Biopsy-Proven Small-Fiber Neuropathy in Primary Sjögren's Syndrome: Neuropathic Pain Characteristics, Autoantibody Findings, and Histopathologic Features

Neurological and Psychiatric Clinical Manifestations of Sjögren Syndrome

PURPOSE OF REVIEW

Sjögren Syndrome is a systemic autoimmune disorder that presents mainly with sicca symptoms, but frequently affects other body systems which can lead to a wide variety of manifestations. Understanding the neurological and psychiatric manifestations of Sjögren Syndrome can help with an earlier diagnosis of this disease and leads to better clinical outcomes.

RECENT FINDINGS

We provide an updated overview of the central neurological manifestations, peripheral neurological manifestations and psychiatric manifestations and their diagnosis when associated with primary Sjögren Syndrome. The epidemiology and clinical features of the neurological and psychiatric manifestations are derived from different cohort studies and review articles that were selected from PubMed searches conducted between January 2024 and March 2024. The absence of diagnostic criteria and the scarcity of large, robust studies makes the recognition of the neurological and psychiatric manifestations of Sjögren Syndrome more difficult. Maintaining a high index of suspicion in clinical practice and a close collaboration between the Neurologist and the Rheumatologist will facilitate the diagnosis and management of these patients.

Exploring the mechanisms of action of Zengye decoction (ZYD) against Sjogren's syndrome (SS) using network pharmacology and animal experiment

CONTEXT

Zengye decoction (ZYD) has been considered to have a curative effect on Sjogren's syndrome (SS). However, its therapeutic mechanisms remain obscure.

OBJECTIVES

This research explores the mechanisms of ZYD against SS.

MATERIALS AND METHODS

The active compounds and targets of ZYD were searched in the TCMSP and BATMAN-TCM databases. SS-related targets were obtained from the GeneCards database. The GO and KEGG enrichment analyses elucidated the molecular mechanisms. Animal experiments were performed using 8 C57BL/6 mice that served as the control group (physiological saline treatment) and 16 NOD mice randomly divided into the model group (physiological saline treatment) and the ZYD group (ZYD treatment) for 8 weeks to verify the therapeutic effects of ZYD on SS.

RESULTS

Twenty-nine active compounds with 313 targets of ZYD and 1038 SS-related targets were screened. Thirty-two common targets were identified. β-Sitosterol and stigmasterol might be important components. GO analysis suggested that the action of ZYD against SS mainly involved oxidative stress, apoptotic processes, and tumor necrosis factor receptor superfamily binding, etc. KEGG analysis indicated the most significant signaling pathway was apoptosis-multiple species. Animal experiments showed that ZYD improved lymphocytic infiltration of the submandibular glands (SMGs), reduced the serum levels of TNF-α, IL-1β, IL-6, and IL-17, upregulated the expression of Bcl-2, and downregulated the expression of Bax and Caspase-3 in the model mice.

DISCUSSION AND CONCLUSION

ZYD has anti-inflammatory and anti-apoptotic effects on SS, which provides a theoretical basis for the treatment of SS with ZYD.

Corneal nerve loss and increased Langerhans cells are associated with disease severity in patients with rheumatoid arthritis

BACKGROUND/OBJECTIVES

Rheumatoid arthritis (RA) is a multisystem autoimmune disorder characterized by articular and extra-articular manifestations. Neuropathy is a poorly studied manifestation of RA. The aim of this study was to utilize the rapid non-invasive ophthalmic imaging technique of corneal confocal microscopy to identify whether there is evidence of small nerve fibre injury and immune cell activation in patients with RA.

SUBJECTS/METHODS

Fifty consecutive patients with RA and 35 healthy control participants were enrolled in this single-centre, cross-sectional study conducted at a university hospital. Disease activity was assessed with the 28-Joint Disease Activity Score and erythrocyte sedimentation rate (DAS28-ESR). Central corneal sensitivity was measured with a Cochet-Bonnet contact corneal esthesiometer. A laser scanning in vivo corneal confocal microscope was used to quantify corneal nerve fibre density (CNFD), nerve branch density (CNBD), nerve fibre length (CNFL), and Langerhans cell (LC) density.

RESULTS

Corneal sensitivity (P = 0.01), CNFD (P = 0.02), CNBD (P < 0.001), and CNFL (P < 0.001) were lower, and mature (P = 0.001) and immature LC densities (P = 0.011) were higher in patients with RA compared to control subjects. CNFD (P = 0.016) and CNFL (P = 0.028) were significantly lower in patients with moderate to high (DAS28-ESR > 3.2) compared to mild (DAS28-ESR ≤ 3.2) disease activity. Furthermore, the DAS28-ESR score correlated with CNFD (r = -0.425; P = 0.002), CNBD (ρ = -0.362; P = 0.010), CNFL (r = -0.464; P = 0.001), total LC density (ρ = 0.362; P = 0.010) and immature LC density (ρ = 0.343; P = 0.015).

CONCLUSIONS

This study demonstrates reduced corneal sensitivity, corneal nerve fibre loss and increased LCs which were associated with the severity of disease activity in patients with RA.

Peripheral Neuropathy in Systemic Autoimmune Rheumatic Diseases-Diagnosis and Treatment

Peripheral neuropathy (PN) is frequently observed in systemic rheumatic diseases and is a challenge in clinical practice. We aimed to review the evidence on the subject and proposed a comprehensive approach to these patients, facilitating diagnosis and management. We searched the MEDLINE database for the terms (and its respective Medical Subject Headings (MeSH) terms): "peripheral neuropathy" AND "rheumatic diseases" OR "systemic lupus erythematosus", "rheumatoid arthritis", "Sjogren syndrome", and "vasculitis" from 2000 to 2023. This literature review focuses on the diagnostic workup of PNs related to systemic lupus erythematosus, Sjögren's syndrome, rheumatoid arthritis, and systemic vasculitis. For every type of PN, we provide a pragmatic flowchart for diagnosis and also describe evidence-based strategies of treatment.

Sjögren's syndrome with and without neurological involvement

OBJECTIVE

Neurological manifestations of Sjögren's syndrome can be severe but also treatment-responsive. We aimed to systematically evaluate neurological manifestations of primary Sjögren's syndrome and find clinical features allowing sufficient identification of affected patients (pSSN) among those with Sjögren's syndrome without neurological involvement (pSS).

METHODS

Para-/clinical features of patients with primary Sjögren's syndrome (2016 ACR/EULAR classification criteria) were compared between pSSN and pSS. At our university-based center, patients with suggestive neurological symptoms undergo screening for Sjögren's syndrome, and newly diagnosed pSS patients are thoroughly evaluated for neurologic involvement. pSSN disease activity was rated by the Neurological Involvement of Sjögren's Syndrome Disease Activity Score (NISSDAI).

RESULTS

512 patients treated for pSS/pSSN at our site between 04/2018 and 07/2022 were included (238 pSSN patients [46%] vs. 274 pSS patients [54%], cross-sectional design). Independent predictors of neurological involvement in Sjögren's syndrome were male sex [p < 0.001], older age at disease onset [p < 0.0001], hospitalization at first presentation [p < 0.001], lower IgG levels [p = 0.04] and higher eosinophil values (treatment-naïve) [p = 0.02]. Univariate regression additionally showed older age at diagnosis [p < 0.001], lower prevalence of rheumatoid factor [p = 0.001], SSA(Ro)/SSB(La) antibodies [p = 0.03; p < 0.001], higher white blood cell count [p = 0.02] and CK levels [p = 0.02] (treatment-naïve) in pSSN.

INTERPRETATION

Patients with pSSN had different clinical characteristics than patients with pSS and represented a large proportion of the cohort. Our data suggest that neurological involvement in Sjögren's syndrome has been underestimated. Intensified screening for neurologic involvement should be included in the diagnostic algorithm for Sjögren's syndrome, especially in males of older age and with severe disease course requiring hospitalization.

Clinical and paraclinical features of small fiber neuropathy in Sjögren's syndrome

Sjögren's syndrome is a potentially treatable cause of Small Fiber Neuropathy (SFN)-a condition that severely affects patients' quality of life. We therefore aimed to characterize patients with SFN and Sjögren's syndrome to raise awareness of this disease and facilitate its early recognition as an essential step for appropriate treatment. In 97 SFN patients (median age 48 years, 77% female), we studied the clinical features associated with Sjögren's syndrome compared to the idiopathic SFN subtype. According to the current ACR/EULAR classification criteria (Shiboski et al., Ann Rheum Dis 76:9-16, 2017), 24/97 individuals (25%, median age 48.5 years, 75% female) were diagnosed with Sjögren's syndrome. We did not observe any differences in SFN-defining sensory plus symptoms. Furthermore, intraepidermal nerve fiber densities (IENFD) were significantly lower in patients with SFN and Sjögren's syndrome (mean 2.6 ± 1.2/mm) compared to patients with idiopathic SFN (mean 3.2 ± 1.5/mm; p = 0.048). There were no significant group differences when analyzing cerebrospinal fluid (CSF) parameters. We conclude that Sjögren's syndrome-associated SFN is difficult to distinguish from idiopathic forms based on initial clinical symptoms and CSF results. However, lower IENFD values in patients with Sjögren's syndrome-associated SFN might indicate a distinct different pathomechanism in this entity compared to idiopathic SFN.

Comparison of cutaneous silent period parameters in patients with primary Sjögren's syndrome with the healthy population and determination of ıts relationship with clinical parameters

Small fiber neuropathy (SFN) is one of the main neurological manifestations in primary Sjögren's Syndrome (pSS). For the detection of SFN, cutaneous silent period (CSP) measurement is gaining popularity recently due to its non-invasiveness and practical application. Evaluating SFN involvement in patients with pSS using CSP and evaluating its relationship with clinical parameters. Patients with a diagnosis of pSS and healthy volunteers demographically homogeneous with the patient group were included in the study. The CSP responses were recorded over the abductor pollicis brevis muscle. The latency and duration values of the responses were obtained. In patient group, EULAR Sjögren's Syndrome Patient Reported Index (ESSPRI), Hospital Anxiety and Depression Scale (HADS), Short Form-36 (SF-36) questionnaire, Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) and Central Sensitization Inventory (CSI) were applied for the evaluation of symptom severity, mood, quality of life, presence of neuropathic pain and central sensitization, respectively. The mean CSP latency was significantly longer in patient group compared to control group (p < 0.001). Mean CSP duration was also significantly shorter in patient group (p < 0.001). There were no significant differences in CSP parameters according to patients' neuropathic pain or central sensitization profile. There were significant correlations of CSP parameters (latency and duration, respectively) with ESSPRI dryness (ρ = 0.469, p = 0.004; ρ =  -0.553, p < 0.001), fatigue (ρ = 0.42, p = 0.011; ρ =  -0.505, p = 0.002), pain (ρ = 0.428, p = 0.009; ρ =  -0.57, p < 0.001) subscores and mean ESSPRI score (ρ = 0.631, p < 0.001; ρ = -0.749, p < 0.001). When SF-36 subscores and CSP parameters were investigated, a significant correlation was found only between "bodily pain" subscore and CSP duration (ρ =  -0.395, p = 0.017). In HADS, LANSS and CSI evaluations, a significant correlation was found only between HADS anxiety score and the CSP duration (ρ = 0.364, p = 0.02). As indicated by CSP measurement, SFN is more prominent in patients with pSS than in the healthy population. It is important to investigate the presence of SFN because of its correlation with the leading symptoms in the clinical spectrum of pSS.

Primary Sjögren syndrome-related peripheral neuropathy: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

Primary Sjögren syndrome (pSS) is a chronic, systemic, autoimmune disorder characterized by lymphocytic infiltrates of the exocrine organs, leading to sicca symptoms and parotid enlargement. pSS has been linked to various neurological manifestations, including peripheral neuropathy (PN). We aimed to provide a comprehensive analysis of the currently available evidence regarding pSS-related PN.

METHODS

A literature search in the PubMed database was performed, and 49 papers were eligible to be included in this systematic review and meta-analysis.

RESULTS

The pooled prevalence of PN in pSS is estimated to be 15.0% (95% confidence interval = 10.7%-20.7%). The mean age of pSS patients at PN diagnosis is 59 years. Among the patients with pSS and PN, 83% are females. Neuropathic symptoms usually precede or lead to the pSS diagnosis at a 2:1 ratio in patients with pSS-related PN. The commonest type of pSS-related PN is distal axonal polyneuropathy (80% of patients with pSS-related PN), followed by sensory ganglionopathy. Peripheral and cranial mononeuropathies-particularly trigeminal-are also frequent. Risk factors for developing PN include increasing age and presence of vasculitis. Immune-mediated pathogenetic mechanisms are discussed. Glucocorticoids are the most commonly used treatment option for managing pSS-related PN, when associated with vasculitis, followed by the use of intravenous immunoglobulin.

CONCLUSIONS

PN is very common in pSS patients. Evidence on long-term prognosis of PN in pSS is limited, and further research is needed. Research into the use of immunosuppressive medication in nonvasculitic neuropathies in the context of pSS merits further consideration.

Small fiber neuropathy

Small fiber neuropathy (SFN) is a peripheral nervous system disease due to affection of A-delta or C-fibers in a proximal, distal, or diffuse distribution. Selective SFN (without large fiber affection) manifests with pain, sensory disturbances, or autonomic dysfunction. Though uniform diagnostic criteria are unavailable, most of them request typical clinical features and reduced intra-epidermal nerve fiber density on proximal or distal skin biopsy. Little consensus has been reached about the treatment of SFN, why this narrative review aims at summarizing and discussing treatment options for SFN. Treatment of SFN can be classified as symptomatic, pathophysiologic, or causal. Prerequisites for treating SFN are an established diagnosis, knowledge about the symptoms and signs, and the etiology. Pain usually responds to oral/intravenous pain killers, antidepressants, anti-seizure drugs, or topical, transdermal specifications. Some of the autonomic disturbances respond favorably to symptomatic treatment. SFN related to Fabry disease or hATTR are accessible to pathogenesis-related therapy. Immune-mediated SFN responds to immunosuppression or immune-modulation. Several of the secondary SFNs respond to causal treatment of the underlying disorder. In conclusion, treatment of SFN relies on a multimodal concept and includes causative, pathophysiologic, and symptomatic measures. It strongly depends on the clinical presentation, diagnosis, and etiology, why it is crucial before initiation of treatment to fix the diagnosis and etiology. Due to the heterogeneous clinical presentation and multi-causality, treatment of SFN should be individualized with the goal of controlling the underlying cause, alleviating pain, and optimizing functionality.

Discordant Predictions of Extraglandular Involvement in Primary Sjögren's Syndrome According to the Anti-SSA/Ro60 Antibodies Detection Assay in a Cohort Study

Electrophoresis-derived techniques for anti-SSA/Ro60 KDa (anti-SSA) antibodies detection have been progressively replaced by methods using non-native antigens. We aimed to compare the patients’ phenotypes and the occurrence of extraglandular manifestations in primary Sjögren’s syndrome according to the method used to detect anti-SSA antibodies. Sera from patients with a diagnosis of pSS according to ACR/EULAR 2016 criteria between 2008 and 2017 were tested for anti-SSA antibodies using methods with non-native antigens (magnetic bead multiplex assay; line immunoassays) and one with native antigens (counterimmunoelectrophoresis (CIE)). The population was split into three groups according to anti-SSA antibodies status: absence (SSA−), presence in any method except for CIE (SSA+CIE−), and presence in CIE (SSA+CIE+). The patients in the SSA+CIE+ group (n = 70, 42.7%) were ten years younger and presented more immunological activity compared with both the SSA− (n = 80, 48.8%) and SSA+CIE− groups (n = 14, 8.5%). The SSA− and SSA+CIE− groups were poorly distinct. The presence of anti-SSA antibodies solely in CIE was significantly associated with the occurrence of extraglandular manifestations of pSS (HR = 4.45 (2.35–8.42)). Contrary to CIE, methods using non-native antigens to detect anti-SSA antibodies were unable to predict the occurrence of systemic expression of pSS.

Neuropathic Pain in the Eyes, Body, and Mouth: Insights from the Sjögren's International Collaborative Clinical Alliance

OBJECTIVE

To evaluate how ocular, oral, and bodily neuropathic pain symptoms, which characterize small fiber neuropathies, are associated with Sjögren's syndrome (SS) classification based on the American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) criteria.

METHODS

Participants enrolled in the Sjögren's International Collaborative Clinical Alliance (SICCA) registry had ocular, rheumatologic, oral, and labial salivary gland (LSG) biopsy examinations, blood and saliva samples collected, and completed questionnaires at baseline. We used mixed effects modeling with age, country, gender, and depression being fixed effects and study site, a random effect, to determine if neuropathic pain indicators (assessed via questionnaires) were associated with being classified as SS.

RESULTS

A total of 3,514 participants were enrolled into SICCA, with 1,541 (52.9%) meeting the 2016 ACR/EULAR classification criteria for SS. There was a negative association between being classified as SS and experiencing bodily neuropathic pain features of needle-like pain, prickling/tingling sensation, ocular neuropathic pain of constant burning, and constant light sensitivity, and having a presumptive diagnosis of neuropathic oral pain.

CONCLUSIONS

We found that those classified as SS had lower scores/reports of painful neuropathies compared with those classified as non-SS. Non-SS patients with dry eye disease or symptoms could benefit from pain assessment as they may experience painful small-fiber neuropathies (SFNs). Pain questionnaires may help identify pain associated with SFNs in patients with SS and non-SS dry eye. Future studies would be helpful to correlate self-reports of pain to objective measures of SFNs in those with SS, non-SS dry eye, and healthy controls.

Peripheral nervous system manifestations of rheumatological diseases

Rheumatological diseases result in immune-mediated injury to not only connective tissue, but often components of the peripheral nervous system. These overlap conditions can be broadly categorized as peripheral neuropathies and overlap myositis. The peripheral neuropathies are distinctive as many have unusual presentations such as non-length-dependent, small fiber neuropathies and sensory neuronopathies (both due to dorsal root ganglia dysfunction), multiple mononeuropathies (e.g. vasculitic neuropathies), and even cranial neuropathies. Overlap myositis is increasingly recognized and is often associated with specific autoantibodies. Sarcoidosis also has widespread neurological manifestations and impacts both the peripheral nerves and muscle. Much work is needed to fully characterize the vast presentations of these overlap diseases. Given the rarity of these disorders, they are understudied, resulting in significant knowledge gaps with regards to their underlying pathophysiology and the best treatment approach. A basic knowledge of these disorders is mandatory for both practicing rheumatologists and neurologists as prompt recognition and early initiation of immunotherapy may prevent significant morbidity and permanent disability.

Peripheral Nervous System Involvement in Sjögren's Syndrome: Analysis of a Cohort From the Italian Research Group on Sjögren's Syndrome

Purpose

The prevalence of peripheral nervous system (PNS) involvement in primary Sjögren's syndrome (pSS) has been reported to range from 2% to over 50%. Bias in study designs, including low number of patients and unclearly defined rheumatological and neurological diagnosis could explain such variability. Consequently, the exact depiction of PNS involvement in pSS is still lacking. This study aimed at analyzing the prevalence and the clinical and laboratory factors associated with PNS involvement in a very large cohort of well-characterized pSS patients with a clearly defined neurological diagnosis.

Methods

Clinical and serological data of 1,695 pSS patients with specific and accurate information on PNS involvement were analyzed. Comparisons between patients with and without PNS involvement and between patients with distinct subsets of PNS manifestations were performed.

Results

Prevalence of PNS involvement was 3.7%. The most frequent types observed were pure sensory neuropathies and axonal sensorimotor polyneuropathies (SMP). Patients with PNS involvement exhibited a more active disease profile and were more frequently treated with immunosuppressants. Intriguingly, clinical and serological negative prognostic factors, including purpura, extra-glandular manifestations, leukopenia, low complement and cryoglobulinemia, principally characterized patients with SMP, while subjects with pure sensory neuropathy displayed a milder phenotype.

Conclusion

Our results highlight that PNS involvement is rather rare, but prognostically relevant in pSS. Main adverse prognostic features characterize patients with SMP, while pure sensory neuropathies are usually associated with a mild clinical picture. These findings, useful for patient stratification, may suggest protean pathogenic pathways underlying different types of PNS manifestations in pSS.

A Systematic Review of Pharmacologic and Rehabilitative Treatment of Small Fiber Neuropathies

The aim of this systematic review is to guide the physician in defining the pharmacologic and rehabilitative therapeutic approaches for adopting the best strategies described in the current literature. The search was conducted in PubMed, EMBASE, Cochrane Library and Web of Science to identify the treatment of small fiber neuropathies. Two reviewers independently reviewed and came to a consensus on which articles met inclusion/exclusion criteria. The authors excluded the duplicates, animal studies and included the English articles in which the treatment of patients with small fiber neuropathies was described. The search identified a total of 975 articles with the keywords “small fiber neuropathy” AND “rehabilitation” OR “therapy” OR “treatment”. Seventy-eight selected full-text were analyzed by the reviewers. Forty-two publications met the inclusion criteria and were included in the systematic review to describe the rehabilitative and pharmacologic treatment of small fiber neuropathies. Despite the range of different protocols of treatment for small fiber neuropathy, other robust trials are needed. In addition, always different therapeutic approaches are used; a unique protocol could be important for the clinicians. More research is needed to build evidence for the best strategy and to delineate a definitive therapeutic protocol.

Detection of nerve enlargement with ultrasound and correlation with skin biopsy findings in painful sensory neuropathy associated with Sjögren's syndrome

OBJECTIVES

We evaluated usefulness of peripheral nerve ultrasound (US) in detecting abnormality in painful sensory neuropathy (PSN) associated with primary Sjögren's syndrome (pSS), and associations among various clinical factors, US findings, and intraepidermal nerve fiber density (IENFD).

METHODS

We conducted a retrospective, single-center, observational study of patients with pSS-PSN. US image was obtained to measure cross sectional area (CSA) of peripheral nerves and compared with matched pSS control.

RESULTS

We included 11 patients with pSS-PSN (10 women; age 70.5 ± 5.66) and 17 pSS controls (15 women; age 62.5 ± 16.7). Sural nerve CSA were significantly increased in pSS-PSN group (3.48 ± 1.0 mm² vs 2.05 ± 0.65 mm², p = .001). US of sural nerve showed the area under the ROC curve of 0.872 (95% CI, 0.732 - 1). Sural nerve CSA and IENFD of lower leg showed positive correlation. Compared with pSS-PSN patients with abnormal IENFD, those with normal IENFD showed significantly larger sural nerve CSA, and trends toward less systemic disease activity and small fiber impairment with sparing of large fibers.

CONCLUSION

US was useful in discriminating pSS patients with PSN from those without. Additionally, US may disclose distinct subsets of pSS-PSN with different clinical findings and IENFD.

A Systematic Review of the Diagnostic Methods of Small Fiber Neuropathies in Rehabilitation

This systematic review describes the several methods to diagnose and measure the severity of small fiber neuropathies and aims to guide the physician to define all the diagnostic approaches for adopting the best strategies described in the current literature. The search was conducted in PubMed, EMBASE, Cochrane Library and Web of Science. Two reviewers independently reviewed and came to consensus on which articles met inclusion/exclusion criteria. The authors excluded all the duplicates, animals' studies, and included the English articles in which the diagnostic measures were finalized to assess the effectiveness of rehabilitation and pharmacologic treatment of patients with small fiber neuropathies. The search identified a total of 975 articles with the keywords "small fiber neuropathy" AND "rehabilitation" OR "therapy" OR "treatment". Seventy-eight selected full-text were analyzed by the reviewers. Forty-one publications met the inclusion criteria and were included in the systematic review. Despite the range of diagnostic tools for the assessment of small fiber neuropathy, other robust trials are needed. In addition, always different diagnostic approaches are used, a unique protocol could be important for the clinicians. More research is needed to build evidence for the best diagnostic methodologies and to delineate a definitive diagnostic protocol.

PATHOGENESIS OF FIBROMYALGIA IN PATIENTS WITH AUTOIMMUNE DISEASES: SCOPING REVIEW FOR HYPOTHESIS GENERATION

Introduction: Fibromyalgia (FM) prevalence is much higher in patients with other rheumatic diseases than in the general population. This leads to increase in the perceived disease activity scores and prevents patients from reaching remission. Elucidating the pathogenesis of such “secondary” FM can help alleviate some unmet needs in these diseases. Methods: MEDLINE and Scopus databases were searched for a scoping review for hypothesis generation regarding the genesis of secondary FM. Results: FM has been postulated to be due to cytokine dysfunction, neurogenic neuroinflammation, stress, including social defeat, sleep disturbances, sympathetic overactivity, and small fibre neuropathy. These factors increase in most autoimmune and autoinflammatory diseases. Further the evidence for the role of these factors in the pathogenesis of FM is seems strong. Metabolic syndrome and mitochondrial dysfunction are also associated with FM, but it is difficult to distinguish between cause and effect. Conclusion: FM is the common phenotype arising from the amalgamation of various aetiologies. Recruitment or amplification of the above 6 factors by various rheumatic diseases may thus lead precipitation of secondary FM in susceptible individuals.

Unstimulated whole saliva flow for diagnosis of primary Sjögren's syndrome: time to revisit the threshold?

Background

Unstimulated whole saliva (UWS) flow rate is one of the ACR/EULAR 2016 criteria for primary Sjögren’s syndrome (pSS). With a single threshold of ≤ 0.1 mL/min, UWS flow does not take into account the age- and sex-related physiological variations. Furthermore, it has a low sensitivity for the diagnosis of pSS (about 50%), contrary to the screening test for xerophthalmia, Schirmer’s test (sensitivity of about 70%). We aimed to identify UWS thresholds allowing better performances for a screening test for pSS comparable to Schirmer’s test, and considering age- and sex-related variations.

Methods

A prospective cohort of 185 patients with oral and/or ocular dryness was classified into 3 groups: men, women < 50 (< 50 years old), and women ≥ 50 (≥ 50 years old). The diagnostic performances of UWS flow rate in these groups were compared in terms of sensitivity, specificity, positive and negative predictive values, and ROC curves. The identification of thresholds that optimize diagnostic performances was carried out using Youden’s index.

Results

The diagnostic performances of UWS flow rate varied according to age and sex. UWS had poor diagnostic performances whatever the threshold in the women ≥ 50 group. The threshold of 0.2 mL/min had a sensitivity of ≥ 70% and a specificity of ≥ 50% in both men and women < 50 groups. In the whole population and compared to the current cutoff, a threshold of 0.2 mL/min increased sensitivity (+ 19.8%) and positive (+ 2.3%) and negative (+ 7.0%) predictive values, with a better specificity (65.2%) than Schirmer’s test.

Conclusion

For objective assessment of xerostomia, raising the threshold of the UWS flow rate to 0.2 mL/min would optimize its screening performances for pSS.

Small fiber neuropathy in Sjögren syndrome: Comparison with other small fiber neuropathies

INTRODUCTION

We compared histological and clinical profiles of primary Sjögren syndrome (pSS) small fiber neuropathy (SFN; pSS-SFN) with idiopathic SFN (i-SFN) and hereditary transthyretin amyloidosis SFN (hATTR-SFN) and described the evolution of pSS-SFN.

METHODS

All patients with pSS-SFN, i-SFN, and hATTR-SFN confirmed by reduced intraepidermal nerve fiber density on skin biopsy were retrospectively included, and their characteristics were compared. To analyze prognosis of pSS-SFN, patients prospectively underwent a second evaluation.

RESULTS

Fifteen pSS-SFN, 17 hATTR-SFN, and 11 i-SFN were included. Time to diagnosis SFN was longer in pSS-SFN and i-SFN than in hATTR-SFN. Painful and non-length-dependent patterns were more frequent in pSS-SFN than in hATTR-SFN. Twelve (80%) patients with pSS-SFN had a non-length-dependent pattern. Ten patients with pSS were reassessed after 3.1 years (1.7-4.7); none developed large fiber neuropathy linked to pSS.

DISCUSSION

Primary Sjögren syndrome SFN is characterized by a more frequent non-length-dependent pattern compared with i-SFN and hATTR-SFN. Primary Sjögren syndrome SFN did not evolve through large fiber neuropathy.

Small-fiber neuropathy definition, diagnosis, and treatment

In the last 30 years, improvement of diagnostic methods enabled routine evaluation of small A-delta and C nerve fibers impairment, which results with the clinical condition known as a small-fiber neuropathy (SFN). This syndrome develops as a result of metabolic, toxic, immune-mediated, or genetic factors. The main clinical features include neuropathic pain and autonomic disturbance, which are occasionally disclaimed due to outstanding fatigue, daily performance decline, anxiety, and depression. As clinical, neurological, nerve conduction, and electromyography studies are commonly normal, diagnosis often depends on the finding of decreased intra-epidermal density of nerve fibers, per skin biopsy. This review highlights the etiology, clinical, diagnostic aspects, and SFN treatment.

Usefulness of rheumatoid factor as an immunological and prognostic marker in PSS patients

INTRODUCTION

The rheumatoid factor (RF) is present in numerous autoimmune disorders, although its role in many of them remains a subject of research. The study assesses the role of RF as an immunological and prognostic factor in the primary Sjögren's syndrome (pSS).

METHODS

Seventy-five pSS patients (mean age 50.03 ± 15.1), 65 (87%) females, and 10 (13%) males. WBC, CRP, RF, ESR, gammaglobulins, C4, C3 component of complement, cryoglobulins, ANA, anti-SS-A, and anti-SS-B antibodies were determined. The disease activity assessed with ESSDAI. Minor salivary gland biopsy (focus score and immunochemistry) was conducted. Results were analyzed with U Mann-Whitney (continuous variables) tests, correlations between quantitative variables assessed with the Spearman correlation coefficient with statistical significance set at p < 0.05. The approval of the Bioethics Committee was obtained.

RESULTS

Two subgroups I-RF(+) (61%) and II-RF(-) (39%) were established, with lower WBC (p = 0.012) and higher ESR (p = 0.016), gammaglobulin concentration (p = 0.007) in group I. Conjunctivitis sicca was more severe in group I. There was positive correlation between RF and lnANA (rho = 0.496), anti-SS-A, anti-SS-B antibodies (rho = 0.448; rho = 0.397 respectively). There was higher disease activity ESSDAI in group I than in group II (Me, 3.0 vs 2.0; p < 0.003). RF correlated negatively with WBC (rho = - 0.374). RF did not correlate with serum concentrations of BAFF, APRIL, CRP, and C3, C4 and with CD19+, CD3+, CD4+, CD 21+, and CD35+.

CONCLUSIONS

RF should be considered as a prognostic, but not diagnostic, factor in patients with pSS, as it is associated with more severe disease course (sicca eye symptoms, ESSDAI) and parameters (production of gammaglobulins, ANA, anti SS-A, anti-SS-B autoantibodies) indicating increased B cell activity.

Update on Sjögren's Syndrome 2018

Primary Sjögren’s syndrome (pSS) is a chronic systemic autoimmune disease with a diverse clinical picture, extending from exocrine involvement to extraglandular manifestations. Although pSS remains a disease of unknown etiology, an interaction between genetic susceptibility and environmental triggers is thought to play a key role in disease initiation and progress. Despite the extensive research during the past years, the pathogenetic mechanisms are still elusive and effective therapeutic intervention is still missing. This review aims to provide an overview of the recent literature on the pathogenesis, clinical features and new therapeutic aspects of pSS.