Plasma Neurofilament Light for Prediction of Disease Progression in Familial Frontotemporal Lobar Degeneration

Objective: We tested the hypothesis that plasma neurofilament light chain (NfL) identifies asymptomatic carriers of familial frontotemporal lobar degeneration (FTLD)-causing mutations at risk of disease progression. Methods: Baseline plasma NfL concentrations were measured with single-molecule array in original (n = 277) and validation (n = 297) cohorts. C9orf72, GRN, and MAPT mutation carriers and noncarriers from the same families were classified by disease severity (asymptomatic, prodromal, and full phenotype) using the CDR Dementia Staging Instrument plus behavior and language domains from the National Alzheimer's Disease Coordinating Center FTLD module (CDR+NACC-FTLD). Linear mixed-effect models related NfL to clinical variables. Results: In both cohorts, baseline NfL was higher in asymptomatic mutation carriers who showed phenoconversion or disease progression compared to nonprogressors (original: 11.4 ± 7 pg/mL vs 6.7 ± 5 pg/mL, p = 0.002; validation: 14.1 ± 12 pg/mL vs 8.7 ± 6 pg/mL, p = 0.035). Plasma NfL discriminated symptomatic from asymptomatic mutation carriers or those with prodromal disease (original cutoff: 13.6 pg/mL, 87.5% sensitivity, 82.7% specificity; validation cutoff: 19.8 pg/mL, 87.4% sensitivity, 84.3% specificity). Higher baseline NfL correlated with worse longitudinal CDR+NACC-FTLD sum of boxes scores, neuropsychological function, and atrophy, regardless of genotype or disease severity, including asymptomatic mutation carriers. Conclusions: Plasma NfL identifies asymptomatic carriers of FTLD-causing mutations at short-term risk of disease progression and is a potential tool to select participants for prevention clinical trials. Trial registration information: ClinicalTrials.gov Identifier: NCT02372773 and NCT02365922. Classification of evidence: This study provides Class I evidence that in carriers of FTLD-causing mutations, elevation of plasma NfL predicts short-term risk of clinical progression

Feasibility of the use of combinatorial chemokine arrays to study blood and CSF in multiple sclerosis.

Meningeal inflammation, including the presence of semi-organized tertiary lymphoid tissue, has been associated with cortical pathology at autopsy in secondary progressive multiple sclerosis (SPMS). Accessible and robust biochemical markers of cortical inflammation for use in SPMS clinical trials are needed. Increased levels of chemokines in the cerebrospinal fluid (CSF) can report on inflammatory processes occurring in the cerebral cortex of MS patients. A multiplexed chemokine array that included BAFF, a high sensitivity CXCL13 assay and composite chemokine scores were developed to explore differences in lymphoid (CXCL12, CXCL13, CCL19 and CCL21) and inflammatory (CCL2, CXCL9, CXCL10 and CXCL11) chemokines in a small pilot study. Paired CSF and serum samples were obtained from healthy controls (n=12), relapsing-remitting MS (RRMS) (n=21) and SPMS (N=12). A subset of the RRMS patients (n = 9) was assessed upon disease exacerbation and 1 month later following iv methylprednisone. SPMS patients were sampled twice to ascertain stability. Both lymphoid and inflammatory chemokines were elevated in RRMS and SPMS with the highest levels found in the active RRMS group. Inflammatory and lymphoid chemokine signatures were defined and generally correlated with each other. This small exploratory clinical study shows the feasibility of measuring complex and potentially more robust chemokine signatures in the CSF of MS patients during clinical trials. No differences were found between stable RRMS and SPMS. Future trials with larger patient cohorts with this chemokine array are needed to further characterize the differences, or the lack thereof, between stable RRMS and SPMS

Ratio of CSF to serum chemokine levels in normal patients as well as the relationship to molecular size.

<p>A). Ratio of the CSF to serum chemokine concentrations for normal controls. B). Relationship between the molecular weight of the analyte and the CSF/serum ratio (only normal subjects). Only CCL21 and CXCL12 are plotted and CXCL9, CXCL13 and CCL19 would roughly overlay these values. Chemokines were assumed to be dimeric, BAFF trimeric, IgG dimeric, IgA tetrameric and IgM pentameric. Values above the line are consistent with local CNS production. C). Corresponding Ig indices for the different cohorts. </p

Comparison of the levels of the lymphoid chemokines CXCL12, CXCL13, CCL19 and CCL21 in serum and CSF.

<p>Chemokine concentrations are plotted with box and whiskers (10-90% range) overlaid on the scatter plots (each patient is a symbol). The CSF/serum ratio is presented on the right side. Data are shown for normal controls (NC), relapsing-remitting MS (RRMS), RRMS patients with acute exacerbations (EX-RRMS) and secondary progressive MS patients (SPMS). In those cases with EX-RRMS (9), SPMS (11) and RRMS (2) patients with second lumbar punctures, data from both samples are included. Statistical significance was assessed using only the baseline data and is indicated by asterisks at the bottom of each graph (ANOVA). Data at the lower limit of quantitation were excluded from the ratio plots. </p

Comparison of three different assays to quantitate CXCL13 in CSF.

<p>“ELISA” refers to a commercial kit (R&D), the “Luminex” is a custom chemokine multiplex assay and Immuno-PCR refers to the ELISA with PCR based quantitation. Samples from all four cohorts of patients are included. The low limit of quantitation (LLOQ) was determined for CXCL13 in CSF and is not the buffer-based assay performance. </p

Comparison of the levels of the inflammatory chemokines in serum and CSF.

<p>(A) Concentrations of CXCL9, CXCL10, and CCL2 and (B) the cytokine BAFF are plotted as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0081007#pone-0081007-g002" target="_blank">Figure 2</a>. </p

Relationship between the CSF lymphoid and inflammatory scores for MS patients and healthy normal controls.

<p>Solid circles show the baseline data while open circles are from the repeat lumbar puncture. Lines with arrow heads indicate paired samples from each patient (most MS subjects from the RRMS group did not have two lumbar punctures).</p

Trend analyses for each analyte for those individuals with two CSF samples.

<p>Both EX-RRMS and SPMS patients are grouped in the same graph.</p

The lymphotoxin β receptor is a potential therapeutic target in renal inflammation

Accumulation of inflammatory cells in different renal compartments is a hallmark of progressive kidney diseases including glomerulonephritis (GN). Lymphotoxin β receptor (LTβR) signaling is crucial for the formation of lymphoid tissue, and inhibition of LTβR signaling has ameliorated several non-renal inflammatory models. Therefore, we tested whether LTβR signaling could also have a role in renal injury. Renal biopsies from patients with GN were found to express both LTα and LTβ ligands, as well as LTβR. The LTβR protein and mRNA were localized to tubular epithelial cells, parietal epithelial cells, crescents, and cells of the glomerular tuft, whereas LTβ was found on lymphocytes and tubular epithelial cells. Human tubular epithelial cells, mesangial cells, and mouse parietal epithelial cells expressed both LTα and LTβ mRNA upon stimulation with TNF in vitro. Several chemokine mRNAs and proteins were expressed in response to LTβR signaling. Importantly, in a murine lupus model, LTβR blockade improved renal function without the reduction of serum autoantibody titers or glomerular immune complex deposition. Thus, a preclinical mouse model and human studies strongly suggest that LTβR signaling is involved in renal injury and may be a suitable therapeutic target in renal diseases.Kidney International advance online publication, 23 September 2015; doi:10.1038/ki.2015.280