Bipolar disorder (BD) is a leading cause of worldwide disability among mood disorders. Pathological mechanisms are still vastly unclear, and current treatments with conventional medications are often unsatisfactory in maintaining symptoms control and an adequate quality of life. Consequently, current research is focusing on shedding new light on disease pathogenesis, to improve therapeutic effectiveness. Recent evidence has suggested a prominent role of inflammation in mood disorders. Elevated levels of peripheral proinflammatory mediators have been reported in BD, as well as in other mood disorders, and people with systemic autoimmune diseases have an increased risk of developing BD. These immunological alterations are stable, and current medications are unable to alter peripheral concentrations even when clinical improvement is evident. These findings have also been replicated in the central nervous system (CNS) milieu, whereas genetic studies have shown that these immune alterations are not due to the disorder itself, being detectable before the illness onset. Moreover, these inflammatory modifications seem to be affected by and linked to other biomarkers of the disorder, such as alterations of white matter (WM) microstructure, metabolism, kynurenine pathway, and circadian rhythmicity. Finally, these immune variations seem to be useful as predictors of therapeutic responsiveness to medications, and in discriminating between clinically different outcomes. The objective of this review is to summarize available evidence on the connection between inflammation and BD, focusing on peripheral inflammatory markers and recent findings on their connection with other typical features of BD, to outline a general overview of the disorder. Moreover, it is meant to analyze the issues with data gathering and interpretation, given the partially contradictory and inconsistent nature of results.

Background and Objectives Glial fibrillary acidic protein (GFAP) antibodies can associate with an astrocytopathy often presenting as a meningoencephalitis. Visual involvement has been reported but scarcely defined. We describe 2 cases of GFAP astrocytopathy with predominant visual symptoms and present a systematic review of the literature. Methods We describe 2 patients with GFAP astrocytopathy from our neurology department. We performed a systematic review of the literature according to PRISMA guidelines, including all patients with this disease and available clinical data, focusing on visual involvement. Results Patient 1 presented with bilateral optic disc edema and severe sudden bilateral loss of vision poorly responsive to therapy. Patient 2 showed bilateral optic disc edema, headache, and mild visual loss with complete recovery after steroids. We screened 275 records and included 84 articles (62 case reports and 22 case series) for a total of 592 patients. Visual involvement was reported in 149/592 (25%), with either clinical symptoms or paraclinical test-restricted abnormalities. Bilateral optic disc edema was found in 80/159 (50%) of patients investigated with fundoscopy, among which 49/80 (61%) were asymptomatic. One hundred (100/592, 17%) reported visual symptoms, often described as blurred vision or transient visual obscurations. Optic neuritis was rare and diagnosed in only 6% of all patients with GFAP astrocytopathy, often without consistent clinical and paraclinical evidence to support the diagnosis. Four patients (including patient 1) manifested a severe, bilateral optic neuritis with poor treatment response. In patients with follow-up information, a relapsing disease course was more frequently observed in those with vs without visual involvement (35% vs 11%, p = 0.0035, OR 3.6 [CI 1.44–8.88]). Discussion Visual system involvement in GFAP astrocytopathy is common and heterogeneous, ranging from asymptomatic bilateral optic disc edema to severe bilateral loss of vision, but optic neuritis is rare. GFAP CSF antibody testing should be considered in patients with encephalitis/meningoencephalitis or myelitis and bilateral optic disc edema, even without visual symptoms, and in patients with severe bilateral optic neuritis, especially when AQP4 antibodies are negative. Visual symptoms might associate with a higher relapse risk and help to identify patients who may require chronic immunosuppression.

Background: Cerebrospinal fluid myelin oligodendrocyte glycoprotein IgG (CSF MOG-IgG) are found in a proportion of patients with MOG antibody-associated disorder (MOGAD) and have been associated with severe disease presentations. However, most studies did not systematically investigate the role of MOG-IgG intrathecal synthesis (ITS).Methods: We retrospectively studied 960 consecutive patients with paired serum and CSF samples screened for MOG-IgG using a live cell-based assays. MOG-IgG-specific antibody index (AI_MOG) was systematically calculated using serum and CSF titres to assess MOG-IgG ITS, and clinical features were compared between MOG-IgG CSF+/CSF− and ITS+/ITS− patients.Results: MOG-IgG were found in 55/960 patients (5.7%; serum+/CSF−: 58.2%, serum+/CSF+: 34.5%; serum−/CSF+: 7.3%). Serum/CSF MOG-IgG titres showed a moderate correlation in patients without ITS (ρ=0.47 (CI 0.18 to 0.68), p<0.001), but not in those with ITS (ρ=0.14 (CI −0.46 to –0.65), p=0.65). There were no clinical–paraclinical differences between MOG-IgG CSF+ vs CSF− patients. Conversely, patients with MOG-IgG ITS showed pyramidal symptoms (73% vs 32%, p=0.03), spinal cord involvement (82% vs 39%, p=0.02) and severe outcome at follow-up (36% vs 5%, p=0.02) more frequently than those without MOG-IgG ITS. A multivariate logistic regression model indicated that MOG-IgG ITS was an independent predictor of a poor outcome (OR: 14.93 (CI 1.40 to 19.1); p=0.03). AI_MOGcorrelated with Expanded Disability Status Scale (EDSS) scores at disease nadir and at last follow-up (p=0.02 and p=0.01).Conclusions: Consistently with physiopathology, MOG-IgG ITS is a promising prognostic factor in MOGAD, and its calculation could enhance the clinical relevance of CSF MOG-IgG testing, making a case for its introduction in clinical practice.

Currently available data suggest that the union of a balanced diet and an overall healthy lifestyle may determine an amelioration in several clinical parameters and in the quality of life for patients with MS (pwMS). The study objective was to investigate the possible difference in MS severity in a group of Italian patients with MS based on their adherence to Mediterranean Diet (MedDiet). Eating habits were collected through a validated 110-items Food Frequency Questionnaire, the Medi-Lite score was used for adherence to MedDiet evaluation. MS severity was graded according to Herbert’s severity scale, based on the MSSS. 106 patients were classified in 3 groups according to their MedDiet adherence (low/medium/high). Higher adherence was associated with a 6.18 (95% CI: 1.44, 26.59) higher probability of having a mild-to-moderate MS. When studying the single constituents of the Medi-Lite score, none of them was individually associated with MS severity. It remains unclear whether effects of specific dietary components included in the MedDiet may impact the health status at disease onset or can slow down the symptoms due course of disease. Future studies are needed to reproduce our findings and should focus on answering the latter raised question.

The recent SARS-CoV-2 pandemic and related vaccines have raised several issues. Among them, the potential role of the viral infection (COVID-19) or anti-SARS-CoV-2 vaccines as causal factors of dysimmune CNS disorders, as well as the safety and efficacy of vaccines in patients affected by such diseases and on immune-active treatments have been analyzed. The aim is to better understand the relationship between SARS-CoV-2 infection/vaccines with dysimmune CNS diseases by describing 12 cases of multiple sclerosis/myelitis onset or reactivation after exposure to SARS-CoV-2 infection/vaccines and reviewing all published case reports or case series in which MS onset or reactivation was temporally associated with either COVID-19 (8 case reports, 3 case series) or anti-SARS-CoV-2 vaccines (13 case reports, 6 case series). All the cases share a temporal association between viral/vaccine exposure and symptoms onset. This finding, together with direct or immune-based mechanisms described both during COVID-19 and MS, claims in favor of a role for SARS-CoV-2 infection/vaccines in unmasking dysimmune CNS disorders. The most common clinical presentations involve the optic nerve, brainstem and spinal cord. The preferential tropism of the virus together with the presence of some host-related genetic/immune factors might predispose to the involvement of specific CNS districts.

Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) international panel criteria have been recently proposed to guide MOGAD diagnosis. The aim of this study was to evaluate the criteria performance and assess the discrepancies in their application in the clinical practice in an Italian multicenter cohort and to discuss some challenging aspects. We applied the 2023 MOGAD criteria to patients who tested MOG-Abs positive on cell-based assays and were retrospectively recruited from 29 centers. Detailed clinical and paraclinical data were collected. Patients were classified as true positive/negative (TP/TN) in case of concordance between MOGAD criteria application and enrolling center final diagnosis, as false positive (FP) when MOGAD criteria were fulfilled but final diagnosis was different from MOGAD, and as false negative (FN) when MOGAD criteria were not fulfilled and final diagnosis of MOGAD was confirmed. Central revision of FN and FP cases was performed. We included 214 patients (median age at onset 38.2 years [interquartile range 25.2-50.7], 60.3% female, 23 pediatric patients). Of these, 168 (78.5%) were classified as TP, 9 (4.2%) as FP, 23 (10.7%) as FN, and 14 (6.5%) as TN. The sensitivity of MOGAD criteria was 87.96% (CI 82.5%-92.2%), specificity 60.9% (CI 38.5%-80.3%), positive predictive value 94.9% (CI 91.8%-96.9%), negative predictive value 37.8% (CI 26.7%-50.2%), and accuracy 85.1% (CI 79.6%-89.5%). In 11 of 32 revised cases, available information did not allow a proper diagnosis. Independent revision changed the diagnosis in 17 of 21 remaining cases, increasing the performance of the MOGAD criteria. Of note, in 3 cases, diagnostic criteria were satisfied only at follow-up. The sensitivity and specificity after independent revision were 98.9% (CI 96%-99.9%) and 91.7% (CI 73%-98.9%), respectively. Moreover, 29 of 214 patients (13.6%) had 1 or more asymptomatic radiologic supportive features, and in 50% (3/6) of FP cases, independent revision did not confirm the presence of supportive features. Patients with clear positive serum titer or CSF-only MOG-Abs were those who received more commonly a MOGAD diagnosis. MOGAD criteria demonstrate a good performance across different centers; however, controversial cases might benefit from collegial discussion and reassessment of MOGAD criteria during the follow-up. Main challenges include availability of proper radiologic data and interpretation of radiologic supportive features.