Myelin oligodendrocyte glycoprotein antibody-associated disorders: clinical spectrum, diagnostic evaluation, and treatment options

Can serum C3/C4 complement ratio be used in the differential diagnosis of central nervous system demyelinating diseases?

BACKGROUND

Neuromyelitis Optica Spectrum Disorders (NMOSD) and Multiple Sclerosis (MS) are primary demyelinating diseases of the central nervous system (CNS) with similar clinical features, complicating early differential diagnosis and treatment decisions. While both humoral and cellular immunity contribute to their immunopathogenesis, the complement system's role remains unclear. We considered complement-dependent cytotoxicity might have different roles in the pathophysiology of these diseases. Predictive value of C3 and C4 complement levels at the first attack for the definitive diagnosis aimed to be investigated.

METHODS

Treatment-naive, 14 seronegative (SN) NMO, 28 aquaporin-4-positive [AQP4(+)] NMO, 23 myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), and 15 MS adult patients were included. Serum C3 and C4 levels were evaluated retrospectively. Complement levels were statistically adjusted according to the age of the patients and C3/C4 ratio was used to increase statistical power.

RESULTS

We found that C4 levels were lower and C3/C4 ratio was higher in SNNMO and AQP4(+)-NMO groups compared to the MS group. It has been determined that 5.32 and 4.85 cut-off values of the C3/C4 ratio can discriminate SNNMO and AQP4(+)-NMO groups from MS.

CONCLUSION

The classical complement pathway in SNNMO and AQP4(+)-NMO was thought to be more affected compared to MS, as activation of the classical pathway predominantly decreases the level of C4. Since the involvement of the complement system pathways at different levels may be presented with the C3/C4 ratio, it seems likely that this ratio may have value as a candidate biomarker in the differential diagnosis of primary CNS demyelinating diseases.

Quality of life in patients with myelin oligodendrocyte glycoprotein antibody associated disease compared to patients with AQP4-IgG positive neuromyelitis optica spectrum disorders: A Korean multicenter study

BACKGROUND

Little is known about the quality of life (QOL) of patients with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). We compared QOL and associated factors in patients with MOGAD and aquaporin4 IgG (AQP4-IgG) positive neuromyelitis optica spectrum disorder (NMOSD).

METHODS

This multicenter questionnaire study compared the QOL of 41 patients with MOGAD and 78 with AQP4-IgG positive NMOSD. Patients who were positive for AQP4-IgG or MOG antibodies were included. WHO Quality of Life Scale Brief Version was used to assess QOL in physical, psychological, social, and environmental domains. QOL, sleep quality, pain, fatigue, and depression were compared between the two groups. The factors associated with QOL in each group and the entire cohort were analyzed.

RESULTS

The proportion of patients with poor QOL was not significantly different between MOGAD (51.22 %) and AQP4-IgG positive NMOSD (58.97 %, p = 0.054). In the MOGAD group, the pain score (β=-1.032, p = 0.001) and depression score (β=-0.694, p = 0.007) were negatively associated with physical and psychological QOL, respectively. Sleep quality was negatively associated with physical (β=-1.506, p = 0.034) and psychological (β =-2.064, p = 0.033) QOL. When the entire cohort was analyzed, a positive MOG antibody was independently associated with worse psychological QOL (β=-8.998, p = 0.013) compared to positive AQP4-Ab after adjustment for sleep quality, depression, fatigue, and pain.

CONCLUSIONS

The overall QOL of the patients of MOGAD was comparable to that of AQP4-IgG positive NMOSD. Patients with MOGAD were experiencing sleep disorder, fatigue, and depression at similar degrees to those of patients with AQP4-IgG positive NMOSD. Further consideration of sleep quality and psychological QOL is required to improve QOL in patients with MOGAD.

Detection of MOG-IgG in Clinical Samples by Live Cell-Based Assays: Performance of Immunofluorescence Microscopy and Flow Cytometry

Human antibodies against Myelin Oligodendrocyte Glycoprotein (MOG) from immunoglobulin-G subclasses (MOG-IgG) have been recently associated with a new subgroup of neurological autoimmune diseases with distinct clinical characteristics from multiple sclerosis and neuromyelitis optica spectrum disorders. The use of MOG-IgG as a biomarker is an essential tool to assist in the diagnosis and clinical prognosis. The cell-based assay (CBA) is a methodology that expresses high levels of natively folded human MOG protein in the cell membrane being the methodology most used for clinical MOG-IgG diagnosis. However, there is still no consensus about the best approach to perform CBA to improve the results. The CBA using flow cytometry (CBA-FC) is an automated technique with objective quantification, reducing the subject of human bias that occurred at CBA using immunofluorescence (CBA-IF). In this study, we compared the performance of CBA-IF and CBA-FC as an acquisition tool analysis. The sera of 104 patients diagnosed with inflammatory Central Nervous System diseases were tested in both CBA-IF and CBA-FC. We used the dilution of 1:128 for CBA-IF and three different dilutions (1:20, 1:100, and 1:640) for CBA-FC. The CBA-FC and CBA-IF results had 88.5% agreement between assays and the CBA-IF titers by endpoint-dilution correlated with the CBA-FC titers. The highest serum dilution resulted in an increased CBA-FC specificity, but there was a reduction in the CBA-FC sensitivity. Our study showed that CBA-FC can be used in clinical practice as a diagnostic technique for MOG-IgG. In addition, in some specific cases, the combination of both techniques could be used as a tool to discriminate unspecific binding and overcome single assay limitations.