Clinical and laboratory findings of primary Sjögren's syndrome patients without sicca symptoms.

ABSTRACT

OBJECTIVES: Primary Sjögren's syndrome (pSS) is a systemic autoimmune disease characterised by oral and eye dryness. A minority of patients can present without dryness but studies on their clinico-laboratory manifestations are scarce. Our purpose was to describe the clinical phenotype of pSS patients lacking sicca symptoms. METHODS: From a total of 1738 consecutive pSS patients fulfilling the 2016 ACR-EULAR criteria, those who presented without sicca symptoms were identified (non-dryness group). Their medical data was collected and compared with 2 control groups a) the remaining unmatched sicca pSS patients with both oral and eye dryness (unmatched dryness group) and b) matched sicca pSS patients according to age, sex, and disease duration, in 12 ratio (matched dryness group). RESULTS: Thirty-eight (2.19%) patients lacked sicca manifestations presenting mainly with arthralgias (47%), parotid enlargement (24%), Raynaud's phenomenon (11%) and persistent lymphadenopathy (11%) that led them to be evaluated for pSS. Non-dryness pSS patients were younger than the unmatched sicca controls, displaying a higher frequency of anti-Ro/SSA antibodies (100% vs. 79.7%, p<0.001), ANA positivity (100% vs. 90.4%, p<0.001), neutropenia (20.8% vs. 7.5%, p=0.04) and thrombocytopenia (13.8% vs. 4.2%, p=0.04). They also had lower frequency of positive ocular tests compared to both unmatched and matched dryness patients. No differences were found between non-dryness pSS patients and both control groups regarding focus score or any other extraglandular manifestation. CONCLUSIONS: pSS patients without sicca complaints constitute a distinct phenotype involving younger patients, sharing common immunopathologic mechanisms with typical sicca patients.