Background Sjögren's syndrome (pSS) is a systemic autoimmune disease mainly characterized by exocrine glands dysfunction and inflammation. A great deal of variation in the intensity of the infiltrate in minor salivary gland biopsies (MSGB) and in the salivary flow production has been described in pSS. Moreover, the correlation between the focus score and salivary flow has been generally reported as poor, suggesting that salivary glands dysfunction and inflammation may involve independent pathogenetic processes.
Objectives 1)To estimate the frequency of various patterns of inflammation and dysfunction of the salivary glands in patients with pSS at the time of the diagnosis 2) to compare clinical and serological features of pSS patients stratified into four different subgroups on the basis of the degree of lymphocytic infiltration detected in MSGB and on the variation of the salivary flow rate.
Methods Unselected consecutive patients newly diagnosed with pSS (AECG 2002 criteria) were prospectively included in this study. In all the cases, concomitantly with the rheumatology examination, non-organ-specific autoantibodies were detected and sialometry, salivary gland ultrasonography (SGUS) and MSGB were performed. A modified version of the De Vita score was adopted to record SGUS findings. The ESSDAI was used to score pSS activity. A focus score ≥3 was considered high, while a salivary flow rate ≤1.5ml/15' was defined as low. Patients were subdivided a priori into four different groups: group 1 = high focus score (FS)/low salivary flow rate (SFR); group 2 = low FS/normal SFR; group 3= high FS/normal SFR and group 4 = low FS/low SFR. Independent sample t tests or ANOVA test, and contingency table analysis and Fisher's Exact test were used for statistical analysis. Spearman's rank correlation coefficients were calculated between salivary flow rate and MSGB focus score.
Results Sixty pSS patients (58 F: 2 M, mean age (SD)=53 (14) years) were recruited between Dec 2012 and Dec 2013. The mean (SD) salivary flow rate was 2.6 (3.3) ml/15' and the mean (SD) focus score was 2.2 (2.0). Twelve patients out of 60 (20%) presented germinal centre-like structures. The correlation between salivary flow rate and MSGB focus score was poor (r=0.124, p=ns). The frequency of pSS different subgroups was as follows: group 1 =21/60 (35%); group 2=10/60 (16.7%); group 3=6/60 (10%) and group 4=23/60 (38.3%). No differences were detected between the groups in terms of age of the patients, symptoms' duration and serological features (i.e. antinuclear antibodies, anti-Ro/SSA, anti-La/SSB, Rheumatoid factor). On the other hand, we found that germinal centre-like structures were significantly more frequent in patients belonging to group 1 (9/12) and group 3 (3/12). In addition, ESSDAI scores (p=0.02) and SGUS scores (p<0.0001) were significantly different between groups, with “group 1-patients” presenting the highest ESSDAI scores and the highest SGUS scores and “group 4-patients” showing the lowest ESSDAI and SGUS scores.
Conclusions Our findings support the amount of data indicating distinct processes underlying pSS exocrinopathy. Novel biomarkers that reliably describe the different pathophysiologic aspects of pSS are needed to establish the diagnosis, predict the prognosis, characterize disease activity, and develop effective therapies.
Disclosure of Interest : None declared