Relationships among Antibodies against Extractable Nuclear Antigens, Antinuclear Antibodies, and Autoimmune Diseases in a Brazilian Public Hospital

Abstract

One characteristic of autoimmune diseases (ADs) is the production of autoantibodies for extractable nuclear autoantigens, which may aid in the discrimination of the different types of autoimmune diseases and is related to different antinuclear antibody (ANA) patterns. The present study verified the profile of patient samples tested for extractable nuclear antigens (ENA) antibodies in a public hospital and correlated the ENA results with ANA patterns and patient diagnoses. The study reviewed data in the medical records of patients who underwent anti-ENA tests at a public hospital in the West of the State of Paraná from February 2011 to January 2017. Patients were classified according to age, ethnicity, gender, anti-ENA test results, ANA results, and the presence or absence of AD. Thirty-six (20.9%) samples of the 172 anti-ENA tests were positive, seven (4.1%) samples were undetermined, and 129 (75%) exhibited negative results. The ANA reagent was found in 84.3% of the anti-ENA-positive samples. The anti-SSA/Ro autoantibody exhibited the highest frequency in the group, 41.7% (15/36). The most common pattern was nuclear fine speckled, which was found in 24.3% of the samples. The association results indicated a significant relationship between ANA titer and diagnosis in the anti-ENA- and ANA-positive patients. The anti-ENA-negative patients were diagnosed with an AD in 35% (45/129) of the cases, and 75% (27/36) of the anti-ENA-positive patients were diagnosed with an AD. Systemic lupus erythematosus and scleroderma were the most common pathologies in the antigen-positive patients. The anti-ENA test is a good marker to aid in the complex clinical diagnosis of patients with autoimmune diseases.

Investigation of the dual cascade algorithm in the diagnosis of antinuclear antibodies

“…In our study, the highest rate for nuclear speckled pattern-associated ANAs was found in anti-SS-A (48.1%), indicating a relatively moderate correlation. Consistent with previous studies, the agreement rate for speckled pattern-specific antibodies was higher than other ANAs [1,17,20]. Although anti-dsDNA and nucleosome were the most frequent antibodies in the homogeneous pattern, agreement rates were similar to the speckled pattern, and also had a high detection rate for anti-SS-A, anti-SS-B, anti-Ro-52, anti-Sm and anti-RNP/Sm.…”

Detection of Anti-Extractable Nuclear Antigens in Patients with Systemic Rheumatic Disease via Fluorescence Enzyme Immunoassay and Its Clinical Utility

“…As anti-RNP is a diagnostic marker for SLE and SSc and since a high level of anti-RNP is diagnostic of MCTD, this result could suggest the possibility of false positive cases according to clinical diagnoses, leading to misdiagnosis using the ELISA method 5. The problem of false-positive anti-ENA tests has been continuously raised, and it is recommended that testing be performed with two different methods to avoid false-positive results 2021. Clinical correlation with anti-ENA results can be another solution for avoiding false-positive results.…”

“…5 The problem of falsepositive anti-ENA tests has been continuously raised, and it is recommended that testing be performed with two different methods to avoid false-positive results. 20,21 Clinical correlation with anti-ENA results can be another solution for avoiding falsepositive results.…”

Evaluation of a novel latex enhanced turbidimetric immunoassay for detecting autoantibody against extractable nuclear antigens

“…6 A study suggested that a combined detection of ANA and ENA autoantibodies was more helpful for the diagnosis and prognosis of AID. 7 The identification of ENAs plays a critical role in the diagnosis and management of ANAassociated rheumatic disease (AARD), such as systemic sclerosis (SSc), systemic lupus erythematosus (SLE), Sjogren's syndrome (SS), and mixed connective tissue disease (MCTD). [8][9][10] In addition, study suggests anti-SSA/Ro can be detected in the majority of SS patients (70%-100%) and 35% to 70% SLE patients, and anti-La/SSB is detectable in 45% of patients with SLE and up to 40% to 90% of patients with SS.…”