Alpha fodrin and the diagnosis of primary Sjögren’s syndrome; experience of a Rheumatology Centre in Bogotá, Colombia

Background and objectives: Primary Sjögren's syndrome is an autoimmune disease where the salivary and exocrine glands do not function correctly. This is caused by lymphocytic infiltrates and neuroendocrine components. The diagnostic criteria in this syndrome have subjective and non-specific elements, but in the last few years the performing of IgA and IgG anti-alpha-fodrin antibodies has been considered as a diagnostic option. The main objective of this article is to evaluate the diagnostic performance of the anti-alpha-fodrin test in patients diagnosed with primary Sjögren's syndrome. Materials and methods: The study included patients with a diagnosis of primary Sjögren's syndrome according to the criteria of the American-European consensus or the consensus of the American College of Rheumatology. These were compared with healthy patients with other non-autoimmune diseases. Results: The IgA type antibody was found to have a sensitivity of 0.18 and specificity of 0.92. The IgG type had a sensitivity of 0.05 and specificity of 0.96. The ROC curve for the IgG test was the closest to the point of greatest theoretical sensitivity and specificity. Discussion: The sensitivity of the test was found to be lower than that reported in other studies. This could be explained by factors such as: diagnostic criteria used, different immunoassay techniques, immunoglobulin evaluated, use of drugs, time of diagnosis, and different populations studied. Conclusion: It is considered that the results regarding the specificity of the test in the population of the present study give it validity as a diagnostic test for primary Sjögren's syndrome, however, anti-alpha-fodrin antibodies have shown low sensitivity in our population, and it is considered that more studies are needed to define the role of these antibodies in this disease.