ANTINUCLEAR ANTIBODIES IN THE DIAGNOSIS OF SYSTEMIC LUPUS ERYTHEMASIS (Atena Editora)

Abstract

Systemic Lupus Erythematosus (SLE) is an autoimmune disease involving multiple organs, characterized by a large amount of autoantibodies, particularly antinuclear antibodies (ANAs). Its diagnosis is based on clinical and laboratory criteria manifested over time, with a wide differential diagnosis, especially in the early stages. The classic symptomatology is cutaneous lesions in young women, in the fertile period, but there is an immense syndromic variety. The purpose of this article is to report on the importance of the ANA test in the diagnosis of SLE. One of the most valuable tests in the screening for SLE is the ANA, which uses an indirect immunofluorescence technique using cells of the HEp-2 lineage, derived from human epithelial tumor cells, as a substrate. Depending on the specificity of the antibody present, different stains are found in specific structures of the cell, giving rise to different patterns of cellular fluorescence. The reagent ANA test reveals the presence of serum antibodies that bind to components of the cell nucleus. The ANA titer is the maximum dilution of serum that still produces detectable nuclear staining. Therefore, although the ANA test has a high reactivity, making it highly sensitive for SLE, it does not have high specificity, due to the fact that these antibodies are detected in other autoimmune and infectious diseases, or even in elderly people.