Primary Sjögren’s syndrome (pSS) is a complex heterogeneous disease characterized by a wide spectrum of glandular and extra-glandular manifestations. In this pilot study, a SWATH-MS approach was used to monitor extracellular vesicles-enriched saliva (EVs) sub-proteome in pSS patients, to compare it with whole saliva (WS) proteome, and assess differential expressed proteins between pSS and healthy control EVs samples. Comparison between EVs and WS led to the characterization of compartment-specific proteins with a moderate degree of overlap. A total of 290 proteins were identified and quantified in EVs from healthy and pSS patients. Among those, 121 proteins were found to be differentially expressed in pSS, 82% were found to be upregulated, and 18% downregulated in pSS samples. The most representative functional pathways associated to the protein networks were related to immune-innate response, including several members of S100 protein family, annexin A2, resistin, serpin peptidase inhibitors, azurocidin, and CD14 monocyte differentiation antigen. Our results highlight the usefulness of EVs for the discovery of novel salivary-omic biomarkers and open novel perspectives in pSS for the identification of proteins of clinical relevance that could be used not only for the disease diagnosis but also to improve patients’ stratification and treatment-monitoring. Data are available via ProteomeXchange with identifier PXD025649.

Primary Sjögren’s syndrome (pSS) is a complex autoimmune disorder that particularly affects the salivary and lachrymal glands, generally causing a typical dryness of the eyes and of the mouth. The disease encompasses diverse clinical representations and is characterized by B-cell polyclonal activation and autoantibodies production, including anti-Ro/SSA. Recently, it has been suggested that autoantibody profiling may enable researchers to identify susceptible asymptomatic individuals in a pre-disease state. In this pilot study, we used mass spectrometry to analyze and compare the salivary proteomics of patients with established pSS and patients with pre-clinical SS, identifying a common protein signature in their salivary fluid. We found that several inflammatory, immunity-related, and typical acinar proteins (such as MUC5B, PIP, CST4, and lipocalin 1) were differently expressed in pSS and in pre-clinical SSA+ carriers, compared to healthy controls. This suggests that saliva may closely reflect exocrine gland inflammation from the early phases of the disease. This study confirms the value of salivary proteomics for the identification of reliable biomarkers for SS that could be identified, even in a preclinical phase of the disease.

Sjögren’s disease (SD) is a chronic autoimmune disease primarily affecting lacrimal and salivary glands. The diagnosis of pediatric SD mostly relies on clinical suspect, resulting in a significant diagnostic delay. Recently, ultrahigh-frequency ultrasound (UHFUS) of labial glands has been proposed as a diagnostic method in adults with suspected SD. Until now, there have been no studies about UHFUS in pediatric diagnostic work-up. The aim of the study was to evaluate the potential role of UHFUS of minor salivary glands in pediatric SD. Consecutive pediatric patients with a diagnosis of pediatric SD seen at AOU Meyer IRCSS were evaluated. Intraoral UHFUS scan of the lip mucosa was performed with Vevo MD equipment, using a 70 MHz probe with a standardized protocol and the images were independently reviewed by two operators. Lip salivary glands were assessed by using a four-grade semiquantitative scoring system for parenchymal alteration and vascularization. Twelve patients were included. When applying UHFUS to this cohort of patients, all patients showed a UHFUS grade of ≥1 with 8/12 showing a mild glandular alteration (i.e., grade 1), 2/12 a moderate glandular alteration (i.e., grade 2) and finally 2/12 a severe glandular alteration (i.e., grade 3). Moderate intraglandular vascularization was seen in 9/12, with only 3/12 showing mild intraglandular vascularization. Due to limited size of the sample, the relationship between histological findings, autoantibodies status and UHFUS grade could not be performed. This preliminary study seems to report UHFUS as feasibility technique to identify salivary gland alterations in children with a clinical suspect of SD.

Background: Sjögren’s disease (SD) is an autoimmune condition causing progressive salivary and lacrimal glands dysfunction following lymphocytic infiltration in the glandular tissue. SD patients are more prone to oral health impairment due to a reduction in salivary flow. This study evaluated the relationship between oral health, functional tests, and patient reported outcomes in a cohort of SD patients. Methods: Patients diagnosed with SD underwent complete dental examination, with the recording of the decayed–missing–filled teeth index (DMFT), probing pocket depth (PPD), full mouth bleeding score (FMBS), and full mouth plaque score (FMPS). Hyposalivation was assessed using the unstimulated whole saliva flow rate (UWS). Patients were administered the European League Against Rheumatism (EULAR) Sjögren’s Syndrome Patient Reported Index, EULAR Sjögren’s syndrome disease activity index, Oral Health Impact Profile-14 (OHIP-14), Patient Acceptable Symptom State questionnaires, and a visual analog scale for xerostomia (VASx). Results: Fifty patients in total were enrolled. Reduced UWS was associated with higher DMFT, FMBS, and FMPS. Significant correlation was observed for UWS with VASx and OHIP-14 (p < 0.05). Conclusions: Quality of life and oral health appear mildly impaired in SD patients as an effect of reduced salivary flow, with higher DMFT and tendency towards gingival inflammation and plaque accumulation.

Connexins (Cxs) are transmembrane proteins involved in the formation of hemichannels and gap junctions (GJs). GJs are involved in various physiological functions, including secretion in glandular tissue. It has been demonstrated that Cx26, Cx32, and Cx43 are mainly expressed in glands, but no data are available in human salivary glands to date. The aim of our study was to investigate the presence and the localization of Cxs in human minor labial salivary glands. Immunofluorescence and immunoelectron microscopy were employed to evaluate the Cx26, Cx32, and Cx43 protein in human labial salivary gland biopsies (hLSGBs). RT-PCR was also used to detect their mRNA expression. Cx expression was found at both the mRNA and protein levels in all hLSGBs analysed. Cxs were observed at the level of the duct and acinar cells, as well as in myoepithelial cells. The localization of the three Cx types was very similar, suggesting colocalization of these Cxs in the same connexons. These results demonstrated the presence of Cxs in human salivary glands for the first time. Moreover, the few samples with primary Sjögren’s Syndrome analysed only by immunofluorescence showed an alteration of the Cx expression, indicating that these proteins could be involved in salivary gland dysfunctions.

Background and Objectives: Primary Sjögren’s syndrome (pSS) is a systemic autoimmune disease with heterogeneous extraglandular involvement, including the kidney. Tubulointerstitial nephritis (TIN) is the hallmark kidney lesion of pSS, but its clinical and histological features, compared with other causes of TIN, remain incompletely characterized. This study aimed to describe the clinical, laboratory, and histological features of biopsy-proven pSS-associated TIN (pSS-TIN) and to compare them with TIN of other etiologies. Materials and Methods: We retrospectively analyzed native-kidney biopsies (2015–2025) with histological diagnosis of TIN, from adult and pediatric patients, excluding cases with neoplasms or concomitant acute glomerular injury. Clinical, laboratory, and histological data of pSS-TIN patients were compared with other TIN etiologies using the Mann–Whitney U test, Fisher’s exact test, and Spearman’s correlation; p < 0.05 was significant. Results: Among 690 native-kidney biopsies, 35 showed TIN; after excluding cases with glomerular involvement, 14 patients with pSS-TIN and 16 patients with no-pSS-TIN patients were analyzed. All pSS-TIN patients were female, and biopsy occurred after a significantly longer interval from disease diagnosis than patients with no-pSS-TIN (p = 0.018). Acute kidney injury was less frequent (p = 0.021) and kidney function was better preserved in pSS-TIN, while the urea-to-creatinine ratio was similar between groups. Standard urinalysis was abnormal in only about half of patients in both groups. Longer disease duration correlated with lower eGFR in pSS-TIN (p = 0.033). Predominantly chronic histological damage was associated with higher proteinuria (p = 0.037) across the entire cohort, and germinal-center-like lymphoid structures were observed in two pSS-TIN patients with extensive acute damage. In our cohort, no statistically significant association was detected between kidney function indices and the severity of chronic damage. Conclusions: In this biopsy-based cohort, pSS-TIN showed a predominantly chronic presentation, less acute kidney injury, and a longer diagnostic interval than other TIN forms. Routine urinary and functional parameters may not reliably reflect chronic tubulointerstitial damage, highlighting the importance of careful renal screening and timely nephrological assessment, with kidney biopsy when clinically indicated.