Antinuclear antibodies in children: indirect immunofluorescence patterns, antigen targets and associated diagnoses

Abstract

Antinuclear antibodies tests are of a paramount importance in the diagnosis, classification, prognostic evaluation and management of autoimmune diseases in children. The present study aimed to describe the immuno-clinical profile of antinuclear antibodies tests in a pediatric population in order to guide the clinical practice of biologists and clinicians. Our study enrolled 268 children. Antinuclear antibodies screening was performed using the indirect immunofluorescence assay on HEp-2 cells. Identification of target antigens was conducted using separately or at one timepoint the following techniques: enzyme-linked immunosorbent assay, Immunodot and Chemiluminescence. The average age of patients was 9.6 ± 4.3 years, with a female predominance (sex-ratio = 1.9). Antinuclear antibodies screening was positive in 40.67% of cases. The most frequently observed antinuclear antibodies patterns were speckled (52.3%), homogeneous (13.8%) and mixed homogeneous-speckled (13.8%). Autoantibodies were detected in 4 patients (2.51%) for whom ANA testing using the indirect immunofluorescence assay was negative. Positive antinuclear antibodies specificities were detected in connective tissue diseases (44.03%; n = 48), organ-specific autoimmune diseases (10.09%; n = 11), and in non-autoimmune conditions (inflammatory diseases, infections, hematological diseases, vasculitis and Wilson’s disease) (32.08%; n = 35). Our study revealed a high rate of positive antinuclear antibodies tests in the pediatric population, mainly related to autoimmune diseases (54.12%) besides non-autoimmune conditions (32.08%). Therefore, screening and interpretation of antinuclear antibodies testing in children require the consideration of clinical data and a close collaboration between clinicians and biologists.