AUTHOR=Hao Ran , Liu Ziyuan , Chou Yilin , Wang Yuexin , Ren Xiaotong , Jiang Xiaodan , Li Xuemin 

TITLE=Impression Cytology and In Vivo Confocal Microscopy of Lip Mucosa Compared With Labial Gland Biopsy and Classification Criteria In Patients With Clinically Suspected Primary Sjögren’s Syndrome

JOURNAL=Frontiers in Immunology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2022.829320

DOI=10.3389/fimmu.2022.829320

ISSN=1664-3224

ABSTRACT=Purpose: To assess the validity of impression cytology (IC) and in vivo confocal microscopy (IVCM) of lip mucosa compared with labial gland biopsy, anti-Sjögren’s syndrome A (SSA)/Ro antibody status and classification criteria in suspected primary Sjögren’s syndrome (pSS) patients. 
Methods: Clinically suspected pSS patients (n = 201) were enrolled consecutively and were divided into pSS (n = 56) and control (n = 145, only with dryness) groups according to the American College of Rheumatology-European League Against Rheumatism (ACR-EULAR) criteria. All patients underwent lip mucosa IC (inflammatory cell density) and IVCM (epithelium/intrinsic layer thickness and labial gland density/diameter) analyses. The associations between IC/IVCM parameters and clinical/laboratory results were analyzed. 
Results: The absolute agreements between positive lip mucosal IC (≥ 50 cells/4 mm2) and the ACR-EULAR criteria (94.5%)/labial gland biopsy (95.5%) were good, with sensitivities of 82.1% and 85.2%, specificities of both 99.3%. Compared with controls, IVCM revealed significant lip mucosal atrophy and glands decrease in pSS group (all P = 0.000). The sensitivities for diagnosing pSS corresponding to a lamina propria thickness ≤128 μm and a gland diameter ≤114 μm were 85.7% and 89.3%; the specificities were 90.3% and 95.9%, respectively. A combination of positive IC/IVCM and anti-SSA/Ro antibody results showed a high predictive value for diagnosing pSS.
Conclusions: Characteristic cellular and morphological changes of lip mucosa in patients with pSS could be detected by IC and IVCM. These noninvasive and easy-to-perform examinations may be an alternative to labial gland biopsy for diagnosing pSS.