Clinical Characteristics of Distinct Subgroups of Patients with Primary Sjögren’s Syndrome Classified by Serological Profiles: A Comparison Study

Sjögren's syndrome (SS) is an autoimmune disease characterized by heterogeneous clinical presentation and the presence of various autoantibodies. This study aimed to determine the differences in clinical findings according to antibody positivity in patients with primary Sjögren syndrome (pSS) in the Turkish population. A retrospective study was conducted and 402 patients (378 women and 24 men) with pSS were analyzed. The patients were categorized into three subgroups based on serological tests. These were (1) quadruple seropositivity (positive for anti-Sjögren's syndrome-related antigen A antibodies (anti-SSA; anti-Ro) and anti-Sjögren's syndrome-related antigen B antibodies (anti-SSB; anti-La), rheumatoid factor (RF), and antinuclear antibody (ANA); (2) double seropositivity (positive for ANA and anti-SSA/Ro antibodies); and (3) quadruple seronegativity (negative for ANA, RF, anti-SSA/Ro and anti-SSB/La antibodies). The number of quadruple-seropositive patients was 72 (18.6%), double-seropositive 174 (43.2%), and quadruple-seronegative was 85 (21.1%). The age at diagnosis of quadruple-seropositive pSS was 42.4 ± 10.8, which was significantly younger than that of patients with double-seropositive and quadruple-seronegative pSS (<i>p</i> = 0.021, <i>p</i> = 0.112). In terms of organ involvement, salivary gland enlargement, arthralgia, arthritis, Raynaud's phenomenon, lymphadenopathy, cutaneous vasculitis, interstitial lung disease, neurological involvement, autoimmune thyroiditis, renal interstitial disease, anemia, leukopenia, hypergammaglobulinemia, and hypocomplementemia were more common in quadruple-seropositive patients with pSS than in quadruple-seronegative patients (<i>p</i> < 0.0001). The results of this study confirmed the strong impact of immunological markers on the pSS phenotype at the time of diagnosis. Immunological patterns play a central role in the phenotypic expression of the disease, even during the initial diagnostic phase, and can guide physicians in designing personalized treatment plans for patients with pSS.