Anti-SSA antibodies may be tied to eye dryness in Sjögren’s: Study
Dry-eye symptoms more severe in those positive for antibodies
People with Sjögren’s disease who are positive for self-reactive, anti-SSA antibodies may develop more severe dry eye symptoms than those without anti-SSA and anti-SSB antibodies.
That’s according to a study carried out in Mexico that also found patients with anti-SSA antibodies had significantly more signs of eye dryness associated with faster tear evaporation.
The study, “Is There a Difference Between Seropositive and Seronegative Sjögren Disease Dry Eye?,” was published in The Journal of Cornea and External Disease.
Sjögren’s is a systemic disease that occurs when the immune system mistakenly launches an inflammatory attack against the glands that produce tears and saliva. This leads to the disease’s hallmark symptoms of eye and mouth dryness.
Sjögren’s patients often test positive for self-reactive antibodies, such as anti-Ro (or SSA) and anti-La (or SSB) antibodies, although some may develop the disease without the presence of such antibodies (seronegative patients).
Dry-eye differences
Although seronegative patients are generally considered to have less severe systemic disease, “there is scarce information about the differences in [dry eye disease] prevalence, presentation, and severity between seropositive and seronegative [Sjögren’s disease],” the researchers wrote.
They analyzed data from patients with primary Sjögren’s and dry-eye symptoms who had been recruited at the University Hospital at the Autonomous University of Nuevo León between January 2015 and December 2019.
A total of 80 patients, with a mean age of 52.2, were enrolled in the study. Some 96.3% were female. Fifty-five were seropositive, meaning they tested positive for anti-SSA antibodies, while 25 were seronegative. All seronegative patients tested negative for anti-SSA and anti-SSB antibodies, with some also testing negative for antibodies targeting rheumatoid factor and for antinuclear antibodies.
Seronegative patients most commonly had a positive result in a minor salivary gland biopsy (100% vs. 82%), but a lower focus score (2 vs. 4.1) than seropositive patients. The focus score is a grading system used to quantify the degree of immune cell infiltration in salivary glands. It measures the number of immune cell foci (clusters of 50 cells or more) per 4 mm² of glandular tissue.
The prevalence of dry eye disease was high in both groups, and was not significantly different between them (92.7% in seropositive and 84% in seronegative patients).
Both groups of patients had severe dry eyes according to the ocular surface disease index (mean value of 43.5 in seropositive and 45.7 in seronegative patients), and experienced a significant reduction in vision-related quality of life, as assessed by the National Eye Institute visual health questionnaire 25.
The stability of the tear film — a protective layer covering the cornea, the transparent front part of the eye, that provides lubrication and supports normal vision — was assessed using tear break-up time tests. These tests measure the time it takes for the first dry spot to appear on the cornea after a blink, serving as an indicator of eye dryness.
Results showed that in both patient groups tear break-up time was lower than normal, although the average noninvasive tear break-up time value was significantly lower in seropositive patients (6.61 seconds vs. 8.78 seconds), indicating more severe eye dryness.
Seropositive patients also had a higher tendency to have more severe signs of dry eye disease, including more inflammation on the surface of the eyes as measured by a higher proportion of positive results for MMP-9, an inflammation marker (30% vs. 14%), and eye damage, as assessed by a higher Sicca ocular staining score (7 vs. 5).
There were no significant differences between the two groups of patients regarding coexistent conditions, such as high blood pressure, diabetes, allergies, and rheumatic diseases, or systemic (immunosuppressant agents like methotrexate, and corticosteroids) or topical medications (eye drops and ointments).
“This study adds important information to help clarify the similarities in [dry eye disease] prevalence, symptoms, signs, and vision-related [quality of life] between seronegative and seropositive [Sjögren’s disease],” the researchers wrote. “Further prospective studies focused on [dry eye disease] and with a larger sample size are required to confirm these findings.”
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