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SAT0305 Histology of minor salivary glands in patients with sjÖgren's syndrome, association with clinical and laboratory aspects

Background Minor salivary gland (MSG) biopsy represents an useful tool not only for the diagnosis of primary Sjogren's Syndrome (pSS) but also to evaluate patients prognosis. Recognition of germinal centers (GCs) by hematoxilin eosin (HE) and/or IHC staining for follicular dendritic cells (FDC) detection is mandatory, representing a risk factor for lymphoma development. Focus score (FS) is one of the main instrument to quantify MSG impairment, nonetheless quality information regarding the type of infiltrate such as the entity, structure and localization, are lacking. Objectives Aim of this study is to find any association of specific histological features of MSG from patients with pSS with the principal clinical and laboratory features. Moreover, to investigate the utility of histological parameters, other than FS or GCs, for characterizing patients. Methods Patients with pSS were enrolled in our SS clinic, and clinical/laboratory data (table) referring to the time of MSG biopsy, gathered on a dedicated database. MSG, removed for diagnostic purposes, were preserved as paraffin embedded tissue, then cut and sequentially stained by H&E and IHC [polyclonal rabbit anti-CD3 (lymphocytes T); monoclonal mouse anti-CD20 (lymphocytes B); monoclonal mouse anti-CD21 (FDC)]. Images were collected by Zeiss Axio Scan and analysed (ZEN software) as follows: FS calculation, mean foci area, percentage of infiltration, presence of segregated foci (SF) (specifically, clear evidence of T and B cells area by CD3-CD20 double staining), GCs and lymphoepithelial lesions (LELs) detection. Results 53 MSG from patients with pSS were collected and analysed. Patients clinical and laboratory data are reported in table. FS positively correlated with the percentage of infiltration (p<0.001) as well as with the presence of SF (p=0.005), GCs (p=0.02) and LELs (P=0.005). Mean foci area and percentage of infiltration correlated with SF (p=0.0002 and p<0.001, respectively), GCs (p=0.0004 and p<0.001, respectively) and LELs (both p<0.001). SF correlated with GCs and LEL (p<0.001). Anti nuclear antibodies (ANA) were associated with the presence of SF (p=0.029, OR=5.7 CI=1.1–28.8) while gland swelling was associated with the presence of GCs (p=0.043, OR=4, CI=1.1–15). Conclusions The FS was associated with the presence of GCs and LELs, as well as with more organized infiltrates characterized by segregation in T and B areas (SF), thus representing an useful tool which mirrors the risk of lymphoma. From our study, the qualitative characteristics of the biopsy, including SF, percentage of infiltration or the mean foci area, appear to be strictly linked. Moreover, their association with the presence of GCs and LELs supports the importance to consider also these features during histological examination. The lack of correlation between histological parameters and clinical/laboratory features might reveal a weaker connection between histological findings and specific SS phenotypes except for the relationship between glandular swelling and GCs which confirms how this clinical aspect should be considered as a risk factor for lymphoma development. Disclosure of Interest None declared