Clinical Characterization and Ancillary Tests in Susac Syndrome: A Systematic Review

Susac syndrome (SuS) is an orphan microangiopathic disease characterized by a triad of encephalopathy, visual disturbances due to branch retinal artery occlusions, and sensorineuronal hearing loss. Our previous systematic review on all cases of SuS reported until 2012 allowed for a better understanding of clinical presentation and diagnostic findings. Based on these data, we suggested diagnostic criteria in 2016 to allow early diagnosis and treatment of SuS. In view of the accumulation of new SuS cases reported in the last 10 years and improved diagnostic tools, we here aimed at updating the demographic and clinical features of SuS and to review the updated ancillary tests being used for SuS diagnosis. Therefore, based on the 2016 criteria, we systematically collected and evaluated data on SuS published from January 2013 to March 2022.

Teriflunomide normalizes anti-anxiety effect in anti-ANXA2 APS mice model teriflunomide in anti-ANXA2 mice model

Antiphospholipid syndrome (APS) affects the brain by both hypercoagulation and immunological mechanisms. APS is characterized by several autoantibodies binding to a thrombolytic complex including beta-2-glycoprotein I (β2-GPI) and annexin A2 (ANXA2). Teriflunomide, an oral drug for the treatment of multiple sclerosis (MS), has a cytostatic effect on B cells and is therefore a potential antibody-targeting treatment for APS. In this study, we assessed the effect of teriflunomide in two APS mouse models by inducing autoantibody formation against β2-GPI and ANXA2 in female BALB/c mice. The ANXA2 model displayed a behavioral change suggesting an anti-anxiety effect in open field and forced swim tests, early in the course of the disease. This effect was normalized following teriflunomide treatment. Conversely, behavioral tests done later during the study demonstrated depression-like behavior in the ANXA2 model. No behavioral changes were seen in the β2-GPI model. Total brain IgG levels were significantly elevated in the ANXA2 model but not in the teriflunomide treated group. No such change was noted in the brains of the β2-GPI model. High levels of serum autoantibodies were induced in both models, and their levels were not lowered by teriflunomide treatment. Teriflunomide ameliorated behavioral changes in mice immunized with ANXA2 without a concomitant change in serum antibody levels. These findings are compatible with the effect of teriflunomide on neuroinflammation.Teriflunomide ameliorated behavioral and brain IgG levels in mice immunized with ANXA2 without a concomitant change in serum antibody levels. These findings are compatible with an effect of teriflunomide on the IgG permeability to the brain and neuroinflammation.

Efficacy and safety of alemtuzumab treatment in a real-world cohort of patients with multiple sclerosis

Alemtuzumab is a monoclonal anti-CD52 antibody prescribed to treat relapsing-remitting multiple sclerosis (RRMS). Alemtuzumab affects the balance of the immune system by depleting circulating lymphocytes, leading to the formation of a new immune repertoire less likely to induce autoimmune attack against CNS myelin. We collected real-world data of RRMS patients treated with alemtuzumab. We assessed relapse rate, disability progression, and MRI-related disease activity over a 24 month period. Our study included 35 RRMS patients (19 female and 16 male) with a mean age of 37.3 years (SD = 10.5). The patient cohort had a mean disease duration of 10.4 years, median previous disease modifying treatments (DMTs) of 3.0, and a median expanded disability status scale (EDSS) score of 4.0 (IQR 2.5-6.0). Neurological disability remained stable during treatment and there was no statistically significant change in EDSS score. Prior to treatment, the median relapse rate was 2.0 (IQR 1.0-3.0); after treatment the median relapse rate was 0.0. This 2.0 decrease in relapse rate is statistically significant (p < 0.0001). Moreover, the treated patients exhibited a statistically significant decrease in gadolinium (GD) enhancing lesions on MRI [both in number (p < 0.005) and volume (p < 0.005)]. Thirty-three percent of patients reached NEDA-3 (no evidence of disease activity) status by the end of treatment. In a real-world setting, alemtuzumab treatment significantly decreased relapse rate and GD-enhancing lesions while preventing disability progression. Tolerability of treatment was high, with patients experiencing only minor adverse events.

Autoantibodies to Annexin A2 and cerebral thrombosis: Insights from a mouse model

Introduction

Antiphospholipid syndrome (APS) is an autoimmune disorder manifested by thromboembolic events, recurrent spontaneous abortions and elevated titers of circulating antiphospholipid antibodies. In addition, the presence of antiphospholipid antibodies seems to confer a fivefold higher risk for stroke or transient ischemic attack. Although the major antigen of APS is β₂ glycoprotein I, it is now well established that antiphospholipid antibodies are heterogeneous and bind to various targets. Recently, antibodies to Annexin A2 (ANXA2) have been reported in APS. This is of special interest since data indicated ANXA2 as a key player in fibrinolysis. Therefore, in the present study we assessed whether anti-ANXA2 antibodies play a pathological role in thrombosis associated disease.

Materials and Methods

Mice were induced to produce anti-ANXA2 antibodies by immunization with ANXA2 (iANXA2) and control mice were immunized with adjuvant only. A middle cerebral artery occlusion stroke model was applied to the mice. The outcome of stroke severity was assessed and compared between the two groups.

Results

Our results indicate that antibodies to ANXA2 lead to a more severe stroke as demonstrated by a significant larger stroke infarct volume (iANXA2 133.9 ± 3.3 mm³ and control 113.7 ± 7.4 mm³; p = 0.017) and a more severe neurological outcome (iANXA2 2.2 ± 0.2, and control 1.5 ± 0.18; p = 0.03).

Conclusions

This study supports the hypothesis that auto-antibodies to ANXA2 are an independent risk factor for cerebral thrombosis. Consequently, we propose screening for anti-ANXA2 antibodies should be more widely used and patients that exhibit the manifestations of APS should be closely monitored by physicians.

Differential interactions between Beclin 1 and Bcl-2 family members

Autophagy, a cellular degradation system, promotes both cell death and survival. The interaction between Bcl-2 family proteins and Beclin 1, a Bcl-2 interacting protein that promotes autophagy, can mediate crosstalk between autophagy and apoptosis. We investigated the interaction between anti-and pro-apoptotic Bcl-2 proteins with Beclin 1. Our results show that Beclin 1 directly interacts with Bcl-2, Bcl-x(L), Bcl-w and to a lesser extent with Mcl-1. Beclin 1 does not bind the pro-apoptotic Bcl-2 proteins. The interaction between Beclin 1 and the anti-apoptotic protein Bcl-x(L) was inhibited by BH3-only proteins, but not by multi-domain proteins. Sequence alignment and structural modeling suggest that Beclin 1 contains a putative BH3-like domain which may interact with the hydrophobic grove of Bcl-x(L). Mutation of the Beclin 1 amino acids predicted to mediate this interaction inhibited the association of Beclin 1 with Bcl-x(L). Our results suggest that BH3 only proapoptotic Bcl-2 proteins may modulate the interactions between Bcl-x(L) and Beclin 1.