Persistent viral infection in primary Sjogren's syndrome: review and perspectives

Persistent CD8+ T cell proliferation and activation in COVID-19 adult survivors with post-acute sequelae: a longitudinal, observational cohort study of persistent symptoms and T cell markers

Introduction

Post-acute sequelae of COVID-19 affects the quality of life of many COVID-19 survivors, yet the etiology of post-acute sequelae of COVID-19 remains unknown. We aimed to determine if persistent inflammation and ongoing T-cell activation during convalescence were a contributing factor to the pathogenesis of post-acute sequelae of COVID-19.

Methods

We evaluated 67 individuals diagnosed with COVID-19 by nasopharyngeal polymerase chain reaction for persistent symptoms during convalescence at separate time points occurring up to 180 days post-diagnosis. Fifty-two of these individuals were evaluated longitudinally. We obtained whole blood samples at each study visit, isolated peripheral blood mononuclear cells, and stained for multiple T cell activation markers for flow cytometry analysis. The activation states of participants' CD4+ and CD8+ T-cells were next analyzed for each of the persistent symptoms.

Results

Overall, we found that participants with persistent symptoms had significantly higher levels of inflammation at multiple time points during convalescence when compared to those who fully recovered from COVID-19. Participants with persistent dyspnea, forgetfulness, confusion, and chest pain had significantly higher levels of proliferating effector T-cells (CD8+Ki67+), and those with chest pain, joint pain, difficulty concentrating, and forgetfulness had higher levels of regulatory T-cells (CD4+CD25+). Additionally, those with dyspnea had significantly higher levels of CD8+CD38+, CD8+ Granzyme B+, and CD8+IL10+ cells. A retrospective comparison of acute phase inflammatory markers in adults with and without post-acute sequelae of COVID-19 showed that CD8+Ki67+ cells were significantly higher at the time of acute illness (up to 14 days post-diagnosis) in those who developed persistent dyspnea.

Discussion

These findings suggest continued CD8+ T-cell activation following SARS-CoV-2 infection in adults experiencing post-acute sequelae of COVID-19 and that the increase in T regulatory cells for a subset of these patients represents the ongoing attempt by the host to reduce inflammation.

LAMP3 inhibits autophagy and contributes to cell death by lysosomal membrane permeabilization

ABBREVIATIONS

A253-control: A253 control for LAMP3 stable overexpression; A253- LAMP3: A253 LAPM3 stable overexpression; CASP1: caspase 1; CASP3: caspase 3; CHX: cycloheximide; CTSB: cathepsin B; CTSD: cathepsin D; CQ: chloroquine; DCs: dendritic cells; ER: endoplasmic reticulum; LGALS3: galectin 3; HCV: hepatitis C virus; HSG-control: HSG control for LAMP3 stable overexpression; HSG-LAMP3: HSG LAMP3 stable overexpression; HSP: heat shock protein; HTLV-1: human T-lymphocyte leukemia virus-1; IXA: ixazomib; LAMP: lysosomal associated membrane protein; MHC: major histocompatibility complex; mAb: monoclonal antibody; OE: overexpression; pepA: pepstatin A; pAb: polyclonal antibody; pSS: primary Sjögren syndrome; qRT-PCR: quantitative real- time reverse transcriptase polymerase chain reaction; SLE: systemic lupus erythematosus; SS: Sjögren syndrome; UPR: unfolded protein response; V-ATPase: vacuolar-type proton- translocating ATPase; Y-VAD: Ac-YVAD-cmk; Z-DEVD; Z-DEVD-fmk; Z-VAD: Z-VAD- fmk.

Sjogren's syndrome-An interesting case

OBJECTIVE

To present a case of Sjogren syndrome with pulmonary manifestations in an adult female and discuss its assessment and management.

DESIGN

Case Report.

SETTING

Tertiary care hospital.

PATIENT

One.

RESULTS

A 50 yrs female admitted with complaints of dryness of eyes with decreased salivation causing difficulty in swallowing since last 3 years, with persistent dry cough since 10-15 days and progressive dyspnea since 4-5 days. Anti-nuclear antibody (ANA) profile revealed Anti- Ro/SS-A and Anti- La/SS-B Positive. Also, sub-lingual excisional biopsy was done which was consistent with findings of Sjogren's syndrome. Patient showed significant improvement after starting oral glucocorticoids, systemic anti inflammatory agents (Tab. HCQS), artificial tear drops, oral iron supplements and other supportive treatment.

CONCLUSION

Sjögren syndrome (SS) is a chronic inflammatory disorder characterized by diminished lacrimal and salivary gland function and associated with lymphocytic infiltration of exocrine glands, and can affect extraglandular organ systems including the skin, lung, heart, kidney, neural, and hematopoietic systems. We present a case of Sjogren syndrome in an adult female presenting with xerostomia and dyspnea and was diagnosed upon detection of anti-Ro and anti-La antibodies and confirmed by histopathological examination of lip biopsy. Patient was started on oral steroids and other supportive treatment, General condition improved significantly and is doing very well on regular follow-up.

Minor salivary gland biopsy: Its role in the classification and prognosis of Sjögren's syndrome

Sjögren's syndrome (SS) is an autoimmune disorder characterized by mononuclear cell infiltration in the exocrine glands, which leads to sicca syndrome (xerostomia and xerophthalmia). The etiology of SS is unknown, but multiple environmental factors (infectious, hormonal and stress-related), as well as genetic factors, may play a role in its pathogenesis. The diagnosis of SS is complex considering its clinical and paraclinical parameters may not be very specific. The minor salivary gland biopsy (MSGB) has undoubtedly become crucial for classifying and determining the prognosis of SS. The three main different classification systems for its interpretation have been described by Chisholm and Mason, Greenspan and Daniels, and Tarpley. However, this invasive procedure has variable sensitivity and specificity as well as low reproducibility. The use of additional methods, such as skin biopsy, imaging techniques, and serum/salivary biomarkers, may be combined with current methods to develop a bioscore that could increase diagnostic performance. In this review, we summarized the main pathological findings in SS and the prognosis of patients with SS according to the biopsy results.

Identification of novel genes associated with dysregulation of B cells in patients with primary Sjögren's syndrome

Background

The aim of this study was to identify the molecular mechanism of dysregulation of B cell subpopulations of primary Sjögren’s syndrome (pSS) at the transcriptome level.

Methods

We enrolled patients with pSS (n = 6) and healthy controls (HCs) (n = 6) in the discovery cohort using microarray and pSS (n = 14) and HCs (n = 12) in the validation cohort using quantitative PCR (qPCR). Peripheral B cells acquired from these subjects were separated by cell sorting into four subsets: CD38⁻IgD⁺ (Bm1), CD38⁺IgD⁺ (naive B cells), CD38^highIgD⁺ (pre-germinal centre B cells) and CD38^±IgD⁻ (memory B cells). We performed differentially expressed gene (DEG) analysis and weighted gene co-expression network analysis (WGCNA).

Results

Expression of the long non-coding RNA LINC00487 was significantly upregulated in all B cell subsets, as was that of HLA and interferon (IFN) signature genes. Moreover, the normalized intensity value of LINC00487 significantly correlated with the disease activity score of all pSS B cell subsets. Studies of human B cell lines revealed that the expression of LINC00487 was strongly induced by IFNα. WGCNA revealed six gene clusters associated with the B cell subpopulation of pSS. Further, SOX4 was identified as an inter-module hub gene.

Conclusion

Our transcriptome analysis revealed key genes involved in the dysregulation of B cell subpopulations associated with pSS.

Trial registration

Not required.

Carnitine Palmitoyl Transferase Deficiency in a University Immunology Practice

PURPOSE

This report describes the clinical manifestations of 35 patients sent to a University Immunology clinic with a diagnosis of fatigue and exercise intolerance who were identified to have low carnitine palmitoyl transferase activity on muscle biopsies.

RECENT FINDINGS

All of the patients presented with fatigue and exercise intolerance and many had been diagnosed with fibromyalgia. Their symptoms responded to treatment of the metabolic disease. Associated symptoms included bloating, diarrhea, constipation, gastrointestinal reflux symptoms, recurrent infections, arthritis, dyspnea, dry eye, visual loss, and hearing loss. Associated medical conditions included Hashimoto thyroiditis, Sjogren's syndrome, seronegative arthritis, food hypersensitivities, asthma, sleep apnea, and vasculitis. This study identifies clinical features that should alert physicians to the possibility of an underlying metabolic disease. Treatment of the metabolic disease leads to symptomatic improvement.

Detection of SSA and SSB Antibodies Associated with Primary Sjögren's Syndrome Using Enzyme-Linked Immunosorbent Assay

Antibodies to Ro52/Ro60 (SSA) and La (SSB) are strongly associated to the autoimmune disease primary Sjögren's syndrome and are important in the serologic diagnosis of the disease. Several methods for detection of these antibodies exist such as indirect immunofluorescence, commercial western blot kits, in-house assays, and numerous commercial enzyme-linked immunosorbent assays (ELISAs). Dependent on the type of assay, sensitivity and specificity may vary notably. Especially ELISAs, where the antibody reactivity to synthetic peptides, recombinant or native proteins are determined, are often applied. This chapter describes detection of SSA and SSB antibodies by ELISA.

Interferons and Dry Eye in Sjögren's Syndrome

Various cytokines, including interferon (IFN)-γ and IL-17, are augmented, and autoreactive T cells and B cells are activated in the immune pathogenesis of Sjögren's syndrome (SS). In particular, IFNs are involved in both the early stages of innate immunity by high level of type I IFN in glandular tissue and sera and the later stages of disease progression by type I and type II IFN producing T cells and B cells through B cell activating factor in SS. Genetically modified mouse models for some of these molecules have been reported and will be discussed in this review. New findings from human SS and animal models of SS have elucidated some of the mechanisms underlying SS-related dry eye. We will discuss IFN-γ and several other molecules that represent candidate targets for treating inflammation in SS-related dry eye.

Complexities in the relationship between infection and autoimmunity

The possible role of infections in driving autoimmune disease (AD) has long been debated. Many theories have emerged including release of hidden antigens, epitope spread, anti-idiotypes, molecular mimicry, the adjuvant effect, antigenic complementarity, or simply that AD could be a direct consequence of activation or subversion of the immune response by microbes. A number of issues are not adequately addressed by current theories, including why animal models of AD require adjuvants containing microbial peptides in addition to self tissue to induce disease, and why ADs occur more often in one sex than the other. Reviews published in the past 3 years have focused on the role of the innate immune response in driving AD and the possible role of persistent infections in altering immune responses. Overall, recent evidence suggests that microbes activating specific innate immune responses are critical, while antigenic cross-reactivity may perpetuate immune responses leading to chronic autoinflammatory disease.

Sjögren's syndrome

Sjögren's syndrome (SS) is a chronic autoimmune disorder that typically affects exocrine glands--mainly labial and lacrimal--leading to complaints of dry mouth and eyes. Given that periepithelial mononuclear cell infiltrates, both in exocrine glands and in other parenchymal organs (kidney, lung, and liver), are the histopathological disease hallmark, the term autoimmune epithelitis has been proposed. B cell hyperactivity is another cardinal SS feature manifested by the presence of autoantibodies and hypergammaglobulinemia, as well as clinical/serological phenotypes mediated by immune complexes, such as peripheral neuropathy, vasculitic lesions, and hypocomplementemia. These have been designated adverse predictors for lymphoma development in approximately 5% to 10% of patients. Activation of the type I interferon/B cell-activating factor axis in SS has recently attracted particular attention. Inappropriate overexpression of endogenous nucleic acids in a genetically susceptible individual might provide a plausible scenario for the immune activation observed in SS.

Serologic features of primary Sjögren's syndrome: clinical and prognostic correlation

Sjögren's syndrome (SS) is a chronic inflammatory systemic autoimmune disease. The disease spectrum extends from sicca syndrome to systemic involvement and extraglandular manifestations, and SS may be associated with malignancies, especially non-Hodgkin's lymphoma. Patients with SS present a broad spectrum of serologic features. Certain serological findings are highly correlated with specific clinical features, and can be used as prognostic markers.

Type I interferons in Sjögren's syndrome

Sjögren's syndrome is a chronic autoimmune disease characterized by lymphocytic infiltration of the salivary and lachrymal glands resulting in dry eyes and mouth. Genetic predisposition, pathogenic infections and hormones have been implicated in the pathogenesis of the disease. Studies in the last several years have revealed marked over-expression of the type I interferon (IFN)-inducible genes in the peripheral blood and salivary glands of patients with Sjögren's syndrome. The expression of the type I IFN-inducible genes in Sjögren's syndrome also positively correlates to titers of anti-Ro and anti-La autoantibodies, which are typical for this disease. Plasmacytoid dendritic cells (pDC) are the major source of type I IFN production and activated pDC are detected in minor salivary gland biopsies from patients with primary Sjögren's syndrome. In addition, polymorphisms in genes important both for the production and response to type I IFN are associated to increased risk for Sjögren's syndrome. Because type I IFN bears a variety of biological functions, such as defense against viral infections and activation of the immune system, these results suggest that the type I IFN system has an important role in the pathogenesis of Sjögren's syndrome. A variety of mechanisms causing an activation of the type I IFN system are discussed in this review. Given the pivotal role of type I IFN in the disease process, therapeutic interventions targeting the type I IFN signaling pathway have the potential to benefit the patients with elevated type I IFN status and such hypothesis needs to be carefully evaluated in clinical development.

Detection of HTLV-1 in the Labial Salivary Glands of Patients with Sjögren’s Syndrome: A Distinct Clinical Subgroup?

Objective.

To examine whether patients with Sjögren’s syndrome (SS) can be distinguished based on the expression of human T cell lymphotrophic virus type I (HTLV-1) and, if so, whether the subgroups differ in their clinical features and serological measures.

Methods.

Polymerase chain reaction (PCR) and nested PCR were used to amplify viral DNA from peripheral blood mononuclear cells (PBMC) in 53 patients with SS, using primers from the HTLV-1 pX, p19, pol, and tax regions. Minor salivary gland biopsy specimens from 33 patients with SS were examined for the presence of HTLV-1 p19 or tax proteins immunohistochemically. The sociodemographic, glandular, and extraglandular manifestations, and laboratory findings including autoantibodies, complement, and immunoglobulin levels, were analyzed.

Results.

The HTLV-1 tax gene was detected in PBMC samples from 2 of 53 patients (3.8%), whereas the HTLV-1 pX, p19, and pol genes were not expressed. As well, 100% of PBMC samples from 4 family members of patients in whom the tax gene was detected also expressed the tax gene. Immunohistochemical staining for HTLV-1 p19 and tax was seen in 10 out of 33 (30.3%) patients with SS each. Overall, 14 (42.4%) patients expressed HTLV-1 p19 or tax proteins, and they had lower rheumatoid factor and C3 levels (p = 0.015 and p = 0.005, respectively) and higher lymphocyte counts (p = 0.016). The prevalence of glandular and extraglandular manifestations did not differ between the HTLV-1-positive and negative patients.

Conclusion.

Our findings suggest that HTLV-1 in the salivary glands is involved in the pathogenesis of a subpopulation of SS, and HTLV-1-associated SS might have different immunological patterns than idiopathic SS.

T Cell-Associated Cytokines in the Pathogenesis of Sjögren's Syndrome

Sjögren's syndrome (SjS) is a systemic autoimmune disease that primarily targets salivary and lacrimal glands. SjS affects 2-4 million people in the US alone and greatly affects the life quality of the afflicted individuals. Autoreactive effector T cells are central executors and orchestrators in the pathogenic processes of SjS by mediating target organ inflammation and destruction and by facilitating B cell responses and autoantibody production. A variety of cytokines that are produced by effector T cells or capable of directly affecting effector T cells are elevated in the target organs and circulations of SjS patients. The recent advancement in the understanding about the functions of these cytokines, achieved by using both human samples and mouse disease models, has generated great insights into the cytokine control of autoimmune responses in the SjS disease setting. In this review, we summarized the recent findings on the expression and functions of cytokines in this disease, with specific focus on those derived from T cells and/or directly affecting T cell responses.

Autoimmunity at the ocular surface: pathogenesis and regulation

A healthy ocular surface environment is essential to preserve visual function, and as such the eye has evolved a complex network of mechanisms to maintain homeostasis. Fundamental to the health of the ocular surface is the immune system, designed to respond rapidly to environmental and microbial insults, whereas maintaining tolerance to self-antigens and commensal microbes. To this end, activation of the innate and adaptive immune response is tightly regulated to limit bystander tissue damage. However, aberrant activation of the immune system can result in autoimmunity to self-antigens localized to the ocular surface and associated tissues. Environmental, microbial and endogenous stress, antigen localization, and genetic factors provide the triggers underlying the immunological events that shape the outcome of the diverse spectrum of autoimmune-based ocular surface disorders.

The geoepidemiology of Sjögren's syndrome

Sjogren's syndrome (SS) is a slowly progressing autoimmune disease, affecting predominantly middle-aged women, with a female to male ratio reaching 9:1. It is characterized by lymphocytic infiltration of the exocrine glands, mainly the lacrimal and salivary glands, resulting in reduced secretory functions and oral and ocular dryness. The syndrome can present alone as primary SS (pSS) or in the context of underlying connective tissue disease as secondary SS (sSS). While the pathogenesis of the disease remains elusive, environmental, genetic and hormonal contributors seem to be involved. Over the last years, compelling evidence has suggested a pivotal role of the epithelium in orchestrating the immune response in the histopathological lesion of Sjogren's syndrome and the term "autoimmune epithelitis" has been proposed as an etiological term. Although the clinical manifestations of pSS patients are mainly those of an autoimmune exocrinopathy, almost half of patients develop extraglandular disease, which may be manifested either by epithelial lymphocytic invasion of lung, liver, or kidney (resulting in interstitial nephritis) or by skin vasculitis, peripheral neuropathy, glomerulonephritis, and low C4 levels. The latter reflect immune-complex mediated disease and confer increased risk for lymphoma development.

Viruses induce high expression of BAFF by salivary gland epithelial cells through TLR- and type-I IFN-dependent and -independent pathways

B cell activating factor (BAFF) plays a key role in promoting B lymphocyte activation. We investigated whether danger signals induce BAFF secretion by cultured salivary gland epithelial cells (SGEC), which are the target of primary Sjögren's syndrome, a prototypic systemic autoimmune disease. SGEC cultures were established from minor salivary glands obtained from ten patients with pSS or sicca symptoms. BAFF mRNA and protein were measured after stimulation of the different Toll-like receptors (TLR) by agonists or viruses. The expression of TLR2, -3, and -7 was detected in SGEC. Poly (I:C) (a synthetic TLR3 agonist) and reovirus-1 (a dsRNA virus) induced high expression of BAFF mRNA (multiplied by a factor of 246 +/- 39 (SEM) and 347 +/- 66, respectively) and of BAFF protein secretion (58.49 +/- 4.34 pg/mL and 69.73 +/- 5.67). Inhibition of both the endosomal (by chloroquine) and IFN (by anti-IFNAR antibody) pathways partly inhibited BAFF expression. Treatment with both dsRNA virus and poly (I:C) induced high levels of BAFF mRNA and protein expression by SGEC, through pathways dependent on and independent of TLR and dependent on and independent of IFN. BAFF induction by target organs of autoimmune diseases after viral infection may be a link between innate immunity and autoimmunity.