Influenza and Covid-19 Vaccination in 2023: a descriptive analysis in two Italian Research and Teaching Hospitals. Is the On-Site strategy effective?

Introduction: Vaccinations represent an extremely effective tool for the prevention of certain infectious diseases - such as influenza and COVID-19 -, particularly for those categories at risk due to both their frail condition or professional exposure, such as healthcare workers. The aim of this study is to describe the course of the anti-influenza and anti-COVID-19 vaccination campaign at two Research Hospitals in Milan, Italy. Study design: Multicentre, cross-sectional study. Methods: For the 2023-24 vaccination campaign, the two facilities opted for two different approaches. At the Hospital A, two dif-ferent strategies for vaccinating healthcare workers were implemented: a fixed-site vaccination clinic and two mobile vaccination groups run by Public Health residents of the University of Milan. At the Hospital B, on the other hand, a single fixed-site outpatient clinic run by Public Health residents of the University of Milan was used. On the occasion of the campaign, a survey was also carried out using anonymous online questionnaires to investigate healthcare workers attitudes towards vaccination. Results: A total of 1,937 healthcare workers were vaccinated: 756 were immunized against influenza only, 99 against COVID-19 only, and 1,082 against both. The results show a substantial difference in vaccination adherence among medical and nursing staff compared to other professional categories. In particular, the category with the highest vaccination adhesion turned out to be that of medical doctors with 55.7% adhesion while, on the contrary, the category with the lowest adhesion turned out to be that of auxiliary personnel characterized by 7.4% adhesion. At the same time, the comparison between the two hospital facilities showed a double adherence rate by the staff of Hospital A as regards both the flu vaccine (40.6% and 20.1%) and the anti-COVID-19 vaccine (26.4% and 12.3%). Finally, the survey showed that the attitude towards influenza vaccination is lower among auxiliary staff in terms of both knowledge and vaccination attitude. Conclusions: The results of the study show a vaccination adherence in line with that of previous years, although lower than the values recommended by the principal national and international Organizations. The analysis of the differences between the two facilities and the surveys carried out will allow for the implementation of targeted interventions to increase adherence in future campaigns.

High-throughput sequencing of IgH gene in minor salivary glands from Sjögren's syndrome patients reveals dynamic B cell recirculation between ectopic lymphoid structures.

OBJECTIVES: B cells play a central role in Sjögren's syndrome (SS) whereby autoreactive B-cells populate ectopic germinal centres (GC) in SS salivary glands (SG) and undergo somatic hypermutation (SHM) and class-switch recombination of the immunoglobulin genes. However, the capacity of specific B cell clones to seed ectopic GC in different SG and undergo clonal diversification is unclear. To unravel the dynamics of B cell recirculation among minor SG biopsies, we investigated the immunoglobulin heavy chain (IgH) gene usage and the pattern of SHM using a high-throughput sequencing approach. METHODS: We generated ~166,000 reads longer than 350bp and detected 1631 clonotypes across eight samples from four different SS patients, all characterised by the presence of functional ectopic GC as demonstrated by the expression of activation-induced cytidine deaminase. RESULTS: A large number of shared clonotypes were observed among paired mSG biopsies from each patient but not across different patients. Lineage tree analysis revealed significant clonal expansion within the mSG with the identification of shared dominant B cell clones suggestive of extensive recirculation across different SG. Several shared clonotypes with high proliferating capacity displayed IgH-VH gene usage common in autoreactive B cells, including VH1-69, which is typical of rheumatoid factor+ B cells representing potential lymphoma precursors. CONCLUSIONS: The complex dynamic recirculation of B cells that we observed within ectopic GC responses linked with their ability to independently proliferate, undergo ongoing SHM and Ig class-switching within individual glands may explain the difficulty in achieving consistent eradication of ectopic GCs following B cell depleting agents reported in different studies.

Unique expansion of IL-21+ Tfh and Tph cells under control of ICOS identifies Sjögren's syndrome with ectopic germinal centres and MALT lymphoma.

OBJECTIVES: To explore the relevance of T-follicular-helper (Tfh) and pathogenic peripheral-helper T-cells (Tph) in promoting ectopic lymphoid structures (ELS) and B-cell mucosa-associated lymphoid tissue (MALT) lymphomas (MALT-L) in Sjögren's syndrome (SS) patients. METHODS: Salivary gland (SG) biopsies with matched peripheral blood were collected from four centres across the European Union. Transcriptomic (microarray and quantitative PCR) analysis, FACS T-cell immunophenotyping with intracellular cytokine detection, multicolor immune-fluorescence microscopy and in situ hybridisation were performed to characterise lesional and circulating Tfh and Tph-cells. SG-organ cultures were used to investigate functionally the blockade of T-cell costimulatory pathways on key proinflammatory cytokine production. RESULTS: Transcriptomic analysis in SG identified Tfh-signature, interleukin-21 (IL-21) and the inducible T-cell co-stimulator (ICOS) costimulatory pathway as the most upregulated genes in ELS+SS patients, with parotid MALT-L displaying a 400-folds increase in IL-21 mRNA. Peripheral CD4+CXC-motif chemokine receptor 5 (CXCR5)+programmed cell death protein 1 (PD1)+ICOS+ Tfh-like cells were significantly expanded in ELS+SS patients, were the main producers of IL-21, and closely correlated with circulating IgG and reduced complement C4. In the SG, lesional CD4+CD45RO+ICOS+PD1+ cells selectively infiltrated ELS+ tissues and were aberrantly expanded in parotid MALT-L. In ELS+SG and MALT-L parotids, conventional CXCR5+CD4+PD1+ICOS+Foxp3- Tfh-cells and a uniquely expanded population of CXCR5-CD4+PD1hiICOS+Foxp3- Tph-cells displayed frequent IL-21/interferon-γ double-production but poor IL-17 expression. Finally, ICOS blockade in ex vivo SG-organ cultures significantly reduced the production of IL-21 and inflammatory cytokines IL-6, IL-8 and tumour necrosis factor-α (TNF-α). CONCLUSIONS: Overall, these findings highlight Tfh and Tph-cells, IL-21 and the ICOS costimulatory pathway as key pathogenic players in SS immunopathology and exploitable therapeutic targets in SS.

Ultrasound of the salivary glands is a strong predictor of labial gland biopsy histopathology in patients with sicca symptoms.

BACKGROUND: The international classification criteria for Sjögren's syndrome necessitate the presence of either extractable nuclear antibody or a characteristic focal inflammatory infiltrate in a minor salivary gland. Thus, patients who are extractable nuclear antibody-negative will need to have a labial salivary gland biopsy, which is an invasive procedure associated with morbidity. The aim of this study was to evaluate the viability of ultrasound imaging of the major salivary glands as a predictor of the histology to explore whether ultrasound can help in stratifying Sjögren's patients and reduce the need for biopsy. METHODS: The records of 85 patients suspected of having Sjögren's syndrome and who have had biopsy and ultrasound were analysed retrospectively. The histology and the ultrasound were reported by experts independently. The reporting was impartial as the examiners were blinded to the results of the other investigations and to the diagnosis. RESULTS: Out of the 85 patients, 34 had positive ultrasound, 29 of whom also had positive histology. Fifty-one patients had negative ultrasound, of whom 49 were also negative for histological features of Sjögren's syndrome. The results show that the ultrasound had a positive predictive value of 85% and a striking negative predicative value of 96% of the histology results. The overall concordance between the ultrasound and the histology was 91% (Kappa = 0.826). CONCLUSIONS: Our study shows that potentially the ultrasound has a role in stratifying patients who are extractable nuclear antibody-negative and can help to prioritize the biopsy for those who have sonographic evidence of SS.

CX3CL1 and CX3CR1 expression in tertiary lymphoid structures in salivary gland infiltrates: fractalkine contribution to lymphoid neogenesis in Sjogren's syndrome.

OBJECTIVES: Primary SS is an autoimmune disease characterized by chronic lymphocytic inflammation and ectopic germinal centre (GC) formation within salivary glands. Fractalkine (CX3CL1), associated with the pathogenesis of RA, is the sole member of the CX3C chemokine (CK) family and acts as an adhesion and chemotactic molecule. The objectives of this work are to determine to what extent CX3CL1 and its receptor CX3CR1 expression might be altered in salivary glands obtained from patients and to establish whether these CKs might be involved in SS ectopic lymphoneogenesis. METHODS: We assessed the presence of CX3CL1 protein in sera by ELISA in 21 patients with primary SS, 11 patients with Sicca syndrome (Sicca), 20 RA patients and 10 blood donors. Histological evaluation was performed on sequential sections of salivary gland tissue. Using TaqMan RT-PCR we studied CX3CL1 and CX3CR1 mRNA expression in salivary gland tissues from a molecular point of view. RESULTS: Increased serum levels of CX3CL1 protein were observed in SS patients compared with controls (P < 0.0001) and in RA patients compared with controls (P < 0.0001), but no difference was found between Sicca patients and controls (P = 0.22). We identified histologically the cells expressing CX3CL1 and CX3CR1 in salivary glands of SS patients and we localized the molecule within tertiary lymphoid structures. Finally, the mRNA levels of the CK and its receptor were up-regulated in SS salivary glands. CONCLUSION: We believe that our findings point to the need for future studies on CX3CL1 and CX3CR1 proteins as contributors to the formation of ectopic GCs and possibly as a new tool in the evaluation and diagnosis of SS.

Vaccination Open Day: A Cross-Sectional Study on the 2023 Experience in Lombardy Region, Italy.

BACKGROUND: Vaccination is a highly effective tool for controlling infectious diseases, particularly in populations at high risk of contagion due to clinical conditions or occupational exposure, such as healthcare workers. The purpose of this study is to present the open day event that marked the beginning of the influenza and anti-COVID-19 vaccination campaign in the Lombardy region and to describe the experience of an Istituto di Ricovero e Cura a Carattere Scientifico in Milan. METHODS: During the vaccination open day, eligible individuals received free vaccinations for influenza, COVID-19, pneumococcal disease, and shingles, as provided by the Lombardy Agenzia per la Tutela della Salute. In celebration of the centenary of the Università degli Studi di Milano, the Fondazione Ca'Granda Ospedale Policlinico, a contracted hospital of the university, created a special electronic diary for a total of 150 individuals, equally divided between children aged 2-6, pregnant women, and university staff. RESULTS: At the regional level, a total of 6634 influenza vaccines, 2055 anti-COVID-19 vaccines, 108 anti-pneumococcal vaccines, and 37 anti-zoster vaccines were administered. A total of 3134 (47.3%) influenza vaccines, 1151 (56%) anti-COVID-19 vaccines, and 77 (62%) anti-pneumococcal vaccines, were given to individuals aged 60-79. No differences were observed between the total number of male and female vaccinees (1017 and 1038, respectively), who received the anti-COVID-19 vaccine. At the Policlinico Foundation, out of 150 available booking slots, 154 vaccines were administered, including 117 influenza vaccines. CONCLUSIONS: The establishment of vaccine open days is a beneficial way to increase vaccine compliance. Co-administration of little-known vaccinations outside of healthcare settings could also be a useful tool.

Climate Change Perception and Mental Health. Results from a Systematic Review of the Literature.

Climate change is one of the main global challenges and influences various aspects of human health. Numerous studies have indeed demonstrated an association between extreme climate-related events and physical and mental health outcomes, but little is still known about the association between the perception/awareness of climate change and mental health. In accordance with the PRISMA 2020 guidelines, a search was conducted on PubMed and Scopus. The protocol was registered on PROSPERO. The included studies were original observational studies published in English, reporting the association between the perception/awareness of climate change and mental health. A total of 3018 articles were identified. A total of 10 observational studies were included. The period covered in the included studies ranged between 2012 and 2022. Climate change perception is consistently associated with adverse mental health effects across different types of estimates. In particular, the studies identified an association between a higher level of perception/awareness of climate change and depression, anxiety, eco-anxiety, stress, adjustment disorder, substance use, dysphoria, and even thoughts of suicide. Qualitative data underscore the impact on daily activities, contributing to feelings of loss and suicidal ideation. Moreover, climate change perception correlates with lower well-being and resilience. The association between awareness of climate change and mental health is a complex and still poorly explored phenomenon. The main limitations are the high heterogeneity in terms of exposure assessment and data reporting, which hinders quantitative analysis. These results show that climate change perception impacts mental health. Better understanding the phenomenon represents an opportunity to inform public health interventions that promote mental well-being.

Online extreme challenges putting children at risk: what we know to date.

INTRODUCTION: Extreme online challenges consist in taking part in challenges proposed on web and sharing the results in videos posted on social media. The use of social networks is widespread among the very young, giving easy access to potentially dangerous content with consequences on health. EVIDENCE ACQUISITION: The aim of this literature review was to describe the most common challenges involving children and adolescents over the last 20 years. We focused on participants features (such as age, sex and psychological background) and health implications. The review included research articles and reviews published between 2000 and 2021. We used Pubmed, Scopus and Web of science as search engines. EVIDENCE SYNTHESIS: Many types of online challenges emerged from the analysis of the literature. The most common challenges are those that lead to self-harm, which involve acts at risk of choking and challenges that potentially lead to suicide and ingestion of substances. The extreme challenge phenomenon is a public health issue that affects a vulnerable population, as it is young and susceptible to peer pressure influence. Participants often showed problematic personality traits, making them more likely to get involved in these behaviors. CONCLUSIONS: It is necessary for parents, teachers and health workers to be aware of the spread of the online challenges, to improve prevention interventions in the age groups involved.

Anti-Sars-CoV-2 vaccination campaign in children aged 5-11 years: the experience of a mass vaccination center in the city of Milan.

BACKGROUND AND AIM: After the approval of the anti-Sars-CoV-2 vaccines for the pediatric population, it is necessary to encourage the immunization of children aged 5-11 years, as this can reduce intergenerational transmission. Therefore, this goal has become a priority for the COVID 19 vaccination campaign in Italy. In the city of Milan, the mass vaccination center (MVC) Fiera Milano City, previously settled for general population, became the main site to host pediatric vaccinations. The center was consequently remodeled to ensure a suitable space for children. This paper provides an overview on the organization strategy implemented by Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico. The modular structure and the wide surface available in the center allowed the administration of hundreds of vaccines per day, especially in the first opening phase. METHODS: All the data for the entire period of activity of Fiera MCV, from December 16th 2021 to February 20th 2022, were analyzed using descriptive statistics. RESULTS: During the entire period of activity, from 16 December 2021 to 20 February 2022, 23% of the population in the province of Milan aged 5-11 years has been reached and vaccinated with at least one shot of vaccine in this center. CONCLUSIONS: Despite an enthusiastic response in the first weeks of the campaign, a progressive reduction in vaccination adherence was observed, maybe due to the absence of restrictive measures for unvaccinated children in Italy.

Evolution of ectopic lymphoid neogenesis and in situ autoantibody production in autoimmune nonobese diabetic mice: cellular and molecular characterization of tertiary lymphoid structures in pancreatic islets.

A pivotal role for tertiary lymphoid structures (TLSs) in promoting Ag-specific humoral responses during chronic inflammation is emerging in several autoimmune conditions, including rheumatoid arthritis, Sjogren's syndrome, and autoimmune thyroiditis. However, there is limited evidence on the cellular and molecular mechanisms underlying TLS formation and their contribution to autoimmunity in the pancreas during autoimmune insulitis. In this study, we performed a detailed and comprehensive assessment of the evolution of TLSs during autoimmune insulitis in 126 female NOD mice from 4 to 38 wk of age. We demonstrated that during progression from peri- to intrainsulitis in early diabetic mice, T and B cell infiltration follows a highly regulated process with the formation of lymphoid aggregates characterized by T/B cell segregation, follicular dendritic cell networks, and differentiation of germinal center B cells. This process is preceded by local upregulation of lymphotoxins alpha/beta and lymphoid chemokines CXCL13 and CCL19, and is associated with infiltration of B220(+)/IgD(+)/CD23(+)/CD21(-) follicular B cells expressing CXCR5. Despite a similar incidence of insulitis, late diabetic mice displayed a significantly reduced incidence of fully organized TLSs and reduced levels of lymphotoxins/lymphoid chemokines. Upon development, TLSs were fully functional in supporting in situ autoreactive B cell differentiation, as demonstrated by the expression of activation-induced cytidine deaminase, the enzyme required for Ig affinity maturation and class switching, and the presence of CD138(+) plasma cells displaying anti-insulin reactivity. Overall, our work provides direct evidence that TLSs are of critical relevance in promoting autoimmunity and chronic inflammation during autoimmune insulitis and diabetes in NOD mice.

Blue eyes as a risk factor for type 1 diabetes.

BACKGROUND: A high frequency of blue eyes and fair skin are reported in northern European Caucasians with type 1 diabetes (T1D). Also there is an inverse relationship between latitude and T1D incidence. We determined whether iris colour and skin pigmentation are risk factors in a Caucasian population living in two Mediterranean regions located at the same latitude with higher ultraviolet B irradiance, but with different T1D incidence. METHODS: We studied iris colour in 281 consecutive subjects with T1D and 298 controls. Skin type was evaluated by melanin quantification. RESULTS: In Lazio, blue eyes and fair skin type are significantly more common in T1D subjects than in controls (21 versus 9%, p = 0.002; 50 versus 35%, p < 0.001, respectively). In Sardinia, the frequency of blue eyes in T1D subjects is twice that in controls (5.8 versus 2.6% and significantly higher when compared to the expected calculated frequency in the entire population). By logistic regression analysis, only blue eyes are independent and significant predictors of T1D [odds ratio for blue eyes = 2.2; 95% confidence interval (1.1-4.4), p = 0.019]. CONCLUSIONS: As previously shown in a Caucasian population from northern Europe, blue eyes and a trend for fair skin increase the risk for T1D also in a Caucasian population born and residing in a Mediterranean region (Continental Italy). This finding may be relevant for explaining different T1D incidence as prevalence of blue eyes differ substantially between northern and southern European Caucasians.

CD4 T lymphocyte autophagy is upregulated in the salivary glands of primary Sjögren's syndrome patients and correlates with focus score and disease activity.

BACKGROUND: Primary Sjögren's syndrome (pSS) is a common chronic autoimmune disease characterized by lymphocytic infiltration of exocrine glands and peripheral lymphocyte perturbation. In the current study, we aimed to investigate the possible pathogenic implication of autophagy in T lymphocytes in patients with pSS. METHODS: Thirty consecutive pSS patients were recruited together with 20 patients affected by sicca syndrome and/or chronic sialoadenitis and 30 healthy controls. Disease activity and damage were evaluated according to SS disease activity index, EULAR SS disease activity index, and SS disease damage index. T lymphocytes were analyzed for the expression of autophagy-specific markers by biochemical, molecular, and histological assays in peripheral blood and labial gland biopsies. Serum interleukin (IL)-23 and IL-21 levels were quantified by enzyme-linked immunosorbent assay. RESULTS: Our study provides evidence for the first time that autophagy is upregulated in CD4+ T lymphocyte salivary glands from pSS patients. Furthermore, a statistically significant correlation was detected between lymphocyte autophagy levels, disease activity, and damage indexes. We also found a positive correlation between autophagy enhancement and the increased salivary gland expression of IL-21 and IL-23, providing a further link between innate and adaptive immune responses in pSS. CONCLUSIONS: These findings suggest that CD4+ T lymphocyte autophagy could play a key role in pSS pathogenesis. Additionally, our data highlight the potential exploitation of T cell autophagy as a biomarker of disease activity and provide new ground to verify the therapeutic implications of autophagy as an innovative drug target in pSS.

Hepatitis Delta Virus Detected in Salivary Glands of Sjögren's Syndrome Patients and Recapitulates a Sjögren's Syndrome-Like Phenotype in Vivo.

BACKGROUND: Low-level, chronic viral infections have been suspect in the development of select autoimmune diseases, including primary Sjögren's syndrome (pSS). Multiple studies have shown stimulation of antiviral response pathways in pSS tissues suggestive of a viral infection. Yet, with this data in hand, a causal link between a viral infection and development of pSS had not been identified. Therefore, a study was designed to further define the viral landscape within pSS-affected salivary gland tissue to identify potential viral-mediated triggers in the pathogenesis of this autoimmune disease. METHODS: A viral microarray was utilized to measure viral transcripts present in salivary gland tissue from patients diagnosed with pSS compared to healthy controls. Murine models of salivary gland localized HDV antigen expression were developed to evaluate the capacity of a chronic HDV signature to trigger the development of a pSS-like phenotype. RESULTS: Through this analysis, two distinct viral profiles were identified, including the increased presence of hepatitis delta virus (HDV) in 50% of pSS patients evaluated. Presence of HDV antigen and sequence were confirmed in minor salivary gland tissue. Patients with elevated HDV levels in salivary gland tissue were negative for detectible hepatitis B virus (HBV) surface antigen and antibodies to HBV or HDV. Expression of HDV antigens in vivo resulted in reduced stimulated saliva flow, increase in focal lymphocytic infiltrates, and development of autoantibodies. CONCLUSION: Identification of HDV in pSS patients and induction of a complete pSS-like phenotype in vivo provides further support of a viral-mediated etiopathology in the development of pSS.

Towards a stratified targeted approach with biologic treatments in rheumatoid arthritis: role of synovial pathobiology.

Rheumatoid Arthritis (RA) is a chronic, inflammatory, autoimmune disease affecting diarthrodial joints and extra-articular tissues; in the absence of an effective treatment, it is characterized by persistent symmetrical and erosive synovitis which leads to structural joint damage and lifelong disability. Several autoantibodies have been associated with RA such as rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPA). B cells have been shown to play a crucial role in the pathogenesis of RA by producing autoantibodies and promoting synovial inflammation through antigen presentation, T cells activation and cytokines production [1]. Although biologic agents have notably improved disease outcome and patients' quality of life, currently around 30-40% of subjects do not respond to treatment and the mechanisms leading to resistance are still not known [2]. For this reason, new prognostic biomarkers and predictors of response are needed. We and others have postulated that the development of biomarkers for patients' stratification prior therapeutic intervention may be possible through a better understanding of the different histopathological patterns present both in early and established individual RA patient and the related underlying cellular and molecular mechanisms. To date, Tumor Necrosis Factor (TNF)-α has been shown to be one of the master elements of inflammation in RA; however, even though therapies aimed at blocking this key cytokine have emerged as a major tool in the treatment of RA, a large proportion of patients (approximately 30-40%) do not achieve a meaningful clinical response assessed by either the American College of Rheumatology (ACR) or the European League Against Rheumatism (EULAR) criteria. The same limitation can be applied to the use of rituximab, a chimeric monoclonal antibody directed against CD20, which is uniquely expressed by all B-lymphocytes during the maturation process from late stage pro-B cells to memory cells. The clinical efficacy of rituximab has been proved by several clinical studies [3] but it is highly variable. Currently, NICE guidelines recommend rituximab in patients with inadequate response to a first-line biologic therapy, including at least one anti-TNFα agent independently of their pre-treatment chance to respond. In all cases, whether considering biologics used for several years in RA patients (anti-TNFα or rituximab) or relatively newer biologics in clinical use (i.e. tocilizumab, an anti-interleukin (IL) -6 receptor blocking monoclonal antibody or abatacept, a CTLA4 inhibitor fusion protein designed to target the T cell co-stimulatory signal mediated through the CD28-CD80/86 pathway), no validated biomarkers predictive of clinical response currently exist. Consequently, to date a "trial-and-error" approach is used in the prescription of biologics in RA, which has the obvious disadvantage of potentially exposing patients to drugs that they may not respond, with potential unnecessary side-effects, delaying use of an effective treatment and causing a significant economic burden to society. Therefore, identifying pre-treatment predictors of response with a customized stratification approach would be of invaluable importance in RA, also in consideration of the large number of biologics in development targeting novel pathways currently being tested in clinical trials. In this manuscript, we review existing data and provide future perspectives with regard to the role of synovial histopathology as a potential prognostic biomarker for patient stratification in RA, in particular regarding the use of specific biologic therapies.

Implication of Epstein-Barr virus infection in disease-specific autoreactive B cell activation in ectopic lymphoid structures of Sjögren's syndrome.

OBJECTIVE: To examine whether the B cell tropic γ-herpesvirus Epstein-Barr virus (EBV) is aberrantly expressed in its latent and lytic forms within ectopic lymphoid structures (ELS) in the salivary glands of patients with Sjögren's syndrome (SS), and to investigate the relationship between EBV dysregulation, B cell activation, in situ differentiation of autoreactive plasma cells, disease-specific autoantibody production, and cytotoxicity. METHODS: Latent and lytic EBV infection in the salivary glands of 28 patients with SS and 38 patients with nonspecific chronic sialadenitis (NSCS), characterized for the presence or absence of ELS, was investigated by reverse transcription-polymerase chain reaction, in situ hybridization, and immunohistochemical/immunofluorescence staining. Glandular versus synovial production of anti-Ro 52, anti-citrullinated protein antibodies (ACPAs), and anti-EBV peptide antibodies was analyzed in situ or in vivo in human SS/SCID and human rheumatoid arthritis/SCID mouse chimeras. RESULTS: EBV dysregulation within inflammatory infiltrates was observed exclusively in ELS+ SS salivary gland tissue, as revealed by latent EBV infection and lytic EBV infection in B cells and plasma cells, respectively. Conversely, epithelial latent membrane protein 2A expression was observed in both patients with SS and patients with NSCS. Importantly, perifollicular plasma cells displaying Ro 52 immunoreactivity were frequently infected by EBV. Furthermore, ELS-containing SS salivary gland tissue that was transplanted into SCID mice supported the production of anti-Ro 52/anti-La 48 and anti-EBV antibodies but not ACPAs. Analysis of CD4+ and CD8+ T cell localization and granzyme B expression demonstrated that the persistence of EBV in ELS-containing SS salivary glands was associated with follicular exclusion of CD8+ T cells and impaired CD8-mediated cytotoxicity. CONCLUSION: Active EBV infection is selectively associated with ELS in the salivary glands of patients with SS and appears to contribute to local growth and differentiation of disease-specific autoreactive B cells.