Different blood-brain-barrier disruption profiles in multiple sclerosis, neuromyelitis optica spectrum disorders, and neuropsychiatric systemic lupus erythematosus.

AIM OF THE STUDY: To assess differences in BBB damage profiles by measuring serum levels of soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble platelet endothelial cell adhesion molecule-1 (sPECAM-1), soluble intercellular adhesion molecule-1 (sICAM-1), and S100 calcium-binding protein B (S100B) in relapsing-remitting multiple sclerosis (RRMS), neuromyelitis optica spectrum disorders (NMOsd), and neuropsychiatric systemic lupus erythematosus (NPSLE) patients. CLINICAL RATIONALE FOR THE STUDY: Blood-brain-barrier (BBB) disruption is one of the key pathological processes involved in various demyelinating diseases of the central nervous system (CNS) and is associated with shedding of cell adhesion molecules and S100B into the serum compartment. Therefore, making an assessment of serum levels of the above-mentioned molecules could provide information about disease pathogenesis, severity of BBB disruption, and disease activity. MATERIAL AND METHODS: We recruited 42 RRMS, 19 NMOsd and 35 NPSLE patients. Subjects were treated with beta-interferons or glatiramer acetate (RRMS), oral steroids and/or azathioprine (NMOsd, NPSLE), other immunosuppressants (NPSLE), or antimalarials (NPSLE). The clinical condition of the patients was assessed using the Kurtzke Expanded Disability Status Scale for MS and NMOsd, and the Systemic Lupus Erythematosus Disease Activity Index for NPSLE. Serum levels of sVCAM-1, sPECAM-1, sICAM-1 and S100B were determined using enzyme-linked immunosorbent assay (ELISA). RESULTS: We found the lowest levels of sPECAM-1, sICAM-1 and S100B in sera from NMOsd patients. The highest levels of sPECAM-1 and sICAM-1 were observed in NPSLE, and in NPSLE and MS, respectively. There were no statistically significant differences in sVCAM-1 levels between the examined groups. In MS and NMOsd, there was a negative correlation between the EDSS score and the following molecules: sPECAM-1, sICAM-1 and S100B. CONCLUSIONS AND CLINICAL IMPLICATIONS: We conclude that there is a different profile of blood-brain-barrier disruption reflected by cell adhesion molecules shedding in the spectrum of autoimmune CNS disorders with disseminated white matter lesions. These molecules could become new biomarkers to be used in CNS demyelinating diseases differential diagnoses and monitoring disease activity, but further studies on larger groups of patients are necessary.

Relationship between blood-brain permeability and antibodies against aquaporins in neuromyelitis optica spectrum disorders and multiple sclerosis patients.

AIM OF THE STUDY: To evaluate serum anti-aquaporin antibodies profile, to measure serum levels of cell-cell adhesion molecules as potential markers of blood-brain barrier (BBB) permeability, and to assess their relationship in neuromyelitis optica spectrum disorders (NMOsd) and multiple sclerosis (MS). CLINICAL RATIONALE FOR THE STUDY: Serum levels of cell-cell adhesion molecules could provide information about BBB disruption in demyelinating diseases of the central nervous system. Improved knowledge about differences in their profile in NMOsd and MS patients, as well as about their relationship with antibody serostatus, would facilitate early and accurate diagnosis. MATERIAL AND METHODS: Sera from 20 NMOsd and 59 MS patients were collected and assessed for anti-aquaporin 4 antibodies (AQP4-IgG) and antibodies against myelin oligodendrocyte glycoprotein (MOG-Ab) using an indirect immunofluorescence test (IIFT). Anti-aquaporin 1 antibodies (AQP1-Ab), vascular endothelial growth factor (VEGF), and vascular endothelial cadherin (VE-Cadherin) levels were assessed using commercial enzyme-linked immunosorbent assay (ELISA) kits. For occludin (OCLN) and claudin-5 (CLDN5) serum levels, we employed home-made ELISAs elaborated in the Department of Neurochemistry and Neuropathology, Poznan University of Medical Sciences, Poland. RESULTS: AQP4-IgG appeared only in 6/20 NMOsd patients who were all originally AQP4-IgG seropositive. All MS and NMOsd patients were seronegative for MOG-Ab. Patients with MS had higher AQP1-Ab levels than those with NMOsd (median 782.32 vs. 203.16 pg/mL; p < 0.001). CLND5 levels were significantly higher in MS than in NMOsd patients (median 1.65 vs. 1.00 ng/mL; p = 0.004). No statistically significant differences between MS and NMOsd were found for OCLN, VEGF and VE-Cadherin serum levels. In MS, AQ1-Ab levels were significantly lower in MS patients treated with immunomodulatory drugs vs. the treatment-naive (median 712.46 pg/mL vs. 942.73 pg/mL, respectively). There was a positive correlation between CLDN5 and OCLN in both the MS and the NMOsd groups. CONCLUSIONS AND CLINICAL IMPLICATIONS: There is a different BBB disruption profile in MS and NMOsd, reflected by significantly higher CLDN5 and AQP1-Ab levels in MS samples. AQP1-Ab can be considered as a promising indicator of BBB disruption possibly associated with astrocytopathy.

The Immunology of Neuromyelitis Optica-Current Knowledge, Clinical Implications, Controversies and Future Perspectives.

Neuromyelitis optica (NMO) is an autoimmune, demyelinating disorder of the central nervous system (CNS) with typical clinical manifestations of optic neuritis and acute transverse myelitis attacks. Previously believed to be a variant of multiple sclerosis (MS), it is now considered an independent disorder which needs to be differentiated from MS. The discovery of autoantibodies against aquaporin-4 (AQP4-IgGs) changed our understanding of NMO immunopathogenesis and revolutionized the diagnostic process. AQP4-IgG is currently regarded as a specific biomarker of NMO and NMO spectrum disorders (NMOsd) and a key factor in its pathogenesis. Nevertheless, AQP4-IgG seronegativity in 10%-25% of NMO patients suggests that there are several other factors involved in NMO immunopathogenesis, i.e., autoantibodies against aquaporin-1 (AQP1-Abs) and antibodies against myelin oligodendrocyte glycoprotein (MOG-IgGs). This manuscript reviews current knowledge about NMO immunopathogenesis, pointing out the controversial issues and showing potential directions for future research. Further efforts should be made to broaden our knowledge of NMO immunology which could have important implications for clinical practice, including the use of potential novel biomarkers to facilitate an early and accurate diagnosis, and modern treatment strategies improving long-term outcome of NMO patients.