Serum Peptide Immunoglobulin G Autoantibody Response in Patients with Different Central Nervous System Inflammatory Demyelinating Disorders

Cytomegalovirus and Epstein-Barr virus infections in patients with neuromyelitis optica spectrum disorder

OBJECTIVES

Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) infections in patients with Neuromyelitis optica spectrum disorder (NMOSD) remain unclear. The objective of this study was to investigate CMV and EBV infections in patients with NMOSD.

METHODS

Serum immunoglobin (Ig) G antibodies against CMV and EBV were measured in patients with NMOSD and healthy controls (HCs), including anti-CMV, anti-EBV nuclear antigen-1 (EBNA-1), anti-EBV virus capsid antigen (VCA), and anti-EBV early antigen (EA) IgGs. The immune status ratio (ISR) was used to evaluate the serum anti-CMV and anti-EBV IgG levels and ISR ≧1.10 was defined as seropositivity.

RESULTS

In total, 238 serum samples were collected from 94 patients with NMOSD and 144 HCs, and no significant difference of sex and age between NMOSD and HCs. Comparing to the HCs, patients with NMOSD exhibited significantly higher serum anti-CMV IgG level. In contrast, the serum anti-EBNA1 IgG level was significantly lower in patients with NMOSD than in HCs. The serum anti-VCA and anti-EA IgG levels did not differ between the two groups, but the anti-EA seropositivity was significantly higher in NMOSD group than that in HC group. We did not find associations between serum anti-CMV or anti-EBV IgG levels and NMOSD disease stage, immunotherapy, or disability score.

CONCLUSIONS

Our findings indicated that increased CMV infection and EBV recent infection, as well as reduced EBV latency infection were associated with the risk of NMOSD. Prospective cohort studies are needed to verify our findings and clarify the correlation between CMV and EBV infections and clinical characteristics of NMOSD.

Immune Repertoire Profiling Reveals Its Clinical Application Potential and Triggers for Neuromyelitis Optica Spectrum Disorders

BACKGROUND AND OBJECTIVES

Neuromyelitis optica spectrum disorders (NMOSD) is widely recognized as a CNS demyelinating disease associated with AQP4-IgG (T cell-dependent antibody), and its trigger is still unclear. In addition, although the treatment of NMOSD currently can rely on traditional immunosuppressive and modulating agents, effective methods to predict the efficacy of these therapeutics are lacking.

METHODS

In this study, high-throughput T-cell receptor (TCR) sequencing was performed on peripheral blood from 151 pretreatment patients with AQP4-IgG⁺ NMOSD and 151 healthy individuals. We compared the TCR repertoire of those with NMOSD with that of healthy individuals and identified TCR clones that were significantly enriched in NMOSD. In addition, we treated 28 patients with AQP4-IgG⁺ NMOSD with immunosuppressants and followed up for 6 months to compare changes in NMOSD-specific TCRs (NMOSD-TCRs) before and after treatment. Moreover, we analyzed transcriptome and single-cell B-cell receptor (BCR) data from public databases and performed T-cell activation experiments using antigenic epitopes of cytomegalovirus (CMV) to further explore the triggers of AQP4-IgG⁺ NMOSD.

RESULTS

Compared with healthy controls, patients with AQP4-IgG⁺ NMOSD had significantly reduced diversity and shorter CDR3 length of TCRβ repertoire. Furthermore, we identified 597 NMOSD-TCRs with a high sequence similarity that have the potential to be used in the diagnosis and prognosis of NMOSD. The characterization of NMOSD-TCRs and pathology-associated clonotype annotation indicated that the occurrence of AQP4-IgG⁺ NMOSD may be associated with CMV infection, which was further corroborated by transcriptome and single-cell BCR analysis results from public databases and T-cell activation experiments.

DISCUSSION

Our findings suggest that the occurrence of AQP4-IgG⁺ NMOSD may be associated with CMV infection. In conclusion, our study provides new clues to uncover the causative factors of AQP4-IgG⁺ NMOSD and provides a theoretical foundation for treating and monitoring the disease.

Immunoglobulin profiling with large high-density peptide microarrays as screening method to detect candidate proteins for future biomarker detection in dogs with steroid-responsive meningitis-arteritis

Steroid responsive meningitis arteritis (SRMA) is an aberrant Th2-mediated systemic inflammatory disease in dogs. The etiopathogenesis still remains unclear as no triggering pathogen or autoantigen could be found so far.

HYPOTHESIS

Large high-density peptide microarrays are a suitable screening method to detect possible autoantigens which might be involved in the pathogenesis of SRMA.

METHODS

The IgA and IgG profile of pooled serum samples of 5 dogs with SRMA and 5 dogs with neck pain due to intervertebral disc herniation (IVDH) without ataxia or paresis were compared via commercially available high-density peptide microarrays (Discovery Microarray) containing 29,240 random linear peptides. Canine distemper virus nucleoprotein (CDVN) served as positive control as all dogs were vaccinated. Common motifs were compared to amino acid sequences of known proteins via databank search. One suitable protein was manually selected for further analysis with a smaller customized high-density peptide microarray.

RESULTS

Pooled serum of dogs with SRMA and IVDH showed different IgA and IgG responses on Discovery Microarray. Only top IgG responses of dogs with SRMA showed a common motif not related to the control protein CDVN. This common motif is part of the interleukin 1 receptor antagonist protein (IL1Ra). On IL1Ra, dogs with SRMA displayed IgA binding to an additional epitope, which dogs with IVDH did not show.

DISCUSSION

IL1Ra is an anti-inflammatory acute phase protein. Different immunoglobulin binding patterns on IL1Ra could be involved in the pathogenesis of SRMA and IL1Ra might be developed as future biomarker for SRMA.

Autoantibodies in central nervous system and neuromuscular autoimmune disorders: A narrative review

The discovery of novel autoantibodies in neurological disorders contributes to a better understanding of its pathogenesis, improves the accuracy of diagnosis, and leads to new treatment strategies. Advances in techniques for the screening and detection of autoantibodies have enabled the discovery of new antibodies in the central nervous system (CNS) and neuromuscular diseases. Cell-based assays using live or fixed cells overexpressing target antigens are widely used for autoantibody-based diagnosis in clinical practice. Common pathogenic autoantibodies are unknown in most patients with multiple sclerosis (MS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Novel pathogenic autoantibodies to aquaporin-4 and myelin oligodendrocyte glycoprotein (MOG) have been identified in neuromyelitis optica spectrum disorder and MOG antibody-associated disease, respectively. These diseases have clinical similarities to MS, but with the discovery of pathogenic autoantibodies, they are now recognized as distinct disease entities. Antibodies to paranodal membrane proteins such as neurofascin-155, contactin‑1, contactin‑associated protein‑1 in CIDP and muscle-specific kinase and low-density lipoprotein receptor–related protein 4 in myasthenia gravis were added to the profiles of autoantibodies in neurological disorders. Despite the relatively low frequency of seropositivity, autoantibody detection is currently essential for the clinical diagnosis of CNS and neuromuscular autoimmune disorders, and differential approaches to seropositive patients will contribute to more personalized medicine. We reviewed recent discoveries of autoantibodies and their clinical implications in CNS and neuromuscular disorders.