Anti-Ro/SSA Antibodies May Be Responsible for Cerebellar Degeneration in Sjogren's Syndrome

Ro60-Roles in RNA Processing, Inflammation, and Rheumatic Autoimmune Diseases

The Ro60/SSA2 autoantigen is an RNA-binding protein and a core component of nucleocytoplasmic ribonucleoprotein (RNP) complexes. Ro60 is essential in RNA metabolism, cell stress response pathways, and cellular homeostasis. It stabilises and mediates the quality control and cellular distribution of small RNAs, including YRNAs (for the 'y' in 'cytoplasmic'), retroelement transcripts, and misfolded RNAs. Ro60 transcriptional dysregulation or loss of function can result in the generation and release of RNA fragments from YRNAs and other small RNAs. Small RNA fragments can instigate an inflammatory cascade through endosomal toll-like receptors (TLRs) and cytoplasmic RNA sensors, which typically sense pathogen-associated molecular patterns, and mount the first line of defence against invading pathogens. However, the recognition of host-originating RNA moieties from Ro60 RNP complexes can activate inflammatory response pathways and compromise self-tolerance. Autoreactive B cells may produce antibodies targeting extracellular Ro60 RNP complexes. Ro60 autoantibodies serve as diagnostic markers for various autoimmune diseases, including Sjögren's disease (SjD) and systemic lupus erythematosus (SLE), and they may also act as predictive markers for anti-drug antibody responses among rheumatic patients. Understanding Ro60's structure, function, and role in self-tolerance can enhance our understanding of the underlying molecular mechanisms of autoimmune conditions.

A Case of Superficial Siderosis with Elevated Anti-Ro/SSA Antibody

Superficial siderosis (SS) of the central nervous system is a rare disorder that is caused by chronic or recurrent hemorrhage in the subarachnoid space via a dural defect at the spinal level. The most common clinical features of SS include slow-progressive sensorineural deafness, cerebellar symptoms, and pyramidal tract signs. Considering that SS can present with broad clinical manifestations, for precise diagnosis, this disease must be understood. Anti-Ro/SSA antibodies are commonly detected in patients with Sjögren's syndrome and are utilized as markers for autoimmune diseases. In this report, we present a unique pathological condition in which SS coincided with a positive anti-Ro/SSA antibody test result. During the diagnosis of gait disturbance, an elevation in anti-Ro/SSA antibody was detected, and steroid pulse therapy was initiated as the initial treatment for autoimmune diseases. Head magnetic resonance imaging (MRI) revealed extensive hypointensity as a dark band that surrounded the intracranial basal structures and cerebellar hemispheres. Spinal MRI indicated ventral longitudinal intraspinal fluid collection extending from C7 to T5 as well as a defect in the ventral T2-3 dura mater. Intraoperative visualization revealed that the intradural venous plexus was the source of bleeding that caused the SS. To our knowledge, this report is the first to discuss the presence of anti-Ro/SSA antibodies in patients with SS. The role of anti-Ro/SSA antibodies in the pathophysiology of SS remains unclear; therefore, to confirm a possible association, further research and accumulation of cases are required.

It's a TRIM-endous view from the top: the varied roles of TRIpartite Motif proteins in brain development and disease

The tripartite motif (TRIM) protein family members have been implicated in a multitude of physiologies and pathologies in different tissues. With diverse functions in cellular processes including regulation of signaling pathways, protein degradation, and transcriptional control, the impact of TRIM dysregulation can be multifaceted and complex. Here, we focus on the cellular and molecular roles of TRIMs identified in the brain in the context of a selection of pathologies including cancer and neurodegeneration. By examining each disease in parallel with described roles in brain development, we aim to highlight fundamental common mechanisms employed by TRIM proteins and identify opportunities for therapeutic intervention.

Atypical posterior reversible encephalopathy syndrome associated with Sjögren'‍s syndrome: a case report

Sjögren'‍s syndrome (SJS) is a common autoimmune disease. Generally, posterior reversible encephalopathy syndrome (PRES) is often concomitant with autoimmune disease; however, PRES rarely complicates SJS. Thus, the detailed clinical course of cases with SJS and PRES remains unknown. We present the case of a 71-year-old female patient with primary SJS, whose magnetic resonance (MR) images showed bilateral vasogenic edema in the basal ganglia, brainstem, and cerebellum. Cerebrospinal fluid (CSF) examination revealed increased IgG index and higher interleukin-6 and anti-SSA-autoantibody levels. Management of her blood pressure combined with corticosteroid therapy improved her neurological symptoms, including abnormal CSF and MR imaging findings.

Central Nervous System Involvement in Primary Sjögren's Syndrome: Narrative Review of MRI Findings

Central nervous system (CNS) involvement is one of the numerous extraglandular manifestations of primary Sjögren's syndrome (pSS). Moreover, neurological complaints precede the sicca symptoms in 25-60% of the cases. We review the magnetic resonance imaging (MRI) lesions typical for pSS, involving the conventional examination, volumetric and morphometric studies, diffusion tensor imaging (DTI) and resting-state fMRI. The most common radiological lesions in pSS are white matter hyperintensities (WMH), scattered alterations hyperlucent on T2 and FLAIR sequences, typically located periventricularly and subcortically. Cortical atrophy and ventricular dilatation can also occur in pSS. Whilst these conditions are thought to be more common in pSS than healthy controls, DTI and resting-state fMRI alterations demonstrate evident microstructural changes in pSS. As pSS is often accompanied by cognitive symptoms, these MRI alterations are expectedly related to them. This relationship is not clearly delineated in conventional MRI studies, but DTI and resting-state fMRI examinations show more convincing correlations. In conclusion, the CNS manifestations of pSS do not follow a certain pattern. As the link between the MRI lesions and clinical manifestations is not well established, more studies involving larger populations should be performed to elucidate the correlations.

Differentiating central nervous system demyelinating disorders: The role of clinical, laboratory, imaging characteristics and peripheral blood type I interferon activity

Objective: While multiple sclerosis (MS) is considered the cornerstone of autoimmune demyelinating CNS disorders, systemic autoimmune diseases (SADs) are important MS mimickers. We sought to explore whether distinct clinical, laboratory, and imaging characteristics along with quantitation of peripheral blood type I interferon (IFN) activity could aid in differentiating between them.

Methods: A total of 193 consecutive patients with imaging features suggesting the presence of CNS demyelinating disease with or without relevant clinical manifestations underwent full clinical, laboratory, and imaging evaluation, including testing for specific antibodies against 15 cellular antigens. Expression analysis of type I IFN-inducible genes (MX-1, IFIT-1, and IFI44) was performed by real-time PCR, and a type I IFN score, reflecting type I IFN peripheral activity, was calculated. After joint neurological/rheumatological evaluation and 1 year of follow-up, patients were classified into MS spectrum and CNS autoimmune disorders.

Results: While 66.3% (n = 128) of the patients were diagnosed with MS spectrum disorders (predominantly relapsing–remitting MS), 24.9% (n = 48) were included in the CNS autoimmune group, and out of those, one-fourth met the criteria for SAD (6.7% of the cohort, n = 13); the rest (18.1% of the cohort, n = 35), despite showing evidence of systemic autoimmunity, did not fulfill SAD criteria and comprised the “demyelinating disease with autoimmune features” (DAF) subgroup. Compared to the MS spectrum, CNS autoimmune patients were older, more frequently females, with increased rates of hypertension/hyperlipidemia, family history of autoimmunity, cortical dysfunction, anti-nuclear antibody titers ≥1/320, anticardiolipin IgM positivity, and atypical for MS magnetic resonance imaging lesions. Conversely, lower rates of infratentorial and callosal MRI lesions, CSF T2 oligoclonal bands, and IgG-index positivity were observed in CNS autoimmune patients. Patients fulfilling SAD criteria, but not the DAF group, had significantly higher peripheral blood type I IFN scores at baseline compared to MS spectrum [median (IQR)]: 50.18 (152.50) vs. −0.64 (6.75), p-value: 0.0001.

Conclusion: Our study suggests that underlying systemic autoimmunity is not uncommon in patients evaluated for possible CNS demyelination. Distinct clinical, imaging and laboratory characteristics can aid in early differentiation between MS and CNS-involving systemic autoimmunity allowing for optimal therapeutic strategies. Activated type I IFN pathway could represent a key mediator among MS-like-presenting SADs and therefore a potential therapeutic target.

Aseptic meningitis as initial presentation of subclinical Sjögren's syndrome: Could the cerebrospinal fluid anti-Ro/SSA and anti-La/SSB antibody system be the culprit?

Aseptic meningitis sometimes occurs as a consequence of central nervous system (CNS) involvement in patients with primary Sjögren's syndrome (SS), even in paediatric-onset cases. However, little information is available regarding the pathological role of CSF anti-Ro/SSA and anti-La/SSB antibodies in the CNS involvement in patients with primary SS. We experienced an 18-year-old adolescent female with a 7-year history of suspicion of subclinical SS who subsequently developed aseptic meningitis as an initial presentation of probable SS. Her CSF exhibited marked elevation of anti-Ro/SSA and anti-La/SSB antibodies. When compared to her CSF IgG/serum IgG ratio (0.0058), her CSF/serum ratios of anti-Ro/SSA and anti-La/SSB antibody titres were higher (0.448 and 0.068, respectively; these were 77.5 and 11.7 times higher than that of IgG, respectively), suggesting that regional production of these antibodies was attributable, at least partly, to the development of meningitis. After the initiation of prednisolone treatment, her clinical manifestations promptly subsided. Since the clinical and pathological roles of the Ro/SSA antibody system in several autoimmune conditions have been postulated, our clinical observation may add novel insight to this theory.