EZH2 warrants additional studies to explore more in depth the pathogenic potential of EZH2+-positive cells in MS.

Matrix metalloproteinase 9 is decreased in natalizumab-treated multiple sclerosis patients at risk for progressive multifocal leukoencephalopathy.

OBJECTIVE: To identify biomarkers associated with the development of progressive multifocal leukoencephalopathy (PML) in multiple sclerosis (MS) patients treated with natalizumab (NTZ). METHODS: Relapsing-remitting MS patients who developed PML under NTZ therapy (pre-PML) and non-PML NTZ-treated patients (NTZ-ctr) were included in the study. Cryopreserved peripheral blood mononuclear cells and serum samples collected at baseline, at 1- and 2-year treated time points, and during PML were analyzed for gene expression by RNA sequencing and for serum protein levels by Luminex and enzyme-linked immunosorbent assays, respectively. RESULTS: Among top differentially expressed genes in the RNA sequencing between pre-PML and NTZ-ctr patients, pathway analysis revealed a high representation of genes belonging to the following categories: proangiogenic factors (MMP9, VEGFA), chemokines (CXCL1, CXCL5, IL8, CCL2), cytokines (IL1B, IFNG), and plasminogen- and coagulation-related molecules (SERPINB2, PLAU, PLAUR, TFPI, THBD). Serum protein levels for these candidates were measured in a 2-step manner in a screening cohort and a validation cohort of pre-PML and NTZ-ctr patients. Only matrix metalloproteinase 9 (MMP9) was validated; in pre-PML patients, MMP9 protein levels were significantly reduced at baseline compared with NTZ-ctr patients, and levels remained lower at later time points during NTZ treatment. INTERPRETATION: The results from this study suggest that the proangiogenic factor MMP9 may play a role as a biomarker associated with the development of PML in MS patients treated with NTZ. Ann Neurol 2017;82:186-195.

Molecular dynamics and intracellular signaling of the TNF-R1 with the R92Q mutation.

The tumor necrosis factor receptor superfamily, member 1A (TNFRSF1A) gene encodes the TNF-R1, one of the main TNF receptors that mediates its inflammatory actions. In a recent study, serum levels of the soluble TNF-R1 and mRNA levels of the full-length receptor were found to be significantly increased in multiple sclerosis (MS) patients carrying the R92Q mutation. Interestingly, R92Q-mutated patients were younger at disease onset and progressed slower as compared to non-carriers. Building on these previous findings, here we aimed to investigate by means of both in silico and in vitro approaches the mechanisms relating the R92Q substitution with functional changes of the receptor and their potential effects modulating MS disease course. Models of the extracellular domains of the human TNF-R1 and human TNF-R1 carrying the R92Q mutation, alone or bound to TNF, were constructed and submitted to molecular dynamics. TRAF2 and CASP3 mRNA expression levels were determined by real-time PCR in peripheral blood mononuclear cells (PBMC) from 61 MS patients, 9 R92Q carriers and 52 non-carriers (CT and CC genotypes for SNP rs4149584, respectively). Molecular dynamic studies revealed that the R92Q mutation increased the contact area between receptor and TNF (1070 and 1388Å(2) for native and mutated receptor) and decreased the distance between them (28.7 to 27.9Å), while Van der Waals and electrostatic interaction energies were increased. In PBMC from MS patients carrying the R92Q mutation, CASP3 mRNA expression levels were significantly increased compared to non-carriers, whereas a trend was observed for TRAF2. These data suggest that the R92Q mutation gives rise to a stronger interaction between the receptor and its ligand, which results in the potentiation of TNF-mediated pathways. Although further studies are needed, these functional changes may be related with the modulation in disease course reported in MS patients carrying the R92Q mutation.

Levels of soluble TNF-RII are increased in serum of patients with primary progressive multiple sclerosis.

The levels of soluble tumor necrosis factor receptor II (sTNF-RII) were determined in serum of 161 untreated multiple sclerosis (MS) patients with different clinical forms and 46 healthy controls (HC) by ELISA. Our results show that serum sTNF-RII levels were significantly increased in patients with primary progressive MS (PPMS) compared with other MS forms and HC. Although sTNF-RII levels significantly increased over a 2-year follow-up period in a subgroup of PPMS patients, they could not discriminate between patients with and without disability progression. Additional studies are needed to further implicate sTNF-RII in patients with PPMS.

Naturally presented peptides on major histocompatibility complex I and II molecules eluted from central nervous system of multiple sclerosis patients.

Tandem mass spectrometry was used to identify naturally processed peptides bound to major histocompatibility complex (MHC) I and MHC II molecules in central nervous system (CNS) of eight patients with multiple sclerosis (MS). MHC molecules were purified from autopsy CNS material by immunoaffinity chromatography with monoclonal antibody directed against HLA-A, -B, -C, and -DR. Subsequently peptides were separated by reversed-phase HPLC and analyzed by mass spectrometry. Database searches revealed 118 amino acid sequences from self-proteins eluted from MHC I molecules and 191 from MHC II molecules, corresponding to 174 identified source proteins. These sequences define previously known and potentially novel autoantigens in MS possibly involved in disease induction and antigen spreading. Taken together, we have initiated the characterization of the CNS-expressed MHC ligandome in CNS diseases and were able to demonstrate the presentation of naturally processed myelin basic protein peptides in the brain of MS patients.

A stress protein-facilitated antigen expression system for plasmid DNA vaccines.

In DNA vaccination, an exciting new immunization technique with potential applications in clinical medicine, expression plasmid DNA containing antigen-encoding sequences cloned under heterologous promoter control are delivered by techniques that lead in vivo to antigen expression in transfected cells. DNA vaccination efficiently primes both humoral and cellular immune responses. We developed a novel expression system for DNA vaccines in which a fusion protein with a small, N-terminal, viral DnaJ-like sequence (J domain) is translated in frame with C-terminal antigen-encoding sequences. The J domain stable bind to constitutively expressed, cytosolic stress protein hsp73 and triggers intracellular accumulation of antigen/hsp73 complexes. The system supports enhanced expression of chimeric antigens of >800 residues in length in immunogenic form. A unique advantage of the system is that even unstable or toxic proteins (or protein domains) can be expressed. We describe the design of DNA vaccines expressing antigens with a stress protein-capturing domain and characterize the immunogenicity of the antigens produced by this expression system.

AID expression identifies interfollicular large B cells as putative precursors of mature B-cell malignancies.

Neoplastic transformation of mature B cells can be triggered by class-switch recombination of the immunoglobulin gene, which aberrantly targets a protooncogene and promotes translocation. Class-switch recombination is initiated by the B-cell-specific protein activation-induced cytidine deaminase (AID). Using immunohistochemistry with a newly generated monoclonal antibody and quantitative reverse-transcription-polymerase chain reaction (RT-PCR) on microdissected tissue from lymph node, tonsil, and thymus, we demonstrate that AID expression is found in secondary lymphoid organs outside germinal centers and in the thymic medulla at substantial levels. This is accompanied by the presence of circle transcripts, indicating class-switch recombination to be active at these sites. The dominant AID-expressing cell population outside germinal centers displays cytomorphologic properties corresponding to those that define the recently characterized interfollicular large B-cell subset. These findings indicate that interfollicular large B cells and AID-expressing B lymphocytes of the thymic medulla could give rise to mature B-cell malignancies.

DNA vaccines prime CD8+ T cell responses to epitopes of viral antigens produced from overlapping reading frames of a single coding sequence.

A hepatitis B virus (HBV)-derived sequence that encodes the 832-residue polymerase (Pol) protein of HBV in the primary open reading frame (ORF), and the three (large, middle and small) hepatitis B surface antigen (HBsAg) variants in an alternative ORF was used. This sequence was cloned into expression vectors in which Pol was expressed under heterologous (HCMV, SV40 or metallothionin) promoter control. Some Pol-encoding vectors coexpressed Pol as well as readily detectable amounts of HBsAg. Efficient HBsAg expression depended on endogenous HBV promoter sequences but was apparently also facilitated by heterologous promoter sequences located upstream of the HBV Pol sequence. DNA immunization of mice efficiently coprimed CD8(+) T cell responses to epitopes of Pol and HBsAg. Over expression of Pol (using an hsp73-facilitated expression system) did not correlate with the immunogenicity of the K(d)/Pol(140-148) epitope. Immunodominant L(d)-restricted CD8(+) T cell responses to HBsAg down-modulated priming of CD8(+) T cell responses to other HBsAg epitopes but not to the K(d)/Pol(140-148) epitope. Different antigens transcribed from alternative reading frames of a single sequence in a DNA vaccine can thus efficiently prime multispecific T cell responses.

Enhanced priming of multispecific, murine CD8+ T cell responses by DNA vaccines expressing stress protein-binding polytope peptides.

A polytope DNA vaccine (pCI/pt10) was used that encodes within a 106-residue sequence 10-well characterized epitopes binding MHC class I molecules encoded by the K, D, or L locus (of H-2(d), H-2(b), and H-2(k) haplotype mice). The pCI/pt10 DNA vaccine efficiently primed all four K(b)/D(b)-restricted CD8(+) T cell responses in H-2(b) mice, but was deficient in stimulating most CD8(+) T cell responses in H-2(d) mice. Comparing CD8(+) T cell responses elicited with the pCI/pt10 DNA vaccine in L(d+) BALB/c and L(d-) BALB/c(dm2) (dm2) mice revealed that L(d)-restricted CD8(+) T cell responses down-regulated copriming of CD8(+) T cell responses to other epitopes regardless of their restriction or epitope specificity. Although the pt10 vaccine could thus efficiently co prime multispecific CD8(+) T cell responses, this priming was impaired by copriming L(d)-restricted CD8(+) T cell responses. When the pt10 sequence was fused to a 77-residue DnaJ-homologous, heat shock protein 73-binding domain (to generate a 183-residue cT(77)-pt10 fusion protein), expression and immunogenicity (for CD8(+) T cells) of the chimeric Ag were greatly enhanced. Furthermore, priming of multispecific CD8(+) T cell responses was readily elicited even under conditions in which the suppressive, L(d)-dependent immunodominance operated. The expression of polytope vaccines as chimeric peptides that endogenously capture stress proteins during in situ production thus facilitates copriming of CD8(+) T cell populations with a diverse repertoire.

Priming polyvalent immunity by DNA vaccines expressing chimeric antigens with a stress protein-capturing, viral J-domain.

The N-terminal domain of large tumor antigens (T-Ag) of polyomaviruses forms a DnaJ-like structure with a conserved J domain that associates with constitutively expressed stress protein heat shock protein (hsp)73. Mutant (but not wild-type) SV40 T-Ag show stable, ATP-dependent binding to the stress protein hsp73 when expressed in cells from different vertebrate tissues. Intracellular T/hsp73 complexes accumulate to high steady-state levels. From this observation, we designed a vector system that supports stable expression of a large variety of hsp73-capturing, chimeric antigens containing an N-terminal, T-Ag-derived domain, and different C-terminal antigenic domains from unrelated antigens. Most antigenic domains tested could be stably expressed only in eukaryotic cells as fusion protein/hsp73 complexes. The N-terminal 77 residues representing the J domain of T-Ag were required for stable hsp73 binding and efficient expression of chimeric antigens. Hsp73-bound chimeric antigens expressed by DNA vaccines showed strikingly enhanced immunogenicity evident in humoral (antibody) and cellular cytolytic T lymphocytes (CTL) responses. The described system supports efficient expression of chimeric, polyvalent antigens and their codelivery with hsp73 as a "natural adjuvant" for enhanced immunogenicity for T and B cells.