Recently, the total area of the inflammatory infiltrate and the percentage of inflammatory infiltrate have been proposed as novel histopathological parameters to improve the stratification of patients with Sjögren's syndrome (SS) in clinical trials. Both these parameters provide a more accurate assessment of the extent of the infiltrate in minor salivary gland biopsies (MSGBs) and may overcome the bias related to the Focus score (FS). To date, however, only few studies have investigated their clinical value and feasibility. In this study we revised consecutive MSGBs obtained routinely in a real-life clinical setting and correlated the total area of the inflammatory infiltrate and the percentage of inflammatory infiltrate both with the other MSGB histopathological parameters and with patients' clinical features in order to explore their usefulness in SS diagnostic work-up.
We assessed the area of the inflammatory infiltrate and the percentage of the inflammatory infiltrate in consecutive MSGBs and correlated these parameters with the number of foci, the FS and the presence of ectopic lymphoid structures (ELS). We also correlated these additional parameters with patients' clinical and biological data.
We revised 69 MSGB samples: 46 from patients with a diagnosis of SS and 23 from subjects with no SS. The total area of inflammatory infiltrate and the percentage of inflammatory infiltrate appeared significantly higher in patients fulfilling the ACR/EULAR classification criteria for SS and correlated significantly with both the number of foci (p<0.001) and the FS (p<0.001). Particularly, they correlated better with the ELS in MSGBs than the number of foci and the FS. When we limited the analysis to the 32/69 patients with a FS<1, both the total area of the inflammatory infiltrate (p=0.02) and the percentage of the inflammatory infiltrate (p=0.03), but not the number of foci (p=0.12) remained significantly higher in the 10/32 anti-Ro/SSA positive patients fulfilling the ACR/EULAR classification criteria. Finally, the total area of inflammatory infiltrate and the percentage of inflammatory infiltrate correlated significantly with several biological and haematological SS-related abnormalities including hypergammaglobulinaemia, C4 levels, total number of white blood cells and the number of circulating lymphocytes.
The total area of the inflammatory infiltrate and the percentage of the inflammatory infiltrate in SS referral centres, and particularly for selected cases, may maximise the information on disease activity at tissue level, ultimately improving SS patients' assessment.