A retrospective investigation looked at the clinical and immune system characteristics of 232 Sjögren’s patients in China. The study was published in April 2024 in BMC Rheumatology: “Seronegative primary Sjögren’s syndrome, a distinct subtype of primary Sjögren’s syndrome in Chinese patients”. Patients positive for SS-A and/or SS-B antibodies were termed as seropositive Sjögren’s and those negative for both SS-A and SS-B antibodies were described as seronegative Sjögren’s.
Among the 232 patients with Sjögren’s in the study, 192 (82.8%) were seropositive and 40 (17.2%) were seronegative. Those who were seropositive were younger than the seronegative patients (48 years versus 56.5years). Here are some of the other comparisons:ere are
· ESSDAI scores (EULAR Sjögren's Syndrome Disease Activity Index) which focuses on objective measures of systemic disease activity, were more likely to be lower (under 5) in seronegative patients.
· Glandular dysfunction, including xerostomia (dry mouth) and xerophthalmia (dry eyes) was more prevalent in seronegative patients.
· Levels of ESR, indicating a condition that causes inflammation in the body, were lower in seronegative patients but platelet count, serum bilirubin, and creatine kinase were significantly higher.
· In parameters associated with the immune system and B lymphocyte infiltration, seronegative Sjögren’s patients had significantly lower levels of gamma globulins, immunoglobulin G, and immunoglobulin A compared to seropositive patients. Anti-nuclear antibodies (ANA) and rheumatoid factor (RF) were also much higher in seropositive than seronegative patients.
· Lip biopsy histological results showed there was more lymphocytic infiltration and IgG deposition in seronegative patients’ minor salivary glands compared to seropositive patients (100.0% versus 79.8%).
The researchers concluded that “seronegative Sjögren’s was a distinct subtype of Sjögren’s different from seropositive Sjögren’s. Clinical manifestations of patients with seronegative Sjögren’s were restricted to exocrine glands, while seropositive Sjögren’s patients were prone to present with systemic involvement and high disease activity.” The underlying pathogenesis mechanisms and treatment strategies in these subtypes will need to be further studied.
https://bmcrheumatol.biomedcentral.com/articles/10.1186/s41927-024-00384-9
