Cerebrospinal fluid soluble CD27 is associated with CD8+ T cells, B cells and biomarkers of B cell activity in relapsing-remitting multiple sclerosis

Immunology of multiple sclerosis: an update

PURPOSE OF REVIEW

The immunological processes that lead to multiple sclerosis (MS) and occur during the progressive phase of the disease are manifold and still not well understood. This review summarizes new insights on this topic that were gained through recent studies with diverse scientific approaches.

RECENT FINDINGS

While genetic risk clearly contributes to MS, external factors play a key role in its pathogenesis as well. Epstein-Barr virus infection correlates significantly with MS risk and seems to be a major causal factor. Even though our knowledge on the human gut microbiome and its connection to the central nervous system is far from being complete, several studies have proven that the gut-brain axis influences neuroinflammation and disease progression in MS. It has become much clearer that MS is not solely a T cell-mediated disease but is also strongly driven by B cells and pathogenic antibodies. Beyond the peripheral immune cells, glial cells and their interactions with neurons are important players contributing to disease activity and progression in MS.

SUMMARY

Taken together, recent publications on immunological processes in the context of MS implicate a multitude of noncanonical mechanisms that need to be further explored regarding their interplay and contribution to the degenerative course of the disease.

Multifaceted Biomarkers Suggest a Similar Profile of CNS Pathology in Relapsing and Progressive MS

BACKGROUND

Relapsing-remitting (RR) and primary progressive (PP) multiple sclerosis (MS) have distinct clinical courses, but underlying pathophysiological differences remain unclear. We compared pathological components between RRMS, PPMS, and other inflammatory and neurodegenerative disorders, leveraging soluble biomarkers and post-mortem pathology.

METHODS

Serum and cerebrospinal fluid (CSF) of people diagnosed with (pw) PPMS (n = 104), RRMS (n = 38), Alzheimer's disease (AD, n = 22), neuromyelitis optica spectrum disorder (NMOSD, n = 10), and myelin oligodendrocyte glycoprotein-associated disease (MOGAD, n = 10) were collected. B-cell maturation antigen (BCMA), soluble CD27 (sCD27), osteopontin (OPN), chitinase-3-like-1 (CHI3L1), glial fibrillary acidic protein (GFAP), neurofilament light chain (NfL) and synaptosomal-associated protein-25 (SNAP25) were measured. Lymphocytes (CD20+, CD138+, CD3+) and pyramidal-tract axonal density in RR-onset (n = 86) and PPMS (n = 45) post-mortem brain tissue were quantified.

RESULTS

Soluble and post-mortem tissue biomarkers did not differ between pwRRMS and pwPPMS. Compared to AD, MS had higher CSF sCD27 (p < 0.001) but lower serum CHI3L1 and GFAP, and CSF OPN and SNAP25 (all p < 0.05). Serum OPN was lower in RRMS than NMOSD (p = 0.013). Principal component analyses and K-means clustering showed substantial overlap of RRMS and PPMS biomarkers, distinct from AD. In all pwMS, serum NfL and CSF BCMA correlated with clinical/radiological disease activity, CSF BCMA and sCD27 with inflammatory parameters, and serum GFAP, CSF GFAP, and CSF NfL with Expanded Disability Status Scale (EDSS) score.

CONCLUSIONS

Serum and CSF soluble biomarker profiles and post-mortem pathology do not differentiate RRMS from PPMS diagnoses but reflect the extent of inflammation and tissue damage. Detailed assessment of MS-associated inflammation and tissue damage may enhance classification and therapeutic strategies.

Cerebrospinal fluid soluble CD27 is a sensitive biomarker of inflammation in autoimmune encephalitis

BACKGROUND

Autoimmune encephalitis (AE) comprises a group of rare, severe neuroinflammatory conditions. Current biomarkers of neuroinflammation are often normal in AE which therefore can be difficult to rule out in patients with seizures, cognitive and/or neuropsychiatric symptoms. Cerebrospinal fluid (CSF) soluble CD27 (sCD27) and soluble B-cell maturation antigen (sBCMA) have high sensitivity for neuroinflammation in other neuroinflammatory conditions. In this exploratory study we investigate the potential of sCD27 and sBCMA in CSF as biomarkers of neuroinflammation in AE.

METHODS

Concentrations of sCD27 and sBCMA were measured in CSF from 40 AE patients (20 patients were untreated (12 with anti-N-Methyl-d-Aspartate receptor antibodies (NMDA) and 8 with anti-Leucine-rich Glioma-Inactivated 1 antibodies (LGI1)), and 37 symptomatic controls (SCs).

RESULTS

CSF concentrations of sCD27 were increased in untreated NMDA AE patients (median 1571 pg/ml; p < 0.001) and untreated LGI1 AE patients (median 551 pg/ml; p < 0.05) compared to SCs (median 250 pg/ml). CSF sBCMA was increased in untreated NMDA AE patients (median 832 pg/ml) compared to SCs (median 429 pg/ml). CSF sCD27 and sBCMA correlated with the CSF cell count. Receiver operating characteristic curve analysis of untreated AE patients versus SCs showed an area under the curve of 0.97 for sCD27 and 0.76 for sBCMA.

CONCLUSION

CSF sCD27 is a suitable biomarker of neuroinflammation in AE with an ability to discriminate patients with NMDA AE and LGI1 AE from symptomatic controls. CSF sCD27 may be suited for ruling out AE and other neuroinflammatory conditions in the early phase of the diagnostic work-up.

Soluble CD27 is an intrathecal biomarker of T-cell-mediated lesion activity in multiple sclerosis

OBJECTIVE

Soluble CD27 is a promising cerebrospinal fluid inflammatory biomarker in multiple sclerosis. In this study, we investigate relevant immune and neuro-pathological features of soluble CD27 in multiple sclerosis.

METHODS

Protein levels of soluble CD27 were correlated to inflammatory cell subpopulations and inflammatory cytokines and chemokines detected in cerebrospinal fluid of 137 patients with multiple sclerosis and 47 patients with inflammatory and non-inflammatory neurological disease from three independent cohorts. Production of soluble CD27 was investigated in cell cultures of activated T and B cells and CD27-knockout T cells. In a study including matched cerebrospinal fluid and post-mortem brain tissues of patients with multiple sclerosis and control cases, levels of soluble CD27 were correlated with perivascular and meningeal infiltrates and with neuropathological features.

RESULTS

We demonstrate that soluble CD27 favours the differentiation of interferon-γ-producing T cells and is released through a secretory mechanism activated by TCR engagement and regulated by neutral sphingomyelinase. We also show that the levels of soluble CD27 correlate with the representation of inflammatory T cell subsets in the CSF of patients with relapsing-remitting multiple sclerosis and with the magnitude of perivascular and meningeal CD27 + CD4 + and CD8 + T cell infiltrates in post-mortem central nervous system tissue, defining a subgroup of patients with extensive active inflammatory lesions.

INTERPRETATION

Our results demonstrate that soluble CD27 is a biomarker of disease activity, potentially informative for personalized treatment and monitoring of treatment outcomes.

Drugs Targeting CD20 in Multiple Sclerosis: Pharmacology, Efficacy, Safety, and Tolerability

Currently, there are four monoclonal antibodies (mAbs) that target the cluster of differentiation (CD) 20 receptor available to treat multiple sclerosis (MS): rituximab, ocrelizumab, ofatumumab, and ublituximab. B-cell depletion therapy has changed the therapeutic landscape of MS through robust efficacy on clinical manifestations and MRI lesion activity, and the currently available anti-CD20 mAb therapies for use in MS are a cornerstone of highly effective disease-modifying treatment. Ocrelizumab is currently the only therapy with regulatory approval for primary progressive MS. There are currently few data regarding the relative efficacy of these therapies, though several clinical trials are ongoing. Safety concerns applicable to this class of therapeutics relate primarily to immunogenicity and mechanism of action, and include infusion-related or injection-related reactions, development of hypogammaglobulinemia (leading to increased infection and malignancy risk), and decreased vaccine response. Exploration of alternative dose/dosing schedules might be an effective strategy for mitigating these risks. Future development of biosimilar medications might make these therapies more readily available. Although anti-CD20 mAb therapies have led to significant improvements in disease outcomes, CNS-penetrant therapies are still needed to more effectively address the compartmentalized inflammation thought to play an important role in disability progression.

Causal relationship between immune cells and neurodegenerative diseases: a two-sample Mendelian randomisation study

Background

There is increasing evidence that the types of immune cells are associated with various neurodegenerative diseases. However, it is currently unclear whether these associations reflect causal relationships.

Objective

To elucidate the causal relationship between immune cells and neurodegenerative diseases, we conducted a two-sample Mendelian randomization (MR) analysis.

Materials and methods

The exposure and outcome GWAS data used in this study were obtained from an open-access database (https://gwas.mrcieu.ac.uk/), the study employed two-sample MR analysis to assess the causal relationship between 731 immune cell features and four neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS). All immune cell data was obtained from Multiple MR methods were used to minimize bias and obtain reliable estimates of the causal relationship between the variables of interest and the outcomes. Instrumental variable selection criteria were restricted to ensure the accuracy and effectiveness of the causal relationship between species of immune cells and the risk of these neurodegenerative diseases.

Results

The study identified potential causal relationships between various immune cells and different neurodegenerative diseases. Specifically, we found that 8 different types of immune cells have potential causal relationships with AD, 1 type of immune cells has potential causal relationships with PD, 6 different types of immune cells have potential causal relationships with ALS, and 6 different types of immune cells have potential causal relationships with MS.

Conclusion

Our study, through genetic means, demonstrates close causal associations between the specific types of immune cells and AD, PD, ALS and MS, providing useful guidance for future clinical researches.

Proteomics reveal biomarkers for diagnosis, disease activity and long-term disability outcomes in multiple sclerosis

Sensitive and reliable protein biomarkers are needed to predict disease trajectory and personalize treatment strategies for multiple sclerosis (MS). Here, we use the highly sensitive proximity-extension assay combined with next-generation sequencing (Olink Explore) to quantify 1463 proteins in cerebrospinal fluid (CSF) and plasma from 143 people with early-stage MS and 43 healthy controls. With longitudinally followed discovery and replication cohorts, we identify CSF proteins that consistently predicted both short- and long-term disease progression. Lower levels of neurofilament light chain (NfL) in CSF is superior in predicting the absence of disease activity two years after sampling (replication AUC = 0.77) compared to all other tested proteins. Importantly, we also identify a combination of 11 CSF proteins (CXCL13, LTA, FCN2, ICAM3, LY9, SLAMF7, TYMP, CHI3L1, FYB1, TNFRSF1B and NfL) that predict the severity of disability worsening according to the normalized age-related MS severity score (replication AUC = 0.90). The identification of these proteins may help elucidate pathogenetic processes and might aid decisions on treatment strategies for persons with MS.